zek HYDRO 2024

Alpine hydropower technology masters challenges in Nepal

Alpine hydropower technology masters challenges in Nepal

Global Hydro refits old power plants for modern requirements

Global Hydro refits old power plants for modern requirements

Innovative

Innovative

Revitalizing hydro asset for timeless energy.

VISIONARY POWER. WHEREVER YOU WANT.

Empowering Hydropower's Tomorrow, Today. As a leading expert, Global Hydro combines stateof-the-art technology, industry expertise, and a commitment to excellence to ensure the seamless modernization of hydropower plants.

THE IMPORTANCE OF HYDROPOWER WILL CONTINUE TO GROW

The hydropower plants of the 27 EU member states contribute 13 per cent of the Union’s total electricity generation. If Switzerland, Norway and Turkey are also included, the figure rises to 18 per cent. In total, that’s around 600 TWh. Worldwide, there is still more electricity produced by hydropower than by all the other renewable energy sources combined. According to experts at the International Energy Agency (IEA), hydropower will remain globally dominant until the 2030s. Quite understandably, Europe no longer offers the greatest expansion potential for new plants. IEA calculations also suggest that around a quarter of global hydropower investment (ca. US$ 127 million) will have been spent on modernisation and refurbishment by 2030 – above all in North America and Europe, where it is expected to apply to 90 per cent of projects by the end of the decade. European politicians need to be reminded of the economics more frequently. According to VERBUND, Austria‘s leading hydropower company, the added economic value of hydropower in Europe (EU plus Switzerland, Norway and Turkey) amounts to €38 billion per year – the rough equivalent of Slovenia’s entire annual GDP. In Europe the hydropower sector also provides around 120,000 skilled jobs and it’s no secret that the European hydropower industry plays a leading role worldwide. European manufacturers currently account for around two thirds of the global market. However, the position of Europe’s industrial companies is in severe jeopardy if European politicians turn their backs on their oldest renewable technology – hydropower. China has been moving into dominant positions in all kinds of markets for many years, and the preconception that Chinese industry conquers markets with cheap and inferior technology should be quickly discarded. China is now able to provide high­quality solutions and products that can hold their own with European technologies. Explicit political support for hydropower is necessary if we are not to lose ground in this field. Europe’s hydropower industry must not be allowed to suffer the same fate as that of the European photovoltaic industry.

One thing is now certain; the share of electricity in the overall European energy mix will continue to increase significantly over the coming years. Fossil fuel consumption is to be cut back as part of an accelerated energy transition, being replaced by electricity from renewable resources. Consequently, hydropower will maintain and indeed expand its role within the European electricity industry – in part due to its base load capability, and also because it can store energy more efficiently than any other option currently available. There is another seldom­discussed yet highly relevant aspect to consider: The unrivalled ratio between energy input during construction and operation and the energy yield over the entire operating life of a plant. For wind power this ratio is 1:15, for run­of­river power plants it’s 1:200 – and a stunning 1:300 for pumped storage power plants. However, the ever­new challenges thrown up by climate change, and specific energy transition guidelines for hydropower, will necessitate technological adjustments over the coming years. Similarly, extended droughts followed by unprecedented bouts of heavy regional rainfall will pose challenges and demand various changes in hydropower generation. Structural adaptation and the introduction of new technical aids, particularly in control technology, will probably provide certain solutions. Regardless, a strong political lobby is required to provide effective pan­European or EU­level political support for hydropower as an important energy mainstay. So the ball is firmly in the politicians‘ court.

I wish all our valued readers an enjoyable and informative time reading the latest edition of zek HYDRO.

Best regards,

Roland Gruber Editor-in-Chief

Hydropower. Complete solutions for a sustainable future.

Reliability beyond tomorrow.

Short Cuts

08 Short News out of the World of Hydropower SHORT CUTS

16 The new EU legislative period –issues and new opportunities [ POLITICS ]

18 Alpine technology mastering challenges in the Himalayas [ NEPAL ]

21 Commissioning work on Tyrol’s highest small hydropower plant [ AUSTRIA ]

24 African large-scale farmer relies on German hydropower expertise [ SOUTH AFRICA ]

26 Hydropower plant in Styria goes online with regional expertise [ AUSTRIA ]

03 Editorial 06 Table of Content 08 Masthead

28 Modernisation resulted in a 13 percent performance increase [ ALBANIA ]

30 New hydropower station provides green energy for 7,700 households [ SWITZERLAND ]

33 Screen cleaning technology proves its worth in mine hydropower plant [ PAPUA NEW GUINEA ]

36 Hydro-Construct supplies the biggest rubber dam in Europe [ ITALY ]

39 Symbiosis between two hydropower plants in Austria [ AUSTRIA ]

42 Emphasising on the value of hydropower in the energy transition [ CONVENTION ]

44 Specialists deliver professional screen cleaning solutions [ TECHNOLOGY ]

46 Global Hydro refits old power plants for modern requirements [ TECHNOLOGY ]

50 Innovative technology impresses across a wide range of applications [ TECHNOLOGY ]

53 Unleashing the digital potentials of electric actuators [ TECHNOLOGY ]

54 Repeatedly successful in international field tests [ TECHNOLOGY ]

56 Acoustic multi-path flow metering is becoming state-of-the-art [ TECHNOLOGY ]

59 Industry pros impress with innovative screen cleaning technology [ TECHNOLOGY ]

62 Pelfa – a reliable manufacturer of large hydropower components [ INDUSTRY ]

64 Increasing the safety of high head power plants [ SCIENCE ]

Industry specialist demonstrates innovative spirit in Tyrol again [ TECHNOLOGY ]

Austrian industrial service providers confirm their reputation [

OFFICIAL OPENING OF RIVER LAB ON THE RIVER DANUBE

On June 12, the University of Natural Resources and Applied Life Sciences, Vienna, hosted the official opening of their new hydraulic engineering laboratory at Brigittenauer Sporn in Vienna. The ceremony marked the completion of a technology-focussed infrastructure project that had required a lot of time, money and patience to implement. The time gap between the initial idea and the official opening of the hydraulic engineering laboratory is around 14 years wide. The overall costs amount to around 49 million euros. In future, research and teaching will be provided in different sections of the 12,300 square metre premises, which include a lecture hall, a seminar room, two large-scale laboratory facilities, a library, and many other facilities. In addition to the Institute for Hydraulic Engineering and River Research, the Institute for Hydraulic Engineering and Hydromentry (Federal Agency for Water Management) also moved into the new laboratory complex, ensuring the efficient use of the building’s infrastructure. As the project’s initiator and manager, Helmut Habersack, of the Institute for Hydraulic Engineering and River Research, explains, “Our new hydraulic engineering laboratory provides a flow rate of 10,000 litres per second, which makes it second to none worldwide. This will allow us to run pilot projects up to a scale of 1:1 and promote valuable knowledge about the utilisation and protection of rivers.”

POWER PLANT GABI INAUGURATED AFTER OPTIMISATION

On September 23, Energie Electrique du Simplon (EES) celebrated the official inauguration of Swiss hydropower plant Gabi. In the spring of 2023, EES had completed a full rehabilitation of the facility. The work performed on the equipment raised the average annual output by 15 percent to 44 million kilowatt-hours. After completing the renovation of hydropower plants Gondo (2017), Tannuwald (2020) and Gabi (2023), EES now has a series of powerful facilities at its disposal to ensure the sustained reliable production of hydropower on the southern slope of the Simplon pass for many decades to come. After more than 60 years of continuous operation, the machines had to be replaced. Starting in March 2023, the plant equipment was subjected to a full-scale rehabilitation. Within a year, the entire original equipment was rebuilt, a new building put up, and the hydroelectric and mechanical components replaced. Overall, around 37 million Swiss Francs were invested in the project.

With the construction of the new hydraulic engineering laboratory on the upstream stretches of the Danube Canal, a unique laboratory facility is now available to serve the purposes of both basic and applied research.

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Offical inauguration with: Amédée Murisier, Sebastian Arnold, Antje Kanngiesser, Roberto Schmidt, Philipp-Matthias Bregy, Rolf Kalbermatter and David Jossen. (left to right)

The power house of Swiss hydropower plant Gabi has also been completely renewed.

The new hydraulic engineering laboratory in Vienna has been inaugurated in last years June.

MANAGEMENT REINFORCED AT VOITH HYDRO

As from March 1st, Andreas Wellmann, the current CEO & President of Voith Hydro EMEA, will also take over as head of the firm’s project business in the role of President, Projects. His additional responsibilities include Project Management, Field Service, and Scheduling. After completing his business studies at universities in Germany and the UK, Wellmann took over various management functions in turn-key facility construction with a focus on petrochemicals and energy production, as well as building construction and civil engineering, in Germany and Latin America. After joining Voith Hydro as Head of Service for Chile, he advanced to the position of CEO, Latin America in São Paulo. Since May of last year, he has been applying his wideranging project business experience as regional director for Europe, the Middle East and Africa (EMEA).

Fabrication of Kaplan runner Complete assembly, ready for erection

SITOP CELEBRATES 30TH ANNIVERSARY

Siemens Manufacturing Wien is celebrating the 30th anniversary of its SITOP power supply technology. What was originally launched by Manufacturing Wien in 1993 under the name “SITOP Power Basic Line” has evolved into a core element of automation, driving today’s digital transformation of the industry. At two of its facilities – one in Sibiu in Romania, and the one in Vienna – Siemens produces a comprehensive range of SITOP products, which ensure efficient power generation for industrial operations. As global leader in DIN rail industrial power supplies, Siemens uses its Austrian-based facility to help shape the future of its product development and production automation through the networked use of the products’ digital twins. The production technology employed at the Manufacturing Wien facilities is based on the Siemens Xcelerator.

Machining process of Kaplan blade and finish Pelton runner different dimensions till 4,5 diameter

and finish assembly injectors ready for erection

Francis runners fabricated in forge and welding process in three parts

We are a family company with experience of more than 40 years specialize on precision machining. We have experience on hydro market since 30 years. On this moment we can fabricate more than 40 Pelton runners in forge per year and more than 20 Francis runners. We fabricate and complete assemblies ready for erection of injectors, headcover, bottom ring, regulating ring, shaftseal, guide bearing, Kaplan distributors, etc.

Information on the machine list and reference list can be found on our homepage.

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PHONE: 0034 94512200 • FAX: 0034 945289046 • Contact person: Karlos Balsategui E-mail: aratz@talleresaratz.com • www.talleresaratz.com

Fabrication

© Voith

© Siemens

As of May 1, 2024, Andreas Wellman will join Voith Hydro’s global management board with responsibility for the firm’s project business.

Today approximately one million SITOP devices leave the Siemens factory in Floridsdorf every year and are used worldwide.

AUMA SERVICE

MAXIMISE AVAILABILITY

CLIMATE CHANGE TO BOOST IMPORTANCE OF AUSTRIAN HYDROPOWER, STUDY SAYS

What does the rapidly progressing climate change mean for hydropower in Austria? This question is at the centre of a new study published by consultancy firm Afry on behalf of Oesterreichs Energie. The authors conclude that, contrary to frequent calls of alarm, hydropower will grow in significance in the future. One of the reasons identified by the authors is the progressing shift of precipitation to the winter months, which should help to compensate for the typical gap in supply during the cold time of year. The experts also recommend a further expansion of storage and pumped-storage facilities. These types of facility serve as a complementary technology for volatile energy sources such as wind power and photovoltaics. What is more, they are able to dampen regional extreme events and compensate fluctuations in the available water volume. Storage power plants contribute to the flexibility of the power supply system on various time scales, with short-term and long-term compensation capabilities being particularly relevant with respect to climate change issues. As a result of changing climatic conditions, the frequency of heavy rains is showing an upward trend. Reservoirs can help to mitigate the effects of short, heavy rains in their catchment area, allowing the extra water to be stored for later use, for example, during times of low output from wind and photovoltaic facilities.

A new study says, that Austrian hydropower will grow in significance in the future.

KELAG ACQUIRES THREE SPANISH SMALL HYDROPOWER PLANTS

Austrian-based electricity group Kelag is in the process of acquiring three small hydropower plants from Spanish energy provider Iberdrola. Kelag had already acquired four Spanish small hydropower plants from Iberdrola last year. The three new ones are situated around 100 kilometres south of Valencia, on the Rio Mijares. The turbines of the hydropower plants in Los Cantos are expected to achieve a total annual output of 60 million kilowatt-hours. “These facilities had already been offered for sale by Iberdrola, and in the end our tender was accepted. The three hydropower plants in Los Cantos achieve a combined peak output of 32 MW. This means they generate 69 million kilowatt-hours of electricity,” as a statement from Kelag explains. In total the investment cost the Austrian energy provider 55 million euros. Together with the four small hydropower plants acquired last year, they say they are able to feed 88 million kilowatt-hours to the Spanish grid.

OFFICIAL INAUGURATION OF GRANDE DIXENCE’S NEWLY RENOVATED HPP

On October 20 2024, Grande Dixence SA celebrated the official recommissioning of their turbine houses at Fionnay and Nendaz, and the penstock that runs from the Lac des Dix to the plain of the river Rhône. The original facilities of the hydropower plants, which date back to the 1960s, were completely renovated and taken back into operation in stages, starting in early 2023. The six machine combinations at each of the two turbine houses in Fionnay and Nendaz had their valves, turbines, generators, automatic control mechanisms and ancillary systems refurbished. Grande Dixence SA and its shareholders have invested a total of CHF 240 million in the complex renovation project. Thanks to the comprehensive refurbishment, the facility is now ready and able to contribute to the reliable supply of energy in Switzerland.

Photo:

Mikko Törmänen

The fishway that

KELAG has acquired three hydroelectric power plants from Iberdrola north of the Spanish city of Valencia.

The fully refurbished penstock between the Lac des Dix and the plain of the Rhône was officially inaugurated in a second ceremony.

© Iberdrola

©

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The plan calls for a new power plant to be constructed between the existing facilities of Litzirüti and Pradapunt. The required investment and building permits are expected to be granted by 2027 or thereabouts.

POWER PLANT JETTENBACH-TÖGING WINS ARCHITECTURAL AWARD

Power plant Jettenbach-Töging on the River Inn is recognised for its well-rounded symbiosis of traditional architecture and modern engineering. The building’s owner, VERBUND Innkraftwerke, and the architects’ office of Robert Maier, received an award for outstanding achievements in the project for the construction of a new hydropower plant next to the existing listed facility buildings. The award was presented as part of the Federation of German Architectural Award 2024, under the motto, “About Upper Bavaria”. Töging am Inn is now home to a hydropower plant that boldly transcends the limits of historical demands on modern industrial buildings. After four years of construction, VERBUND’s renovated and extended power plant on the river Inn was finally taken online. The new power plant design has raised the output by around 40 percent to 118 MW, boosting annual production by around 25 percent.

AXPO RESUMES PLANNING FOR POWER PLANT PRADAPUNT

Project consortium “Wasserkraft Plessur” has resumed its plans for all-new hydropower plant Pradapunt in Switzerland. Once online, the facility could supply energy to 10,000 households. It is to utilise the drop of the Plessur river between Litzirüti and Pradapunt to generate around 42 GWh of energy a year. The new power plant would close the existing gap in the cascade of power stations on the Plessur, eliminating the fluctuations in discharge water volume from hydropower plant Litzirüti. The consortium consists of the three partners of Arosa Energie, IBC Energie Wasser Chur, and Axpo. Together they had already begun planning for hydropower plant Pradapunt in 2014, but then decided to put the project on ice in 2017 due to the unfavourable economic forecast for that year. With the economic situation having improved over the last few years, the consortium is switching into high gear again.

Small hydro Topics:

Innovation, trends and future technologies

Flexibilisation and smart grids

Requirements from electrical grid to power generation and storage

Pumps and Pumpturbines

Digitalisation on Machine- and Systemleveltechnological aspects

Planning and Operation of Varspeed Pumped

Storage Plants

Operation, Maintenance, Rehabilitation and Modernisation

Design rules, Standardisation and Legal aspects

Physical modelling and numerical simulations

Experimental Investigations on models and prototypes

Cavitation under extreme load conditions

Hydraulic systems and transient behaviour

Market change, Business Models and Economics of Hydro Power

Sustainability and environmental impact

For more details referring to the topics please visit our website: http://www.viennahydro.com

The jury members appreciated especially the aesthetic integration of the new building with the existing historical environment. In keeping with the award-winning design, the new power house blends in seamlessly yet powerfully with the surrounding landscape.

THE NEW EU LEGISLATIVE PERIOD – ISSUES AND NEW OPPORTUNITIES FOR HYDROPOWER

The current European legislative period (2019 to 2024) has been defined by the European Green Deal presented by the President of the Commission, Ursula von der Leyen, in November 2019. This Green Deal should set the course for a modern, resource-efficient and competitive economy that achieves net-zero greenhouse gas emissions by 2050, decouples growth from resource use and makes this transition fair and inclusive for all. [by Dirk Hendricks, Secretary General at EREF]

In recent months, negotiations on new and revised EU legislative procedures provided for under the European Green Deal have been finalised under high time pressure between the EU institutions so that the European Parliament could formally adopt them by the end of the session at the end of April 2024. Despite facing strong opposition to small-scale hydropower, the political work of national and European associations has led to successes in favour of hydropower, which will now form the basis for the coming years. EREF succeeded in including pro-hydropower provisions to EU policy files, especially the revision of the Renewable Energy Directive, the reform of the Electricity Market Design, the Nature Restoration Regulation, the Net Zero Industry Act, the 2040 EU Climate targets and several public consultations of the European Commission. EREF and its members of its Hydropower Chapter worked

with governments on the improvement of draft NECPs, demanding explicit national 2030 hydropower targets and the development of national hydropower strategies.

OVERRIDING PUBLIC INTEREST FOR RENEWABLES

Of particular significance is the establishment of the legal principle of overriding public interest for renewable energies, including hydropower. In addition, the EU institutions have been instructed to integrate this legal principle into existing and new European nature conservation legislation. Other political successes include the explicit recognition of (small-scale) hydropower as renewable energy; the rejection of proposed negative amendments to small hydropower; the rejection of the strict sustainability criteria for hydropower; and the decision by Member States on whether hydropower in renewable energy acceleration areas. The new legislative period will see the revision

of the Water Framework Directive. After more than 20 years, this presents an opportunity for the sector to adapt restrictive legal passages to the fact that hydropower and the good ecological status of a river can go hand in hand. Small hydropower plants create habitats for rare and valuable aquatic plants and birds as well as for fish, enrich the waters with oxygen and clean the rivers of all kinds of floating debris. The same applies to the finalisation of the definition of free-flowing rivers. It should be emphasised here that, at this stage of the negotiations, there is a broad consensus not to demolish any existing hydropower plants. In conjunction with the potential national implementation of the new EU regulation on nature restoration, only barriers that are no longer needed for energy production, shipping, water supply or flood protection should be removed. In this context, EREF continues advocating for detailed case-by-case assessments of barriers in

© Elke Barbara Bachler_pixelio.de

EREF succeeded in including pro-hydropower provisions to EU policy files, especially the revision of the Renewable Energy Directive, the reform of the Electricity Market Design, the Nature Restoration Regulation, the Net Zero Industry Act, the 2040 EU Climate targets and several public consultations of the European Commission.

order to secure the future potential for small hydropower.

NEW DESIGN FOR THE ELECTRICITY MARKET

Even though the agenda for the new EU legislative period is still being discussed, indications suggest that the debate on a new design for the electricity market will continue.The new agreement on market design from December 2023 emphasises the extension of the service life of power plants (repowering) and the promotion of flexibility as key issues for the hydropower sector. However, there is still a lack of business models on flexibility from which hydropower owners could potentially benefit. Furthermore, the distinction between storage and run-of-river power plants ignores the continuum of flexibility performance of hydropower plants. A possible solution could be drawn from the United States, where flexibility is assessed through the MW-mile tariff. This approach ensures that the remuneration is proportional to the length of the load curve in order to support flexibility sources compared to generation with a flat load curve. A Bavarian study on hydropower plants generating less than 1 MW concludes that run-of-river power plants have a potential modulation capacity of 800 MW. For France, initial estimates suggest a modulation potential of 300 MW over a two-hour period for hydropower plants under 10 MW, which is equivalent to the output of thousands of batteries.

HYDROPOWER CONTRIBUTES TO GRID STABILITY

Moreover, other hydropower services such as black start, congestion management and voltage regulation within distribution grids should be remunerated. Hydropower plants contribute to the stability of distribution grids, thus facilitating the increased production of green electricity from variable renewable sources, especially from photovoltaic systems. The need to accelerate the decarbonisation of the Europe-

an economy has become increasingly evident, particularly in light of the breach of the 1.5°C limit in the last twelve months and the escalating frequency of climate-related disasters. EREF therefore advocates for the resolute and full implementation of the European Green Deal and a clear and ambitious policy path for the next decade from 2030 to 2040 as a priority for the new EU legislature. With regard to the recently set target to reduce European greenhouse gas emissions by 90% by 2040, EREF urges the newly elected EU decision-makers to establish correspondingly high targets for a renewable energy expansion for 2040. At the same time, EREF calls for the expansion of hydropower to be included as an explicit item on the new EU agenda and for the development of a dedicated action programme to advance this objective.

RED IS PENDING AT NATIONAL LEVEL

At national level, the implementation of the Renewable Energy Directive (RED) is pending. According to the RED, the decision to include hydropower in the national acceleration areas for renewables lies with the Member States. In addition, it should be ensured that national governments adhere to the proposed accelerated authorisation procedures for hydropower projects. With the support of its members, EREF will inform the newly elected decision-makers in the European Parliament and the European Commission about the benefits and opportunities of hydropower and continue to advocate for its expansion. This is supported by activities under the EU project European Technology and Innovation Platform (ETIP) HYDROPOWER. Based on a network of hydropower stakeholders (HYDROPOWER EUROPE Forum), the project promotes the European hydropower sector regarding future collaborative R&I initiatives and increased public awareness. It aims to be a recognised interlocutor for the European

Commission, Member States and Associated Countries about the hydropower's sector specific R&I needs. ETIP Hydropower cooperates with national/regional/EU-level platforms to ensure synergies between EU, national and regional activities. The project recently published the new Hydropower in Europe Research & Innovation platform, HERI. HERI aims at supporting the European hydropower sector through the tracking of research, innovation and strategic actions as well as organisations active in hydropower research and compiles research funding organisations at European, national and local levels.

FOCUS ON R&I PRIORITIES

The year 2024 foresees the start of activities under four ETIP HYDROPOWER Working Groups (WGs). These groups gather experts from different hydropower sectors and stakeholder groups to focus on R&I priorities and strategic actions identified in the Hydropower Research and Innovation Agenda (RIA) and the Strategic Industry Roadmap (SIR) that the consortium had developed under a former project called Hydropower Europe. The four initial working groups (WG) cover flexibility and storage (WG1), biodiversity (WG2), Climate change (adaptation and mitigation, WG3) and the promotion, dissemination and uptake of past and current European hydropower R&I projects (WG4). Members of these working groups will draft white papers with accessible messages to increase decisionmakers and public awareness; identify, prioritize and draft key Hydropower Research & Innovation needs; draft technical statement reports; and help to facilitate strategic actions of the ETIP Secretariat and Chairing team. If you still would like to join one or more of these WGs, please contact us by email to secretariat@etip-hydropower.eu with ‘ETIP WG:’ starting the email header.

