In February it was announced that Hitachi Energy has completed and handed over to Austrian power generator Verbund the world’s first static frequency converter (SFC) solution to use modular multi-level technology in a pumped hydro storage application.

This innovation enables Verbund to optimize the pumped storage process at Malta Oberstufe, a pumped storage plant belonging to the Malta-Reisseck power generation group, which has a total turbine power of 1500MW.

The Hitachi Energy solution enables the 45-year-old pumped storage plant to switch its two pump-turbine units from traditional fixed-speed to state-of-the-art variable-speed operation. Instead of constantly running at the same speed, the pump turbines adjust their speed automatically according to grid conditions and reservoir water levels. This considerably improves the efficiency of the pumped storage process.

The solution enables the operator of the Malta-Oberstufe power plant to actively participate in balancing the Austrian power grid. Moreover, it improves the integration of more green energy, such as wind and solar into the European grid.

“This technology breakthrough is the result of a close and deep collaboration with VERBUND to enhance the performance and extend the operating life of one of its most important assets,” said Marco Berardi, Head of Hitachi Energy’s Grid & Power Quality Solutions global product group. “By making the plant more efficient and by stabilizing the power grid, our unique technology and application know-how is advancing the world’s energy system to be more sustainable, flexible, and secure.”

“The defining features of the Hitachi Energy solution are its low losses, robust modular design, limited maintenance requirements, and durability,” said Karl Zikulnig, Head of the Electrical Engineering Department at VERBUND. “Its inherent redundancy is also key – we need exceptional reliability and availability, as the plant is inaccessible during the heavy winter snows.”

A number of firsts

Earlier this year, OPG and Northland Power proposed a first-of-a-kind project for Canada that would develop a pumped storage project at an inactive, open-pit iron ore mine.

The Marmora Pumped Storage Project would be a 400MW closed-loop pumped storage facility that could power up to 400,000 homes at peak demand for up to five hours.

The project design would utilise Marmora’s long inactive iron ore mine, now an artificial lake and local attraction, as the facility’s lower reservoir. The upper reservoir will be created on the site of the mine’s waste rock pile. Repurposing a former mine in this way is a “first” across Canadian power utilities.

If constructed, the facility’s closed-loop design would recirculate water between its two reservoirs to generate electricity. This approach would avoid drawing water from nearby waterways and lakes, eliminating impacts on fisheries and waterway levels.

The 75-acre mine pit, which reaches a depth of more than 200m below ground level, was created for mining operations in the mid-20th century and closed in the late 1970s. Since then, the pit has been filled with a combination of rain and groundwater.

Another first was recently announced by Gilkes Energy in the UK, who released details of its planned 900MW Earba Storage Project in Scotland, the company’s first pumped storage hydropower scheme.

Earba Storage Project will store up to 33,000 MWh of energy, making it the largest such scheme in the UK in terms of energy stored. The proposal is to use Loch a’ Bhealaich Leamhain as the upper reservoir and Lochan na h-Earba as the lower reservoir. A tunnel approximately 3km long will connect the two water bodies.

A powerhouse will be constructed on the shore of Loch Earba which will extend deep underground.

Commenting on the project, Carl Crompton Managing Director of Gilkes Energy said: “The Earba project is in an excellent location with the geography in the area providing some natural water storage, and allowing the project to be sensitively blended into the landscape.

By developing and investing in PSH capacity, we are helping more renewables to be added to the UK System, displacing expensive and carbon-emitting gas generation and ultimately speeding up the transition to a clean, carbon-free economy. We look forward to bringing this ambitious project to fruition.”

The Earba Storage development would be a major civil engineering project. It is anticipated that the construction period will last approximately three to four years and the workforce will average 300 to 400 people on-site throughout this construction phase. Public consultations on the project were due to be held as the magazine went to press.

Construction work is set to start in the summer of 2024 on the first pumped storage project in Estonia, with developer Energiasalv announcing it has received an official permit to build the 550MW plant.

Named Zero Terrain, the underground project is set to be constructed in Paldiski with minor environmental and land-use impacts. The project will enable the deployment of renewable energy generation in the region and will significantly lower consumers’ electricity bills.

