GE Vernova to Replant First Two Units at Europe's Largest Pumped Storage Plant

First Hydro Company, a joint venture between ENGIE and Canadian pension fund La Caisse, has selected GE Vernova to modernize and replant the first two units of the Dinorwig pumped storage hydropower plant in North Wales, U.K., the companies recently announced.¹ GE Vernova will replace two 315-MW units as part of First Hydro's long-term replanting program, which covers key components across all six of the plant's generating units.¹

A 40-Year-Old Fleet Built for Speed

Commissioned in the early 1980s, Dinorwig is Europe's largest pumped storage plant and is built for rapid response: the release states it can deliver up to 1,320 MW within 12 seconds from standby and up to 1,800 MW in under a minute, enough to support roughly a million homes.¹ The plant runs on six reversible Francis-type pump-turbines, each rated around 330 MVA, housed in what's considered the largest man-made cavern in Europe.² Together with the smaller Ffestiniog station, Dinorwig gives First Hydro 2.1 GW of installed capacity, about 74% of the U.K.'s pumped storage total.¹

What's Being Replaced

GE Vernova's scope covers the upgraded motor generators and pump turbines, plus refurbishment of embedded parts including the spiral case, stay ring, and draft tube.¹ The project also adds an upgraded station control system and new low-voltage, medium-voltage, and DC power supply equipment. The pump turbines and motor generators were engineered at GE Vernova's centers of excellence in Grenoble, France, and Birr, Switzerland, following successful model test validation in Grenoble.¹ The work draws on several GE Vernova business units: Power Conversion in Germany supplied the variable frequency starting equipment, Grid Solutions in Spain provided the protection system, and Gas Power in Switzerland is manufacturing the generator shaft.¹

Why First Hydro Is Doing This Now

"This contract marks an important milestone in our long-term investment programme at Dinorwig," said Delphine Cherel-Sparham, managing director of ENGIE Hydro UK. "As majority owner and operator of the plant, ENGIE is committed to ensuring Dinorwig continues to provide the flexibility, resilience and energy storage capabilities that the UK electricity system increasingly depends upon. Together with GE Vernova, we are investing in the modernization of key generating units to help secure the plant's performance for decades to come."¹

Emmanuel Mercier, GE Vernova's hydro power EMEA leader, framed the deal similarly: "This project is a strong example of how GE Vernova can bring innovation and engineering expertise to a landmark hydro asset. Dinorwig is a highly strategic facility for the UK power system, and we are proud to support First Hydro Company in strengthening the reliability and performance of this important plant."¹

The Bigger Picture

Pumped storage remains the workhorse of grid-scale energy storage even as batteries dominate the headlines, and aging fleets built in the 1970s and '80s are reaching the point where operators must choose between replacement and retirement. GE Vernova says it holds nearly 30% of the global pumped storage installed base and is currently developing more than 3 GW of new projects worldwide, positioning the Dinorwig order as one data point in a broader replanting cycle likely to reach other vintage plants as grids lean harder on long-duration storage to firm up renewables.¹

References
1. ENGIE and La Caisse select GE Vernova for next phase of Dinorwig modernization/replanting. Press release. First Hydro Company/GE Vernova; June 30, 2026.
2. Essential safety – Dinorwig, Wales. Andritz Hydro News. Accessed July 24, 2026. https://www.andritz.com/hydro-en/hydronews/hn36/dinorwig-wales