ALPINE HYDROPOWER TECHNOLOGY FROM SOUTH TYROL EXCELS IN MASTERING CHALLENGES AT THE FOOT OF THE HIMALAYAS

Early this year a brand new hydropower plant went online on the Chepe river in the central Nepalese district of Gorkha. The project is part of a comprehensive expansion programme that is set to transform the country at the foot of the Himalayas into one of the foremost hydropower nations worldwide. In implementing the new Super Chepe plant, the operators relied on the competence and qualities of a European-based hydropower specialist from the Alpine region. Prominent South Tyrolean water-to-wire provider Troyer was contracted to supply the entire electromechanical and control engineering equipment for the facility. Equipped with two 2-nozzle Pelton turbines representing an installed overall bottleneck capacity of 9.05 MW, the new power plant is designed to supply around 55 GWh of clean energy to the local grid.

Nepal’s hydropower potential has always been considered to be somewhat legendary. However, a lot of water had to flow down the country’s 6,000 or so rivers before initial steps could be taken to harness this vast potential. One reason for this was the low domestic per-capita energy consumption – the lowest, in fact, in all of Southeast Asia, at a mere 325 kWh, and there was another reason, albeit a rather more political one: for decades, hydropower construction had been within the purview of the state, which generally lacked the necessary funds to fulfil its responsibility – while the private sector was barred from stepping into the breach. Only with democratisation in the 1990s and the accompanying liberalisation of the electricity market did this gradually change. Even after this turning point, however, the prevalent

blackouts that had afflicted the country for many years kept putting a damper on further hydropower expansion plans. As of the end of 2023, Nepal’s 142 hydropower plants represented an installed capacity of 2,603 MW, according to the latest SINTEF Report. This is rather underwhelming, considering that a brand new study published by the “Asian Development Bank” found the country’s realistic hydropower potential to be around 72,000 MW. Note that this estimate is taking only the country’s ten largest rivers and their major tributaries into account.

KICK-OFF TO CONSTRUCTION IN 2021

Still, unlike years ago when high-large-scale hydropower plans rarely used to come to fruition, the Nepalese market has recently been seized by a new, altogether different kind

of dynamic. As of the beginning of this year, 244 new hydropower projects were under construction. These alone represent a total energy supply of around 8,760 MW, with further ambitious plans already in the works: By 2035, Nepal plans to expand its hydropower capacity to around 28,000 MW. One of the latest and most advanced facilities among the new hydropower projects, Super Chepe in the Gorkha district, went online early this year. Situated in the central Himalayas and sharing its border with China, the Gorkha district is home to four major rivers, the Chepe being one of them. The plan for a new power plant to utilise the river’s hydroelectric potential was developed by Ridge Line Energy Pvt. Ltd, one of Nepal’s leading providers in the fast-growing renewable energy sector. In 2018, the project’s operator had

A new, powerful hydropower plant using the River Chepe has been built in the Gorkha district of Nepal. The new power house was built at around 1,290 m above sea level.

© Troyer AG

signed a Power Purchase Agreement with NEA (Nepal Electricity Authority). Not long after that, they were granted official planning permission by the Nepalese Department of Electricity Development. With the administrative hurdles cleared, construction could finally commence in June 2021.

CONSTRUCTION HAMPERED BY DIFFICULT CONDITIONS

The Super Chepe hydropower plant is a high-pressure run-of-river facility with a catchment area of 49.23 square kilometres. Complementing a lateral intake and two long sand trap channels, the water chamber was built at 1,848 m above sea level. From there, the DN900 overground penstock runs along a 4.4 km route to the new power house, 1,290 m above sea level. This way, the facility can

make full use of a natural terraced gradient of almost 560 m. Using a 33 kV line, the power generated is fed to the substation at Tanahu, around 30 km away.

Implementing the construction project posed quite a few challenges. The heavy rainfall during and especially after the monsoon season ultimately caused delays in the construction process. Added to this was the risk of landslides, which was already known in advance due to the geographical location. A landslide occurred during the commissioning work in 2023, damaging part of the penstock. The work could only be completed once the section had been replaced.

WATER-TO-WIRE QUALITIES IN HIGH DEMAND

Ensuring a high level of quality throughout was a top priority for the plant’s operators at

Ridge Line Energy Pvt. Ltd, which is run by a young and highly competent management team. Hydropower plant Super Chepe was awarded the status of a true flagship project. For this reason, any compromise in terms of quality or implementation was to be avoided, especially where the electromechanical equipment was concerned. For the management team at Ridge Line Energy and their technical consultants, this was reason enough to contract one of the foremost hydropower specialists in the Alpine region: Troyer, which is headquartered in South Tyrol, Italy. Signed in May 2021 in Nepal, the contract was for an all-in-one technical package, consisting of the delivery, installation and commissioning of the electromechanical equipment, including the generators as well as the control engineering and secondary equipment. It was a great opportunity for the South Tyrolean provider to prove its competence as a water-to-wire specialist far away from home, in South Asia.

BRINGING TOGETHER EFFICIENCY AND DURABILITY

The core elements of the facility are two identical 2-nozzle Pelton turbines by Troyer, each of them crafted for a design flow rate of each 1.100 l/s at a net head of 540 m. Together, the two machines have a bottleneck capacity of 9,05 MW. Each of the turbines drives a DC coupled synchronous generator with a nominal rotational speed of 1,000 rpm. For the Nepalese operators, the deciding factors that convinced them to rely on

The identical machine sets were supplied by the South Tyrolean hydropower all-rounder Troyer AG. The two 2-nozzle Pelton turbines are designed for a bottleneck output of 9.05 MW. They have been in operation since January.

© Troyer AG

© Troyer AG

The entire control and guidance technology also comes from the South Tyrolean industry professional Troyer AG.

high-quality technology by the South Tyrolean hydropower all-rounders were twofold: the efficiency of latest-generation impeller technology, and the superior manufacturing quality, durability and sustained operational reliability. The experience gained from thousands of power plant projects completed in the Alpine region – and far beyond – throughout the company’s history provided the solid basis for Troyer’s first project in Nepal.

CHALLENGING TRANSPORT AND INSTALLATION

“A project in a new country always brings new challenges. You don't know in advance all the circumstances that await you there – whether it's the culture, the people or simply customs requirements,” says Troyer AG’s project manager, Florian Winkler. Especially the transport of the machines held some considerable challenges. After all, the delivery all the way to the Nepalese border had to be organised from the firm’s head offices in the South Tyrolean town of Sterzing. The assembly also played a decisive role. Although several assistant fitters were assigned by the client, in order to be able to guarantee the usual Troyer quality, a fitter from the South Tyrolean company was required to be on site.

"The assemblyl was certainly a challenge for our team. Accommodation was set up right next to the construction site, where the team lived and was always catered for. Work was quite strenuous, with several weeks scheduled to complete the installation,” as Florian Winkler explains. In the end, however, the effort was to pay off. On January 6, 2024, the power station was finally taken online and has been running like clockwork ever since.

INDIA NEEDS NEPAL’S HYDROPOWER

In a normal year, the Super Chepe hydropower facility will deliver around 54,75 GWh of clean energy to the local grid. This makes it not only a key project for the operators at Ridge Line Energy Pvt. Ltd, it also marks a major step in meeting the Nepalese government’s overall expansion target. And this target is also closely associated with Nepal’s big southern neighbor, India. India’s own energy programme calls for 50 % of the country’s required energy to be supplied by renewable sources. Nepalese hydropower also plays a crucial role in meeting this target. As reported by the Reuters news agency, the governments in New Delhi and

Kathmandu have signed an agreement to buy electricity produced in Nepal for more than 10,000 MW of hydropower over the next ten years. No doubt this deal will add further momentum to Nepal’s dynamic hydropower expansion efforts. As a result, the Super Chepe facility stands as a symbol of advanced, quality-driven hydropower utilisation in the country at the foot of the Himalayas. For South Tyrolean provider Troyer AG as equipment supplier for the plant, this market premiere has definitely paid off as well. Super Chepe is an attractive reference project that has already earned the Alpine-based hydropower all-rounders nine follow-up contracts in Nepal.

Technical Data

• Type of plant: High head - power plant

• Country: Nepal

• River: Chepe River

• Flow rate: 2.2 m3/s max.

• Net head: 540 m

• Number of turbines: 2

• Type: 2-nozzle Pelton turbine

• Rotation speed: 1000 rpm

• Manufacturer: Troyer AG

• Generators: synchronous

• Manufacturer: Indar

• Bottleneck capacity: 9.05 MW

• Penstock: length: 1208 km

• Diameter: DN900

• Automation: Troyer AG

• Commissioning: January 2024

• Average annual output: 54.75 GWh

The Super Chepe power plant sets new standards in terms of machine technology and automation in the region. The customised visualisation is clear and user-friendly at the same time.

Modern shut-off devices in front of the turbine inlet ensure safety in the new Super Chepe hydropower plant.

© Troyer AG

FINAL COMMISSIONING WORK ON TYROL’S

HIGHEST NEW SMALL-SCALE HYDROPOWER PLANT

This project went right down to the wire! VERBUND's power plant team only just managed to complete final commissioning work for the new Spiegelwald power plant in mid-November 2023 – before the onset of winter. At around 1,800 metres above sea level in Tyrol’s Zillertal Valley, the power plant utilises water from the upper Zemmbach overflow into the Schlegeis reservoir. It provides an annual yield of around 10.5 GWh of clean electricity using a powerful Francis spiral turbine made by Kochendörfer – the German hydropower specialists. It’s ‘only’ a small hydropower plant in terms of output capacity, but in many respects it bears the hallmarks of larger-scale projects.

Schlegeis reservoir in Zillertal Valley in Tyrol is an integral part of the Zemm-Ziller power plant group. The complex of power plants is operated by Verbund Hydro Power GmbH over several stages and reservoirs. It has a capacity of over 1,900 MW, making it one of the most powerful impoundment facility groups in Austria. The Schlegeis reservoir double-curvature arch dam was completed in 1973. Along its curved geometry it’s the longest dam wall of the group at 725 m bank to bank. Water from the Schlegeis reservoir flows via an 8.6 km tunnel to the Roßhag power plant, where four radial pump Francis turbines manage a total output of 230 MW.

A sturdily-built toll road with single-lane tunnels, some equipped with traffic lights, leads to the Schlegeis reservoir. At this altitude it’s only open to conventional road traffic from May to the end of October; and at the height of the Schlegeis reservoir every construction project poses key logistical challenges. This was certainly the case at the new Spiegelwald power plant.

STREAM CONNECTION AND STORAGE CHAMBER ENABLE POWER PLANT REALISATION

Manfred Kanduth is an engineer, and the overall project manager for the Verbund power plant project. He explains: “In principle, planning for the Spiegelwald power plant

was completed ten years ago, but repeated rescheduling delayed construction commencement.” He references accessibility problems in the construction site area, which had required finely-tuned coordination between the individual construction sites; and the extremely short construction season in high alpine terrain. Once planning had been finalised and official approvals granted, initial preparatory work finally began in 2021.

The hydraulic source that makes the Spiegelwald power plant possible in the first place is the Zemmbach River. A natural high-altitude alpine watercourse whose water is channelled through the mountain to the Schlegeis reservoir via a tunnel around 6 kilometres long. The water from the Zemmbach River is a key supply source for the Schlegeis reservoir, delivering an average annual water volume of around 60 million cubic metres. Although, hydroelectrically speaking, it had previously been unexploited on its approximately 80 metres descent, everything changed with the new power station.

In terms of the power plant project, although essentially the water intake and headrace were already present, it was necessary to install a penstock, a powerhouse, an underwater basin – and a very sophisticated power transmission system. Manfred Kanduth described the difficult conditions: “The Spiegelwald power plant is a small hydropower plant, but the effort and logistical planning involved meant there was little need to fear comparisons with large hydropower projects. In addition to the

VERBUND has built a new small power plant above the Schlegeis reservoir. In a regular year it will supply 10.5 GWh of electricity. Construction, high up in the Alps above Zillertal Valley, proved to be exceedingly challenging.

The water hits the annular piston valve at the tunnel portal at a pressure of around 30 mWs. When it is opened, a fountain pours into the reservoir.

VERBUND

extensive safety precautions, we regularly faced enormous challenges in terms of weather, access and equipment – and at these heights construction is only possible from June to the end of October.”

GRAVITY TUNNEL BECOMES A PENSTOCK TUNNEL

First, to create the penstock, the gravity tunnel was converted into a pressure tunnel. High-pressure GRP DN1400 piping was elevated 65 metres and connected to the tight concrete seal of the pressure tunnel carrying the headrace water to the tunnel exit. A bespoke-manufactured Y-pipe was installed at the tunnel portal to divide the headrace. Depending on regulation and requirements, water can be diverted to an annular piston valve and discharged directly into the Schlegeis reservoir at the level of the tunnel exit. Alternatively, it can be fed into the cast iron underground pipeline to the powerhouse around 40 metres below. There is a transition to an optimised steel inlet pipe at the entrance to the powerhouse, with a DN1200 butterfly valve located in the powerhouse itself, followed by the turbine spiral. Finally, the discharged water reaches the underwater basin via an elbow suction pipe. The first pressure test, held at the beginning of October, was an immediate success, proving that all components of the penstock and tunnel descent corresponded with professional construction standards.

ENERGY TRANSMISSION VIA SUBMARINE CABLE

Installation of the power transmission infrastructure was a more unusual aspect of the project, as it was only possible to route the power conduit through the Schlegeis reservoir. Consequently, this required the laying of

a submarine cable and the correspondingly complicated installation process, as engineer Horst Rass, project manager for electrical and control technology at VERBUND, confirms: “We needed to procure a special steelarmoured cable to ensure it was protected from falling rocks.” The 3.75 km length of submarine cable was installed by excavating a cable trench into the floor of the empty reservoir, laying out the cable on a bed of sand, and sealing the trench. Nevertheless, at the end of August 2023, heavy rainfall undermined the cable bedding and a mudslide ripped the cable in one place. As Horst Rass describes: “Repair procedures were problematic as the affected section of cable was now submerged at around 80 metres below the water surface.” Ultimately,

the team’s endeavours were successful. Everyone involved was relieved when the transformer immediately sprang to life during initial commissioning trials.

CAVERN

ACTS AS A STORAGE FACILITY

Finally, in autumn 2023, cavern tunnel filling commenced, and reaffirmed one of the positive findings of prior geological investigations: More water flows into the tunnel from the mountain than is lost through leaks and fissures. “This is also of relevance since the tunnel has to withstand pressure and fulfil the function of an intermediate storage basin when required. To be more specific, at a length of 6 km it provides around 40,000 m³ of storage volume, allowing it to operate as a small daily reservoir," explains Verbund’s

Once the Schlegeis reservoir had been emptied, submarine cable was laid in a trench at the bottom of the reservoir. Weeks later, the cable was broken by a mudslide.

Delivery and installation of a synchronous generator weighing over 20 metric tons turned out to be a tough challenge.

Kochendörfer’s vertical-axis Francis spiral turbine is designed to manage a nominal capacity of around 4 MW.

Dipl.-Ing. Andreas Prackwieser – Project Manager for Mechanical and Hydraulic Steel Engineering. Fellow manager Horst Rass adds: “The system can be stopped and started as needed, especially in winter when there is little water. The tunnel is filled and the full load of water is processed by the turbine in around two hours.” In contrast, when more water is produced than the turbine can accommodate, the annular piston valve is activated, and channels the excess water directly into the Schlegeis reservoir. Andreas Prackwieser points out: “Our top priority was to ensure that water drawn from the Zemmbach River reaches the reservoir. After all, hydroelectric processing takes place via the Roßhag facilities and the main Mayrhofen station along a further descent of 1,000 metres.”

HIGH-PERFORMANCE TURBINE

Theoretically, in a year of normal operation, almost 60 hm³ can be channelled to the new Spiegelwald hydropower plant. The turbine, a vertical-axis Francis spiral turbine, was designed by the German hydropower specialists at Kochendörfer to process an expansion water volume of 6 m³/s. A net head of 74 metres generates an output of 4,063 MW. As is standard practice at Kochendörfer, the runner was crafted via CNC milling to guarantee maximum precision, modern hydraulic design aesthetics and supreme performance. In the powerhouse of the Spiegelwald power plant, it drives an air-cooled Indar synchronous generator designed for a rated output of 4.2 MVA. “The generator weighs over 20 (metric) tons, so getting it to the site was accordingly difficult,” Manfred Kanduth recalls.

The machine control technology adapts the inflow at any given moment. “In summer this means that it is controlled via output – as with a target level. In winter, when the water level is low, it can be operated intermittently," explains Horst Rass. In a regular year, the new

machine group is expected to supply around 10.5 GWh of electricity.

A RACE AGAINST TIME

However, at the onset of winter last year it wasn’t even a certainty that project completion would be achieved on time. In fact, all three project managers agreed that the final weeks from the beginning of October to mid-November had been a race against time. Up at 1,800 metres above sea level everything stops once the snow comes. Avalanches above the construction sites and the access road make work too hazardous. “In winter, the site can only be reached by helicopter, so it was essential to have completed all electrical and mechanical trials and tests prior to the onset of winter to enable trial operations to be initiated in the spring,” states Manfred Kanduth. Conditions were already wintry when commissioning was carried out in the first week of November. Closing times were set, and this stage was immediately followed by wet commissioning – involving adaptation of the control technology, of protective infra-

structure and the synchronising of operations. Although the commissioning phase has not yet been completed, an initial summary offers up positive conclusions: Ultimately, the race against time was won, and all the key objectives were achieved by the responsible parties at VERBUND – and their partners –with a combination of professional coordination, flexibility and team spirit.

Technical Data

• Type of plant: High head - power plant

• Country: Austria

• River: Zemmbach

• Flow rate: 6 m3/s

• Gross head: 74 m

• Number of turbines: 1

• Type: Francis spiral turbine

• Manufacturer: Kochendörfer

• Generators: synchronous

• Nominal capacity: 4,063 MW

• Average annual output: 10.05 GWh

In the new powerhouse with overall project manager, Manfred Kanduth, and the project manager for electrical engineering, Horst Rass. In collaboration with their partners, they successfully implemented this challenging power plant project in the Tyrolean Alps.

LARGE-SCALE SOUTH AFRICAN FARMER RELIES ON GERMAN HYDROPOWER EXPERTISE FOR A THIRD TIME

The South African farmer Michael Vermaak has become a loyal and regular customer for Ossberger, the German hydro-industry experts. Since 2008, three small hydropower plants have been built on the expansive Klipfontein farm in the village of Cookhouse. All three have been equipped with comprehensive Ossberger electromechanical packages. The latest plant went online for the first time in September 2023 with another one of Ossberger’s high-performance technology packages – including a crossflow turbine with a bottleneck capacity of 412 kW, and all the electrical fittings and control equipment. Furthermore, at the oldest plant all the control technology was updated. Resultantly, all three power plants can now operate as island solutions or in parallel grid operation – and each one is equipped with black-start capabilities.

Anyone in South Africa self-sufficient enough to meet their own electricity needs with a proprietary power plant can count themselves very lucky. So-called ‘load-shedding’ is part of everyday life for around 60 million inhabitants in the southernmost country on the African continent. Power cuts can last up to twelve hours, with entire regions and cities being taken offgrid. According to ESKOM, the state-owned energy supplier, South Africa’s power supply would collapse completely without loadshedding. Corroborative media reports suggest that a major reason for the problematic situation is the generally desolate state of the country’s energy infrastructure, resulting from decades of mismanagement and corruption.

KLIPFONTEIN FARM IS SELF-SUFFICIENT

Having taken matters into his own hands in 2008, building a small hydropower plant on his extensive Klipfontein Farm property in the village of Cookhouse, Eastern Cape Province, the nationwide energy supply problem is no longer a cause for concern for Michael Vermaak. The plant utilises the hydro-energetic potential of an irrigation canal branching off from the local Fish River, and supplies water to a number of farms. Acquisition of additional properties enabled the operator to

expand his farm and led to increased demand for energy. In response, in 2018 a second hydropower plant was built and commissioned, and in September 2023 a third plant went into operation.

OSSBERGER SUPPLIES RELIABLE SOLUTIONS

Ossberger crossflow turbines have been in use worldwide for over 100 years and the expertise of these German industry specialists was the operator’s first choice from the first plant on; and for the full range of technical hydropower plant infrastructure – machine sets, hydraulic steel structures, electrical fittings

and control technology. Christian Habermann, Ossberger’s Technical Director explained: “Generally, South Africa is a favourable market for us, and in our experience, Ossberger turbines are particularly appreciated by operators of systems on irrigation channels as on Klipfontein Farm. The objective for a basic crossflow turbine is not to harvest the last possible percentage point of its efficiency potential, but to deliver electricity reliably and uncomplicatedly. This is the core characteristic of our solutions and, ultimately, something our customers consider to be particularly important.”

A maximum of 2,500 l/s of expansion water for the new power station is discharged at the inlet area of the irrigation canal, and channelled to the underground machine room via a penstock.

Three small hydropower plants at Klipfontein Farm in Cookhouse, South Africa, provide power for energy-intensive agricultural infrastructure, and also feed into the public power grid. As small hydropower experts, Ossberger’s specialists were able to supply the electromechanical instrumentation and control equipment for all of the reliable crossflow turbine hydropower plants.

© all photos

Ossberger

Technical Data

• Flow Rate: 2.5 m³/s

• Net Head: ca. 20 m

• Turbine: Crossflow Turbine

• Rotation Speed: 280 rpm

• Max. Output: 412 kW

• Manufacturer: Ossberger

• Gear Ratio: 1:3.6

• Generator: Synchronous

• Frequency: 50 Hz

• Voltage: 400 V

• Nominal Output: 475 kVA

The small hydropower plants in Cookhouse generate electricity for energy-intensive agriculture, and to feed into the public grid. A significant proportion of the electricity generated is directed to a pumping station with several variable-speed pumps. The station is used mainly during the night to fill a reservoir excavated from a hillside for the irrigation of surrounding farmland.

MULTI-MODAL OPERATING EQUIPMENT

The first plant, built in 2008, was designed purely for island operation. Now, however, all three power plants can operate in island and grid-parallel modes, and all have black-start capabilities. Ossberger’s scope of delivery for the latest hydropower plant in Klipfontein consisted of the crossflow turbine, gearbox and synchronous generator, the flywheel, the butterfly valve and all electrical and I&C equipment. The horizontally-fed crossflow turbine is designed to achieve a discharge water volume of 2.5 m³/s with a net head of around 20 m, for a bottleneck output of 412 kW under full load conditions. Drive water for the turbine is provided via an under-

ground penstock pipeline connected to a newly-built inlet on the irrigation canal. No separate screen cleaning machine was installed at the inlet area. However, Christian Habermann explained that, if required, such a machine could be retrofitted without great effort. After driving the turbine, the headrace water is returned to the diversion channel and, after a short distance, flows into the Fish River. Plant construction took around a year and was completed in autumn 2023. The operator and several local companies played an active role in the plant construction phase. The machine building is completely subterranean, and assembly of the electromechanical equipment and cabling laying were tasks conducted by local labour teams. Ultimately, the power plant was commissioned in September 2023 under the supervision of an Ossberger technician.

THREE IS THE MAGIC NUMBER

Operation of the state-of-the-art system is fully automatic. The control system can be accessed using touch panels installed in the machine buildings, or accessed online via

smartphones and PCs. As well as being experts in the construction of turbines, the German all-rounders at Ossberger demonstrated their hydropower expertise by providing the full scope of control technology for the plant network. “In the course of order implementation it was also necessary to modernise the electrical engineering in the oldest power plant. As a result, all three plants can now generate electricity individually, or combine automatically to form a completely synchronised network, depending on the current requirements”, Ossberger’s Area Sales Manager Markus Sauerbeck told us. Christian Habermann summarised: “The entire project went very smoothly, and coordination and communication were flawless. It was definitely of benefit to be familiar with each other from previous projects, and to be able to form a well-oiled team. We are certainly in a good position to implement further projects in the field of agricultural or municipal irrigation systems. The Cookhouse project is a good example of how an existing irrigation channel can now be used three times to generate clean electricity.”