“Emission-free energy with a high security of supply at an affordable price is only possible with large-scale and long-term energy storage. I am proud that Energiasalv’s Zero Terrain project can provide the region with an energy supply that will meet future requirements,” said Peep Siitam, CEO of Energiasalv. “Considering we are in the middle of an energy crisis; our team is moving at a speed and strength comparable to the water itself.”

Another first was also announced for the Western Australian town of Walpole, which will be home to the state’s first-ever pumped hydro microgrid. A joint project between Western Power, a state government-owned corporation responsible for building, maintaining, and operating an electricity network that connects 2.3 million customers to traditional and renewable energy sources, and Western Australian-based engineering company Power Research and Development (PRD), the renewable microgrid solution will significantly improve power reliability for Walpole homes and businesses.

The solution is much smaller than typical pumped hydroelectric energy storage schemes. It is referred to as ‘mini hydro’ because it has a capacity of 1.5MW and only requires an incline or drop of 90m.

This new technology aims to significantly improve power reliability for the Walpole community with up to 80 per cent of outages expected to be mitigated by the pumped hydro microgrid.

Walpole is at the end of a 125km long feeder line from Albany that is exposed to the elements and weather events such as bushfires, storms, strong winds and/or falling branches. Improving power reliability in the town is a focus for Western Power and the ate government. In early 2022 the project was awarded A$2m as part of the government’s Clean Energy Future Fund.

When there is an upstream fault on the feeder line the pumped hydro facility will operate as a microgrid to supply Walpole. It will be connected to the Western Power network and supply power to just over 500 local customers.

The microgrid is comprised of two farm dams, a lower dam and an upper dam, connected by a buried glass-fibre reinforced plastic pipe through a pump skid.  The system enables potential energy to be stored by pumping water from the lower dam to the upper dam. Energy can then be recovered by releasing the water from the upper dam back to the lower dam through a generator, driving the pump in reverse and producing energy.

The generator, connected to the pump, is interconnected to the main distribution grid to enable the stored energy to be imported or exported from the grid.

Solar panels and batteries will power the pumping action and shift the water, making it self-sufficient when required during outages as a result of faults on the main feeder line.

The pumped hydro microgrid will enable more intermittent generation to be installed in the grid and enable consumers to store their surplus renewable generation.

The facility will be fully operational by the end of 2023.

Funding for projects

In January, it was announced that the European Regional Development Fund (ERDF) has granted €90 million to the System Operator to finance the Salto de Chira energy storage project in Gran Canaria.

This financial help represents the European recognition of a key and essential project to achieve the decarbonisation of the island of Gran Canaria. The specific objective of the ERDF funding is to “create energy systems, grids and smart equipment of energy storage outside the trans-European energy networks”.

It is estimated that Salto de Chira will increase renewable production by 37%, reaching 51% of renewables in the average annual energy mix on Gran Canaria (a figure that at given moments of the year could be much higher) and reduce CO2 emissions by 20%. The facility has been designed with the utmost respect for the environment, as 91% of the infrastructure is underground, guaranteeing the facility has been blended into the landscape and thus minimising the visual impact.

The power station will have an energy storage capacity of 3.6GWh which, once commissioned, will allow hydro storage using surplus renewable energy that cannot be integrated into the electricity system to pump water from the lower reservoir to the upper one, so that it can be used at a later date when needed.

The project includes the construction of a pumped storage hydroelectric power station with a capacity of 200 MW in turbine mode and 220 MW in pumping mode, a seawater desalination plant and the associated marine works, as well as the necessary facilities for its connection to the transmission grid in order to evacuate the energy into Gran Canaria’s electricity system.

In the Canary Islands, due to the fact that it is an isolated island electricity system, energy dependence on non-renewables is much greater than on the Spanish mainland. In 2022, renewable generation in the Canary Islands accounted for 20.1% of the final energy mix, compared to 43.7% of renewable generation in the mainland system.

Therefore, it is a priority to achieve the objective established in the Canary Islands’ Climate Emergency Declaration to decarbonise its economy by 2040, which necessarily involves promoting and leading a profound change in its energy model towards a new sustainable one, based on energy efficiency and renewable energy.

