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Development of Small Hydro Power Examining the potential of small hydropower plants. By Christine Lins and Maria Laguna, European Small Hydropower Association (ESHA).

Approximately 70% of the earth’s surface is covered with water, a resource that has been exploited for many centuries. The exploitation of hydropower has been characterised by continuous technical development, making it the leading renewable energy source in the EU. Hydropower now accounts for about 84% of the electricity generation from renewable sources and for 13% of total electricity production in the EU. This article is limited to small hydropower plants, since large hydropower is technically mature and already well exploited. Small hydropower schemes generate electricity or mechanical power by converting the energy available in the flowing water of rivers, canals and streams. Small hydropower has a huge, as yet largely untapped potential, which should enable it to make a significant contribution to future energy needs, offering a very good alternative to conventional sources of electricity, not only in Europe, but also in developing countries.

Small hydropower (SHP) schemes are mainly “run of the river”, with little or no reservoir impoundement, using the flow of water within the river’s natural range.

Little dams create little pond, which is very favourable for ecosystems, fish and water storage. They can be designed with a small head, generally on small rivers with gentle gradients, or with a high head, generally on small rivers with steep gradients. Run-of-river projects can use all the river flow or only a fraction of it and have limited environmental impact. Therefore, SHP is not simply a smaller version of a large hydro

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plant. Specific equipment is necessary to meet fundamental requirements with regard to simplicity, high energy output, maximum reliability, and easy maintenance by non-specialists.

There are different definitions of small and large hydropower. The EU definition classifies as large hydropower schemes as those with over 10MWe of installed capacity, and small hydropower schemes as those up to 10MWe of installed capacity. The definition of small hydropower schemes also covers micro schemes (those with installed capacity up to 1MWe). Micro hydropower schemes are more suitable for rural dispersed communities. In particular, the power generated from micro

hydropower schemes can be used for agro-processing, local lighting, waterpumps, small businesses and industries, farms, and household in rural communities.

To develop both small and micro hydropower schemes, the principal technical requirements are: • Suitable rainfall catchments area.

• Hydraulic head.

• A means of transporting water from the intake to the turbine, such as a pipe or a millrace.

• A turbine house containing the power generation equipment and valve gear.

• A tailrace to return the water to its natural course.

THE ADVANTAGES OF SMALL HYDROPOWER Small hydropower plants combine the advantages of hydropower with those of decentralised power generation, without

Figure 1: Small hydropower schemes are mainly run-of-river.

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the disadvantages of large-scale installations. Small hydropower is: • A sustainable resource. It meets the needs of the present without compromising the ability of future generations to meet their own needs.

• An efficient resource. It can satisfy energy demand with no depletion of the resource and with little impact on the environment.

• A secure resource. Small hydropower is available within the borders of one country, and is not subject to disruption by international political events.

This guarantees its security of supply.

• A clean resource. It does not involve a process of combustion, thus avoiding polluting and greenhouse gas emissions.

• A renewable resource. The fuel for hydropower is water, which is not consumed in the electricity generation process.

Small hydropower has been technically feasible for decades. Given a favourable site, it can be economically attractive, sometimes even offering the least-cost method of generating electricity. High head sites tend to be in areas of low population density, and long transmission distances to the main centres of population can often nullify the low cost advantages at the hydropower plant. Low head sites are statistically much more common and tend to be found in or near concentrations of population where there is a demand for electricity. Small hydropower has the ability to generate electricity instantly, to supply both base and peak load generation, has a long life, is easy to maintain and is highly reliable.

OPPORTUNITIES Small hydropower has a key role to play in the development of renewable energy sources in Europe, and an even greater role in the developing world. In the light of increasing electricity demand, international agreements to reduce greenhouse gases limiting the use of fossil energy, environment problems, and the fact that in most European countries, the sites for large hydropower plants are mostly exploited, there is an increasing interest in developing SHP.

Figure 2: Small hydropower has only limited environmental impact.

This trend has been enhanced by the EU Commission issuing the White Paper: “Energy for the Future: Renewable Sources of Energy”, and the Directive 2001/77/EC, “Promotion of Electricity Produced from Renewable Energy Sources”, giving clear signals to increase the use of renewable energy in order to reduce environmental impacts and create a sustainable energy system.

Small hydropower has a key role to play in the development of renewable energy sources in Europe

The White Paper calls for the use of 12% energy from renewables, and the Directive sets up specific goals to reach 22% use of electricity from renewables in the EU by 2010. For SHP, this means that there is an ambitious target of reaching 14GWe of installed capacity by 2010, and generating 55TWh annually.