The pump station receives electricity from the small hydropower plants and is equipped with a whole battery of variable-speed water pumps to fill the reservoir.

Touch panel visualisation of system control in the machine room.

WALDBACH HYDROPOWER PLANT IN STYRIA GOES ONLINE WITH REGIONAL EXPERTISE

The newly-built Waldbach small hydropower plant in Eastern Styria has now been generating clean electricity for almost two years. Having already overseen the construction of two photovoltaic systems, committed local residents also oversaw the implementation of this small hydropower plant project. The operators at ÖKO Energie RIPO KG are proud to have realised the power plant project largely using regional industry expertise. The centrepiece of the plant is a crossflow turbine with a bottleneck capacity of 110 kW and a standard operating capacity of around 300,000 kWh.

Joglland in north-east Styria was the home of famous Austrian author Peter Rossegger. Here conditions are ideal for the generating hydroelectric power. The topography is hilly and offers numerous bodies of water. The densely-wooded region stretches across the districts of Hartberg-Fürstenfeld and Weiz, where the power of water has been harnessed for many centuries. For hundreds of years, craftsmen used traditional water wheels to power mechanical transmissions in mills, forges and sawmills. “Once electricity was introduced, increasing numbers of island power stations were built, and commonly shared by several farms. It is said that around 30 small plants operated in the region,” recounts Franz Riegler, Managing Director of ÖKO Energie RIPO KG, the constructors of one of the latest small-scale hydropower plants in the Waldbach-Mönichwald area.

RENEWABLES PRIORITISED

In his interview with zek HYDRO, Franz Riegler highlights the importance of sustainable power generation in the region, mentioning a whole range of renewable energy sources in use in Waldbach-Mönichwald. A combined heat and power biomass plant is fuelled with local wood to generate electricity and heat. Furthermore, two photovoltaic systems went operational in 2014 and 2016, producing a combined total output of over 500 kWp. Finally, a new small hydropower plant on Weißenbach River went online in the summer of 2022. “We were already considering building a hydropower plant while planning the first photovoltaic system. Con-

struction ultimately began in autumn 2021 after comprehensive consideration of design options,” explained Riegler, emphasising the broad range of conditions that had to be taken into account when designing the plant. “Fortunately, several members of the power plant company are also very talented craftsmen, so we were able to conduct a lot of the work – such as laying the pipes – ourselves. Obviously, this had a positive impact on costs.”

COMPACT WEIR SYSTEM

The Weißenbach River is dammed at the water intake by a hydraulically-operated weir flap. Headwater is channelled to the side inlet on the right – orographically speaking. Subsequently, the water flows from the outlet through the desanding basin, where fine sediments in the water settle. Larger travelling and floating debris is stopped by a fine vertical

screen at the rear end of the desander. The screen is cleaned by a hydraulically-operated telescopic cleaning device that removes debris to a flushing channel. The fish ladder is adjacent to the desander basin and was constructed to provide a technical solution. Total residual water discharge is adjusted every three months. Depending on the time of year it ranges between 88 and 104 l/s. Franz Riegler adds that measures were also implemented to improve fish passability in the residual flow section, including the removal of the existing drop steps, and the specific placement of river stones to raise the water level in certain areas. The full range of hydraulic engineering equipment was supplied by the Styrian hydropower experts at Mayrhofer Maschinenbau.

GRP PENSTOCK PIPING

According to Franz Riegler, the largest challenge during the entire project was the in-

The newly-built Waldbach small hydropower plant has been connected to the grid since the summer of 2022 and generates around 300,000 kWh of green electricity in an average operating year.

© zek

© Riegler

The perfectly smooth inner surface of the pipes from the manufacturer SUPERLIT avoids hydraulic losses.

Technical Data

• Flow Rate: 420 l/s

• Net Head: 34 m

• Penstock: app. 1.3 km

• Ø: DN600

• Material: GRP

• Manufacturer: SUPERLIT

• Supplier: Geotrade Tiefbauprodukte GmbH

• Turbine: Crossflow-Turbine

• Drehzahl: 485 pm

• Manufacturer: Mayrhofer Maschinenbau

• Generator: Asynchron

• Nominal Output: 110 kW

• Avarage annual production: app. 300 000 kWh

stallation of almost 1.3-km of pipeline to transport the water downhill. This consisted entirely of glass fibre reinforced plastic (GRP) pipe sections. “Some sections of the pipe routing run close to an existing 20-kV power line – the underground power transmission conduit from a neighbouring wind farm. For this reason, great care was required when laying the pipes. The grid operator was present wherever the medium-voltage line was crossed.” As well as crossing the wind farm power conduit, the penstock also had to traverse multiple items of municipal infrastructure – including sewers and power lines. This task was made easier due to the installation of GRP pipe sections. The piping has proven its worth around the world, as its low weight, compared to much heavier cast iron or steel pipes, makes handling far easier during installation. All pipe material and special fittings were supplied by the expert Upper Austrian distributors Geotrade Tiefbauprodukte GmbH. SUPERLIT piping is lightweight, the material is robust and offers a whole range of advantages – including excellent hydraulic properties, resistance to environmental influences, consistently high abrasion resistance, and very favourable flow properties that minimise frictional resistance. A power cable and a fibreoptic cable were also laid during installation of the GRP penstock to provide for the digital hook-up of the weir system, in turn enabling remote monitoring via video camera.

HIGHLY VERSATILE CROSS-FLOW TURBINE

The centrepiece of the plant is a crossflow turbine with a directly coupled asynchronous generator. The entire machine set was built by the Styrian hydropower all-rounders at Mayrhofer Maschinenbau. The 2-cell turbine provides constant power generation, even when

the water supply is greatly reduced. The machine set is designed to process a discharge water volume of 420l/s and a 34-m net head, so at full volume it can generate 110 kW of electrical power. The comprehensive scope of delivery provided by the Styrian industry specialists was rounded off with a full range of electrical equipment and control technology infrastructure. This included automatic plant control with visualisation, remote maintenance access via PC, smartphone and tablet, weir flap and turbine water-level regulation tech, automatic control of the screen cleaning system, and reactive current compensation. The electricity generated is fed onto the public grid through a transformer in the immediate vicinity of the powerhouse run by the grid operator Feistritzwerke.

IN OPERATION FOR ALMOST TWO YEARS

The new building was commissioned in July 2022, a mere ten months or so after the ground-breaking ceremony. Franz Riegler expanded: “Although the technological infrastructure worked perfectly, the initial period of operation did not yield much electricity due to the extremely dry weather over a period of several months. This led to a large-scale restriction of hydropower electricity generation capacity across many borders. Fortunately, precipitation has returned to stable levels again, enabling the power plant to operate normally and generate electricity effectively.” Franz Riegler then pointed out that, additionally, green electricity was being generated by roof-mounted PV infrastructure on the machine building.

The water intake provides up to 420l/s of headwater from the watercourse. It is equipped with a fish-belly weir flap.

Franz Riegler, Managing Director of ÖKO Energie RIPO KG, at zek HYDRO’s site inspection in north-east Styria.

The penstock is approximately 1.3 km long and consists of DN600 GRP pipes supplied by the Upper Austrian company Geotrade Tiefbauprodukte GmbH.

© Riegler

THE MODERNIZATION OF THE SHKOPETI HYDROPOWER STATION BY VOITH HYDRO RESULTED IN A 13 PERCENT PERFORMANCE INCREASE

The modernization of the Shkopeti hydropower station for the customer Kürüm International SHA was successfully completed by Voith Hydro in January 2024. The hydropower station, dating back to the 1960s, underwent comprehensive renewal over a period of two and a half years, with commissioning occurring ahead of schedule and earlier power generation than planned. Targeted modernization measures also resulted in a 13 percent increase in performance. The outstanding feature of this project is the innovative seven-blade runner, which is rare in the industry.

The Shkopeti reservoir, located approximately 35 kilometers north of Tirana in central Albania, supplies water to the Shkopeti hydropower station, where two Kaplan turbines are in operation. The reservoir impounds the Mat River, the sixth longest river in Albania, at an elevation of 102 meters above sea level. With a length of approximately nine kilometers, the reservoir extends to the dam of the Ulza reservoir, which forms the uppermost dam on the Mat River.

PERFORMANCE INCREASE FROM THE ORIGINAL 24 MW TO 27 MW

The Shkopeti hydropower station, first commissioned in 1963, required modernization after 60

years of operation. Voith Hydro, in collaboration with its subsidiaries Sintaksa (a Voith Hydro company) and Elin Motoren (a Voith Group company), successfully modernized the existing power station while simultaneously increasing the capacity from the original 24 MW to 27 MW. From Voith Hydro's perspective, the biggest

Dankrägten Fertigungstiefe im Hause EFG können

challenge was adapting to the existing structure and embedded components – a task that was successfully accomplished by the experts.

TIMELINE AND TECHNICAL SPECIFICATIONS

"Voith Hydro exceeded our expectations in the modernization of the Shkopeti hydropower station, achieving an impressive result through excellent collaboration. The early commissioning and the 13 percent performance increase are clear evidence of Voith Hydro's expertise and the successful partnership," emphasized Julian Zoto, Technical Director at KÜRÜM International SHA.

The project was initiated in May 2021 and was completed in January 2024. The performance increase was achieved through a new hydraulic design and excellent collaboration between Voith Hydro, Elin Motoren, and Sintaksa, who jointly provided complete power station equipment, including two vertical Kaplan turbines with 13.5 MW each, generators, and electrical equipment.

Activities at the Voith Hydro facility in Austria

© Voith Hydro

TECHNOLOGICAL INNOVATION AND CUSTOMER SATISFACTION

The turbine supplied by Voith Hydro with its complex design distinguishes the Shkopeti hydropower station as a technological flagship project. The delivery was not only timely but also smooth – from assembly to commissioning.

The modernized turbines are designed to handle a water flow rate of 40.60 m³/s and a head of 36.20 meters, resulting in an installed capacity of 13.5 MW each. The power station can achieve an extended output of 14 MW in standalone operation. Due to specific hydraulic conditions, this is only achievable with one unit in operation at a time.

VOITH HYDRO

Voith Hydro not only delivered Kaplan turbines with innovative hydraulic design but

Technical Details

• Turbine type: Vertical Kaplan turbines

• Turbine manufacturer: Voith Hydro

• Head: 36.20 m

• Flow rate: 40.60 m3/s

• Power: 13.5 MW per turbine

• Generator manufacturer: Elin Motoren, a subsidiary of Voith Group

• Electrical equipment: Sintaksa, a subsidiary of Voith Hydro

also significantly contributed to the performance enhancement of the hydropower station. The scope of supply also included the tailored renewal of cooling water and drainage systems, as well as the provision of the

ELIN MOTOREN

Elin Motoren played a crucial role by supplying the generators for the Shkopeti hydropower station. The customized generators were designed to efficiently harness the increased power output of the station.

SINTAKSA

Sintaksa was responsible for the electrical equipment. The company provided comprehensive electrical infrastructure essential for the smooth operation of the modernized hydropower station. This included the installation of switchgear, transformers, and other electrical components to interconnect the entire facility and maximize energy efficiency.

ENERGY AUTONOMY AND ENVIRONMENTAL FRIENDLINESS

Albania, as one of only four countries worldwide whose energy is generated 100 % from renewable sources, sets a clear example of energy autonomy and environmental friendliness with the Shkopeti hydropower station. Despite the low per capita CO2 emissions, the country has only utilized about one third of its enormous hydropower potential – a circum­

Dankrägten Fertigungstiefe im Hause EFG können "13.5 MW per unit is an impressive performance that exceeds the dimensions of a small hydropower station." Georg Schmit, Head of Project Execution, proudly emphasizes the outstanding design and delivery of these turbines, which boldly ventured beyond the usual scope of Voith Hydro's Small Hydro Division in Austria.

HPU (Hydraulic Power Unit). Special emphasis was placed on replacing only what was necessary to ensure efficiency and sustainability. The expertise gained from Voith Hydro's globally successful reference projects was also leveraged purposefully and effectively in this project.

stance that projects like Shkopeti are supposed to change.

SUMMARY AND OUTLOOK

With the modernized Shkopeti hydropower station, Voith Hydro has not only achieved a technological feat but also made a significant contribution to Albania's sustainable energy supply. The enhanced performance, complex design, and timely implementation make this project a prime example of Voith Hydro's expertise and that of its subsidiaries. It represents a significant step towards a greener, more sustainable future for Albania.

Shkopeti power station – inside view

Shkopeti power station – outside view

HYDROPOWER STATION AUGAND ON THE RIVER KANDER PROVIDES GREEN ENERGY FOR 7,700 HOUSEHOLDS

The construction of hydropower plant Augand in the Swiss canton of Berne marked the utilisation for a greenenergy project of a stretch of the river Kander that had never before been used for hydropower generation. The Augand facility is a joint project of BKW Energie AG and Energie Thun AG, the co-founders of Kraftwerk Augand AG. The power house is home to two horizontally aligned Kaplan turbines by Global Hydro Energy. When under full load, they provide a bottleneck capacity of 8.3 MW. Optimised specifically for efficiency, the synchronous generators of both machine units are provided by hydropower specialist KONČAR – Generators and Motors Ltd.. The facility was officially inaugurated in September 2023, after three years of construction.

From 2020 to 2023, a new hydropower plant was constructed on the river Kander, to the southwest of Lake Thun. Initially, two competing license applications were submitted for the energetically unexploited stretch of the river upstream of the Spiez hydropower station. After the projecting phase, which took around 10 years to complete and included the assessment of various implementation versions, BKW Energie AG and Energie Thun AG finally joined forces to get the project underway. As a result, Kraftwerk Augand AG was founded to provide the legal framework for the project.

CHALLENGING CONDITIONS

Hydropower plant Augand was essentially designed as a diversion plant on the river Kander, upstream of the existing Spiez facility. As Patrik Eichenberger, BKW’s project manager and representative of the owner, explains, ecologic considerations were a major factor in selecting the site for the water chamber next to the BLS railway tracks. “We had to comply with environmental regulations, which eventually limited our possibilities for the plant layout to a single option for the site of the water chamber. The Lötschberg line, which is operated by BLS, is one of the most essential transalpine railway lines. Planning our hydropower facility right next to the railway tracks turned out to be extremely challenging, due to the constrained spatial conditions.” To support the

required outflow of up to 30 m³/s of motive water, which crosses under the railway tracks straight after the water chamber, the engineers opted for a 1.4 km non­pressure tunnel, which runs underground to the surge tank.

RAILWAY TRACKS CROSSED UNDER WITHOUT INTERRUPTING TRAIN SERVICES

One of the most challenging tasks of the project was the construction of the culvert under the double­track Lötschberg railway line while train services continued as normal above ground. The construction work to culvert the river was completed within three

weeks in late summer 2020. While construction work was going on, the tracks and railway poles, as well as the embankment within the range of the underpass had to be monitored geodetically for safety reasons. The motive water from the Kander is dammed up by means of a two­part weir baffle and flows out by way of a collateral intake. From there it is guided through two upstream basins, where the floating debris is removed from the outflow reach by a rack cleaning machine mounted in front of a vertically aligned fine mesh grating. Ensuring full continuity for fish migration at the weir gate also required con­

Built between 2020 and 2023, hydropower plant Augand to the southwest of Lake Thun is a joint project of BKW Energie AG and Energie Thun AG. In a normal year, the facility generates around 35 GWh of clean energy.

© all photos

BKW

The machine building was constructed around 80 m upstream of the existing weir gate of hydropower plant Spiez.

siderable constructional effort. To enable aquatic animals to overcome the 7 metres of difference in altitude between the downstream and upstream end water, a fish ladder was installed in the form of a vertical slot pass consisting of a series of 49 individual basins. The residual water flow at the water chamber was regulated primarily to suit the life and migration cycles of the local brownie trout population. Allowing for seasonal fluctuations, the flow volume varies between 1.5 and 4 m³/s.

WORKING UNDERGROUND FOR 1½ YEARS

Excavating the 1,360 m horseshoe­profiled non­pressure tunnel was done in classic miner’s fashion by means of tunnel heading and cutting machines with milling attachments and demolition hammers, complemented by protective construction measures. The tunnel passes over a frequently used railway tunnel of the BLS line, as well as another, disused tunnel, at distances between 1.9 and 5.9 m. This part of the project required com­

Technical Data

• Flow Rate: 30 m ³/s

• Gross Head: ca. 32 m

• Net Head: ca. 30 m

• Turbines: 2 x Kaplan-Turbines

• Rotation Speed: 2 x 428 rpm

• Ø Turbine Runners: 2 x 1.480 mm

• Maximum Output: 2 x 4,150 kW

• Manufacturer: Global Hydro Energy GmbH

• Generators: 2 x Synchronous

• Voltage: 2 x 6,300 V

• Nominal Output: 2 x 5,200 kVA

• Manufacturer: KONCAR – Generators and

Ltd.

• Annual Average: Production: ca. 35 GWh

prehensive advance planning, calculations and proof of safety. “We had to install a tachymeter inside the double­tracked tunnel to be able to constantly monitor the tracks, the tunnel crown and the tunnel floor. This tachymeter was in constant operation from the start of the excavation work until after the final stress tests. We also had to monitor the geodetics along the crown of the second one, the unused Hondrich tunnel,” as Patrik Eichenberger explains. The breakthrough, which the miners had been working towards from both sides for around 18 months, was finally achieved in March 2022.

TURBINES SHINE WITH RECORD PERFORMANCE

Located at the end of the underground conduit is the plant’s water reservoir, which houses the probes of the level­controlled turbines. From the water reservoir, a GRP­based DN2400 double penstock leads directly to the machine building. Delivered as part of an electromechanical all­in­one package, the two

Kaplan bulb turbines by Austrian hydropower specialist Global Hydro Energy form the core elements of the machine house. Each of the two horizontally aligned turbines is configured for a design flow rate of 15 m³/s and a net head of 30 m. This allows them to achieve a bottleneck capacity of 4,150 kW under full load. Since the machines are equipped with adjustable gate operating mechanisms and runner blades, they are able to provide a consistently high level of efficiency across a wide operational bandwidth even when the available water volume happens to fall below normal levels. Complementing the machine units are two synchronous generators, manufactured by KONČAR – Generators and Motors Ltd. in a water­cooled design, including the corresponding equipment, i.e., butterfly valves, turbine governors, and cooling and greasing aggregates. With its custom­crafted generators, both of which are designed for ultimate efficiency, KONČAR has earned an excellent reputation in the renewable­energy

The process of finding the appropriate location for the water chamber next to the double-tracked BLS railway line was accompanied by a series of challenges.

It took the engineers around three weeks to culvert the river under the railway tracks without interrupting the train services.

Motors

Patrik Eichenberger, BKW’s leading project manager (right) and Andreas Schmidt, master of ceremonies, at the inauguration ceremony.

industry. To meet the requirements of the Augand project, the Croatian specialists custombuilt two high­efficiency machines, each of them designed to deliver 6,300 V of voltage and 5,200 kVA of rated apparent power. The energy generated by the machine units is conducted from the medium­voltage switchgear

to the transformers. Near the plant’s downstream weir gate it is fed into BKW’s grid.

A POWER STATION FOR MANY GENERATIONS

In June 2023, hydropower plant Augand was ready for its first trial run. In September it was finally time to take the joint power plant pro­

ject of BKW and Energie Thun AG into operation at an official inauguration ceremony. The new facility represents an investment of around 68 million Swiss Francs. In a normal year it generates approximately 35 GWh of green energy – enough to supply around 7,700 average four­person households with clean energy. As Patrik Eichenberger explains, the facility was completed in time without any major incidents, despite adverse circumstances ranging from the COVID­19 pandemic and the resulting supply shortages to rising prices, time pressure and two major flood events. Besides ensuring the unimpeded passage of fish, Kraftwerk Augand AG was also able to adjust a stretch of the Kander downstream of the power station in cooperation with the local community of Aeschi near Spiez and the Schwellenkorporation Wimmis, with the federal and cantonal governments providing financial support. After the completion of this revitalisation project from the Cantonal Structure Plan for Water Bodies, the Kander is to regain as much of its original riparian terrain as possible along a stretch of about 450 metres. As a further measure, Kraftwerk Augand AG has added a stream ramp to an existing flood barrier to ensure that the fish are also able to find their way upstream of the river weir.

Each of the machine units was complemented by a water-cooled synchronous generator manufactured by KONCAR – Generators and Motors Ltd.

GERMAN SCREEN CLEANING TECHNOLOGY PROVES ITS WORTH IN PAPUA NEW GUINEA MINE HYDROPOWER PLANT

Since late summer 2023, technology “made in Germany” has been removing floating debris from the intake area of a small hydropower plant in Papua New Guinea that provides energy for the local Ok Tedi gold and silver mine. The new screen cleaning system was supplied by hydropower specialists Wiegert & Bähr Turbinen- und Stahlwasserbau GmbH from Baden-Wuerttemberg, who implemented the reference project on the opposite side of the globe in exemplary fashion. Equipped with three separate cleaning arms to significantly speed up the cleaning process, the machine had to be installed within a rather narrow time window to keep the power plant’s downtime as short as possible. Thanks to painstaking preparations, including an extensive system pre-assembly and test run in Germany, complemented by a perfectly coordinated on-site mounting process, the installation could be completed in record time.

Known and appreciated beyond Germany’s borders as a competent small-scale hydropower partner, Wiegert & Bähr recently celebrated the successful completion of an international reference project. “From a German perspective, you can’t get much more international than that,” says Managing Director Markus Rest, commenting on the contract for the project in Papua New Guinea, the world’s third-largest island state after Indonesia and Madagascar. Essentially, the contract called for a complete refurbishment of a water screening system for the hydropower plant that supplies the operating power for the extensive gold, silver and copper mining operation in the local Ok Tedi mine. The mine takes its name from the nearby Ok Tedi river, which runs along the national border with the Indonesian part of the island.

NEW PARTNER ‘DOWN UNDER’

The contract for the Papua New Guinea project has a rather long pre-history, as Markus Rest explains. Metaval Consolidated Pty Ltd. is headquartered in northern Australia and focusses primarily on serving the energy and industrial sector. The company had been on the lookout for a new partner for the imple-

mentation of hydropower projects. Metaval had also contacted their German-based business partner to make enquiries about competent firms in the industry. As a result, Wiegert

& Bähr was highly recommended by Metaval’s partner. “The first time I met Metaval’s CEO, Andrew Garland, was about five years ago, at an industry trade show in Munich.

The mine takes its name from the nearby Ok Tedi river, some stretches of which form a natural border to neighbouring Indonesia.

© all photos Wiegert & Bähr

Expert care and attention was the order of the day when the screen cleaner by Wiegert & Bähr was installed at the hydropower plant for the Ok Tedi mine in Papua New Guinea.

During our conversation, we agreed that we would showcase our product portfolio ‘down under’ soon after. In 2019, my colleague Bernhard Wallmeyer and myself boarded a plane to Australia, where we met with Andrew Garland and his Sales Director, Dale Eastick. Together we went on a tour of potential customers in the water supply and hydropower industries. Among others, we also visited the ‘Entura’ engineering office, which was busy refurbishing the screen cleaning system for the Ok Tedi Mine in Papua New Guinea. Back in Germany we worked out an optimised screen cleaning concept for the project, which we then offered to the customer,” as Markus Rest recalls.

