For much of the past three decades, pumped storage hydropower (PSH) projects developed slowly, with a handful of refurbishments and few new schemes. But recently, the pace of announcements, approvals, and inaugurations has shifted dramatically.
The reason is simple: as more wind and solar enter power systems, operators require flexible, long-duration storage. Grid stability cannot be left solely to lithium-ion batteries, which are suited to short-duration cycling but not multi-hour or multi-day balancing. Pumped storage fills that gap, providing not only storage capacity but also ancillary services: frequency regulation, black-start capability, inertia, and peak-shaving.
Globally, PSH represents more than 90% of installed grid-scale storage. Plants built in the 1960s and 1970s are still running reliably today. New projects aim for design lives of 70–100 years, creating infrastructure that will support multiple generations of renewable integration.
The resurgence of projects in Europe, Asia, the Middle East, and the Americas demonstrates how countries with very different energy systems are converging on the same solution. For hydropower engineers, this creates opportunities but also challenges: tighter timelines, more complex underground works, and integration with digital optimisation tools.
Europe: engineering beneath the mountains
Limberg III, Austria
Austria’s Limberg III pumped storage power plant entered service in September 2025 after four years of intensive construction. Located in Kaprun, it adds 480MW to the Kaprun group, bringing total turbine capacity to 1382MW and pumping capacity to 1120MW.
The project makes use of the existing Mooserboden and Wasserfallboden reservoirs, avoiding the need for new surface impoundments. A focus was on underground works:
- A 558m vertical pressure shaft was bored through challenging alpine geology.
- The powerhouse cavern lies 450m below ground level, requiring precision blasting and stabilisation.
- Installation of a 355-tonne rotor, assembled from 80,000 stacked steel sheets over the course of a year, represented one of the most complex logistical operations in Austrian hydropower history.
Each of the two machine sets is capable of variable-speed operation. In turbine mode, the output range is 20–240MW, while in pumping mode it is 100–240MW. This flexibility allows Limberg III to respond rapidly to load fluctuations, making it a key element of Austria’s “Green Battery” strategy.
AFRY provided site supervision, geological services, and hazard consulting. Ernst Zeller, Head of Hydro at AFRY, said: “I’m incredibly proud of our team’s dedication and precision throughout this project, from the first geological surveys to the final inspections. Their expertise and commitment have been instrumental in delivering such a complex and forward-looking facility. I also want to sincerely thank our client, VERBUND Hydro Power GmbH, for the trust they placed in AFRY.”
Andritz Hydro provided two variable-speed motor generators (280 MVA each) for the project.
Riedl, Germany
Just across the border, Germany recently approved the 300MW Energiespeicher Riedl after more than a decade of permitting. Located near the Danube power plant Jochenstein, the project has long been identified by the European Commission as strategically important for renewable integration in Bavaria.
The long approval timeline reflects Europe’s regulatory complexity. Environmental assessments, cross-border water impacts, and public consultations slowed progress since planning began in 2012. For engineers, this underlines the importance of early-stage design that can withstand rigorous ecological and community scrutiny.
Construction is due to start in October 2025 with ecological measures implemented on both the Austrian and German sides of the border. Once complete, Riedl will provide crucial flexibility for Bavaria, where solar penetration is high and seasonal variability significant.
Pracomune, Italy
Not all progress in Europe is new build. In South Tyrol, Alperia Greenpower has contracted ANDRITZ to rehabilitate the Pracomune plant, in operation since the 1960s. The plant operates between the Quaira and Fontana Bianca reservoirs and features a ternary unit – a configuration capable of operating simultaneously in pump and turbine mode to optimise response to grid needs.
The rehabilitation will replace the existing Francis turbine with a new 42.5MW unit, upgrade the motor-generator from 43 to 45 MVA, and fully refurbish the 37MW multistage horizontal pump. Automation and control systems will also be modernised.
On-site work, scheduled from May 2026 to February 2027, must contend with alpine weather conditions and a tight shutdown window. For engineers, this demonstrates the growing role of refurbishments in extending the value of existing assets, where upgrades can significantly boost performance at lower cost and environmental impact than new builds.
China and India: Scaling at speed
China: Shangyi and Meizhou
China continues to set the global pace for pumped storage expansion.
At Shangyi in Hebei Province, construction has reached two milestones: closure of the lower reservoir and installation of Unit 1’s 372-tonne rotor. With a planned capacity of 1,400MW, Shangyi will provide frequency regulation, peak shaving, and emergency backup for the Beijing–Tianjin and northern Hebei grids. Civil works included a sediment retention reservoir, weir, flood discharge tunnel, and extensive intake/outlet structures.
In Guangdong, the Meizhou pumped storage project (2,400MW) is notable for its record-setting timelines. The first unit of Phase II entered operation in August 2025, only 18 months after installation began. Phase I was already completed in May 2022. Once fully operational, Meizhou will absorb 7.2 TWh of renewable energy annually, reducing coal use by 2.18 Mt and CO2 emissions by 5.9 Mt.
