16 minute read
MAKING A BIGGER SPLASH
Pumped hydro has been a long staple of the energy storage markets. It can harness spare generating capacity at all times of the day and provide power that can be tapped at the opening of a valve. But it is limited in what it can do. Moreover, the sector’s development has been stunted by neglect. A fresh look — using batteries — is offering unexpected benefits.
Making a bigger splash
Although it has long been far out in front of the rest of the field when it comes to global energy storage capacity (with more than 94%), recent growth in the pumped storage hydropower (PSH) sector has stagnated, says the International Hydropower Association.
A lack of policy and financial incentives for new developments, as well as environmental considerations, are to blame — and now, with two major initiatives, they are being addressed.
“While significant amounts of variable renewables are placed on to grids and ageing thermal plants retire, pumped storage development remains almost stagnant,” says the Londonbased IHA. “Outside China, the world’s largest pumped storage producer, year-on-year installed capacity growth has been just 1.5% since 2014.
“This has been due to a combination of factors, including a lack of understanding or awareness about PSH’s capabilities, complex permitting arrangements, and outdated market and regulatory frameworks that fail to provide appropriate incentives for development. Investment decisions are now needed urgently.”
The increase of renewables such as wind and solar has been widely hailed as answering the need for less burning of fossil fuels, but their lack of inertia and volatility means they will never be the complete answer. Hydro, the oldest renewable energy resource, can fill that gap — but it needs to be updated in order to do so.
“Hydro is an existing, proven, flexible technology but there has to be a focus on bringing it online to meet the needs of the evolving energy mix,” says David Samuel, senior hydropower sector analyst with the IHA.
“By 2050 there will be a drastic emphasis on renewables and decarbonization and there’s a real need to modernize the services that hydropower already provides and improve it even more.”
Before the sector gets caught napping, the IHA and the US Department of Energy have launched two major initiatives to bring the technology up to date — an International Forum on Pumped Storage Hydropower and a raft of demo technologies all looking to innovate the world’s water batteries.
Launch of international forum
For the first time in the pumped storage hydropower sector an international forum has been launched, bringing 11 governments and 60 other organizations together to work out how to tap hydropower’s potential as a ‘clean, green battery’.
Under the umbrella of the IHA and US Department of Energy, the governments of the US, Austria, Brazil, Estonia, Greece, India, Indonesia, Israel, Morocco, Norway and Switzerland gathered together this November with financial institutions, NGOs and energy companies to put PSH at the forefront of policies to cement the technology’s leading position in global storage and make sure it stays there.
Energy companies involved include the likes of SSE, GE Renewable Energy and EDF; international funding banks include the World Bank, European Bank for Reconstruction and Development and Asian Development Bank; and agencies include IRENA, the IEA, and GEIDCO — the Global Energy Interconnection Development and Cooperation Organization.
In a wide-ranging programme to prepare for an ‘upsurge in pumped storage developments’ and also to improve existing capacity, the forum will spend 12 months exploring regulation/permit and investment barriers; sharing best practices; examining new market mechanisms; assessing differences between regions and opportunities; working out incentives to development; and learning from other sectors.
EU WATER FRAMEWORK DIRECTIVE AND HOW BATTERIES COME INTO PLAY
In 2000 the European Union launched the Water Framework 2000/60/EC, which shows ‘how hydropower can be made to operate in accordance with the requirements of the Habitats and Birds Directives’.
New projects must meet a raft of regulations such as river basin management, flood and water flow management to protect flora and fauna that can be affected by changing water levels, water temperature changes (which are often noticeable during peak discharge periods and which certain species cannot survive) and dams.
This affects the levels of water permitted in reservoirs and how quickly the levels can be changed — and if batteries can take up the slack, this can be addressed, smoothing peaks and troughs without compromising power, says Andritz Hydro marketing director Jens Päutz.
The Directive also says that modernizing existing plants is preferable to building new ones, and by combining batteries with old facilities this ticks that box too.