SINGLE-STEP INTAKE CLEANING

The concept developed by the hydropower experts must have really struck a chord with the facility’s operators, as Wiegert & Bähr

were already awarded the contract for the project in early 2021. As the company’s Head of Construction, Michael Wiegert, explains, “The old machine was running on rails to clean the screening area, which was segmented into three sections. Since the machine was only able to work on one section at a time, it took quite a long time to complete a full cleaning cycle. Our concept focussed on speeding up the cleaning process by using three telescope arms working in parallel to clean the entire screening area in one go.” Thorsten Vonthron, the project’s coordinator, names the time factor as one of the project’s key challenges: “While reconstruction work was going on in the intake area, the two turbines in the power house couldn’t be operated and had to be shut off. During this time, the operating power for the mine was supplied by a series of diesel generators. However, the high fuel prices meant that their use had to be

kept as short as possible. So, delays during the installation of the new screen cleaners were a definite no-no, which is why great efforts were taken in advance to keep things going as smoothly as possible during the actual installation.”

TEST RUN IN BADEN-WUERTTEMBERG

The entire system was manufactured at Wiegert & Bähr’s headquarters in the small town of Renchen. Before it could be packed up for shipping (literally on the high seas), it had to be fully assembled at the production facilities and subjected to a series of trial runs. “When we designed the system we made sure that it could be delivered in a highly pre-assembled state so on-site installation would be as quick and straightforward as possible. So the central electrotechnical and oil-hydraulic components were all installed in an all-in-one switchbox, which was then mounted right on top of the structural steelwork of the machine. The mechanical construction was based on extradurable gear racks that were suited to the required cleaning depth of around 11 metres,” says Michael Wiegert, adding that “the tropical climate in Oceania required certain special design details that wouldn’t have been an issue anywhere else in the world. For example, the electromechanical and hydraulic components had to be fitted with extra-high quality insulation to withstand the high levels of atmospheric humidity. In addition, some of the cable harnesses had to be fitted with additional protective sheathing to protect them against scavenging rodents.

FLEXIBILITY IS KEY

With factory acceptance testing completed, the system was packed into two shipping containers in February 2022 and shipped from Rotterdam Harbour to Brisbane. In the end it took around a month, including the required stopover in Singapore, for the shipment to finally arrive. In coordinating the final installation, Wiegert & Bähr had to prove their professional flexibility on more than one occasion. For one thing, the installation date, originally scheduled for early summer of 2022, could not be kept due to ongoing coronavirus protection measures. Once the pandemic restrictions were lifted, the installation was rescheduled for autumn the year before. However, due to the rising prices of the fuel needed for the emergency power supply units to sustain the mining operation, the installation had to be postponed yet again. It was not until late summer 2023 that the final installation could go ahead, implemented by Wiegert & Bähr technicians in cooperation with local experts. “Our guys had been in

The front view of the plant’s intake area, which was equipped with screen cleaning technology “made in Germany” in early autumn 2023 after two delays.

With the machine’s trial run successfully completed, the components were packaged for high-seas shipping and sent off on its overseas voyage.

the country already three weeks before the official start of the installation to prepare for the installation in painstaking detail. In installing the system in the intake area, the technicians proceeded by assembling the required components for the facility right next to the old machine. With the obsolete equipment removed, it was finally time to lift the entire assembly towards the screening area with the help of a mobile heavy-lift crane, anchor it into place and take it into operation. Everything went very smoothly at the installation site, so I have to give high marks to our technicians and the on-site crew for a job very well done,” says project coordinator Thorsten Vonthron.

INTERNATIONAL CONTRACTS ARE MOST WELCOME

Managing Director Markus Rest is also very happy with the result of the first Wiegert & Bähr project on the opposite side of the globe: “Of course we’re thrilled to be able to win another international customer and partner with Metaval. It seems our project implementation made a good impression. Ever since the new screen cleaner was put in operation we’ve had nothing but positive feedback about its functionality and the practical experience gained during its operation. The huge effort behind the project, like the trial assembly, the test runs at our facilities, and the elaborate coordination of the project have definitely

paid off. With this reference project to our name, I’m convinced it won’t be too long before we’ll be able to make our next international appearance.” That said, the Managing Director does not fail to mention that Wiegert & Bähr has already had the opportunity to prove its international competence in Africa. “We’ve been working as sub-contractors on the Nangbeto dam in Togo for more than three years now. It’s a long-term project, which has been prolonged even further due to the coronavirus pandemic, and it involves a complete revision of the hydraulic steelwork for a large hydropower facility that gets its water from the dam lake.”

The system allows the entire inlet grate to be cleaned in a single cycle.

Only three days were allowed for the installation of the entire new cleaning system. The installation was implemented by local technicians in cooperation with the experts from Wiegert & Bähr.

HYDRO-CONSTRUCT SUPPLIES THE BIGGEST RUBBER DAM IN EUROPE FOR THE RIVER PO IN PIEDMONT, ITALY

Austrian Hydro-Construct GmbH completed this project successfully on the River Po in the famous Piedmont region of Italy in 2020. The rubber dam is part of the Casale Monferrato hydropower plant – named after the nearby town. The Austrians supplied a rubber dam with four spans – at an overall length of 200 m. At a regulation height of 4.3 m this structure is the biggest of its kind in Europe, and the largest project Hydro-Construct has ever built. The rubber dam has a flexible, heavy-duty membrane and operates as a water-inflated system to ensure the water level in the reservoir remains at an exact height, regardless of river flow volumes - while also allowing the free passage of floodwater extremes. Despite the general difficulties caused by the corona crisis, the 4.4 MW power plant was successfully commissioned and put into operation that May.

The Austrian company Hydro-Construct is known for breaking its own records. Especially considering the dimensions of this flexible weir system. Compared with conventional technologies, the advantage of this rubber dam system is its use for damming reservoirs on broad rivers without the need of fixed weir structures that artificially narrow the flow opening. HydroConstruct supplied another large rubber dam with an overall length of 265 m and a height of 2.3 m in Albania in 2012, and in 2017, in Uttar Pradesh in India a further project was installed at 270 m in length and at a height of 3.2 m. These innovative solutions are available for regulation heights up to 4.5 m. This kind of system has also been implemented in Turkey and France. The project on the River Po involved the installation of a rubber dam with 4 spans at an overall length of 200 m,

and a regulating height of 4.3 m, near the town of Casale Monferrato in Piedmont. This project enabled Hydro-Construct to set a new European record for rubber dams.

Hydro-Construct Austria supplied its largest rubber dam ever in Europe for Casale Monferrato on the River Po in Piedmont, Italy, at an overall length of 200 m and a regulation height of 4.30 m. The rubber dam has been in operation since May 2020.

Costanzo Villosio (left) and his nephew Sebastiano developed and implemented the project with their company, Idro Baveno S.r.l.

BEST PRACTICE CO-OPERATION

Hydro-Construct’s CEO DI Dr. Rudolf Fritsch explains that this hydro project was developed by the privately-owned company Idro Baveno S.r.l. from Turin. Idro Baveno CEO, Constanzo Villosio, and his nephew Sebastiano are the driving forces behind this important project. The co-operation was reportedly a success the first time around, as in 2012 Hydro-Construct supplied this company with a 2-span rubber dam for Casalgrasso at a length of 215 m and a height of 1.2 m. Rudolf Fritsch reveals that the project costs of 26 million euros for a hydroelectric power plant with a head of just 5 m and a rated flow of 4 x 30 m³/s are only feasible with supported feedin tariffs. This is an example of a private initiative development designed to generate renewable energy. The hydroelectric power plant is equipped with vertical Kaplan turbines and synchronous generators supplied by the Italian company Scotta S.p.A. The capacity of the power plant is 4.4 MW and annual production of renewable energy is 25 million kWh.

20 TONS PER MEMBRANE

Hydro-Construct has enjoyed increasing success in the upper Italian area of Piedmont. To date 8 rubber dam projects have been implemented here. The Casale Monferrato project was supplied and installed between February and December 2019, commissioning took place in 2020. Internal resources

were challenged by the need to complete within this short installation period. HydroConstruct was supported by their partner companies Aquatis of Brno, who provided engineering and installation management, and Rubena of Nachod, who produced the membranes with an endless vulcanisation press and incorporated four layers of fibre fabric. The membrane is 22 mm thick in dimensions of 60 m by 15 m. Each piece of the membrane weighs 20 metric tons.

AUSTRIAN / ITALIAN PARTNERSHIP

Mr. Fritsch informed that the dimensions and the weight of the rolled-up membrane posed transport logistics problems and construction site handling challenges. Installation of one span took around two weeks. A precondition for installation of the membranes was completion of the concrete structures with embedded fittings for clamping and for the pipe system. He was complimentary about the collaboration with all the companies

Installation of rubber dam membranes took around 2 weeks for each span.

involved in construction work: “Every aspect of the cooperation with other companies went smoothly, and it must be mentioned that our Italian partner company, Puntel & Capellari & Associati Ingegneria from Udine, deserves praise for their complete dedication in the preparation of the entire project. Dr. Ing. Michaela Diracca was especially helpful with her technical expertise and charm. She provided important support to Hydro-Construct and made a strong impact on the success of the project.”

SEPARATE REGULATION OF SPANS

The 4 weir spans are operated by two separate control units: one for the middle spans and the other for the end spans. The operating system enables both systems to communicate with each other, running in automatic mode in regular use. For maintenance purposes, all four spans can be operated manually, and a special operating mode for flushing sediments during reservoir regulation has also been implemented. It is technically feasible to regulate each span separately and this solution was implemented at the Indian project in Uttar Pradesh where the dam is 270 m wide

and 3.2 m high. Hydro-Construct is co-operating with the Austrian company ESA on the supply of electric and electronic operation & control equipment of rubber dams. ESA supplied and installed all the electric and electronic equipment for Casale Monferrato. The operating system is fully automatic and ESA experts can be linked up via the internet if required.

SYSTEM SECURED MULTIPLE TIMES

The regulation system is situated in a shaft building which is 12 m deep, and in which all the regulation devices such as pumps, valves and motor drive systems are installed. The building is located on the left bank near the hydroelectric power plant powerhouse. The regulation shafts have different functions with water being filled in and drained out by pumps. These are connected to the weir by a pipe system and are like ‘communicating vessels’. The drainage pump and outlet valve enable the rubber dam to be lowered downwards continuously until its body drops completely to the weir sill. To guarantee the highest standard of safety, Hydro-Construct rubber dams feature a threefold safety system:

Firstly, the overflow section infill shaft triggers a pressure limiter. Secondly, there’s the manually opened outlet valve and, thirdly, there’s an automatic discharge device for a defined water pressure limit. This works even during electricity power supply black-outs.

SUMMARY AND PROSPECTS

Construction of the Casale Monferrato project was influenced by the restrictions and negative impacts of the corona crisis. Moreover, atypically strong flooding in the area of the construction site delayed construction. Ultimately, the project was completed in May 2020 and the power plant was then able to commence production of renewable electric energy. Rudolf Fritsch says: “The Casale Monferrato project shows that on broad rivers there are no restrictions to the number of rubber dam spans. Technically and economically feasible hydropower solutions can be achieved up to the maximum applicable height of 4.5 m.” The next rubber dam projects in Northern Italy are already in the pipeline and HydroConstruct is ready to serve the market with their economical expertise and best technical practices.

Installation of embedded parts for a water-filled rubber dam system.

Regulation of the 4 weir spans by 2 separate control units. The 2 middle sections communicate with the 2 end sections.

Hydro-Construct’s globally successful rubber dam system facilitates optimal reservoir management and guarantees a safe passing of floods.

SYMBIOSIS BETWEEN OBERVELLACH II TRACTION POWER PLANT AND KAPONIGBACH SMALL HYDROELECTRIC POWER STATION

Construction of the new Obervellach II traction power plant in Mölltal Valley, Carinthia is a role-model green electricity project now nearing completion. Realisation of the plant, devised to enable the Austrian Federal Railways (ÖBB) to produce around 125 GWh of electricity per year, generated considerable construction costs. The contract included construction of a headrace approximately 4 kilometres long, installation of a storage tunnel with a capacity of 60,000 m³ and the building of three new water intakes on the Mallnitzbach, Dösenbach and Kaponigbach rivers. A new small hydropower plant was also built on Kaponigbach River and equipped by GUGLER Water Turbines GmbH with a complete electromechanical package. The Austrian industry experts provided a 1.6 MW 3-nozzle Pelton turbine to ensure the hydro-energetic potential of the Kaponigbach was used to produce green electricity before being turbined a second time at the traction power plant.

The ÖBB has been producing environmentally-friendly energy with hydropower for more than 100 years. In the mountainous provinces of Vorarlberg, Tyrol, Salzburg and Carinthia, the first hydroelectric power plants were built for railways as early as the 1920s. Nowadays in Austria the annual consumption of electricity by a railway at 16.7 Hz is around 2,000 GWh. Approximately a third of this demand is generated by the ÖBB‘s own hydroelectric power plants. The remainder is supplied by partner hydropower plants, drawn from the public grid, and converted to traction current frequency by the ÖBB with frequency converters.

RAILWAY HYDROPOWER

In Carinthia, completed in 1929 after seven years of construction, Obervellach I hydroelectric power station was an important cornerstone of the railway power supply in southern Austria. The power plant was expanded in the 1940s as electrification of the rail network progressed, integrating a second penstock and a third set of machines. The addition of the Kaponigbach further expanded the power infrastructure in 1947 and 1948.

In fact, the smaller Lassach power plant, whose headrace water was later used by the Obervellach I power plant, supplied the Tauern railway tunnel construction site with electricity as early as 1910. After more than 100 and 90 years of operation respectively, ÖBB looked to modernise the two power plants comprehensively as they had reached the end of their technical service lives. The Carinthian provincial government gave approval for the project in 2015, and the main construction phase for the new Obervellach II power plant to replace the two old railway power plants – Obervellach I and Lassach – commenced in 2020.

COMPREHENSIVE MODERNISATION

The complete refurbishment will increase the plant‘s control energy capacity by around 35 per cent. In a standard year, Obervellach II is expected to generate around 125 GWh of green electricity, the equivalent of the power required for around 30,000 journeys on the Railjet from Villach to Vienna. Electricity is generated by two Pelton machine sets mounted in the new powerhouse. Together they will produce a bottleneck output of around 37 MW, a total expansion water volume of 9 m³/s and a gross head of 488 metres. Works water for the new ÖBB hydropower plant is sourced via three separate water

GUGLER Water Turbines GmbH supplied an impressive all-round package for the new ÖBB Kaponigbach small hydropower plant. The centrepiece is a 3-nozzle Pelton turbine with a bottleneck capacity of 1.6 MW.

© GUGLER

© GUGLER

A maximum of 900 l/s is taken from the stream at the water intake of the small hydropower plant.

intakes on the Mallnitzbach, Dösenbach and Kaponigbach rivers. Catchments on the Mallnitzbach and the Dösenbach feed headrace water along a tunnel almost 4 kilometres in length with a diameter of approximately 3 m to a storage tunnel with a capacity of 60,000 m³. The third water intake on Kaponigbach River first guides the water to the newly-built small hydropower plant before the headrace water is then channelled into a storage tunnel to serve the traction power plant. The final section of the headrace begins at the storage tunnel machine room, and leads to the powerhouse in Obervellach via a 1.8-metre diameter penstock.

INDUSTRY EXPERTS PROVE CALCULATION SKILLS

GUGLER Water Turbines GmbH is an internationally renowned company and was res-

ponsible for providing the hydroelectric equipment at the Kaponingbach power station, demonstrating its expertise to the ÖBB for the first time within the framework of this project. The scope of delivery for the Upper Austrian-based hydroelectric allrounders included a 3-nozzle Pelton turbine with a directly coupled synchronous generator, a ball valve, a hydraulic unit and a bypass system with shut-off valves, the full range of electrical infrastructure – and the power plant control system. “The machine building was integrated into a mountainside at around 1,100 metres above sea level. This location posed a number of logistical challenges as equipment could only be transported along a narrow access road. The horizontal-axisdesign 3-nozzle Pelton turbine was an ideal solution for the power station on Kaponig-

bach River, in terms of its hydraulic design and the space available in the powerhouse. The limited space in the machine building was also taken into account in its compact design. The hydraulically-controlled Pelton nozzle adjustment mechanism was mounted within the turbine,” explains GUGLER project manager Thomas Berger, who also mentioned that GUGLER had a wealth of experience in the design of horizontal-axis-design 3-nozzle Pelton turbines. Moreover, Berger emphasises that a customer as distinguished as the ÖBB places extremely high demands on its electromechanical equipment. During the complex engineering phase GUGLER gave an impressive demonstration of its calculation expertise. “The ÖBB operate a whole series of large power stations, and apply the same high safety standards to their smaller hydroelectric power facilities. Pressure surge calculations for the Kaponigbach power plant involved using specialised software to dry-run more than 17 distinct scenarios. Having been milled from stainless steel monoblock, turbine runner strength was verified via the finite element method (FEM). FEM simulation was also applied to calculate the strength of the turbine ring and distribution pipes. Evaluation took into account load spectra determined in the pressure surge calculation but also temperature changes and traffic loads”, Berger explains.

EQUIPPED FOR ALL MODES OF OPERATION

All calculations were checked and approved by the Vienna-based Technical Testing and Research Institute (TVFA). GUGLER’s R&D department conducted model testing at the Vienna University of Technology for a 3-nozzle Pelton turbine. “Turbine design is

Technical Data

• Flow Rate: 0.9 m ³/s

• Gross Head: ca. 211 m

• Penstock: ca. 2,200 m

• Ø: DN700

• Material: Ductile Cast Iron/Steel

• Turbine: 3-Nozzle Pelton-Turbine

• Turbine Axis: Horizontal

• Ø Turbine Runner: 778 mm

• Maximum Output: 1.6 MW

• Manufacturer: GUGLER Water Turbines GmbH

• Generator: Synchronous

• Voltage: 950 V

• Nominal Output: 2,000 kVA

An air-cooled synchronous generator directly coupled to the Pelton runner completes the machine set.

The strength of the turbine runner was verified using FEM simulation.

GUGLER

GUGLER

based on the findings of the test series. This enables us to guarantee maximum efficiency in practice,“ says Thomas Berger. The turbine was designed for an expansion water volume of 900 l/s, a gross head of 211 m and a bottleneck output of approximately 1.6 MW at full load. GUGLER equipped the machine set with a bypass line including a ring piston valve to allow the traction power plant to continue being fed by Kaponigbach River during maintenance work, or if the small power plant went offline. Obervellach II produces traction current only. However, the Kaponigbach power plant was designed to generate electricity at 50 Hz, meaning the small power plant ensures the traction current power plant is self-sufficient and can even feed electricity onto the public grid. Furthermore, Kaponigbach power plant has black start and island operation capabilities so, as Thomas Berger reports, Obervellach II can be reconnected to the grid should there ever be a large-scale blackout: “Load sheddings in island operation were also part of the simulation process to ensure the machine always remained within acceptable frequency fluctuations.”

REGULAR OPERATION AROUND THE CORNER

The first power plant test runs started at Obervellach II in the autumn of 2023 after a con-

struction phase of around 3½ years. The Kaponigbach power plant was finally commissioned for the first time in the spring of 2024. “Commissioning went off smoothly, and all dry, wet and signal tests were completed successfully. Snowmelt provided enough water to run the turbine at 100 per cent capacity. It was a challenging project all round with multiple interfaces that all now interact seamlessly. We

are proud to have successfully provided renowned clients with a solution that meets their very high standards,” Berger summarises. The two new power plants are scheduled to go into regular operation in the summer of 2024. By expanding their domestic hydropower capacities, the ÖBB have clearly underpinned their status as one of the most environmentally friendly rail companies in Europe.

The machine building of the new Carinthian traction energy hydroelectric power plant Obervellach II.

VIENNAHYDRO EMPHASISES THE VALUE OF HYDROPOWER IN THE ENERGY TRANSITION

The Viennahydro is one of the world's most renowned hydropower conferences. This year it is being held for the 22nd time on 13th to 15th November in the sophisticated setting of Laxenburg Castle on the outskirts of Vienna. Focus will again be on key topics in hydropower with the traditionally diverse audience of international experts enjoying excellent presentations, lively discussions and an inspirational supporting programme. This year's main topics all feature under the leitmotiv ‘The value of hydropower in the energy transition’ – and include issues such as flexibilisation, storage and digitalisation.

Which innovations are required, and what direction must research take to ensure hydropower meets future challenges? This autumn, these central questions are to be discussed at the 22nd edition of the Viennahydro. Experienced industry leaders and young researchers provide new impetus and a variety of perspectives on these questions. The event committee has repeatedly proven its worth, ensuring the quality of the issues and presentations remains high.

“Our event committee consists of 35 internationally­recognised experts, whose work guarantees no mediocre or below­average papers are approved. Only papers exhibiting highly­innovative content, academic maturity and the appropriate preparation are endorsed for the event,” says Prof. Christian Bauer, Head of the Fluid Mechanics Department at the Technical University of Vienna. As usual, Christian and his team will be hosting and organising the event.

EXCELLENCE OF PRESENTATIONS GUARANTEED

The Viennahydro is organised every two years. This certainly adds to its appeal, and

means there is more time to develop new topics and select higher­quality presentations. The event was cancelled in 2020, due to the Coronavirus, but made a successful comeback in 2022 – and this proven event format is returning this year. Online participation was an innovation first featured at the previous edition, and is also to be implemented again. As Christian Bauer explains: “We offered the online format for the first time in 2022. It worked well, so we decided to provide the option for conference participants and some speakers this year, too.”

Traditionally, the degree of international participation at the Viennahydro is very high. The organisation team is led by Christian Bauer and assumes that in 2024 around 40 percent of participants will come from abroad. The event is fundamentally bilingual, with communication and presentations taking place in both German and English.

The Viennahydro takes place every two years at Laxenburg Castle and is a major highlight in the international hydropower industry's event schedule.

Host of Viennahydro: Prof. Christian Bauer

© Viennahydro

© Viennahydro

PROGRAMME ENHANCED BY PHD STUDENTS

The Viennahydro is absolutely unique in that it offers doctoral students from all over the world the opportunity to present their research work to an international audience of experts. The event's good reputation has led to the increasing interest and participation of numerous PHD students. “The majority of PHD students at this year’s event come from abroad, presenting topics that are wide­ranging, but have very close relevance to the most important international research priorities,” says Christian Bauer. He references a selection of interesting doctoral students' presentations approved for the event – such as: ‘Flexible power grids of the future’, ‘Validation of model investigations by prototype measurements in the field of transient operation management’, ‘Integration of photovoltaics and hydrokinetic energy into the hydropower system’, ‘Dynamic performance evaluation of a pumped storage power plant connected to a power grid’, ‘Investigation of the scaling effects of cavitation in shear flows’, ‘Detection and stabilisation of plants in island operation’, or ‘Numerical investigation with CFD of a Pelton nozzle with structured and unstructured computational meshes’.

FOCUS ON CURRENT TOPICS

The doctoral students’ work corresponds perfectly with the topics to be covered in Laxenburg in 2024. A small selection from the wideranging list of accepted submissions includes: ‘Flexibilisation and smart grids’, ‘Pumps and pump turbines’, ‘Digitalisation at machine level’, ‘Planning and operation of variablespeed pumped storage power plants’, ‘Physical models and numerical simulations’, ‘Hydraulic systems and transient behaviour’, ‘Experimental tests on prototypes’ and ‘Cavitation under extreme loads’.

Chief organiser Christian Bauer emphasises that the course of the event will not deviate in

any significant way from previous conferences, stating that the participants appreciate the high standard of lectures and discussion panels, and the dignified setting of the venue, Laxenburg Castle, around six kilometres south of Vienna, which – for this reason – has been retained.

PARTICIPANTS APPRECIATE SIDE-EVENTS PROGRAMME

The supporting side­events at the Viennahydro are also held in high regard. For many years Viennese tradition, flair and relaxed moods are known to have been essential parts of the supporting programme. So, this year, as in previous years, the evening reception is to take place in the Wappensaal at Vienna City Hall, a wonderful venue steeped in Viennese history and culture. On the second evening, there’s an equally popular and well­established visit to the traditional Fuhrgasslhuber wine tavern, sponsored by industry specialist Voith

work.

