Engie's First Hydro to upgrade Welsh hydropower plant

LONDON, July 28 (Reuters) - Engie's First Hydro Company will upgrade its more than 40-year old Dinorwig pumped hydropower storage plant in Wales, with GE Vernova supplying new units, the companies said on Tuesday.

• Dinorwig can deliver up to 1,320 megawatts of electricity within 12 seconds from standby and up to 1,800 MW in under a minute, providing capacity equivalent to powering around one million UK homes, First Hydro Company said.

• Pumped storage hydropower is a large-scale energy storage system. During periods of low electricity demand, or if there is excess power form renewables on the grid, water is pumped from a lower reservoir to an upper reservoir.

• When electricity demand is high, water is released from the upper reservoir down through turbines which generate electricity.

• First Hydro Company is a joint venture 75% owned by France’s Engie and 25% by La Caisse.

• GE Vernova has been chosen to replace two 315 MW units as part of a broader overhaul covering all six generating units at the more-than-40-year-old plant.

• Financial details of the deal were not disclosed.

• The overall modernisation programme is expected to extend the plant's operational life by at least 25 years.

(Reporting by Susanna Twidale, Editing by Louise Heavens)