Andritz is even hopeful that the technology could provide a home for second-life lithium batteries when they are no longer fit for EV use – once there is a market available, says Päutz.
“For the time being there are no second-life batteries available but in the long term that could be an answer — you need a second market for the battery and long term this could be a potential one,” he says.
BATTERY BENEFITS
Batteries in combination with hydropower plants can:
• Extend lifetime by reducing mechanical stress • Expand opportunities to enter energy markets • Offer flexible storage — peak shifting • Up to 25% extension of operation range • Be installed in existing plants.
FURTHER DEMONSTRATIONS
Other XFLEX HYDRO demonstrations being run alongside that in Vogelgrun in north-east France, all of which are monitored by Andritz’s new Smart Power Plant Supervisor software:
Portugal
• Alto Lindoso (630MW) — To evaluate the cost of converting the plant to variable speed turbines • Alqueva (520MW) — To demonstrate the use of hydraulic short circuit operation (where pumps can be operated at the same time as the turbines) • Caniçada (70MW) — To assess potential of enhanced system integration of full-scale frequency converter technology • Frades 2 (780MW) — To demonstrate hydraulic short circuit operation, variable speed units and smart controls
France
• Grand Maison (1,800MW) —
To demonstrate hydraulic short circuit, new turbine runners and automation techniques at
Europe’s largest PSH plant
Switzerland
• Z’Mutt (88MW) — To demonstrate variable speed turbine with smart controls to provide greater flexibility.
The forum has been divided into three main focus areas — Policy and Market Frameworks, which will be led by GE, a big turbine manufacturer; Capabilities, Costs and Innovation, led by mechanical engineers Voith Group; and Sustainability, led by energy firm EDF.
It will meet three times — the first meeting was held virtually on November 3 — between now and September 2021 to update and give progress reports.
“IRENA (the International Renewable Energy Agency) has said that pumped storage hydropower needs to nearly double by 2050 to meet ambitious global climate targets. The good news is that there is massive potential, with 600,000 potential off-river sites identified, plus opportunities for modernizing existing plants,” says Eddie Rich, CEO of the IHA.
“Over the next year, the forum’s partners are expected to exchange good practices and agree proposals to clear the way for an upsurge in pumped storage developments while also looking at ways to improve the sustainability and efficiency of existing facilities.”
XFLEX HYDRO battery hybrid trial
The other major initiative that has been launched this year by the IHA thanks to €18 million ($21.5 million) from the EU is XFLEX HYDRO, in which 19 partners are working on seven projects in three countries in an effort to modernize and improve what hydropower already offers (see separate box on facing page).
The projects are all demonstrating technologies such as variable speed turbines, hydraulic short circuit operations and a battery hybrid, which is an example of an early trend that has appeared in Europe’s northern regions — of hydropower facilities incorporating conventional lithium-ion batteries with PSH plants to enhance their performance and save wear and tear on the turbines.
With 23,000 hydropower plants in Europe, according to the EU, the potential for battery makers could be vast. Of these plants, the vast majority — 91% — have less than 10MWh capacity each. The rest, just 9% of plants, generate 87% of all hydropower.
EDF’s master of engineering, JeanLouis Drommi, is working on the XFLEX HYDRO project’s battery hybrid. It has been installed at the Vogelgrun 142MW run-of-river power station on the Rhine, on the border with France and Germany.
It generates about 776GWh of electricity a year, which supplies 200,000 households, and its four Kaplan turbines have been in service since 1959.
Now a small 600kW/300kWh battery has been added to work with one of the turbines to add storage and high-duty power supply to increase its grid frequency control capability and reduce the wear and tear on the turbine.
“As long as the maintenance cost of the turbines, avoided because of the battery, is greater than the cost of the battery you have to replace, then you make a profit,” says Drommi.
“This is a new perspective to hydro, using a battery to reduce the wear and tear on the turbines — which when they are spinning with constant power, are fine. But they wear when the water flow has to change.