Other projects underway include the Tiantai PSH station in Zhejiang Province, featuring China’s highest rated head (724m) and largest units (425MW). Projects like the 1.2GW Huoshan, 1.8GW Nanzhang, and 2.1GW Huanglong plants are also advancing, supporting regional energy needs and displacing carbon emissions. In Guangxi, the 1.6GW Guilin Longsheng project broke ground in February 2025. Expected to generate nearly 2 billion kWh annually, it will cut CO2 emissions by more than 1.4 million tons.
The speed of delivery reflects China’s coordinated approach: component supply is industrialised, with multiple rotor assemblies and turbine components fabricated in parallel, while tunnelling and civil works proceed on accelerated schedules. For engineers, this raises the question of whether similar methods could be adapted in other countries with more fragmented permitting and supply chains.
India: Gandikota and beyond
India is pursuing large pumped storage projects to complement its rapidly expanding solar and wind fleet. The 1,800MW Gandikota project in Andhra Pradesh, developed by Adani Green Energy Limited (AGEL), will use reversible pump turbines and motor-generators supplied by ANDRITZ.
The contract, worth a low three-digit million-euro figure, includes design, manufacturing, installation, testing, and commissioning. Importantly, much of the equipment will be produced in India, building local capability while drawing on ANDRITZ’s global expertise.
Gandikota is AGEL’s third PSH project with ANDRITZ, after Chitravathi (500MW) and Tarali (1,500MW). Together, these plants represent a pipeline exceeding 3.8GW, reflecting India’s strategy of coupling intermittent renewable generation with large-scale, long-duration storage.
A milestone was also reached at Greenko’s Pinnapuram Integrated Renewable Energy Project in Andhra Pradesh, where Unit 1 was successfully wet-commissioned in pump mode. India’s first co-located project integrates 1,000MW solar, 550MW wind, and a 1,200MW closed-loop PSH system. Future phases could expand capacity to 2,400MW of PSH.
The project uses two purpose-built reservoirs in natural depressions, filled via the Gorakallu irrigation system. Spanning 714 hectares, it features a subsurface powerhouse with eight variable-speed turbines and environmental measures such as compensatory afforestation and local resettlement support. The facility has been designed to provide up to six hours of continuous discharge and can ramp up or down quickly, enhancing India’s grid flexibility.
Elsewhere, Greenko is advancing its 1,800MW Shahpur project in Rajasthan, with AFRY handling detailed design and supervision. In Maharashtra, Adani Green Energy awarded a contract to ANDRITZ for the 1,500MW Tarali plant, following their earlier collaboration on the 500MW Chitravathi project. ANDRITZ is now involved in four major Indian PSH schemes, highlighting growing momentum to strengthen grid stability. India’s Central Electricity Authority has also identified over 100GW of PSH potential and is encouraging private sector participation through policy and tariff reforms.
For hydropower engineers, India’s scale presents both opportunities and technical challenges: ensuring grid synchronisation across vast areas, managing sediment loads in reservoirs, and designing reversible machinery for multi-hour daily cycling.
Emerging markets: tailored solutions
Chile: Data-driven feasibility
Chile’s electricity market faces extreme solar penetration, with wholesale prices frequently dropping to near zero during daytime hours. To manage this, HYVITY is developing a 450MW closed-loop pumped storage project, supported by HYDROGRID’s simulation platform.
Using HYDROGRID Insight, engineers can model curtailment risks, simulate investment scenarios, and compare hardware configurations before committing capital. This digital-first approach is increasingly important in markets where financial viability depends on arbitraging volatile power prices. For engineers, the challenge lies in designing schemes flexible enough to respond to rapid swings in market conditions while minimising water losses and efficiency penalties.
Philippines: Wawa
In Southeast Asia, the Wawa project (600MW) in Rizal Province, Philippines, highlights pumped storage’s role in national energy planning. Phase 2 construction, with SMEC as Owner’s Engineer, will include dams, reservoirs, a powerhouse, and complex tunnel systems. The project is valued at US$2.57 billion and will provide 6,000MWh of storage daily.
Wawa is intended to supply mid-merit and peak power to the Luzon grid, reducing dependence on imported fossil fuels and improving reliability during peak demand periods. For engineers, the key tasks include designing tunnels and reservoirs in steep
terrain subject to seismic risks, and integrating the plant with the Luzon grid’s evolving renewable mix.
Middle East: Hatta pumped storage
Dubai Electricity and Water Authority (DEWA) has started trial operations at the 250MW Hatta PSH plant. With a storage capacity of 1,500MWh and a design life of 80 years, the plant represents the first such facility in the Gulf region.
Hatta features:
- An upper dam with a capacity of 5.3 million m³
- A powerhouse 60 m underground
- Two water valves weighing 110 tonnes each
The project is designed to complement Dubai’s large-scale solar PV and concentrated solar power projects, supporting the emirate’s Net-Zero Carbon Emissions Strategy 2050. For engineers, Hatta demonstrates how PSH can be adapted to arid regions with limited hydrological resources, relying on a closed-loop design and careful water management.
