• First Hydro Company – a joint venture between ENGIE and La Caisse with a 75:25 ownership split – has appointed GE Vernova to lead the modernization and replanting of the first two generating units at the Dinorwig pumped storage hydropower facility in North Wales, UK.
• Under the agreement, GE Vernova will replace two existing 315 Megawatt (MW) units, enhancing the plant’s operational efficiency, reliability, and availability.
• By the end of the 2020s, the upgraded units at Dinorwig are expected to continue delivering rapid-response power generation, a critical function for maintaining the stability and resilience of the UK’s electricity grid.

Paris, FRANCE (July 28, 2026) — First Hydro Company, a joint venture between ENGIE and La Caisse, and GE Vernova Inc. (NYSE: GEV), have announced the next step in the comprehensive modernization of the Dinorwig pumped storage hydropower plant in North Wales. As part of this initiative, GE Vernova will supply and install replacements for two of the plant’s six pumped storage units, supporting First Hydro’s long-term replanting strategy. This investment aims to extend the facility’s operational lifespan by decades while improving performance, reliability, and contribution to UK grid stability.

Now more than four decades old, Dinorwig remains one of Europe’s most powerful pumped storage hydropower stations. It is famed for its exceptional responsiveness, capable of delivering 1,320 MW within 12 seconds from standby mode and reaching up to 1,800 MW in under 60 seconds. These capabilities make it a cornerstone of grid resilience and frequency regulation, supplying power equivalent to approximately one million UK homes.*

As the majority owner and operator of Dinorwig through First Hydro Company, ENGIE is making a substantial long-term commitment to modernize the facility. The broader replanting programme involves replacing critical components across all six generating units, along with major infrastructure enhancements.

This modernization effort is part of one of the largest hydroelectric refurbishment initiatives in the UK, reinforcing long-term grid reliability and enabling greater integration of renewable energy sources into the nation’s evolving power system. The project is projected to extend the plant’s operational life by at least 25 years, ensuring continued provision of fast, flexible, and low-carbon electricity.

“This contract represents a key milestone in our ongoing investment at Dinorwig,” said Delphine Cherel-Sparham, Managing Director of ENGIE Hydro UK. “As the primary owner and operator, ENGIE is fully committed to maintaining Dinorwig’s vital role in delivering flexibility, energy storage, and grid resilience. Partnering with GE Vernova, we are advancing the upgrade of core generating units to secure the plant’s high performance for future generations.”

“This project highlights GE Vernova’s ability to deliver cutting-edge engineering and innovation to a globally recognized hydro asset,” said Emmanuel Mercier, GE Vernova’s Hydro Power EMEA Leader. “Dinorwig is a strategic asset for the UK’s power infrastructure, and we are proud to support First Hydro Company in enhancing the plant’s reliability and operational excellence.”

The announcement follows the successful validation of the pumped storage unit model tests conducted at GE Vernova’s research facility in Grenoble, France. As part of its scope, GE Vernova will deliver upgraded motor generators and pump turbines, along with refurbishing embedded components such as the spiral case, stay ring, and draft tube. The project also includes modernizing the plant’s control system and upgrading low-voltage, medium-voltage, and DC power supply systems. The pump turbines and motor generators are being engineered at GE Vernova’s Centers of Excellence in Grenoble, France, and Birr, Switzerland, respectively.

The initiative leverages GE Vernova’s integrated global capabilities, including Variable Frequency Starting Equipment designed and installed by GE Vernova’s Power Conversion team in Germany, protection systems supplied by Grid Solutions in Spain, and generator shaft manufacturing by Gas Power in Switzerland. The station’s control system will also be modernized using GE Vernova’s industrial expertise.

Pumped Storage Projects

Pumped storage hydropower offers large-scale energy storage and rapid-response flexibility, playing a crucial role in balancing electricity supply and demand and supporting the growth of renewable energy. Through First Hydro Company, ENGIE and La Caisse own and operate both the Dinorwig and Ffestiniog pumped storage facilities in North Wales. Together, these stations provide 2.1 GW of installed capacity, accounting for approximately 74% of the UK’s total pumped storage hydro capacity.

GE Vernova is a leading global provider in the pumped storage sector, with nearly 30% of the world’s installed capacity. The company is currently advancing over 3 GW of pumped storage projects worldwide.

About ENGIE

ENGIE is a key driver in the global energy transition, dedicated to accelerating the shift toward a carbon-neutral economy. With over 90,000 employees operating in 30 countries, the company manages the full energy value chain—from generation to infrastructure and customer supply. ENGIE integrates a range of complementary activities, including renewable power and green gas production, energy storage (such as batteries), gas and electricity transmission and distribution networks, local energy systems like heating and cooling grids, and energy services for residential, municipal, and commercial clients. The Group invests an average of €12 billion annually to advance the energy transition and achieve net-zero carbon emissions by 2045.

About ENGIE in the UK

ENGIE employs over 8,000 people in the UK and operates across the entire energy value chain, generating, storing, distributing, and supplying energy. It manages a diverse portfolio of renewable and flexible energy assets, including Europe’s largest pumped-storage hydro plant. The company supplies energy to more than 17,000 business customers and produces over 200 GWh of biomethane annually.

ENGIE owns UK Power Networks, the UK’s leading electricity distribution network operator, serving 8.5 million customers across London, the South East, and East of England. Through Ocean Winds, its joint venture, ENGIE ranks as one of Scotland’s top offshore wind energy providers with 1.8 GW of installed capacity. For over two decades, ENGIE has invested heavily in the UK’s energy transition, bolstering energy security and enabling large-scale decarbonization for its customers.

ENGIE Financials

Revenue in 2025: €71.9 billion. The company is listed on the Paris and Brussels stock exchanges (ENGI) and is included in major financial indices such as CAC 40, Euronext 100, FTSE Euro 100, and MSCI Europe. It is also represented in key sustainability indices, including DJSI World, Euronext Vigeo Eiris – Europe 120 / France 20, MSCI EMU ESG screened, MSCI EUROPE ESG Universal Select, and Stoxx Europe 600 ESG-X.

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