Drax already has a 440 MW pumped hydro storage station at the site of Ben Cruachan, Argyll's highest mountain, in the west of Scotland.

However, it seeks to build a new 600 MW power station which would be located inside the mountain to increase the site's total capacity to 1.04 gigawatts, the company said.

The new station would have the capacity to generate enough power for around a million homes and construction could begin in 2024, pending planning permission approval.

By using reversible turbines to pump water from Loch Awe to the upper reservoir on the mountainside, the plant would be able to store power from wind farms when supply outstrips demand.

The stored water would then be released back through the turbines to generate power when demand increases.

(Reporting by Nina Chestney; editing by Emelia Sithole-Matarise)