The Directive gives Member States a reason to look at SHP, because it is the best proven of all renewable energy technologies. Of special interest for Europe, from both the economic and environmental points of view, is exploiting the high potential for upgrading and refurbishing existing plants.

Despite the RES-E Directive seeking to simplify the national administrative procedures in the process of setting and running a SHP plant, currently there are an increasing number of institutional and environmental barriers which operators face in gaining permission to implement new small hydropower schemes and in gaining affordable connections to the grid. This is mainly because of the pressure of environmental groups, which oppose SHP for its negative local environmental impacts on the river ecosystem. This hinders progress in many developed countries. Sometimes no distinction is made between the impact of large hydro and the impacts of small hydro schemes and such arguments are, however, often related to specific cases and cannot be applied generally to SHP. However, new technology and improved methods of operating SHP are steadily reducing the local environmental impacts by integrating environmental issues and local populations in the planning, design and management process.

Hence the small hydropower industry has been affected by exaggerated criticisms of negative environmental impacts, since SHP also has important environmental and social benefits: it replaces fuel-based power production, and thus contributes to climate change mitigation by avoiding greenhouse gas emissions. It can boost the local economic development of isolated populations by producing autonomous and reliable energy, it is suitable for cooperative or communal ownership,

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and combined with irrigation systems, it is an appropriate solution in developing countries. Finally, small hydropower also reduces the risk of river flooding and, in some cases, it can also increase biological diversity.

Because of all these reasons, the issue of public acceptance has therefore become a high priority for the small hydropower industry, together with the analysis of the advantages and disadvantages that new regulatory supporting schemes could bring to the sector.

Indeed, one of the measures introduced by the RES-E Directive is the development of National support schemes and, if necessary, a future EU-wide harmonised support scheme. Currently, these schemes vary from country to country and range from feed-in-tariff schemes with premium payments to RES, to tradable green certificates schemes, and other types of investment grants.

Small and medium sized enterprises, which constitute the majority of goods and services suppliers in the field of small hydro, do not have easy access to RD&D, essentially for financial reasons.

The fact that a large number of plant operators are not aware of the benefits they can achieve through the use of efficient technology prevents equipment suppliers from profiting from any potential investments.

CHALLENGES

Moreover, the fact that hydropower production has existed for many years has created the impression that nonprofessionals can easily design sites and equipment. The unhappy consequence of this is that organisations, which generally support RD&D, imagine that everything has already been developed in this field, and that small hydro therefore does not need support. Worse still, bad solutions to specific problems have led to the construction of plants that were unreliable or did not respect nature protection rules, thus leading to mistrust or outright refusal of this type of development. Nonetheless, the majority of small hydropower plants built during the 20th century do not suffer from such defects.

Small hydropower’s main challenges relate to both economics and ecology.

Small hydropower can be successfully developed as long as it produces electricity at competitive prices and under conditions that respect the environment.

In order to increase the profitability of small hydropower, either the sale price must be increased, or production costs have to be reduced. The first is a political option, and the second depends essentially on the technology. Reducing production costs implies firstly, reducing construction, operation and maintenance costs and secondly, improving hydro and electromechanical performances. It is therefore essential to have well-structured and coordinated Research, Development and Demonstration (RD&D) programmes in order to develop new machines and construction techniques which are simple, reliable and efficient. At the same time, the costs of environmental protection activities are at present so high that they discourage the building of new developments or the refurbishing of existing plants. RD&D is essential in this field in order to develop efficient and economic equipment and construction methods. An example of this is the design of “fish friendly” turbines.

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Small hydropower also reduces the risk of river flooding and, in some cases, it can also increase biological diversity

RD&D ACTIVITIES IN SMALL HYDROPOWER RD&D activities in the small hydropower area have concentrated on: Electromechanical, control and monitoring equipment Current RD&D includes: systemised design of turbines, testing of new construction materials, submersible turbo-generators, squirrel cage induction generators, synchronous generators, variable speed operation,

programmable logic controllers, digital control and graphical user interface.

These activities are carried out and financed by constructors and suppliers of equipment.

Civil engineering works and general design For large developments, RD&D is done on an individual plant basis, Calculations and tests are carried out in university laboratories, where scale models of water intake systems, dams, etc are used. A number of companies have made specific efforts in this field, for example, in the use of geotextiles or inflatable weirs, the improvement of “Tyrolean” self-cleaning water intakes, the development of screening systems for downstream migrating fish and integrated designs. This type of RD&D is more likely to be financed through public funds.