“Because of the non-regulated renewables, the so-called non-dispatchable renewables — solar and wind — you have to take the sun and wind as they come, so it means the grid frequency has to be adjusted in real time almost, with the sun, the clouds and the wind.
“Therefore, this led the grid operators to ask for a new product — fast frequency regulation. Traditional power generation — thermal and hydro — is not able to respond with speed as fast as ten seconds, so this is where batteries come into play, because they can respond in less than a second, and this is why they are jumping into this market.
“But to put a battery system on the grid you need a grid connection point, and these are scarce, expensive and difficult to obtain because you need a switch of high voltage, quite costly equipment — but the beauty is that with hydropower, we already have
these connection points to the grid. The same point can be used by the battery system.”
Drommi says so far, they have found lithium-ion batteries to be the best compromise between cost and life expectancy, but they are not the only option.
“They are expensive and although their price is decreasing, nevertheless when coming to other options for frequency and pure storage we are looking at zinc-air batteries.
“They are better for a solution when cycling is not the main purpose of the battery, it’s storage.”
HyBaTec battery solution
Andritz Hydro is also working on the XFLEX HYDRO battery hybrid demonstration at Vogelgrun, having already developed its own solution.
Part of the Austrian plant engineering group Andritz AG, the Andritz Hydro subsidiary supplies electromechanical systems and services for PSH plants all over the world, claiming global installations more than 30,000 turbines (with a total power capacity of more than 420GW).
The firm has come up with what it calls a HyBaTec battery solution for the hydropower industry, which integrates a lithium-ion battery with the plant and its control system to extend the lifetime of the turbines and optimize revenue by offering grid services.
This is one of the keys to the future in making hydropower profitable, says Andritz Hydro marketing director Jens Päutz.
“If you’re only participating in base load you have a very bad tariff,” he says. “Hydropower is in most cases a base load application, but if other renewables like wind and solar take over the market and hydropower is left in the background, all the units will find it challenging to operate in frequency control.
“Before, you operated the unit and the level of flow control, but today if you are working in frequency control and try to support the grid for a better tariff, then you have up to 3,000 movements per day, which is mechanically stressing the unit.
“Also, in the developed market you have more opportunity to participate in the primary, secondary and frequency control markets, but in most cases the mechanical inertia of the hydropower unit is not as quick as the grid quota or contractual need for participating.
“In Austria, for example, if you want to participate with 1MW in the primary control market, we have to supply that 1MW within 30 seconds. In most cases hydropower units are not capable of handling that. You are over stressing the unit as the inertia is blocking it.
“The battery in combination will cover that missing link and can very smoothly support that, especially with primary control, where the battery can be used to deliver very fast additional guaranteed power to the grid in case of need.
“With secondary control, the battery can be used to respond as soon as the grid requests it, the turbine can be started slowly and not have to operate at very low load — which helps with the lifetime of the turbine.”
They can also step in when blackstart is required, eliminating the need for emergency diesel generators, he says.
Early promise for batteries
No one is suggesting that pumped storage hydropower has a competitor in batteries, whatever chemistry they are.
But they could have the potential to bring the old workhorse up to a thoroughbred class.
“Where batteries come in is not for bulk storage applications,” says Samuel, at the IHA.
“This is where pumped hydro is in a league of its own. At the moment it has top spot and in the next few years that won’t reduce significantly.
“One of the problems with batteries as grid support is that they have only synthetic inertia, whereas the turbines in a hydropower plant provide natural inertia to give the grid a level of stability that it needs to withstand shocks or variability on the system.
“However, where batteries are good is that they can provide quick, fast response — and battery capacity is going up per project. But in terms of cost there’s a long way to go compared with hydro on a macro scale.”
Päutz says Andritz’s HyBaTec solution is one of just a handful of projects — such as XFLEX HYDRO — that are beginning to explore the feasibility of batteries in this environment.
“We are one of the first to try to offer this solution, and we are just starting ourselves,” he says.
“There are a few projects in the market, mostly realized by the operator or owner themselves. The technology is only making small steps … but we are opening the door.”