Among other objectives, this project seeks to decarbonise the electricity system on the island of Gran Canaria, boost the development of renewable energy in isolated systems and the development of smart energy storage technologies with a 100% renewable cycle, both for the consumption of energy from renewable facilities for storing water, and for the production of electricity through the use of falling water.

At the end of last year, it was announced that India’a Greenko Group would be investing 10,000 Crores to set up a Pumped Storage Project near Gandhi Sagar in the Neemuch District of Madhya Pradesh with a daily storage capacity of 11 GWh. The new project will enable the state to meet its statutory RPO (Renewable Power Obligation) and the recently notified ESO (Energy Storage Obligation) targets. This project is expected to provide employment to over ,000 people.

Greenko currently operates over 50 MW wind and solar capacities across five districts of Madhya Pradesh. Greenko’s pumped storage project is expected to be commissioned by December 2024 and will be connected to the ISTS Network.

In February, it was announced that, in partnership with the University of Greenwich and the University of Exeter, UK firm RheEnergise had secured a grant of £1 million from the UK government to help identify and test waste materials that could be used as part of a new form of pumped hydro-energy storage.

The grant, funded through the Net Zero Innovation Portfolio (NZIP) as part of the UK Government’s Energy Entrepreneurs Fund, will waste materials that could be used in the high-density fluid (HDF) that is integral to RheEnergise’s grid-scale High-Density Hydro® energy storage system.

The HDF is an environmentally benign alternative to water the company said, claiming that the fluid used in the system is 2½ times denser than water and is therefore able to provide 2½ times the power and 2½ times the energy when compared to conventional low-density hydro-power systems that rely on water and operate in the Scottish Highlands, Wales and across Europe

RheEnergise said it can deploy its long-duration energy storage system beneath the surface of hills rather than mountains, opening up commercial opportunities in the UK, Europe and further afield.

The new research project, funded by BEIS’s Energy Entrepreneurs Fund (EEF), wants to identify suitable minerals and waste streams which can be recycled into high-density fluid which can be locally sourced and are lower-cost, rather than having to rely on minerals imported from overseas.

“The opportunities presented by the EEF grant are phenomenal,” explained Stephen Crosher, Chief Executive of RheEnergise. “We are delighted to be able to lead and partner with two outstanding universities – Greenwich and Exeter. The project has the potential to solve three huge questions that affect people daily and globally: those of climate change mitigation, delivering firm power supply from renewables and how to use waste from other industries for new purposes, creating truly circular economies.

“The government grant, from the Department for Business, Energy & Industrial Strategy, will help us to cut the operating cost of our hydro energy storage system, whilst increasing its sustainability. By using locally sourced waste materials, we can lower the costs of our projects, reduce carbon emissions from transportation and processing and create a new circular economy where none currently exists.”

Graham Stuart MP, UK Energy Minister, commenting on the EEF grants said: “This funding will see the next generation of energy pioneers drive forward cheap and sustainable low-carbon technologies. This will not only deliver green jobs and lower the costs of energy to businesses but also foster world-leading solutions to net zero and economic growth.”

Later this year, RheEnergise will start work on building a 250kW/1MWh (4 hours) demonstrator of its High-Density Hydro® energy storage system at a site near Plymouth (announced in November 2022) and is planning to have its first 5MW grid-scale project in commercial operation within the next 3-5 years.

Project updates

A major pumped storage project currently under construction is the Snowy 2.0, a project that has been described as Australia’s largest renewable energy project. It will link Tantangara Reservoir (top storage) with Talbingo Reservoir (bottom storage) through 27km of tunnels and a power station with pumping capabilities.

Solid construction progress is occurring at the project, Snowy Hydro has recently said, despite the temporary halt of one of the project’s TBMs following the discovery of a surface depression.

In December TBM Florence, which is digging the headrace tunnel at Tantangara, was transitioning from soft material into harder rock conditions when a depression developed on the surface above the machine. At the time, Snowy Hydro said the integrity of the tunnel had not been compromised, and tunnelling was continuing while work to remediate the surface depression was carried out. A safety exclusion zone had been imposed around the surface depression.