Hydro. A further highlight, one marking the start of the three­day event, is the panel discussion held in the main hall. “The panel discussion recently received a very positive response, leading to the scheduling of another top­class discussion this year on the key topic of ‘The value of hydropower for the energy transition’”, Christian Bauer reveals. Anyone with an interest in hydropower should make a note of the dates from 13th to 15th November immediately.

NB: Registration on the homepage will be open for the conference from 15.05.2024.

FOR MORE INFORMATION – GO TO: www.viennahydro.com

• INNOVATION, TRENDS and FUTURE TECHNOLOGIES

• FLEXIBILISATION and SMART GRIDS

• REQUIREMENTS FROM ELECTRICAL GRID TO POWER GENERATION AND STORAGE

• PUMPS and PUMPTURBINES

• DIGITALISATION ON MACHINE and SYSTEMLEVEL TECHNOLOGICAL ASPECTS

• PLANNING and OPERATION of VARSPEED PUMPED STORAGE PLANTS

• OPERATION, MAINTENANCE, REHABILITATION and MODERNISATION

• DESIGN RULES, STANDARDISATION and LEGAL ASPECTS

• PHYSICAL MODELLING and NUMERICAL SIMULATIONS

• EXPERIMENTAL INVESTIGATIONS on MODELS AND PROTOTYPES

• CAVITATION UNDER EXTREME LOAD CONDITIONS

• HYDRAULIC SYSTEMS and TRANSIENT BEHAVIOUR

• MARKET CHANGE, BUSINESS MODELS and ECONOMICS OF HYDRO POWER

• SUSTAINABILITY and ENVIRONMENTAL IMPACT

• SMALL HYDRO

Laxenburg Castle lies to the south of Vienna and provides a sophisticated setting for the event.

© Viennahydro

© Viennahydro

The Viennahydro is an unmissable event for all major names in the hydropower industry and for young researchers, of whom some will be given an opportunity to present their own

SOUTH TYROLEAN HYDRAULIC STEEL CONSTRUCTION SPECIALISTS DELIVER PROFESSIONAL SCREEN CLEANING SOLUTIONS

Gufler Metall KG from the Passeier Valley in South Tyrol has been satisfying customers on the inner-Alpine hydropower market with its hydraulic steel construction products for over three decades. Gufler Metall provides modern solutions, especially debris rakes and screen cleaning machinery, impressing operators with their functionality, durability and robustness. The portfolio ranges from self-cleaning Coanda rakes to various types of telescopic and excavator-arm screen cleaners. The list of hydropower industry references for these solutions alone is extremely long, highlighting the expertise and quality offered by this South Tyrolean company in screens and screen cleaners.

The machine efficiency of a hydropower plant is often measured to the second decimal point, but is determined overall by more than just the performance of its machines. The trash rack situation is at least as important and determines whether the available motive water is drawn at optimum volumes and speeds, or whether there are efficiency losses due to blockages caused by debris or leaves. Hence, a completely unobstructed inlet screen is absolutely invaluable. Technical solutions for debris-free screens have existed for decades. Over time, companies have continually optimised them to serve the needs of power plant operators; ultimately developing them to become completely self-cleaning plant components.

Gufler Metall KG is a medium-sized South Tyrolean company, based in Moos in the Passeier Valley. It has been active in this market segment for over three decades and has built up an excellent reputation for its hydraulic steel construction solutions. It is acknowledged for its expertise in steel pipe welding, and valued throughout the Alpine region for its hydraulic steel engineering solutions, high-quality rake screens and screen cleaning machinery.

COANDA SYSTEM EXPERIENCE

Today, Gufler Metall is one of the few suppliers in our part of the world to offer a self-cleaning protective Coanda rake in its product portfolio. The Coanda rake has

established itself as an economically and ecologically viable option for water catchments on mountain streams with high wash loads and bed loads, particularly in Alpine regions. Thanks to the system’s inherent wall adhesion effect, and to the shearing effect on the profile bars, the Coanda rake is effective at preventing sediment and smaller aquatic organisms from flowing into the catchment system. There is also an inherent ecological benefit as flotsam, debris and leaves deposited on the Coanda screen are removed by water flowing over it and moving it on downstream. This makes screen cleaning machinery obsolete, and allows a reduction in the cubic capacity of the connected desander – in turn having a positive effect on hydropower plant profitability.

In addition to hydraulic steelwork for hydroelectric power stations, Gufler Metall has also been supplying various types of debris racks and rack cleaning machines for many years.

© Gufler

The Gufler Metall Coanda screen is made entirely of stainless steel – and in various designs. The fine screen retains particles of up to 0.5 mm in size. The Passeier industry specialists have been installing their Coanda systems for over 20 years, and experience has shown that these systems still run smoothly, even in midwinter at air temperatures down to -25°C.

COUNTER-RAKE SYSTEM PROVES ITS WORTH

Of course, there is still demand for classic Tyrolean weirs and various forms of inlet screens. Gufler Metall meets this demand with rake systems built using raw metal, hot-dip galvanised metal and stainless steel. Protective steel cladding and built-in residual water basins are also supplied on request. Similarly, there is still a need for modern screen cleaning machines, to which Gufler Metall responds with single and multiple telescopic versions, and with excavator arm screen cleaners. The experienced hydraulic steel construction

specialists from the Passeier Valley also supply the appropriate hydraulic drive systems – via hydraulic cylinders and power packs and, on request, produce electromechanical drives.

The hydraulically operated counter-rake deployed to clean the inside of Tyrolean weirs was ingeniously custom-designed and purpose-built by the South Tyroleans, using another rake that moves up from the base of the weir body and into the openings between the profile bars during the cleaning process. A hydraulic cylinder pushes the movable rake arm upwards at the pivot point, ensuring all the small material and debris that has collected on the rake or between the bars is transported to the surface and washed away. Although this is still not a common solution, it is extremely practical for water catchments exposed to heavy debris flow.

INTEGRITY AND RELIABILITY COUNT

Today there’s a long list of references confirming the dependability of the technical solutions provided by Gufler Metall. It includes the most important power plant projects in South Tyrol's recent past, and numerous projects in neighbouring countries. Renowned operators such as Vorarlberg's illwerke vkw, ÖBB and TIWAG in Tyrol, to name just a few, rely on the expertise and quality of these industry specialists from the Passeier Valley. The virtues of integrity and reliability, adherence to deadlines and a guarantee of supreme quality, still remain decisive factors in Alpine hydropower.

Gufler Metall’s trusty and powerful inlet rake with an underground counter-rake for cleaning and keeping integrated residual water basins free.

© Gufler

Certainly not an everyday rake cleaning system in Tyrolean weirs: The tried and tested counter-rake is pressed through the profile bars from below.

REVITALIZATION

– GLOBAL HYDRO REFITS OLD POWER PLANTS FOR MODERN REQUIREMENTS

Around the world today there are thousands of hydropower plants that are outdated or in need of modernisation. The task of transforming old power plants into state-of-the-art operations has created a market worth billions. However, success in this market is only reserved for hydropower companies with an immense wealth of know-how, experience and all the relevant expertise. Global Hydro is an Austrian industry specialist in the provision of flawless turnkey hydropower solutions, and is now in a position to deliver economically-mature technical solutions to guarantee the professional revitalization of every type of hydropower plant. Under the leadership of Thierry Burckhart, a highly-experienced hydropower professional, Global Hydro's revitalization department is active on a global scale.

There are numerous hydropower plants around the world that have been in operation for 100 years or more, and which fascinate tech enthusiasts to this day. Especially on closer inspection, it’s hard not to admire the engineering achievements of the original hydropower pioneers. Global Hydro is a highly-renowned Upper Austrian hydropower specialist and the company’s Head of Revitalization Thierry Burckhart shares this admiration: “Back then engineers didn’t have computers to assist them; just a pencil, a sheet of paper and engineering expertise; yet they managed to build power plants that operated for decades – and are still in operation. That’s an enormous achievement.” Nevertheless, the experienced hydro industry expert admits even the best main-

tained plants of the era are now showing their age, and can only meet the complex requirements placed on modern hydropower to a limited extent.

A BURGEONING REVITALIZATION MARKET

Often, as well as suffering the wear damage caused by sustained use down the years, the functionality of old systems is limited by other circumstances, too. Particularly in Central Europe, wherever possible, machine infrastructure was designed to accommodate the passage of the entire volume of a water body. A problem often found with old plants in times of residual water discharge requirements, and dosed volumes for up- and downstream fish passability, is the fact that the old machines are generally too large, so

they can no longer guarantee optimum operational efficiency. Another issue is posed at plants built in times of shortage, such as between the two world wars and shortly after the Second World War. During these periods, funding for new, customised and optimised turbines was scarce, so used machines were often reinstalled without further evaluation – operating reasonably well, but never at their best. Subsequently, these circumstances have created a market for infrastructural revitalization in Europe; and an opportunity that companies such as Global Hydro are well-prepared to seize. The all-round hydropower specialists from Upper Austria have identified an opportunity to utilise the expertise they have acquired in this field over decades. Now, consequently, the company's internal re-

Many old hydropower plants are in need of revitalisation. Global Hydro has its own revitalization department and with it the expertise and personnel to transform old plants into state-of-the-art operations.

© Global Hydro

sources and work processes have been adapted and expanded to accommodate this development.

CONSIDERATION OF MULTIPLE FACTORS

Old turbines may need to be redesigned, renewed and modernised, blades may have to be replaced and other components repaired. Whatever is required, Global Hydro offers a broad portfolio of services facilitating the provision of an all-round solution package –ranging from the refurbishment of individual parts to the full-scale revitalization of a hydropower plant. Customer benefit is always given the highest priority.

Efficiency and performance are not always the only items topping an operator's list of priorities. As Thierry Burckhart emphasises, several factors play a role in revitalization: “Nowadays, technically speaking anything is possible, but there are two other key factors at the centre of revitalization projects: Firstly, the physical structures at the plant. What do the structure and cubature of the existing infrastructure allow? Are there any restrictions on the remodelling of old listed facilities? This automatically feeds into the second key factor – that of economic viability for the customer. These are precisely the questions we discuss with customers to ensure we develop the right concept for each individual revitalization project.”

EXPERTISE AND REFERENCES REQUIRED

Thierry Burckhart, the experienced Global Hydro hydropower professional is convinced that today, as well as the technical skills, a great deal of experience is required: “Nothing is possible without many years of expertise, and the references that go with it.” Every ‘greenfield’ project – a new project built from scratch – is less demanding and complex than the revitalization of an existing plant. Both in

terms of technical realisation and, ultimately, with regard to areas such as documentation and customer interaction. Furthermore, as Burckhart explains, revitalization projects in particular rely on in-depth hydropower expertise. Solutions are identified with respected fellow specialists who know their plants inside out, and can discuss sophisticated issues eye-to-eye. Global Hydro is ideally equipped in this respect, having an exceptionally efficient design and manufacturing side, and being able to rely on a young, highlytrained team with interdisciplinary capabilities, knowledge of the respective markets and an excellent international contact network.

A SINGLE POINT OF CONTACT

In recent years, numerous reference projects have provided impressive proof of what this team is capable. Burckhart recalls a revitaliza-

tion project just a few years ago, carried out on a turbine built over 100 years ago: “Professional modernisation enabled nominal output to be increased by 36 % and annual production by 23 %.” He also mentions a project in Switzerland that achieved a double-digit percentage output increase by improving runner geometry. “One item in Global Hydro's favour is our extensive production line, enabling us to manufacture virtually every core component ourselves, beginning with proprietary runner design and certainly not ending with our own butterfly valves. Against this background, we have the best-possible control over an order – from start to finish. Moreover, as a turnkey specialist, we provide solutions without needing to coordinate with external firms. Heinz-Peter Knass, Managing Director of Global Hydro, explains how this allows the customer to

Significant efficiency optimisation of old systems is possible using modern hydraulic designs, as the engineers at Global Hydro regularly prove.

Francis runner in need of renovation State-of-the-art machines recondition runners back to good-as-new.

manage an entire project through a single contact person.” This is claim that’s true for the D-A-CH region, and the rest of Europe. Over the past few years and decades, Global Hydro has built up an excellent reputation within the industry as an expert provider of turnkey solutions. It’s a reputation upon which the company is able to build in the field of revitalization.

FORWARD-THINKING REVERSE ENGINEERING

Global Hydro’s many years of experience have also equipped the company to deal with machines originally built by other manufacturers. The company’s familiarity with all types of turbines, various sub-variants and their components, enables it to restore them to ‘asgood-as-new’ with ultimate professionalism. Sometimes the original plans for old power plants can no longer be located, but as Thierry Burckhart explains, this is not a significant obstacle for Global Hydro professionals: “The tools available to us today enable us to reverse engineer the construction process – and work in reverse gear, so to speak.” This means the machines are dismantled –without documents on the original geometry – and dissembled into their individual parts. Each of the parts is measured is subjected to ultra-precise measurement, and these data are used by engineers to generate new design

drawings. In the course of further material testing, the necessity of replacing a component is analysed if hairline cracks or wear are detected. Of course, the Upper Austrian hydropower specialists use only high-performance, state-of-the-art materials. Only the highest quality steels are used to guarantee component longevity. Innovative coatings like HVOF can also be applied if necessitated by

drive-water sediments. Strict quality management guarantees Global Hydro's solutions always meet the highest quality standards.

XXL RUNNERS? NO PROBLEM!

Global Hydro’s versatility in the revitalization segment is also reflected in the ability to accommodate a comprehensive range of runner dimensions. According to Thierry Burckhart, who has been working successfully in the hydropower sector for 37 years: “In the revitalization sector it’s no problem for us to handle runner sizes from small to large, even up to a capacity of 50 MW. We recently completed a project in Austria that required two 22.5 MW pump turbines, and can refer back to projects in Scandinavia with extremely large output ranges.”

Thierry Burckhart continues, pointing out that Global Hydro has been very successful in positioning its new EVO turbine series on the market, especially in Scandinavia, where old propeller turbines are now gradually being replaced. The new Kaplan EVOline turbine is ideal for the purpose, as it minimises the need for conversion work on existing structures – as does the Francis EVOline, too.

INTO A NEW ERA WITH HEROS

Turbine control systems also deserve special attention as they bear primary responsibility for ensuring turbines constantly operate at optimum capacities. In this regard, one key consideration is the fact that innovation in control technology and software development is far more rapid than in turbine construction. Resultantly, new technologies are constantly appearing on the market, enabling operators to maximise plant yield and minimise main-

Francis runner with cutting-edge HVOF-coating

In action in Scandinavia: In Sweden in 2021, Global Hydro completely revitalized the Mälarenergi Vattenfall Jäder power plant machine set. An old Kaplan runner was replaced with a modern Kaplan turbine fitted with a 2.3-metre diameter runner. At an expansion flow rate of 25 m3/s and a head of 4.95 m, the machine now generates an output of 1087 kW. This project enabled the power plant to enter a new era.

tenance intervals. Furthermore, the energy market is in a constant state of flux, continuously offering up new opportunities for yield optimisation. There are new opportunities to optimise energy yields, and ultimately a plant’s regular overall output, as well as new demands and requirements, such as new grid codes. There are certainly enough reasons today for hydropower operators to guarantee their control systems are up-to-date. The Global Hydro HEROS power plant management system is a state-of-the-art digital solution for the operational handling of hydropower infrastructure. It controls, monitors and optimises the entirety of plant operations. The latest version of HEROS can be equipped with an IoT (Internet of Things) gateway to transmit the operating data to dedicated cloud infrastructure, from which it is read and used for two purposes: The first is the analysis of data supported by machine learning to maximise production and detect any anomalies at an early stage. Early detection of deviations in readings can reduce maintenance time and repair costs, and lower the risk of failure significantly. The second is the use of data to visualise situations in the IoT SCADA HEROS Connect system. “HEROS Connect allows operators to visualise, analyse and control all systems on a single platform. The software facilitates the utilisation of previously unexploited synergies,” Managing Director Heinz-Peter Knass declares. Another significant benefit offered by the system is that both solutions – machine learning-based data analysis and HEROS Connect – can be used regardless of the control system manufacturer, so it is not necessary to install a HEROS control system. This provides a simple way of modernising outdated, obsolete control systems, particularly in the event of comprehensive revitalization, while keeping the requisite financial investment, construction work and downtimes to an absolute minimum.

ALTERNATIVE SOLUTIONS

Global Hydro’s expertise in handling international revitalization projects has also enabled it to play an active role on the American and Canadian markets, where the technical requirements are somewhat different: Especially at the beginning of the 20th century, so-called ‘camelback’ turbines were frequently installed at low-pressure locations on the North American continent. Since the Kaplan turbine had not yet been invented, or become the all-conquering installation on the global market, camelback turbines were the only viable technical solution for locations with high flow rates and low heads. The name ‘camelback’ refers to the fact that several Francis runners are installed on a single shaft, usually two or four, occasionally even more. The name ‘camelback’ turbine refers to the arrangement of the intake manifolds. This

specific type of turbine has reached the end of its working life in many parts of North America, and has gained a reputation of being inefficient, prone to faults and malfunctions, and in need of modernisation. Consequently, Global Hydro is keenly aware of the revitalization potential in this segment.

OVERALL ECONOMIC EFFICIENCY

Fundamentally speaking, the vast majority of revitalization projects focus on two premises: increasing efficiency and minimising downtimes. At Global Hydro engineers utilise their entire portfolio of services to this end. Thierry Burckhart summarises: “We consider the overall economics of every project. So alongside all the technical issues, there’s also the question: How much operational downtime will there be during plant conversion? Only when all aspects are taken into account is it possible to compile the perfect revitalization package for a customer.”

Similarly, Managing Director Heinz-Peter Knass confirms that in the years ahead emphasis will be placed on revitalization. “Strictly speaking, we have been providing revitalization services for decades, but for a long time there was no separate department and no specialised staff exclusively dedicated to this important area. This has changed with the establishment of the revitalization department at Global Hydro due to the sharp increase in demand. Customers can rely on the quality and services we guarantee for green field and revitalization projects.”

For more information, please contact our experts: revitalization@global-hydro.eu

Global Hydro's machine learning-based data analysis enables any damage to be identified very early, reducing failure risks and repair costs. Here is a generator undergoing bearing vibration analysis.

The HEROS power plant management system optimises hydropower plant operation.

WILD METAL SCREEN CLEANING TECHNOLOGY IMPRESSES ACROSS A WIDE RANGE

OF APPLICATIONS

Wild

Metal

GmbH of Ratschings

in South Tyrol is an acknowledged hydropower industry specialist for sophisticated hydraulic and mechanical engineering – and not without good reason. The company provides for a wide range of hydro-mechanical application scenarios with a comprehensive solution portfolio. The South Tyrolean industry experts’ success is explained in part by their customised solutions, supreme technical standards and flexibility in project management. Wild Metal‘s hydraulic steel structures now offer practical benefits throughout the Alpine region, and on an international stage. The rake cleaning sector provides a comprehensive overview of the technical expertise provided the South Tyrolean hydraulic steel construction professionals.

As industry specialists in hydraulic steel construction, we understand the individual requirements and challenges facing the sector, offering tailor-made, customer-specific solutions that reflect our flexibility and customer-centricity. The many years of experience and the innovative strength we offer make us the right choice for all hydraulic steel construction requirements – as we make plants more efficient, safer and more sustainable, while meeting the strictest quality standards,” emphasises Wild Metal Managing Director Markus Wild. Furthermore, Wild highlights the central importance of hydromechanical engineering at the intake area of a power plant. It’s undoubtedly a good thing if one or two extra percent of turbine and generator output can be achieved via technical optimisation, but if not all of the drive water reaches the machine set due to restrictions at the inlet area, machine efficiency optimisation fails to achieve the desired result.

CUSTOM-BUILT SCREEN CLEANERS

Project Manager Daniel Polig points out that Wild Metal trash rack cleaning machinery functions well and is highly reliable, allowing the often extreme demands of alpine hydropower systems to be met: “It’s very important for us to provide robust, low-maintenance, highly-functional infrastructure that also impresses with external aesthetic appeal. Customers can choose from a variety of electro-mechanical and oil-hydraulic solutions. Similarly,

environmental compatibility and sustainability play an important role in every project we develop.” Accessibility to spare and wear parts, and to components that require maintenance, is a major priority integrated at the basic design stage. “The robust and stable design of screen cleaning machinery guarantees a long service life, even in situations subject to the most adverse conditions – in turn reducing operating costs and increasing the operational reliability of a system,” Polig explains.

BESPOKE ARTICULATED ARM RAKE CLEANER

Last year, Wild Metal realised one of its most recent reference projects in articulated arm

screen cleaning technology for the Schattwald power station in the north-eastern part of Tyrol. As part of a large-scale revitalisation project, the old screen-cleaning system at the Vilshofen storage power plant water intake was replaced with a modern articulated-arm screen cleaner using an oil-hydraulic drive. The South Tyroleans equipped the machine with a grab rake, and all the sensors needed for triggering a fully automatic cleaning cycle. “The limited availability of space at the water intake necessitated precise planning and implementation in order to optimise integration of the articulated arm cleaner to work with the rake debris container. The problem was

© Wild Metal

© Wild Metal

The new articulated arm screen cleaner ensures free flow at the Vilshofen day storage tank.

Wild Metal manufactured a bespoke-design articulated arm screen cleaner for the water intake at the Vilshofen storage power plant in Tyrol. This included a protected pedestrian passage and built-in screen debris container.

solved with a customised, innovative solution,” says Daniel Polig: “The existing situation had been particularly challenging. It was necessary to dismantle the roof structure of the factory building above the intake screen to make room for the machine‘s articulated arm.” These extreme conditions necessitated a solution tailored to handling floating material removed from the protective screen. Wild Metal designed a special screen debris container with a built-in footbridge protected by a hood structure of Corten steel to meet these requirements. Corten steel is weather-resistant structural steel. Oxidation due to weathering causes a layer of rust to form on the surface. This protects the underlying structure from corrosion damage. After cleaning, the grab rake moves debris into the container positioned behind the protected pedestrian bridge. The machine’s automatic setting offers two operating modes: Normal operation activates a pump unit with an output of 11 kW. In the event of flooding, a second 11-kW-output pump unit is switched on to ensure demandorientated, flexible and efficient operation. The floodwater set-up allows a full cleaning cycle to be completed in less than 2½ minutes. Special attention was also paid to the energy efficiency of the machine with the installation of a proportional valve hydraulic unit fitted with a variable displacement pump.

OLD POWER PLANT –

NEW HORIZONTAL SCREEN CLEANER

Wild Metal supplied an archetypal example of a horizontal screen cleaner in the Swiss canton of St. Gallen for the almost 120-year-old

Lienz hydropower plant on the Rheintal inland canal. The project was initiated by plant operator St. Gallisch-Appenzellische Kraftwerke AG (SAK), as the canton required a solution to guarantee a free-flowing continuation of up- and downstream fish migration at the power plant. The project, implemented between October 2021 and November 2022, involved the construction of a technical vertical slot pass fish ladder, and the redesign of the entire intake area. In addition to sup-

plying a trash rack cleaning system, Wild Metal’s scope of delivery encompassed provision of the complete hydraulic steel construction equipment, a weir flap and a special fish ladder. The flap design was reminiscent of a funnel, producing a higher flow velocity towards the end of the funnel, ultimately beneficial for the descent of the fish. SAK project manager Christian Neff describes two significant improvements achieved at the power plant intake on installation of the fish-friendly 18.5 m

© Wild Metal

In the canton of St. Gallen, Wild Metal equipped the redesigned intake area of the Lienz power station on the Rheintal inland canal with a complete hydro-mechanical package.