— Jean-Louis Drommi, EDF
XFLEX HYDRO project led by EDF, using a lithium battery with the hydropower plant at Vogelgrun
Battery/hydro hybrid case studies
Italian multinational electricity generating firm Nidec ASI has taken up the hydropower/battery combination challenge, with projects in Sweden and Austria.
Case study: Sweden
Nidec ASI is supplying two systems at two sites, a 6MW installation in Edsele and a 9MW installation in Lövön, both owned by energy producer Uniper, which owns gas, nuclear, coal and hydro plants in Germany, the UK, France, the Netherlands, Hungary and Russia.
It produced 12.7TWh of electricity from hydropower in 2019, which came second to gas in the country at 60.2TWh.
The Edsele and Lövön power plants will provide fast frequency reserve service to Swedish grid operator Svenska Kraftnät, and combining hydropower with battery storage will enable Uniper to operate the turbines in the hydroelectric plants more steadily, helping to preserve their operational lifetime. The Lövön battery was being installed at the time of going to press.
Laurent Gagneur, battery energy storage system sizing and energy management system engineer with Nidec France, says combining hydropower with batteries potentially opens up more grid services that the hybrid plant can provide, increasing revenue opportunities.
“By integrating each source with each other it can also be mutually beneficial, in terms of helping to optimize the operational lifetime of the battery system but also the hydropower plant’s turbines,” says Gagneur.
The goal is to find the sweet spot for the systems to perform and operate as a hybrid plant, compared with running them as individual assets.
“During the commissioning phases for these projects we have a certain degree of freedom because we needed to understand how hydroelectric plants operate and how the battery storage system will work when coupled with it,” says Gagneur.
“There were lots of discussions about how to couple the technologies as we embarked on the projects. We’ll be able to see how the hydropower plant and the BESS operate and behave during the commissioning phase and then adapt.”
He says another important part is the specification set by the transmission system operator for the services the hybrid assets will be expected to meet.
“They have to perform by achieving a certain dynamic responsiveness to the grid and how they integrate must also ensure this is met.
“That meant we had to work out how the turbines would work with the batteries and achieve the best operational sweet spot for both systems but also in relation to the TSO’s grid services.”
Case study: Austria
Nidec has provided a battery to the Austrian electricity firm Verbund, also the largest owner of hydropower plants in the country, at a hydroelectric plant in Wallsee-Mitterkirchen, on the River Danube.
The battery, which has been operating for about two months, provides 10MW (8MW primary control plus 2MW output for charging management)/14.2MWh storage. It is Austria’s largest battery installation to date.
Verbund’s goal is to aggregate the battery with hydropower plants within its pool of these plants. While the turbines can provide the primary control power service on their own, integration with the battery limits the stress on them.
Like other markets, Austria is seeing increasing levels of solar and wind generation, which is increasing the need for more flexibility, compounded by the closure of thermal power generation — Austria closed its last coal-powered power plant in April.
The ‘BlueBattery’ at Wallsee-Mitterkirchen, comprising 61,000 lithium ion battery cells in modules that are housed in five containers, will show how the hydropower/battery combination can help provide flexibility and maintain security of supply.
When the grid needs primary control reserve for short periods, the BlueBattery releases energy and is recharged directly by the hydropower plant.
In exceptional cases, when frequency deviations are too great, the plant’s turbine supplies primary control. Together, the combined storage system and hydropower plant capacity can provide the Austrian grid with a total of 16MW of primary control power.
The battery installation is part of a much wider overhaul and upgrade of the 210MW run-of-river hydropower facility at Wallsee-Mitterkirchen, which sits between upper and lower Austria.
The plant is more than 50 years old. Each of the facility’s six turbines and rotors are being renovated in an extensive programme of works that will be complete by 2026.
Renovations include repairs to turbines due to wear and tear, new transformers and works to the generator and switchgear. Each rotor is 11 metres high and weighs more than 200 tonnes.