North America: seasonal storage ambitions
In the United States, focus has shifted from daily balancing to long-duration storage. The proposed Carrizo Four Corners PSH project on Navajo Nation land would provide 1,500MW of generation, 1,338MW pumping, and up to 70 hours of storage.
Led by New Mexico State University with $14.2 million in funding, the project aims to shift seasonal surpluses of wind and solar into periods of deficit. It would also provide backup for large industrial and data centre loads, stabilising operations during outages or prolonged lulls in renewable production.
The Navajo Nation is supporting site access and cultural/environmental reviews, highlighting the importance of community partnerships. For engineers, the project illustrates how PSH design can be pushed beyond diurnal cycles to meet multi-day or even seasonal requirements, opening new frontiers in reservoir sizing, hydraulic head management, and reversible turbine design.
Australasia: mining legacy meets energy future
Australia is investing heavily in PSH as it transitions to renewables. Flagship projects include Snowy 2.0 in New South Wales and the Kidston and Borumba Pumped Storage Hydro Projects in Queensland.
Snowy 2.0, an expansion of the Snowy Mountains Scheme, will add 2,000 MW of capacity and triple the system’s pumping ability. Delivered by Future Generation Joint Venture (led by Webuild and Clough), the project involves tunnelling between the Tantangara and Talbingo reservoirs and a deep underground power station.
Three tunnel boring machines – Florence, Lady Eileen Hudson, and Kirsten – are active, while a fourth (TBM Monica) is being prepared for more difficult terrain. Key milestones include excavation of the machine and transformer halls and concrete lining of the Tantangara tunnel. Despite earlier delays, works have resumed and the project is back on track, with first power targeted for late 2027.
In September, Voith said it has completed two major Factory Acceptance Tests (FATs) for the project, finalising work on key components in Shanghai, China, and Heidenheim, Germany.
In Shanghai, tests were carried out on generator components including the rotor poles for Unit 4 and stator bars for Unit 2. The rotor poles showed uniform magnetic flux density, precise winding, and high-quality lamination. The stator bars met requirements for insulation thickness, partial discharge values, and bar end shaping. The FAT process was conducted under a structured quality framework, which customer representatives described as showing strong manufacturing discipline and effective quality management.
At Voith’s Heidenheim site, the Automation team completed FATs for digital and hydraulic governors for Units 5 and 6. The systems were tested in their final cabinet configuration with live control connections. The FATs marked the first use of bus-controlled proportional valves on an Allen-Bradley PLC platform. After calibration, the system performed as expected. Hydraulic opening and closing times were optimized, and emergency shutdown procedures were successfully tested.
More than 30 engineers and technicians took part in the Heidenheim FATs, using the process to build experience for upcoming commissioning work in Australia.
In Queensland, the Kidston PSH project is transforming an old gold mine into a 250 MW, 2,000 MWh storage facility. Developed by Genex Power, it repurposes two former mine pits and is the first private-sector PSH project in Australia. A dedicated transmission line will link it to the grid, with synchronous generation boosting system stability. The Queensland government and federal agencies are supporting the $777 million project as part of Australia’s National Electricity Market reforms.
Construction is progressing, with Unit 2’s spiral case and stay ring installed in April 2025. Energisation is planned for the second half of the year, marking a major step in Australia’s clean energy future. Genex has also signed a 30-year offtake agreement with EnergyAustralia, ensuring bankability and long-term returns for the project.
The Borumba project is currently advancing through detailed design and environmental assessment. Sited at Lake Borumba it will deliver 2,000 MW of generation with 48,000 MWh of storage, supporting continuous output at maximum load for 24 hours. Its design involves a new upper reservoir of approximately 178 GL constructed at elevation, paired with an expanded lower reservoir (Lake Borumba), increasing its capacity from 46 GL to 224 GL and requiring a new dam wall of about 105 metres in height and multiple saddle dams totalling up to 2.3km in length. The gross hydraulic head across the system is planned at roughly 600m. Large-diameter tunnels, an underground powerhouse, and new high-voltage transmission links are key infrastructure components. The scheme’s location, detailed geotechnical investigations, and independent reviews confirm its technical feasibility and its ability to provide grid-scale firming for Queensland’s planned renewable energy penetration targets beyond 70% by 2032
Lessons and outlook for pumped storage
The projects advanced in 2025 show a technology both mature and adaptable:
- Design innovation: underground caverns (Limberg III), ternary units (Pracomune), and variable-speed machines are extending the operational envelope.
- Build speed vs. permitting: China’s accelerated timelines contrast with Europe’s decade-long approvals, showing how governance affects engineering execution.
- Market integration: Chile and the Philippines illustrate how PSH can be tailored to liberalised versus centrally planned markets.
- Refurbishment value: modernising legacy plants remains a cost-effective way to maintain system stability.
- Investment intensity: billion-dollar budgets are now routine, reflecting the scale of underground works and the value of flexibility.
As 2025 shows, pumped storage is not a relic. It is increasingly the backbone of renewable grids worldwide.