© Wild Metal

The South Tyrolean industry specialists’ innovative screen cleaning solutions are in international demand, too. The picture shows a chain screen cleaner in operation in Iceland.

The new horizontal screen cleaner at the Lienz power station provides a wide range of operational benefits.

© Wild Metal

wide and 1.75 m high horizontal screen, and of the hydraulically operated screen cleaner:

“The conversion means the intake area has now been equipped with a horizontal protective screen and associated screen cleaning machine, instead of a coarse screen and a fine screen positioned further downstream. This is an enhancement on an operational level, but also offers benefits for SAK plant operators. Prior to conversion, in the event of blockages the coarse screen had to be laboriously cleaned by hand. Workers had been required to be roped and harnessed for safety reasons. The new screen cleaning system means these efforts are now a thing of the past.”

COMBINED TYROLEAN WEIR AND COANDA SYSTEM

Wild Metal again demonstrated its expertise in innovative hydraulic steel construction and trash rack cleaning solutions during the construction of the new small hydropower plant in Dürrenbach, Vorarlberg, which was officially opened in summer 2023. The pro-

ject, realised by regional energy supplier illwerke vkw, is a classic diversion power plant in which, after being extracted from the watercourse, the headrace water is channelled through a penstock to the 6-nozzle Pelton turbine in the powerhouse. The water intake was fully equipped by Wild Metal, and built at an existing torrent stabilisation stage along the eponymous Dürrenbach. It was not possible to build a desanding basin, usually used for plants of this size, due to the limited space available at the site. Consequently, the South Tyrolean industry professionals were required to provide a special solution. Wild Metal manufactured a Tyrolean weir for the discharge of the headrace water, whose solid protective grid is cleaned by an internally-mounted counter-rake. The fully-automatic screen cleaning system is driven by a total of seven hydraulic cylinders, ensuring reliable weir surface cleaning. The motive water then flows directly to the eight-field ‘Grizzly Power Optimus’ coanda system. Developed and paten-

ted by Wild Metal, the system features a largely self-cleaning protective screen for use in the drinking water and hydropower sector. The fine screen has a minimum gap of just 0.6mm and is made of special abrasion-resistant stainless steel. The system is named after, and works according to, the Coanda principle, so debris such as tree needles, moss and fine grains of sand are automatically flushed away from the rake surface by the water flow.

AN EXPERT PARTNER

In principle, Wild Metal‘s portfolio is as bespoke as the design of every hydropower plant. A more comprehensive list of the South Tyrolean company’s technical solutions currently in operation throughout Europe would far exceed the scope of this article. One thing is certain; hydropower operators seeking industry experts that offer top-quality hydraulic steel construction equipment – and finding Markus Wild and his team – have come to the right place.

© Wild Metal

Peter Kritzinger, a Wild Metal fitter, assembling the Tyrolean screen at the Dürrenbach power plant. The screen is cleaned by a hydraulic counter-rake within the structure.

UNLEASHING THE DIGITAL POTENTIALS OF ELECTRIC ACTUATORS

Electric actuators frequently perform key functions in modern hydropower plants. No matter whether they are used for water level regulation at the power plant inlet or at the fish ladder, for shutting off pipelines or for precise turbine control – to ensure smooth hydropower plant operation it is essential that these actuators work correctly and reliably.

For plant operators a key requirement is therefore to be able to evaluate the health status of their actuators at any time in order to stay alert to maintenance requirements and thus ensure long-term operational reliability and safety.

Modern digital solutions such as CORALINK, the AUMA digital ecosystem, provide the basis for this. CORALINK offers a number of smart software modules that allow plant operators to use their AUMA actuators efficiently and ensure their reliable operation.

ENSURING AVAILABILITY

At the heart of CORALINK is the ability to evaluate the extensive operating data that

AUMA actuators record automatically. Data such as the number of starts, motor run time, torque, temperatures and any fault codes give valuable information on the health status of the actuator. Plant operators can easily read out this data from their actuators by using the AUMA Assistant App on a smartphone, and then upload the data to AUMA Cloud for analysis.

As a result of the automated data analysis plant operators receive a detailed action plan with recommendations for each actuator. Plant operators can take appropriate action on time and thus avoid unplanned downtime.

SAVING TIME AND COST

CORALINK also offers a lot of useful functions for AUMA actuators that save time and money in daily plant operation. Hydropower plant operators benefit from an asset overview that shows all the information about their AUMA actuators at a glance. They can quickly and easily order spare parts, request support from AUMA service engineers, and keep track of their service requests. AUMA Assistant App allows users to quickly and in-

tuitively configure, commission and operate their AUMA actuators.

Users can test CORALINK free of charge in a very comprehensive basic version. More information is available at coralink.auma.com

CORALINK’s automated analysis and diagnostics of actuator data result in an action plan with detailed recommendations for each actuator.

CORALINK, the AUMA digital ecosystem, includes software modules such as the AUMA Assistant App, AUMA Cloud and AUMA Commissioning & Diagnostic Tool (CDT), ensuring efficient operation and long-term reliability of AUMA actuators.

AUMA actuators play a key role in reliable operation of hydropower plants.

© AUMA

AUSTRIAN SCREEN CLEANING TECHNOLOGY

REPEATEDLY SUCCESSFUL IN INTERNATIONAL FIELD TESTS

Künz GmbH of Vorarlberg, Austria’s westernmost province, has been providing screen cleaning machinery for the hydropower market since the mid1960s. The company has remained true to one principle to this day: An ideal trash rack cleaning machine is one that has been closely adapted to a customer's wishes and requirements. Künz supplies carefully customised screen cleaning machinery – especially to medium-sized and large-scale plants. A vast wealth of experience gained over more than half a century has made the Vorarlberg-based company one of the leading suppliers in this field – and justifiably so. Künz technology now enjoys an excellent international reputation, too.

The Ryburg-Schwörstadt run-of-river power station is located fairly near the headquarters of Künz GmbH in Vorarlberg. Today, the German-Swiss border hydropower plant, built between 1927 and 1931, is still regarded as a technical masterpiece. At a total output of 120 MW it is still the largest such plant on the High Rhine. Recent modernisation of the headrace area also incorporated a much-needed renewal of the plant’s screen cleaning and crane technology. This was an ideal case for an experienced industry expert like Künz due to the need for outstanding expertise in screen-cleaning technology, and a concept that seamlessly integrated proven screen cleaning infrastructure with the existing power plant cranes – such as the dam gantry crane. In more detail, the two existing screen cleaning machines were replaced with a powerful R100 cable screen cleaning machine unit to meet high performance and availability requirements. Debris is discharged into a standard roll-off container borne by the screen cleaning machine. The containers are provided at the storage area, from where they are transported to the screen cleaning machine with the dam gantry crane. This ensures efficient screen cleaning without any loss of time. In the event of flooding, the additional loading crane mounted on the dam gantry crane enables surface debris to be removed independently of the existing screen cleaning infrastructure.

The additional refurbishment by the Künz retrofit department of the heavy-duty powerhouse cranes, originally installed in 1929, was a particularly noteworthy achievement. This returned the crane to state-of-the-art status, consequently enhancing the performance of the entire system. The decision to refurbish the heavy-duty crane further underlines the significance of retrofit solutions to the industry, and highlights the immense demand for modernised cranes. The ability to offer customised solutions has made Künz

a popular choice in this field. A retrofit is both cost-efficient, and sets an example in sustainability and responsibility. At the Ryburg-Schwörstadt power station, Künz provided operators with a comprehensive solution, modernising its entire load-lifting capabilities.

UPPER SALMON HYDROPOWER STATION

The Austrian company has also established its expert credentials overseas multiple times; most recently at the Upper Salmon power

© Künz © Künz

The existing screen cleaning machines at Ryburg-Schwörstadt power station were replaced by a modern version of the Künz R100.

Künz also modernised the existing heavy-duty cranes at Ryburg-Schwörstadt power plant.

plant in the US state of Idaho. Built in 1937 and 1947 respectively, the overall 4-turbine infrastructure generates an output capacity of 35 MW. The specific project remit was to replace the existing telescopic screen cleaning machine with an ultra-modern Künz RRM-H500 –another milestone achievement for Künz. Due to the structural conditions created by the existing infrastructure, it was necessary to implement a special half-portal to enable the RRM-H500 to clean the inlet at maximum efficiency. Debris is discharged straight into a dump truck, ensuring optimised operation.

A particularly significant aspect of the project is the fact that an almost identical trash rack cleaning machine was implemented at the plant further upstream, emphasising the versatility and effectiveness of the technology deployed. Delivery of the sixth trash rack cleaning machine for the hydropower operators at Idaho Power has enabled Künz to consolidate its position as a leading provider of innovative hydropower plant cleaning solutions on the American and Canadian markets.

WIPFELD HYDROPOWER STATION

Künz recently provided further proof of its expertise in screen-cleaning technology at the Wipfeld power plant on the River Main in Germany, a hydroelectric plant that went into operation in 1951. Today, the power plant operated by Uniper supplies enough electricity for around 5,700 average households. Künz replaced the previously fitted cablescreen cleaning machine with a design-adapted RRM-H200. A special half-portal was installed in response to the structural conditions of the building, and now the RRM-H200 can guarantee the inlet is cleaned efficiently. Collected trash is discharged straight into a new debris pit. Installation of the first H200 unit along the Main River is evidence of Künz's presence in this key region. Another two H200s

have also been produced for Uniper power plants on the Main River, and installation is scheduled for this year.

Successful completion of these projects reaffirms the confidence shown by customers in the quality and performance of Künz products. Künz provides answers to the challenges faced by the hydropower industry with an innovative spirit, state-of-the-art technologies and ideallycustomised solutions.

© Künz

A Künz H200 was installed at Main Power Station in Wipfeld, ensuring the inlet is cleaned effectively.

ACOUSTIC MULTI-PATH FLOW METERING IS BECOMING STATE-OF-THE-ART

Modern hydropower utilization would be quite unthinkable without high-precision flow metering systems. Data collected this way provides the basis for a variety of processes in areas from control technology to safety, ecology, and operational optimisation. Ultrasonic flow metering technology, in particular, has advanced immensely in recent years. Especially the use of multiple acoustic paths and related self-diagnostic options has convinced numerous users of the many benefits, such as high-level precision, wear resistance, low operating and maintenance costs, and long-term stability.

In terms of both quality and quantity, the availability of water is a crucial economic factor in every part of the world. Aside from its importance for domestic use, water it is also essential for agricultural irrigation, as a medium for industrial processes, and as a fluid used for energy production and serving as a coolant. Considering that the globally available water volume remains constant, with irrigation consuming 69 % and industry (including energy production) using 18 % of the overall amount available for human use, the rising demand for freshwater resulting from population growth is set to further take its toll on existing water resources. Studies predict a 40 % deficit between available worldwide water resources and human consumption alone by 2030 (source: The 2030 Water Resources Group).

Apart from irrigation, a significant increase in the demand for water is also being predicted for industrial purposes and energy producti-

on. The accelerated rate of urbanisation, as well as the expansion of municipal water supply and sewage systems, contribute further to the rising demand. As a result, the competition for water resources is likely to intensify between agricultural irrigation and industrial use, as irrigation utilises freshwater with only around 45 % efficiency.

IN HIGH DEMAND FOR MANY APPLICATIONS

High-precision flow metering is set to rise in importance across the board: not just in agricultural irrigation but also in industrial areas, for wastewater disposal billing, in energy production for the use of cooling water, in hydropower generation, for effluent water processing, sewage storage management, water processing for urban landscaping, street cleaning, and water purification for domestic use.

• Wherever it is used, high-precision flow metering helps to provide understanding of

existing systems, localise points of water loss in channels or pipes, optimise processes, control supply networks, and ensure fair, transparent billing.

• Flow metering systems that have only been tested under laboratory conditions are no longer up to the job. What is needed today are metering instruments that deliver a high level of precision under local conditions without the need for on-site calibration.

• Every drop counts when it comes to ensuring a sufficient water supply for everyone, both now and in future.

ACOUSTIC FLOW METERING

Acoustic (ultrasonic) flow metering technology has advanced by leaps and bounds over the last few years. The introduction of acoustic multi-path methods and self-diagnostic capabilities have especially boosted market accep-

Acoustic flow metering systems enjoy a long-standing reputation as a highly accurate and reliable method for determining turbine efficiency.

tance. Multiple acoustic paths are used to measure the cross-sectional flow velocity in several locations, providing highly accurate flow rate readings. In case of flow disturbances, this method eliminates the need for the upstream/ downstream straight lines that are typically required by traditional technologies. This is a key factor to be considered when retrofitting flow metering systems in existing buildings when space is rather limited. By using the acoustic method, adaptations and extensions to existing building structures can be avoided, which drastically reduces the overall investment in a flow metering solution.

Acoustic multi-path systems are well established in the world of hydropower as an in-situ measuring method for monitoring the efficiency of turbines (with an error margin of ≤ ±1 %). This standard is defined by two norms/guidelines:

• ASME PTC 18-2020, hydraulic turbines and pump-turbines, Performance Test Codes

• CEI/IEC 41:1991, Filed acceptance tests to determine the hydraulic performance of hydraulic turbines, storage pumps and pump-turbines

Current high-precision acoustic flow metering systems come in two versions: inline systems and insertion systems. Owing to their wide scope of application and high metering precision, the annual market share of acoustic systems (besides coriolis flow metering devices) is growing more strongly than that of other physical methods such as differential pressure, electromagnetic, turbine impeller, turbulences, and others.

ACOUSTIC PATHS

Insertion systems are used primarily for large-scale pipes (> DN400). Depending on the number of acoustic paths, if the pipe wall is thick enough, the sensors are screwed in directly at specific points. In thinner-walled pipes, additional welding studs are used for stability. Compared to a traditional in-line flow meter this approach does not rely on the calibration of the overall system on a testing station. Instead, the level of accuracy is determined by the quality of the installation and on project-specific parameters that have to be measured on-site and fed to the system. For example, the acoustic path lengths, angles and sensor positions have to be measured to millimetre precision and provided to the system. In addition, the pipe diameter has to be measured to a high degree of accuracy at differing cross-sectional points along the pipe. The penetration deviati on of the sensors must be quantified by the

manufacturer and has to be taken into account when calculating the volumetric flow. Using such an approach, experience from numerous installations shows that using 8 acoustic paths and a straight pipe stretch of 5*D upstream and 1*D downstream of the metered cross-section point will keep the margin of inaccuracy at or below ±0.5%. For longer straight pipe stretches or when using additional metering paths, the error margin may be as low as ≤ ±0,15 %.

Ultrasonic flow metering devices excel in many respects:

• The underlying metering principle is equally applicable to fluids, gas and steam flows

• The accuracy and reproducibility of measurements is independent of fluid-specific characteristics, such as viscosity, temperature, density, and electric conductivity

• There are no moving parts extending into the metered pipe

• The systems don’t wear out

• Operating and maintenance costs are low

• The method provides excellent long-term stability

• The need for re-calibration is eliminated

• Redundant metering paths ensure highly reliable results

• The devices cover a very wide dynamic metering bandwidth

• Very low and very high flow rates can be measured accurately without the need for

INSERTION SYSTEMS WITH MULTIPLE

The Ductus insertion flow metering device by GWF Technologies GmbH, in a hydropower plant (using 4 paths).

Installation of an acoustic flow metering device by GWF Technologies GmbH in a hydropower plant (using 8 paths).

introducing constrictions in the pipe cross section, which otherwise reduces the loss of pressure and therefore the amount of energy expended on pumping

ENABLING SELF-DIAGNOSTICS

The most crucial benefit, however, consists in the fact that when using multiple acoustic paths, the flow velocity is measured at different points of the cross section, which provides valuable information on the existence (or non-existence) of distortions in the velocity profile. Information like this can then be used to calculate the volumetric flow with the help of integration methods. In addition to flow velocity, ultrasonic flow metering systems can also be used to measure other parameters, such as the speed of sound in the fluid, enabling self-diagnostic. This way, differentials between the individual metering paths can be detected independent of the flow velocity, and possible preventive maintenance measures can be suggested as a result.

Where certified metering precision is concerned, customers have traditionally put their trust in a ready-made pipe section with a test certificate. However, there is a growing awareness among users that the metering precision determined this way may deviate considerably from actual on-site metering values.

Whilst there is undoubtedly some further persuasion to be done, the growing adoption of acoustic flow metering using sensors that are installed and calibrated in-situ brings significant advantages in terms of accuracy and cost benefit.

For 125 years highest accuracy. We measure everywhere, from rivers to drops.

Ultrasonic flowmeters for field performance and acceptance testing, leakage monitoring and pipe burst detection.

The Ductus insertion flow metering device by GWF Technologies GmbH, in a water supply facility (using 6 paths).

provides

tailored solutions to suit

INDUSTRY PROS FROM UPPER AUSTRIA MANAGE TO IMPRESS WITH INNOVATIVE SCREEN CLEANING TECHNOLOGY

For decades the trash rack cleaners by Upper Austrian steel and mechanical engineering specialist Braun Maschinenfabrik have been inspired by a guiding principle: The ideal screen cleaning machine is the one that is perfectly suited to local on-site conditions while meeting all the customer’s needs and wants. Innovation-focussed ingenuity, flexibility, and a high level of knowledge and quality have earned the long-established firm from the Upper Austrian town of Vöcklabruck a reputation as one of the industry’s foremost providers of optimised solutions for reliable, efficient inlet grate cleaning.

Floating debris, such as leaves, waste material, deadwood or various sediments, can cause serious obstructions and reduce the rate of water flow at the screen, as well as the plant’s economic viability, as a result. To tackle problems like this head-on, experts in the hydropower industry have come up with various types of screen cleaning machines (sometimes also referred to as trash rack cleaners). Today these machines operate more or less fully automatically, ensuring ultimate reliability and convenience for the operator. Depending on the requirements imposed on screening systems used in the intake area, a variety of different screen cleaning solutions have come on the market over the last decades. The designs basically range from various versions of hydraulic screen cleaners and

rope-operated models to horizontally moving machines. It takes extensive special knowledge for a provider to cover the entire spectrum of types and versions with their portfolio. After all, what is needed is not just the solid competence in experienced mechanical and hydraulic steelwork engineering but also extensive expert knowledge of hydropower operations. Braun Maschinenfabrik, which is headquartered in the Upper Austrian town of Vöcklabruck, has incorporated all this knowledge and has been ranking as one of the industry’s top providers for high-quality screen and screen cleaning solutions for many decades.

NO ‘OFF-THE-SHELF’ SYSTEM

Finding the optimum screen cleaning solu-

tion for a specific site requires the experience of a seasoned mechanical engineer who knows how to take the specific ambient conditions into account. This is because the screen cleaning quality depends crucially on three key factors: the clear bar spacing of the fine mesh grating; the hydrological dynamics in front of the screen (i.e., the possible build-up of turbulences); and the obstructional density of accumulated floating debris. A thorough evaluation of all of these factors tells the experienced mechanical engineer which type of machine is the proper choice for the site in question. Building on the extensive experience of more than 60 years, Braun Maschinenfabrik’s portfolio today covers the entire range of common screen cleaner types and versions, in addition to individually custom-enginee-

© Braun

Braun Maschinenfabrik

custom

any requirements when it comes to efficient screen cleaning. Picture: 3D graphics of a fully mobile dredging screen cleaner on a support base, one of a wide range of screen cleaner models in Braun Maschinenfabrik’s portfolio.

red solutions. Ready-made off-the-shelf solutions are clearly out of the question for the long-standing provider from Vöcklabruck. Instead, they stand by their maxim that individual requirements call for individual technical solutions. Braun’s engineers are committed to the continuous further development of the machines – a testimony to their creatively innovational skills.

DURABILITY MAKES FOR OPERATIONAL SAFETY

Like many others in the industry, Braun Maschinenfabrik had modest beginnings as a provider of cleaning machines. In the late 1950s, they had already begun to professionalise and leverage their knowledge of mechanical and hydraulic steelwork engineering to repair and re-engineer screen cleaning machines for the firm’s own hydropower plants. This provided the initial spark that eventually set off the systematic build-up and success story of a whole new business unit as the foundation for the excellent reputation still enjoyed by Braun’s screen cleaning machines today. A key success factor of Braun screen cleaning systems is their highly durable design. Solid, high-quality sheet metal and components, the firm’s own certified welding technology, and proven hydraulic solutions combine to ensure superior stability, ultimate operational safety and long product lifecycles. Braun also acts as a singlesource service provider for everything from project planning and construction to static analysis and electrical planning. The systems are manufactured and pre-assembled at Braun’s

facilities in Vöcklabruck. It’s thanks to qualities like these that ensure that the technical solutions provided by the Upper-Austrian specialists are fully and seamlessly integrated. No wonder, then, that systems by Braun Maschinenfabrik tend to weigh a little more than others. However, the additional weight comes with a great advantage. Compared to the more flimsily constructed machines that are also

found on the domestic market, Braun’s solutions are not only proven to last much longer, they ensure reliable operation even under challenging conditions. When talking with experienced hydropower operators, there is one sentence that comes up frequently: “This machine is unbreakable.”

OPTIMUM RESULTS ALSO IN HORIZONTAL ALIGNMENT

As a result of new discoveries in fish ecology, among other things, the last few years have seen an increased use of horizontally moving screen cleaners, especially in the context of low-head facilities. The narrow bar spacing of 15 to 30 mm, combined with a low flow velocity, makes it easy for fish to escape the pull of the inlet grate and swim to safety. To ensure an economically viable hydropower operation, hydraulic steelwork engineering specialists like Braun Maschinenfabrik have begun to optimise the streamlined design of the bars. The bar gratings of the horizontally aligned screen cleaners are fitted perfectly to this type of bar design. Best of all, Braun’s horizontally aligned screen cleaning machines are designed specifically for a fully automated cleaning process. Custom solutions are always available on request.

SPECIAL SOLUTIONS: BRAUN’S STRONG POINT

Technical special solutions are a definite strong point of the Upper Austrian hydro-steelwork specialists. The firm’s long history includes a sizeable list of worldwide reference projects involving custom designs to meet special re-

© Brraun

© zek Archiv

Horizontal rakes are preferred for their fishfriendly design, among other things. The engineers at Braun Maschinenfabrik have developed a powerful, innovative version for this purpose.

Fully mobile trash rack cleaner with hydraulic cantilever arm, designed for the Lehen bottom sill section of the hydropower plant on the Salzach river in Salzburg, Austria.

quests and individual requirements. One example is the design of special grasping arms fitted with tailor-made hydraulic jibs, optionally equipped with integrated grappling hooks, which enables the removal of particularly unwieldy floating debris in front of the intake area. It is primarily their high level of flexibility and engineering skills that have earned Braun Maschinenfabrik the reputation as one of the industry’s top providers when it

comes to special designs or replacement designs for old systems. Many customers also prefer to draw on the expert knowledge of the specialists from Vöcklabruck in dealing with issues of automation or renovation.

The same applies to the disposal of floating debris, for which Braun have developed a range of different solutions. From channel system with matching scavenging pumps to conveyor belts, scrapers and containers, there is hardly

Innovations for hydropower

any solution that Braun have not implemented successfully so far. To ensure proper further development along the way, Braun collaborate closely with renowned energy providers that contribute their extensive knowhow and latest concepts to the construction process.

PROVEN ALL OVER THE WORLD

Besides a great deal of innovational spirit, screen cleaning machines by Braun Maschinenfabrik also incorporate more than 60 years of expert experience. Their screen cleaning systems bring together tradition and innovation in a way that is unmatched by other machines on the hydropower market. Supported by their experienced team of engineers, Braun is able today to offer all common types of screen cleaning machines in any size. It has also happened time and again that they developed special solutions to meet particularly challenging requirements when other providers had already given up. It is qualities like these that have earned the team from Vöcklabruck an excellent reputation in the industry, with a long list of reference projects to prove it: today, Braun screen cleaning machines are found not only in the German-speaking regions but throughout Europe, Asia and the Americas.

