GE Vernova signs deal to replace two 315MW units at UK's Dinorwig plant

en.Wedoany.com Reported - Dinorwig, the UK's largest pumped storage hydroelectric plant, is undergoing a major modernization program, with owner First Hydro having signed a contract with US energy company GE Vernova to replace two 315-megawatt (MW) generating units and associated core equipment.

The 1.7-gigawatt (GW) plant, located inside Mount Elidir Fawr in Snowdonia, Wales, has been in operation since 1984 and is known as the "Electric Mountain." First Hydro is 75% owned by French energy group ENGIE and 25% by La Caisse.

Pumped storage facilities store energy by leveraging the elevation difference between two reservoirs: water is pumped from the lower to the upper reservoir when electricity is abundant, and released to drive turbines to generate power when the grid needs it, thus providing clean electricity even during windless and sunless periods. Such plants rely on mountain elevation differences and are typically built in mountainous areas. As one of only four pumped storage plants in the UK, Dinorwig has been a critical component of Britain's grid stability for decades, a role that has become even more prominent as the share of intermittent sources such as wind and solar power connected to the grid has increased.

Under this modernization, GE Vernova is responsible for replacing the motor-generators, pump-turbines, and control systems, as well as refurbishing components including the spiral casings, stay rings, and draft tubes. The pump-turbines and motor-generators are being designed and manufactured at its centers of excellence in France and Switzerland, with starting devices and protection systems coming from plants in Germany and Spain. The contract is part of a broader plan, with First Hydro planning to progressively replace key components across all six generating units at Dinorwig. ENGIE stated that the work is expected to extend the plant's operational life by at least 25 years.

Delphine Cherel-Sparham, Managing Director of ENGIE Hydro UK, said the contract marks a significant milestone in the long-term investment program for Dinorwig. Emmanuel Mercier, EMEA General Manager of GE Vernova's hydropower business, said the project is an example of GE Vernova applying innovation and engineering expertise to an iconic hydropower asset.

Dinorwig, together with the neighboring Ffestiniog plant (also owned by First Hydro), provides a combined capacity of approximately 2.1 GW, accounting for about 74% of the UK's total pumped storage installed capacity. The UK's other two pumped storage plants, Cruachan and Foyers, are located in the Scottish Highlands and were both built before Dinorwig came into operation; Dinorwig is the UK's youngest pumped storage facility, yet it has already been in service for more than 40 years. According to the British Hydropower Association, three new projects in Scotland—Loch Kemp, Coire Glas, and Earba—have been approved, with a further combined capacity of around 10 GW in the pipeline across Scotland and Wales. Among these, SSE Renewables' Coire Glas project on Loch Lochy is the most advanced, expected to add up to 1.5 GW of capacity to the UK grid.

UK Energy Minister Michael Shanks, announcing a batch of new projects in June, said that 40 years after the last pumped storage facility was built, this government is getting Britain building again. He said the lessons of the conflict in Iran are clear: the UK cannot continue to be at the mercy of volatile fossil fuel markets, leaving households exposed to the risk of the next price shock. By promoting a new generation of pumped storage and state-of-the-art batteries, the country needs to make full use of the clean electricity already produced domestically, reduce waste, lower bills, and strengthen energy security.

GE Vernova said Dinorwig is a highly strategic asset for the UK power system, and the company supports First Hydro in strengthening the plant's reliability and performance, contributing to the UK's energy and storage portfolio.