Now in response to a report by the Australian Broadcasting Corporation, a statement on Snowy Hydro’s website said the TBM is temporarily paused while plans to remediate a surface depression above the Tantangara adit are finalised.

“Across the project, and as anticipated, the ground conditions encountered by the Snowy 2.0 TBMs are highly variable, ranging from soft, sandy ground to extremely hard rock,” the statement says.

“Complex and variable ground conditions are not unusual in such projects. Snowy Hydro and the Snowy 2.0 EPC contractor, Future Generation Joint Venture, are focused on delivering the project safely and in a manner respectful of the sensitive environment, while managing impacts caused by external events including Covid-19, high material costs, global supply chain constraints, labour shortages across the Australian construction industry and ongoing weather conditions.

“Commercial claims on construction projects are also common. As with other major infrastructure projects, Future Generation Joint Venture has experienced significant impacts from Covid resourcing and supply chain challenges. Claims submitted to Snowy Hydro by the contractor continue to be assessed and paid appropriately, in accordance with contractual requirements.”

Snowy Hydro said progress is occurring across a large number of Snowy 2.0 work fronts. At Lobs Hole, the Talbingo intake is well underway, the main access tunnel excavation by TBM Lady Eileen Hudson is completed and the emergency, cable and ventilation tunnel excavation by TBM Kirsten is close to completion.

It added that the Snowy 2.0 budget of A$5.9bn (US$4bn) remains unchanged since the project approval.

In late January, it was announced by GE Hydro Solutions that all four units at the 1.2GW Jinzhai pumped storage power plant in China were successfully connected to the grid and have completed 15 days of trial operation.

GE was selected in 2017 by Anhui Jinzhai Pumped Storage Power Co., LTD, one of the divisions of State Grid Xin Yuan, to supply four new 300MW pumped storage turbines, generator motors as well as the balance of plant equipment for the Anhui Jinzhai pumped storage power plant located in the Jinzhai County, Anhui Province, China. The first two units were connected to the grid in October 2022.

The 1.2 GW project, being developed by Anhui Jinzhai Pumped Storage Power Co., LTD, one of the divisions of State Grid XinYuan, will play a role in helping China achieve its goal of building more than 200 pumped storage stations with a combined capacity of 270GW by 2025. The project’s annual generating capacity represents about 1.4 times the annual household electricity consumption in Jinzhai. Acting as a sustainable large-scale energy storage system, the Jinzhai pumped storage station will save up to 89,500 tons of coal and reduce 179,000 tons of carbon dioxide emissions every year.

In January, it was announced that rPlus Hydro has reached a major milestone at its proposed 900MW Seminoe pumped storage project in Wyoming with the submission of its Final License Application to the Federal Energy Regulatory Commission (FERC), This is a milestone that only six pumped storage projects have reached in the United States since the year 2000.

The Seminoe Pumped Storage project, which is expected to provide 10 hours of full-output energy storage capacity, represents a substantial benefit and investment in Wyoming’s energy infrastructure. The project is also a crucial component to the reliability and dependability of the regional transmission grid as it moves towards greater reliance on renewable energy sources like solar and wind. With an estimated construction cost of approximately $2.5 billion, the project expects to create up to 500 highly skilled construction jobs in Carbon County over four to six years. Once operational, the project will provide an estimated 35 full-time skilled positions in the area and generate approximately $9 million in additional annual tax revenue for state and local governments.

“Seminoe Pumped Storage will be an ideal match for Wyoming’s excellent wind energy resource, and will support Wyoming’s role as an energy leader,” noted Matthew Shapiro, rPlus Hydro CEO. “It can also help ensure efficient utilization of new transmission lines that are, or will soon be, under construction, such as the Gateway lines and TransWest Express.”

rPlus Hydro’s submission of its Final License Application is the culmination of a multi-year study and approval process which includes in-depth engineering designs, environmental assessments, and community engagement. The filing of this application will kick off a robust environmental review and licensing process with local, state, and federal agencies.

The submission of the Final License Application is the first of several major milestones for rPlus Hydro coming in 2023. The company expects to submit a Final License Application for its White Pine Pumped Storage project, a 1000MW project located in White Pine County, Nevada in the coming months.

This article first appeared in International Water Power magazine.