First Hydro Company has selected GE Vernova to modernize the first two generating units at the Dinorwig pumped storage hydropower plant in North Wales.
The major replanting project is intended to extend the strategic facility's operating life by more than 25 years.
First Hydro is a joint venture between ENGIE and Canadian pension fund La Caisse.
Its wider investment program covers essential components across all six Dinorwig generating units, establishing a long range path for maintaining one of the United Kingdom's most important electricity storage assets.
GE Vernova will replace two units rated at 315 MW each.
The contract represents the opening phase of a comprehensive renewal effort designed to preserve Dinorwig's formidable generating capability, rapid response performance, and value to an electricity network carrying growing volumes of renewable energy.
Commissioned during the early 1980s, Dinorwig is recognized as the largest pumped storage plant in Europe.
From standby, it can deliver 1,320 MW within 12 seconds and reach as much as 1,800 MW in less than one minute.
That extraordinary responsiveness allows the station to support the electricity needs of roughly one million homes.
More importantly for grid operators, Dinorwig can inject power when sudden demand changes, generation losses, or fluctuations in wind and solar output place pressure on system frequency.
The underground facility contains six reversible Francis type pump turbines, with each machine rated at approximately 330 MVA.
These units are installed within what is considered the largest cavern constructed by people anywhere in Europe, giving the plant an engineering profile as remarkable as its electrical performance.
Together with the smaller Ffestiniog pumped storage station, Dinorwig provides First Hydro with 2.1 GW of installed capacity.
That portfolio accounts for approximately 74 percent of the total pumped storage capacity currently available across the United Kingdom.
GE Vernova's scope includes upgraded motor generators and pump turbines. The company will also refurbish embedded hydraulic components, including the spiral case, stay ring, and draft tube, where condition and geometry are critical to efficiency, structural integrity, and dependable operation.
Additional work includes an upgraded station control system and new low voltage, medium voltage, and direct current power supply equipment.
Protection systems and auxiliary electrical infrastructure will also be renewed, creating a broader modernization package rather than a narrow rotating equipment replacement.
Delphine Cherel Sparham, managing director of ENGIE Hydro UK, said, "This contract marks an important milestone in our long term investment programme at Dinorwig."
She added, "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."
Engineering for the pump turbines and motor generators was completed at GE Vernova centers of excellence in Grenoble, France, and Birr, Switzerland.
The equipment designs advanced after successful model testing in Grenoble, an essential validation step for confirming hydraulic behavior before manufacturing and installation.
Several GE Vernova businesses are contributing specialized technology to the program.
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.
Emmanuel Mercier, GE Vernova's hydro power EMEA leader, said, "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."
The Dinorwig order arrives as pumped storage plants commissioned during the 1970s and 1980s approach major refurbishment decisions.
Operators must increasingly choose between extensive equipment renewal and retirement, even as power systems demand more flexible capacity to balance variable renewable generation.
Although batteries command considerable attention, pumped storage remains the dominant form of grid scale energy storage worldwide.
Its ability to store large quantities of energy for extended periods makes refurbished hydro assets increasingly valuable as conventional generation retires and renewable penetration rises.
GE Vernova says its equipment represents nearly 30 percent of the global installed pumped storage fleet.
With more than 3 GW of new projects under development worldwide, the company is positioning the Dinorwig contract within a much larger cycle of hydro modernization and long duration storage investment.