Braun also provides the perfect screen cleaning solutions for smaller-sized intake areas.

PELFA GROUP ESTABLISHED AS A RELIABLE MANUFACTURER OF LARGE HYDROPOWER COMPONENTS

The Pelfa Group is a long-established business with headquarters near the northern Italian city of Udine. In more recent years it has enjoyed great success specialising in the production of high-quality hydropower components. Offering expertise in all areas of steel processing, its customers include companies in the steel sector, oil and gas, offshore and construction. The Italians are held in high regard by numerous international turbine manufacturers. PELFA has earned its excellent reputation by providing outstanding quality, high material reliability, efficient order processing and customer-orientated service. Over the past decade machinery investment programmes, continuous training and ongoing education for employees have equipped PELFA to manufacture components for the large hydropower sector – producing items with diameters of up to 8 m and weights of up to 100 metric tons.

The Pelfa Group was founded by Redento Fabro in 1979. Over the course of its over 40-year history it has established itself as a reliable manufacturer in various industrial sectors. The steel construction experts offer a portfolio that covers the entire production process and a whole range of components; from order confirmation to the turn-key end products. The Italians’ sustained success is explained by their comprehensive capabilities in the field of industrial steel processing. All work steps are carried out at a single location – from plasma cutting, welding, bending, CNC milling and painting to final assembly. In terms of staff, PELFA relies on qualified skilled workers, of whom some actually completed their apprenticeships at the company. Management considers skilled employees its most valuable asset.

A RELIABLE PARTNER

In the more recent past, this long-established company has increasingly specialised in the production of superior-quality components for the hydropower sector. Significant investment in production capacities and employee training have ensured PELFA is also able to manufacture components at diameters of up to 8 metres, and weights of up to 100 metric tons – parts in demand across the entire large

hydropower sector. In order to manufacture these large-format components the company optimised numerous procedures – in material procurement, cutting and welding technology, thermal treatment, mechanical processing, painting and the factory assembly departments. An experienced technical order and inspection processing team is also responsible for the preparation of relevant documenta-

tion, and undergoes continuous ongoing training in numerous training courses.

SPECIALISED IN MARTENSITIC TURBINE STEEL

Martensitic turbine steel

1.4313 (X3CrNiMo13-4) is a rust- and acid-resistant chromium-nickel steel alloy with added molybdenum and medium-level corrosion resistance. Its toughness ensures 1.4313 can serve a wide

Generous investment in production capacities and specialised employee training have enabled the Italian Pelfa Group steel construction experts to meet large hydropower plant sector requirements.

© all Photos: Pelfa Group

Runner ring for VERBUND AG – Austria’s largest hydropower operator.

range of applications and the ever-increasing demand for highlystressed components in turbine construction – such as runners, housing and components exposed to abrasive water. PELFA takes these needs into account and has become a specialist in material properties and requirements for procurement, testing and steel structure manufacturing. Steel thicknesses of up to 100 mm are required for certain applications, such as heavy runner rings, and are only available via specialised rolling procedures in selected steel and rolling mills. Ongoing staff training and internal quality assurance optimisation now enable PELFA to meet the special manufacturing requirements of large hydropower plant operators and to deliver workpieces of the highest quality.

COMPLETE ASSEMBLY AND INDIVIDUAL COMPONENTS FOR A WIDE RANGE OF APPLICATIONS

In practice, PELFA’s high-quality assembly groups and components reveal their quality merits in various upper performance class systems. Runner rings between 6 m and 8 m in diameter are now in use after the revitalisation of run-of-river power plants on the Inn and Danube rivers. Two spiral casings, weighing 45 metric tons each, were manufactured for the pump turbines at the Kühtai power plant in Tyrol. The large distributer mechanisms for the Kaplan turbines generate a bottleneck capacity of 8.5 MW at the Vallabregues power plant on the French River Rhone and were also provided by PELFA. The Italian company‘s order books are full in the throttle valve sector. PELFA is currently working through an order backlog of twelve butterfly valves, with diameters of up to 4.2 metres, to be delivered by the end of the year. The orders involve component production, coating, factory assembly and pressure testing. In total the pre-assembled butterfly valves weigh up to 80 metric tons.

Distributer mechanism for Vallabregues power station on the French Rhone River.

The turbine spiral for Tyrol’s Kühtai pumped storage power plant weighs around 45 metric tons.

INCREASING THE SAFETY OF HIGH HEAD POWER PLANTS BY MEANS OF NUMERICAL INVESTIGATION OF VALVES AND SYSTEMS

By applying computational fluid dynamics (CFD) methods, the hydraulic characteristics of various types of valves and shut-off devices – such as pressure loss and acting forces –can be precisely determined. This information is of essential interest not only for green filed projects, but also for the refurbishment of existing power plants. With the help of two case studies the presented paper shows, how safety-related problems in hydropower plants can be addressed by expert and careful application of numerical methods.

[by Christian Bodner, Stefan Höller and Jürgen Schiffer]

CASE STUDY #1: PUMPED STORAGE POWER PLANT LIMBERG III

At the hydro power plant site "Kaprun", the power plant capacity will be upgraded with the construction of the Limberg III pumped storage power plant. In the course of this upgrade, a new headrace system (headrace tunnel, surge tank and penstock) will be constructed between the existing reservoir Mooserboden and the Wasserfallboden reservoir, including an all-new cavern powerhouse. Furthermore, a new valve chamber (SK Drossen), hosting a DN4900 tandem butterfly valve arrangement, is to be installed serving as a shut-off and safety device (see Figure 1).

The aim of the presented investigation was to determine the behaviour of the butterfly valves in a catastrophic case of a penstock burst, which hopefully will never occur, but cannot be ruled out. The only possible location in the headwater system where such a disaster could occur is the inlet of the spherical valves at the pressure side of the pumped turbines. If these would be destroyed in terms of a catastrophic event, the shut-off valves provide the only remaining possibility to prevent the entire volume of the dam from flooding the valley below. In order to guarantee a high safety standard, two similar shut-off valves are typically placed in the valve chamber, which have to be suitable for emergency closing independently from each other. As it may happen that one of the shut-off valves fails in course of the emergency closing, the second valve has to be operated independently and should be able to close. Since the flow-rate through the valves in case of a penstock burst will be several times higher than the nominal flow rate, the resulting loads on the mechanical construction of the valves will dramatically increase compared to normal operation. In addition to the investigation of the

butterfly valves, the spherical valves upstream of the pump turbines of this power plant were analysed as well (see Figure 4).

By means of a 3D CFD–analysis (see example presented with Figure 2) the hydrodynamic behaviour of a valve can be analysed. This allows for fast and precise calculation of results concerning the loads to be ex-

Figure 2: 3D-CFD-model for the tandem butterfly valves

Figure 1: Layout of Limberg III Pumped Storage Power Plant

© Jaberg

pected. Another advantage of a CFD-based approach is the ability to react quickly to any geometric adaptations that may become necessary. Additionally, a potential risk of cavitation can be identified.

In high head hydro-power plants, a ventilation downstream of the emergency shut-off valve is often installed to protect the headrace tunnel against inadmissible pressure below ambient pressure. For this purpose, enhanced 3D-CFD-simulations have to be carried out as multi-phase simulations in order to determine the required air volume (Figure 3) on the one hand and its effect on the hydraulic performance and the loads on the other hand. By applying this method, the effect of cavitation on the hydraulic characteristics can be analysed as well.

While the 3D-CFD analysis provides the loads acting on the valve in such a case, a one-dimensional transient CFD calculation (water-hammer analysis) is used to determine the dynamic shut-off behaviour of the emergency valve in the hydraulic system of the hydro power plant in case of a pipe burst. In case of the presented transient analysis for Limberg III, a tailor-made numerical representation was developed for the tandem-valves. Sophisticated mathematical models were required in order to calculate the torque equilibrium and to solve the equation of motion around the valve axis (see Figure 5). Apart from the hydraulic forces resulting from the 3D-CFD simulations all other occurring forces acting on the valve cinematics (like servo pressure, friction and gravity) are considered. By applying this method, the dynamic behaviour of the valves in case of a pipe burst event can be calculated in detail. However, the closing behaviour of the valves, which is of essential interest, can be adjusted in terms of transient 1D simulations by changing the resistance of the servo cylinder

throttling. Hence, the pressure transients in the headrace system of the power plant during such a disaster as well as the loads acting on the valves can be precisely predicted.

The calculation finally provides the shut-off behaviour, the closing time of the valve resulting from the actual flow conditions and all safety-relevant data such as the maximum loads on the components or the amount of water leaking into the environment in course of a pipe burst event.

Another type of valve is the so-called safety valve. In contrast to the valves and flaps shown previously, these open in case of emergency to provide a bypass for the turbine and/ or pump. This arrangement enables to reduce maximum pressure peaks in the piping system and subsequently positively influences the transient hydraulic behavior of the piping system (e.g. faster shutdown of the hydraulic machine).

CASE STUDY #2: PRESSURE REGULATOR FOR PUMP STATION HATTELBERG

As a safety device, a so-called pressure regulator is installed on the suction side of a singlestage high-head-pump with a rotation speed of n=3000 rpm. In case of an emergency, the pressure regulator should reduce the energy and release the water into the absorbation chamber located below the power plant. The release of the water helps to handle water hammer problems in case of pump failure. At the nominal operation point, the pressure regulator should achieve a flow rate of Q = 4.5 m³/s at the nominal pressure head of H = 574.12 mWs (nominal head of the pump ~1450 mWs ).

In course of the simulation, the absorbation chamber was modelled as so-called "outblock"(Figure 6 – CFD-Models). The numerical calculations were carried out with a simplified model as well as with a full model

Figure 3: Flow visualization for an example valve position of the tandem butterfly-valves

Figure 5: 1D numerical model of the power plant (top) and loads acting on the valve body (bottom)

containing the entire piping bewteen the pump suction side and the pressure regulator. Beside the two CFD-models, the numerical calculations were performed with 1-phase calculations (water only) as well as with 2-phase calculations to evaluate the influnce of the water and air filled absorbation chamber. Figure 7 shows the velocity field in the centre plane of the pressure regulator of the 1-phase (left) and of the 2-phase flow calculation with a maximum valve stroke (right). In case of the 1-phase calculation it is assumed that the "outblock" is completely filled with water and in the 2-phase calculation with a mixture of water and air. The exit velocity from the pressure regulator at a distance of about 1.75 m is almost twice as high for the air-filled absorbation chamber (65-70 m/s) as for the water-filled absorbation chamber (35-40 m/s). Due to the extremely large pressure difference between the inlet and outlet, high velocity gradients are obtained. This results in an intense transient behaviour of the flow (flow separation, formation of strong vortex structures, ...) in the area of the pressure regulator (especially after the 1st stage). Figure 8 shows the strongly pronounced vortex zones at different valve openings. At small openings, these vortex structures occur at the piston resulting in a strong influence on the force situation of the piston. With larger openings, the vortex structures shift to the area between the 1st and 2nd stage of the pressure regulator. As a result of very high flow velocities, especially at the second stage of the pressure regulator, cavitation can occur. Due to excessive cavitation, the flow space may be blocked and the discharge through the pressure regulator may decrease. Furthermore, complete blockage leads to chocked flow in valves. However, the calculations carried out do not take this possible chocked-flow effect into account. The cavitation zones do not appear to be large enough to achieve this effect. Nevertheless, Figure 9 illustrates the zones where cavitation could occur.

Using experience in the design and layout of the piping system, as well as the installation of the pressure regulator, the optimal solution was found with the assistance of complex numerical methods. As shown in Figure 10, the pressure regulator and its associated components were dimensioned in such a way that the reduction of the total pressure head (head losses) was evenly distributed across the pipe section and the first and second stages of the pressure regulator (the final version is depicted in purple). The increased pressure loss in the pipe section helped to reduce the significant forces on the pressure regulator piston and additionally lowered its highly dynamic behavior.

© Troyer AG

© Troyer AG

Figure 6: 3D-Model of the initial design and the simplified full CFD-model of the pressure regulator

Figure 7: Difference of the outlet velocity between 1phase flow (water only, left) and 2-phase flow (water and air, right)

Figure 8: Complex and strong transient flow phenomena inside the pressure regulator along different opening positions

Figure 9: Cavitation zones in the pressure regulator, iso-surface pabs = 0,2 mbar (left), wall surfaces with pabs < 0,2 mbar (right)

Figure 10: Different head losses of the individually optimized geometries (right)

© Jaberg

© Jaberg

BAVARIAN INDUSTRY SPECIALIST DEMONSTRATES

INNOVATIVE SPIRIT IN TYROL

For decades, Muhr – the Bavarian hydraulic steel construction and mechanical engineering specialist, has been manufacturing reliable and highly innovative screen cleaning machines that prove their worth at a wide variety of hydropower plants – all over the world. The sophisticated HYDRONIC and CATRONIC system series enable Muhr to cover the entire current spectrum of screen cleaning machine types, meeting every possible requirement for intake screens. The incessant buzz of innovation at Muhr can also be heard in the Bavarians' latest reference project in Tyrol. EWR – Elektrizitätswerke Reutte AG’s Weißhaus power station was fitted with a high­performance Hydronic­M­4000­K screen cleaning machine. This was equipped with a new type of quick­change coupler for attachments such as rakes and orange peel grabs to guarantee increased productivity and high operational availability.

Economic efficiency remains one of the central day-to-day operating tenets for the vast majority of hydropower plant operators. However, this can only be guaranteed if the full intake screen cross-section is available, allowing flow rates to correspond with the maximum usable volume of headrace water. What was previously laborious manual labour is now generally carried out by modern screen cleaning machinery. Over years and decades, each type has been successively adapted to suit the many varieties of tasks and intake screens.

Muhr is a family-run company from Brannenburg in Bavaria and has been one of the international hydropower market’s leading

suppliers for over six decades. Decades of experience and knowledge of the interplay between hydropower and mechanical process engineering are ingrained in the company’s DNA, a company whose original roots lie in mill construction. This background has enabled the business to succeed in constantly developing new hydraulic steel construction solutions and, of course, to drive forward design for trash rack cleaning systems and concepts for debris management.

PERFORMANCE ON SHOW IN TYROL

The good reputation earned by Muhr solutions preceded the company as it was awarded the contract by Elektrizitätswerke

Reutte AG (EWR) for the complete modernisation of the hydraulic steel structures and mechanical engineering at the Weißhaus power plant intake. Seemingly inconspicuous from the outside, the Weißhaus power plant is the Tyrolean operator’s largest power plant, achieving an annual generation capacity of 72GWh. The plant is currently being modernised and completely refurbished. This work includes the tunnel, the electrical engineering and the turbine.

Muhr delivered and installed a state of the art screen cleaner that was already demonstrating its practical suitability over a year ago. Tree trunks, rootstocks and other bulky floating

© Braun

The Bavarian hydro industry specialist Muhr supplied a fully mobile multifunctional screen cleaning machine for the Weißhaus water intake in Reutte in Tyrol. The machine is equipped with an innovative quick-change system for attachments.

© Muhr

debris are not serious challenges for the new Hydronic-M-4000-K. The ‘M’ in the model name stands for ‘Multifunctional’ and epitomises the qualities of the machine: It is a travelling and rotating trash rack cleaning excavator with a claw grabber. It can be operated manually, semi-automatically, or fully automatically.

HIGH EFFICIENCY WITH A NEW RAPID-COUPLING SYSTEM

The Hydronic-M-4000-K has a driver's cab, enabling screen debris to be approached and picked up with pinpoint accuracy. The

machine is able to clean the screen to a depth of 17.7 metres, with a stated performance capacity of 40kN. This screen cleaner has already demonstrated that it can clean the two 6.5m-wide sections of screen easily, and almost seamlessly. What makes the machine truly special is the innovative quick-change system for the rake and orange peel grab. The quick coupler system was designed by Muhr to enable one person to change the tool in just a few steps; an advantage of this being that a convenient and quick locking mechanism increases productivity – another being the high level of operational availability due to perfect

coordination with the screen cleaning machine. The new Hydronic-M-4000-K guarantees permanently unimpeded flow through the Weißhaus power station inlet screen.

THE HYDRONIC SYSTEM SERIES

Muhr’s HYDRONIC series dates back to an innovative leap made in 1981. As one of the very first companies to use hydraulically operated rake systems, Muhr’s continuous development of this solution led to a breakthrough that produced impressive benefits: The hydraulic drive and almost unlimited kinematics and control possibilities give these machines extreme functional versatility to travel, turn, swivel, pick up and unload all types of alluvial material – manually or fully automatically. The Muhr HYDRONIC series can be built with a wide range of machine types. As well as the various systems of the multifunctional HYDRONIC M series, such as the one installed at the Weißhaus hydropower station, there is also Muhr’s T series – with telescopic booms, the K series – using articulated arm debris rack cleaners, the H series – fitted with horizontal screen cleaners, and the U series – featuring underwater cleaners. Each option is designed to address different requirements and equipped to meet special technical specifications. However, they all share sophisticated design work and control concepts, and boast powerful drive technology with controlled force application. HYDRONIC M series rack cleaners are particularly adaptable and flexible, and based on the experience gained from the successful installation of over 900 systems they can be customised to site conditions and delivered with an exten-

© Muhr

© Muhr

The new HYDRONIC-M-4000-K screen cleaning machine keeps the Weißhaus power station intake screen clear of debris. It is one of Muhr’s multifunctional system variants. The boom can be equipped with a rake, an orange-peel grab or a polyp grab, while the powerful and reliable drive technology ensures controlled use of force and guarantees high-level operational availability.

The ingenious quick-change system allows attachments to be replaced quickly and easily, by a single person and with just a few motions.

sive programme of equipment modules. THE CATRONIC SYSTEM SERIES

The second major machine-type in Muhr's screen cleaner portfolio is the CATRONIC series. There’s the stationary version of the S series, the mobile SV series, and the SH series – the overhead conveyor rack cleaner. CATRONIC is a comprehensive range of cablewinch-driven screen cleaning machines, all equipped with state-of-the-art drive and control technology. Cable debris cleaners have proven to be an effective technical solution in the past, being robust in design and capable of cleaning down to depths of 100m and beyond. Their dimensions are generally very compact. Muhr knows how to combine them easily with existing floating debris disposal systems, and how to integrate the necessary solutions. All three CATRONIC series systems are characterised by sophisticated, robust design and a multiple redundant safety concept for seamless operational reliability. CATRONIC screen cleaners are equipped with an innovative lifting and tilting mechanism, and an intelligent control system.

DEBRIS HANDLING ENHANCEMENT

The portfolio of the Bavarian industry experts is rounded off by a sophisticated debris management system that provides operators

with a customised solution. Clear answers are required, particularly for stationary screen cleaning systems – on how to deal with debris, and how to transport it onwards and away. The engineers at Muhr provide the right answers, optimising the removal of floating debris as part of an overall concept designed to meet local requirements and conditions. Over the past few decades Muhr’s

specialists have developed chain conveyors, conveyor belts, scrapers, flume channels and lorry systems. The Bavarians also produce containers with the associated lifting, turning and shifting systems. The family-owned company has earned an excellent reputation within the industry, not least due to its customised solutions – always specifically planned and tailored to each customer's system requi

Engineers at Muhr also offer a comprehensive water-borne debris management concept.

© Muhr

GENERATORS FOR GENERATIONS!

• High efficiency generators up to 40 MVA

• Perfect solutions for all hydro turbines and other drives

• Other solutions on request

• Voltage up to 15 kV

• Warranty up to 5 years

• Worldwide after-sales-service

• "Really made in Germany"

AUSTRIAN INDUSTRIAL SERVICE PROVIDERS CONFIRM THEIR REPUTATION AS AN EXPERT HYDROPOWER PARTNER

Bilfinger Industrial Services GmbH is one of Austria’s largest industrial service providers, and a major European problem-solver when facing challenging hydropower plant construction tasks. The company recently demonstrated its expertise in the Swiss canton of Valais. The company from Upper Austria was commissioned for a partial refurbishment of the penstock at Nendaz power plant near the town of Sion – the largest open-air penstock in Switzerland. The challenging renovation project was completed in summer 2022 after around 2.5 years of hard work.

Normally, around a fifth of all energy stored in Switzerland is sourced from Grande Dixence reservoir in the canton of Valais. The reservoir holds a total capacity of around 400 million cubic metres of water processed in two stages to optimise energy yield. The first stage is Fionnay power station at 1,490 metres above sea level; the second at Nendaz power station 1000 metres further downhill. If the power plant at Bieudron is also added to the output of the two plants, as it also utilises the reservoir via its own penstock, the entire power plant complex achieves an impressive total output of 2,000 MW. State-of-the-art technological infrastructure enables it to supply the grid in a mere 4 minutes with an amount of electricity equivalent to that provided by an average nuclear power plant in the same period. Grande Dixence SA operates the plant as one of the European market’s leading providers of electrical power. Grand Dixence SA is under shared ownership: Alpiq (60%), Axpo (13.3˙%), Repower, BKW (13.3˙%) and IWB (13.3˙%).

A PENSTOCK THAT INSPIRES SUPERLATIVES

The headrace connecting the two power plants in Fionnay and Nendaz is long. The tunnel conduit for the headrace water is 16 km in length, taking it to an equalisation basin around 1,000 m above the Nendaz control centre. Here, an 890-metre section of penstock connects to the powerhouse on the Rhône plain, and had served reliably for almost 60 years. However, the penstock section from the Peroua throttle valve to the transition into the vertical shaft now required complete replacement as part of a proactive maintenance initiative.

Once dismantling of the old pipeline had begun in March 2020, a month later the renowned Austrian industrial services providers at Bilfinger Industrial Services GmbH received an order from Grande Dixence SA to replace the above-mentioned section of pipeline. The penstock is an exposed pipeline braced by ring supports. The 890-metre section has a diameter of 3.15 metres. As regards pressure and diameter parameters it’s the largest exposed penstock in Switzerland.

Bilfinger Industrial Services GmbH used a ropeway conveyor to replace the exposed pipeline section of the penstock at Nendaz power plant.

© Bilfinger / Erich Reiser

© Bilfinger / Erich Reiser

© Bilfinger / Erich Reiser

Bilfinger's fitters used the Flextrack method to apply weld seams to the new penstock with millimetre precision.

The section of penstock at Nendaz power plant is 890 metres long and has a diameter of DN 3150, making it the largest exposed section in Switzerland. This section has now been completely renewed.

ENGINEERING PHASE MARKS PROJECT COMMENCEMENT IN JUNE 2020

“Compared to a new construction project, every refurbishment project poses specific challenges. In this case they included the question of how to reuse the existing concrete supports for the ring braces and the foundations for the elbows. Erich Reiser, Bilfinger’s appointed project manager, explains: “These challenges were factored into our planning considerations.” The 32 supports and 7 fixed points were incorporated into the structural planning of the system to ensure they bore ideal loads during normal operation. To guarantee this occurred in practice, in addition to temperature and pressure development, tolerances were also considered when planning the new penstock.

Scheduling requirements made it necessary to procure materials quickly in parallel with the engineering implementation. Sheet metal was rolled on demand for construction and delivered to the manufacturing facility in Wels, Upper Austria, from November 2020. Production of the manifolds commenced here early on as they required the longest lead time. External and internal anti-corrosive protection was already applied in the factory, except to the intended weld seams required for connection during assembly. The construction site was set up very quickly and ready in March 2021. The construction site was spread over an area between 1050 m and 1400 m above sea level on the northern slope of Dent de Nendaz. The old pipeline had already been dismantled and removed using a cable car, and transported away by lorry.