Environmental issues The main environmental problem with a small hydropower plant is the diversion of water from the river, and the consequent ecosystem modifications. At present, RD&D is aimed at reducing the interruption of river flow. Electromechanical equipment-related RD&D, carried out by big turbine manufacturers in a large number of projects, has dealt with these environmental problems through: • The design of environmentally friendly runner blades, which avoid major injuries to fish which accidentally pass through the turbine.

• New materials and components to eliminate the use of lubricants that cause pollution in the case of leakage.

• Low noise gearboxes and generators.

RD&D addressing environmental impact has almost always been funded by the EU or some other public body.

There is a range of techniques that are able to mitigate environmental and social impacts and these should be considered.

Global environmental integration is essential if small hydro is to be better accepted by the local public. Research on new standardised methods to test local individual sensibility to environmental problems, and new solutions to

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TOTAL HYDROPOWER POTENTIAL BY CONTINENT Technical potential

Economic potential

Exploited potential

Source: EU RES Export Masterplan 2002

Output TWh/year 8.000

transfer that offer good prospects for EU manufacturers. Economic growth and an increase in energy demand will govern hydropower development.

Asia, especially China and India, is set to become a leader in hydropower, with 83,000MW of further potential.

7.000 6.000

RECOMMENDATIONS FOR SUSTAINABLE DEVELOPMENT OF HYDROPOWER

5.000 4.000 3.000

Some recommendations for a sustainable development of hydropower include:

2.000

South America

North & Central America

Europe

Australasia/ Oceania

Asia

0

Africa

1.000

Graph 1: Total hydropower potential by Continent: Source ESHA (European Small Hydropower Association)

achieve a higher participation by the public in the design process, should be favoured. It is the role of governments to put forward policies and regulations that do not unduly favour or penalise specific power generation options, while effectively protecting the environment and the rights of affected population. In setting up such policies and regulations, the positive externalities of small hydropower should be clearly recognised. The producers also have a central role to play. Environmental mitigation measures and compensation for people and communities affected by small hydropower projects are well understood today and should be universally applied. Developers have a responsibility to fully integrate appropriate measures into project design. This also means eliminating unacceptable alternatives early in the planning process and allowing for full community participation.

DEVELOPMENT POTENTIAL OF SHP Small hydropower has a huge, as yet untapped potential, which could allow it to make a significant contribution to future energy needs. There is still a considerable scope for improvement and optimisation. Proper maintenance and refurbishment of existing plants could considerably contribute to the development of small hydro. In Europe, despite a decrease from 86% to 60% of

total renewable energy capacity installed, small hydropower will remain by far the largest contributor.

Asia, especially China and India, is set to become a leader in hydropower, with 83,000MW of further potential

Europe has the best state-of-the-art small hydropower technology to offer, but a domestic market which has become more difficult despite national targets for clean energy production.

There are an increasing number of institutional and environmental barriers to be faced in gaining permissions to implement new small hydro schemes. Apart from this, the best home market for EU manufacturers is the refurbishment of existing plants.

In the EU, the most active countries in developing new small hydropower capacity are Germany, Spain and Greece. Small hydropower capacity is growing more rapidly in these countries than in other EU member countries.

Outside Europe, there are new opportunities for export and technology

• Energy policy framework. Member States should develop energy policies that clearly set out objectives regarding the development of power generation options, including small hydropower.

• Decision-making process. Governments should establish an equitable, credible and effective environmental assessment process that takes into account both environmental and social concerns, with a predictable and reasonable schedule.

• Comparison of small hydropower project alternatives. Project designers should apply environmental and social criteria when comparing project alternatives, in order to eliminate unacceptable schemes early in the planning process.

• Improving environmental management of plants. Project design and operation should be optimised by ensuring the proper management of environmental and social issues through the project cycle.

• Sharing benefits with local communities. Local communities should benefit from a small hydropower project, both in the short- and the long-term.

Small hydropower represents an alternative to fossil fuel generation, and doesn’t contribute to either greenhouse gas emissions or other atmospheric pollutants. However, developing the remaining hydropower potential offers many challenges, and pressures from some environmental action groups over its impact has tended to increase over time. Moreover, in the context of the restructuring of the electricity sector, markets may favour more polluting and less costly options. ■

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