HIGH-PRESSURE PIPELINE ASSEMBLY

A purpose-built ropeway conveyor with a load capacity of 20 metric tons was set up for construction work, serving around 90% of

the site. It played an important role in the assembly stage as many sections were not accessible for mobile cranes. Certain sections ran through wooded areas or, at a gradient of 100%, were so steep that the cable conveyor was the most viable means of installation support. Another challenge was posed by the very limited availability of construction site storage areas. “The little storage space available had to be cleared artificially by moving earth, demanding complex logistics to guarantee just-in-time delivery of components from Austria right after anti-corrosion coating had been applied at the factory,” recalls Erich Reiser.

Assembly was carried out starting at the elbows and working upwards. The elbows were determined as fixed reference points on the way to the top. Two site sections for as-

sembly work were situated very close to the village of Les Condémines. All of the assembly platforms were fitted with a sound-absorbent shell for the local population to minimise noise pollution generated by cutting, grinding and welding during assembly work.

ALL CHALLENGES MASTERED

Approximately 10 % of the site in the lowest section of the construction area could not be accessed using the cable conveyor, so a special gantry crane was devised to serve this section and enable the lowest curve manifold to be positioned on the vertical shaft. Subsequently, the gantry crane was used to install all the other pipe sections.

Particular attention was necessary when routing, assembling and welding the pipeline across a local road. Nevertheless, this was all achieved without disrupting traffic. After a 14-month construction phase the Bilfinger Industrial Services GmbH team ultimately completed the section in May 2022. On-site application of the anti-corrosion coating also began at around the same time. Work on the joining weld seams inside the pipeline was carried out from specially erected platforms. The winch required for positioning was located in the throttle valve house. A total of four platforms were transported with the ropeway cable conveyor – section by section –to complete external anti-corrosion coating. This was sealed with a full top coat of paint in order to give the pipeline a uniform appearance.

WET TRIALS FROM AUTUMN 2022

In July 2022, the steel structure installation was completed on the installation of six ex-

Construction of the curve manifold at the plant in Wels, Upper Austria.

In May 2022, the passover section was installed and welded together above a road crossing beneath without affecting traffic.

© Bilfinger / Erich Reiser

© Bilfinger / Erich Reiser

pandable sections below the fixed positional reference points. The expansion joints adapt to motions caused by forces exerted during operation, and also compensate for terrain subsidence. The customer fitted the entirety of the exposed penstock with sensors, so now the fascinating readings can be subjected to analysis. These measurements reveal details of the effects of forces exerted during the various operating modes at the power plant, as well as of external influences on the steel penstock –such as the position of the sun. The renovation project was completed and handed over to the customer, Grande Dixence SA, for trial operation after an overall duration of around 2.5 years. The entire penstock was refilled with water in early September 2022, and the first machine groups went back into operation at the beginning of 2023.

BROAD-BASED VALUE CHAIN

Bilfinger Industrial Services GmbH once again demonstrated extensive experience and hydropower expertise when fulfilling the Grand Dixence SA order. Bilfinger has its headquarters in Linz, and subsidiaries at nine other locations in Austria and neighbouring countries, making it one of Austria’s largest industrial service providers. The company's

service portfolio covers the entire value chain – including advisory services, engineering, manufacturing, assembly, maintenance, plant expansions and general overhauls, environmentally-friendly technologies and digital

applications. Over the decades, Bilfinger has earned an excellent reputation as a reliable partner, having worked on large numbers of hydropower-sector projects in Germany and further abroad.

WE MAKE HYDROPOWER WORK

The expansion sections are intended to absorb physical motions from operation, and to compensate for any terrain subsidence. In July 2022, installation was completed below the steel structure fixing points.

© Bilfinger / Erich Reiser

BAVARIAN TIMBER FORMWORK PROS SET INDUSTRY STANDARDS FOR COMPLEX CONSTRUCTION TASKS

Building specialised formwork for hydropower plant construction requires both relevant expertise and skilled craftsmanship. These attributes form the basis for crafting what is sometimes highly complex formwork for intake pipes, elbows, cones and intake spirals. Over the past decades, the Bavarian formwork specialists at Mitterfelner Schalungsbau have established their company’s reputation as a key provider in the sector. Mitterfelner has been supplying customised timber solutions for hydropower plant construction almost 30 years; ones that are both easy to assemble and to dismantle. In order to render complex shapes clearly at the planning stage the Bavarians are increasingly turning to precise scaled-down 3D models, produced with a 3D printer. Specialised formwork manufactured by Mitterfelner Schalungsbau is now in use all over the world.

One of the most challenging tasks in hydropower plant construction remains the question of how to shape concrete with formwork. After all, this requires the production of curved, occasionally twisted shapes, with radii that are not always constant, as well as transitioning perfectly from rectangular to round cross-sections. In the vast majority of cases customised formwork is the only solution used in the hydropower industry. Today, very few companies around the world master this craft, or have

enjoyed sustained success in the field. The Bavarian company Mitterfelner Schalungsbau is one of the very few, and has been supplying specialised formwork for hydropower since 1996. The company's expertise is explained by its history. The founding family has been operating its own hydroelectric power plant for several generations. In the mid-1990s conversion work became necessary, and provided the initial impetus for the company to increase its concentration on the construction of special formwork. Construction of formwork is still primarily a manual task and a highly specialised area of the traditional carpentry trade – one that

Mitterfelner has practised very successfully for decades. “As we feel a strong connection to hydropower, we are always well informed about the latest trends and standards in this sector. In turn, this has enabled us to expand our expertise over the years,” says Robert Prielmeier, Managing Director at Mitterfelner Schalungsbau.

SUPPORTED BY 3D MODELLING

Mitterfelner has also continued to develop its planning capabilities for complex special formwork. “As in other industries, 2D planning has long since given way to physical 3D rendering, and is carried out with the help of

Mitterfelner Schalungsbau supplied a special reusable formwork system for a hydroelectric power station not far from Florence in Italy. The ingenious connecting system ensures simple assembly and dismantling.

In use around the world: Specialised Bavarian formwork for a hydroelectric power plant in Guinea, West Africa.

Complex intake formwork for Illspitz power station near Feldkirch, Austria

the latest CAD programmes. True-to-scale 3D-printed models can be extremely useful. Now, a highly representative model is the best possible means of helping everyone involved in production to visualise complex geometries,” Robert Prielmeier explains. Such a model’s importance is particularly evident in formwork crafted for an inlet channel. Quite often, even the most experienced formwork builders at Mitterfelner Schalungsbau face major challenges. Complex geometries must be fine-tuned to previously installed turbine inlets. “All load forces must be transferred to the outside to ensure there is no pressure on the steel components. For this reason our formwork is built from solid wood in a framework structure, and dimensioned sufficiently to withstand the concreting process,” the Managing Director states. Each individual element of the formwork is fully braced, eliminating the necessity for any subsequent construction site bracing.

HYDRAULICALLY OPTIMISED INLET

Not least for sake of sustainability, Mitterfelner Schalungsbau’s pros use regionallysourced, untreated timber. Among several advantages, used timber formwork can be disposed of very easily, and the absorbance of the surface of the wood ensures concrete is harder, more resistant and sets with fewer air pockets. The surface of the planed formwork boards is evened and sanded by hand to create the smoothest possible surface, allowing the formwork builders to guarantee optimum hydraulic conditions and maximum system efficiency within the future water conduit. The supreme quality of Mitterfelner Schalungsbau’s special formwork enables it to be reused. The robust and highly functional connecting system facilitates simple assembly, and makes dismantling easy too. Formwork elements are delivered to the site on trucks, sea containers and even cargo helicopters – divided into individual components whose size is, as a rule, determined by transport dimensions.

IN USE AROUND THE WORLD

The Bavarian formwork builders’ expertise is in great demand especially for power plant conversion projects. Robert Prielmeier: “If the suction pipe requires adaption, formwork must be inserted into the existing suction hose. This demands intensive planning work in order to produce viable formwork, to facilitate reinforcement and ensure sufficient concrete cover in the tightest of spaces.”

There are good reasons for making Mitterfelner Schalungsbau the first port of call when planning and producing premium quality

suction pipe moulds, curved moulds, inlet and cone moulds and casts for spiral inlet chambers. The Bavarians can now point to more than 230 successfully completed reference projects. Mitterfelner Schalungsbau's specialised formwork is regarded as an industry quality seal and a reliable foundation in hydroelectric power plant construction – be it a high-alpine pumped storage power plant, such as the Obervermuntwerk in Vorarlberg, run-of-river power plants on the Inn and Mur rivers, in generally throughout Europe or in Africa.

Foto: BRAUN

© Mitterfelner

© Mitterfelner

The Mitterfelner formwork construction team demonstrated its expertise, producing the inlet formwork for a power plant reference project in Hungary to optimise the cross-section from rectangular to round.

Scaled-down 3D models have become an important pillar of the production process.

BRINGING BACK MIGRATORY FISH

It’s March 2024 and dangling precariously over the Santee River in the United States is the next big global innovation in highly efficient fish passages. The waters below are rising fast… a flood is coming. Hanging from the hook of the crane is 1.3 million USD of funding from the U.S Department of Energy (DOE) in the form of the flagship product of Fishheart Ltd., its state-of-the-art hydraulic Fishheart unit. Some 7500 km away, in Finland, the phone is ringing and Fishheart’s management is dealing with the situation.

Not all pilot projects have as dramatic a story as Fishheart’s latest test in South Carolina, but to understand how it all came to this point, we need to start at the beginning. In 2016, Tarmo Aittaniemi, innovator of Fishheart’s patented system came together with fellow fishermen Mika Sohlberg and Magnus Breitenstein with a common goal in mind; to restore fish populations to their built rivers while providing the technology and knowhow to do so from three lifetimes worth of fishing.

The first Fishheart test unit entered the waters of Finland during the summer of 2017 at the

Merikoski Power Station, Oulu. Since then, their success has gained them traction in the Nordics where they permanently operate five units in four different sites.

Fishheart Ltd. takes its name from its unique design; based, like a heart, on chambers and valves. Unlike most fish passages, Fishheart is a completely adjustable system which eliminates the chance of miscalculation in positioning the entry to the fishway, allowing the team behind Fishheart to continuously monitor and improve the performance of its fishways. A fully functioning fishway is made up of a pipeline, a floating Fishheart unit, a

control container with electrical system hardware and monitoring units. The floating unit is strategically placed below the dam wall and attached to the shore using adjustable wire ropes.

Once fish enter the area, they are attracted by the outer attraction flow coming from the floating Fishheart unit. The outer attraction flow acts as a beacon for the fish who then become attracted by the inner attraction flows under the water. The inner attraction flows lead the migratory fish into one of two chambers. Once inside the chamber, Fishheart’s AI based recognition system identifies

Fishheart

Fishheart

Gizzard-shad

The Fishheart allows a highly efficient fish passage.

the fish, its species, the number of fish inside the chamber, their size, and relays that information to an external or local server before approving or denying the system to open the fishway. The whole process is automated and controlled remotely using preset preferences dependent on the location and takes place in a split second. Once the fish has been approved, the system starts a series of functions and the fish travels over the dam wall through adjustable piping aided by the siphon effect with water used from the upper basin. This makes Fishheart a closed system with fish being protected by water the entire time and all water used in the process returning to the upper basin for use in power production. Invasive species can be taken away from the aquatic ecosystem through a separate pipeline.

At the end of September 2023, in a bid to tackle the biodiversity crisis that continues to be globally tied to the move towards clean, renewable energy sources, the DOE announced its allocation of funding for six fish passage research projects. Fishheart Ltd., together with the Electric Power Research Institute (EPRI), was allocated the largest funding of 1.3 million USD to evaluate the system´s ability to provide safe, timely, and effective passage of American Shad at the Santee Spillway hydropower project in Pineville, South Carolina. The test ran from 28.2–2.4. and was halted between 7­19.3 due to a need of spilling water through

the Santee River, which raised the water level by 8 meters.

With funding from the U.S. Department of Energy (DOE), the field evaluation was hosted by Santee Cooper and led by the Electric Power Research Institute (EPRI) with the testing conducted by Alden Research Laboratory (a Verdantas company) and DOE’s Pacific Northwest National Laboratory (PNNL). The preliminary results recently presented by Alden exceeded expectations with respect to the number of fish and species passed through the system. Over the course of 14 test days after the flooding, the Fishheart unit was able to safely move 3410 fish into a collection tank for recovery and monitoring of condition. Of these 3410 fish, 15 different species were noted with a bonus point being that using its attraction flow and underwater guiding system, the Fishheart fishway was able to provide safe passage to fish swimming at all levels under the water. The unit safely moved 1159 Blue Catfish, known for their bottom dwelling behavior. In addition, 732 fish used the Fishheart during the first week of the test before the flooding started, so in total 4142 fish used the fishway during the entire duration of testing, of which 291 were American Shad, the primary species of interest for the evaluation at the Santee Dam. The well­being of fish after passage was monitored by Alden in separate evaluation tanks and preliminary indications are that passed fish were in good health.

And what about that phone ringing back in Finland? Well, the unforeseen flooding gave Fishheart Ltd an unexpected but positive bonus result for their longevity in the fish migration industry. Once the alarms had been set off and the spillway was soon to be put under extreme pressure, it took only 4 hours to get the Fishheart unit out of the water. The unit was safely moved away from the path of destruction and reinstalled in a similar time frame. There was no need to clear out mud or debris or any other fuss that may have arisen in the same situation with a traditional fish passage.

Following their success in the US, Fishheart is now setting their sights on the central European markets of Germany, Austria, Switzerland, and France, providing an affordable solution to the growing pressure on EU countries to fulfil their commitment to the restoration of their river systems in the coming years. Alongside this they are launching a pilot project in Australia later this year.

Interested in learning more about Fishheart?

Please reach out to our sales representatives:

Mika Sohlberg – Sales Director +358500103344

mika@fishheart.com

Matthew Nimmo – Sales DACH +4915758919326 matt@fishheart.com

The Fishheart unit can easily be installed.

The level of the flooding compared to normal situation

Catfish Gar

Catfish

HYDAC – YOUR PROFESSIONAL PARTNER FOR THE HYDROPOWER INDUSTRY

Today, hydro-electric power stations make an important and sustainable contribution to the world‘s energy supply. HYDAC is determined to play its part in enabling people to gain maximum benefit from hydropower. In opening flood gates and intake gates. And in efficiently regulating and protecting turbines and generators. HYDAC proves its expertise with hydraulic and filtration solutions in all sectors.

HYDAC has decades of experience in oil hydraulics and process water treatment. With individual components constantly being added to the product range, such as filters, accumulators, valves, pumps, coolers and sensors, HYDAC has built up an extensive and complete product portfolio over the years that leaves nothing to be desired when it comes to designing systems for the hydropower industry. In addition to supplying individual components, HYDAC also provides complete systems for almost all hydropower applications. These are comprehensive systems which are specially tailored to suit the customer‘s needs. HYDAC was founded in 1963 as a company for hydraulic accessories and is today an international, family-run company group with over 11‘500 employees, 45 subsidiaries and more than 500 sales and service partners worldwide. Our motto is: global yet local. HYDAC components and systems can be found in all sectors of industrial and mobile hydraulics.

© HYDAC

HYDAC was founded in 1963 as a company for hydraulic accessories and is today an international, family-run company group with more than 11‘500 employees, 45 subsidiaries and more than 500 sales and service partners worldwide.

HYDAC develops tailormade piston accumulators and innovative sensors for hydropower applications. © HYDAC

COMPREHENSIVE PRODUCT PORTFOLIO

In the hydropower industry, HYDAC is represented in the following applications for both large and small hydropower stations:

• Hydraulic steel structures and trash rack cleaners: hydraulic units and cylinders for gate, sluices, weirs and trash rack cleaners

• Shut-off devices: hydraulic systems for ball valves, shut-off valves and needle valves, piston and bladder accumulator stations for storing closing power and water-powered servo motors with corresponding protective filters

• Turbines: bearing lubrication systems, hydraulic turbine controllers, piston and bladder accumulator stations for the emergency shut-down function

• Process and cooling water treatment: for the filtration of seal water, cooling water and extinguishing water, the required components –e.g. the automatic back-flushing filter RF3 or ATF – are mounted on a compact frame (skid)

Generators: lifting and brake cylinders, oil lubrication cooling systems and cooling water systems, high-pressure discharge systems (HP systems), brake lifting systems, oil mist separators.

WORLDWIDE SERVICES

HYDAC also supplies products for Condition Monitoring, such as sensors for monitoring water content (Aqua Sensor), metallic contamination (MCS Sensor) and the automatic monitoring oil cleanliness (CS Sensor) along with service instruments for maintenance such as dewatering units (FAM), offline filtration units (OLF), nitrogen charging units for accumulators (N2 server) and mobile units for measurement and data acquisition (HMG). The HYDAC portfolio is rounded off with extensive fluid engineering services which help to optimise your key components and fluid power systems. We are very happy to support you in areas such as energy efficiency, process and system reliability, conservation of resources and system availability.

Please contact us via our website or directly using the following e-mail address: hydro-power@hydac.com. The HYDAC team looks forward to receiving your enquiry!

In addition to customised hydraulic units, HYDAC supplies standard units in various sizes and versions with its Hydrobox system. This is especially suitable for small hydropower stations. For closed cooling circuits that work with water glycol, HYDAC has developed a compact system (WGK) that is made up of a motor-pump unit, an expansion tank, a mixing valve and sensors.

HYDAC

DIVE AND NATEL ARE RAISING THE BAR FOR SAFE FISH PASSAGE IN SMALL HYDROPOWER

Trusted hydro turbine manufacturer and developer DIVE Turbinen GmbH & Co. KG from Germany is collaborating with sustainable hydropower innovator Natel from the USA to accelerate deployment of FishSafe™ hydropower turbines around the globe. In the race to combat climate change, maintaining and expanding the world’s hydropower fleet has never been more critical. Hydropower is a tested and reliable renewable energy source, but its traditional implementations may come at a cost to river ecosystems, particularly in hindering the safe up- and downstream passage of fish. Many strategies for upstream fish passage exist, but downstream through-turbine passage is of special interest and a true challenge for existing turbines on the market.

Anew collaboration between DIVE and Natel builds on a timely understanding that efforts to combat climate change must also address biodiversity loss. This collaboration will see the integration of the DIVE-Turbine powertrain with Natel's FishSafe™️ runner design. DIVE has a proven track record as a turbine manufacturer,

having installed more than 65 compact, efficient, and reliable turbines at sites across the globe since 2006. With a global installed capacity of 32 MW producing around 160 GWh/a clean energy per year and saving the equivalent of 54,000 tonnes of CO2 emissions per year in comparison to a modern gas-fired power plant. DIVE turbines use

highly efficient direct drive permanent magnet generators in a submersible package that has allowed small hydropower plants to operate with exceptionally low cost and risks. DIVE is committed to advancing fishfriendly hydropower. DIVE-Turbines utilise a runner with fixed blades and speed variation, which has already a lower fish mortality

Site visit at DIVE’s power plant Tegernsee, Germany, with Abe Schneider (Natel), Christian Winkler (DIVE) and Johannes Santen (Natel).

than a Kaplan turbine with variable pitch blades and a fixed speed. By collaborating with Natel, DIVE is working to further increase the fish-friendliness of their turbines. Natel has pioneered unique methods for turbine runner design focused on fish safety in hydropower applications. Through rigorous testing and

refinement, Natel has achieved fish passage survival rates of 98-100 % across multiple fish species and life stages, at high blade speeds. Using Natel's runner designs, the two companies aim to achieve fish safety at all operating conditions (part-load through full-load) without the need for a fine fish exclusion screen.

JOINING FORCES FOR MAINTENANCEFREE FISHSAFE™ HYDROPOWER

The DIVE-Natel Turbine is a high-performance, maintenance-free turbine that is safe for fish passage, combining the strengths of each company. These turbines are available for sites with up to 40 m of head and in unit sizes up to 4.50 MW.

A direct-drive, vertical axis, submersible turbine, the DIVE-Natel Turbine is flood secure and is available pretested and preassembled, minimising work on site. Based on the unique DIVE sealing and DIVE bearing the turbine-generator-unit is also permanent runaway capable and largely maintenancefree, requiring only a 5-year oil change and 20-year bearing change.

The DIVE-Natel Turbine features Natel’s patented, thick, forward-swept blade design, which can eliminate the need for fine screens to protect fish from turbine injury. Without screens, more flow can be used for generation and costs associated with installing and maintaining screening are reduced.

A ONCE-IN-A-GENERATION OPPORTUNITY

The global hydropower fleet faces an urgent need for modernisation, and the DIVENatel Turbine meets that need while additionally helping to bring those sites into compliance with new regulations for fish

Installation of the preassembled and pretested DIVE-Turbine-Generator unit.

Typical DIVE-Turbine setup in a simplified water chamber.

survival. “ We’re excited to offer the DIVENatel Turbine, an efficient, submersible hydroelectric turbine for low and medium head sites that combines high performance and reliability with safe downstream fish passage,” said Christian Winkler, Sales and Product Manager at DIVE. “By incorporating Natel’s FishSafe™️ runner design into our low-maintenance DIVE-Turbine, we can upgrade an existing plant’s efficiency and environmental performance simultaneously.” Like the standard DIVE-Turbine, DIVENatel Turbines generally have fixed runner blades. If needed at variable flow and head conditions, the speed of the DIVE-Natel Turbine can be varied instead of varying the runner blades’ pitch. The speed variation reduces the speed of the turbine as the flow decreases. This achieves a hydraulically similar effect to the mechanical adjustment of the runner blades in Kaplan turbines with

comparable efficiencies. The use of the Natel FishSafe™️ runner with the DIVE-Turbine enables higher operating speeds while still ensuring safe fish passage. The DIVE-Natel Turbine enables safe down- stream fish passage while also simplifying operations & maintenance as well as minimising the flood risk for the Turbine-Generator-Unit. With reduced mechanical complexity, the DIVE-Natel Turbine can achieve equivalent annual production to a Kaplan turbine in typical applications. Most importantly, DIVE-Natel Turbines are both highly efficient and highly reliable, resulting in reduced downtime and improved overall power production.

HIGH FISH SAFETY, LOW CAPEX & OPEX

Submersible DIVE-Turbines, known for their direct-drive generator and unique seal and bearing design, minimise OPEX due to virtually maintenance-free operation and

robustness. Their compactness and customised design allow for easy integration into existing power plants, minimising CAPEX. Through our collaboration with DIVE, we’re joining DIVE’s expertise as a turbine manufacturer with Natel’s breakthrough FishSafe™️ technology” said Gia Schneider, CEO and co-founder of Natel. “Fish are vital to the global economy, food supply, and ecosystem function and it is essential that we plan for a future that sustains fish populations while also enabling us to modernise the existing hydro fleet and advance the transition to a reliable, carbon-free grid.” By combining Natel’s proven FishSafe™️ runner designs with DIVE’s compact, efficient, and reliable turbines and demonstrated manufacturing experience, the two companies have pioneered a solution poised to redefine the standards of fish-friendly hydropower for small hydropower plants.

© Natel

Natel’s FishSafe™ runner design (3-blades) in CFD simulation, with the specific thick, forward-swept blade design.

Natel’s FishSafe™ runner design (2-blades)

Keep your energy flowing Voith Hydro HyService

Voith Hydro is your trusted partner throughout the entire lifecycle of your hydropower station. Our HyService portfolio combines proactive services with tailor-made packages and ensures optimal profitability for your power station. With a global network of experts, including specialists based in Austria,

we are committed to enhancing the performance of your plant. This includes facilitating seamless component interaction, maximizing uptime, and ensuring unparalleled productivity.

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