Drax invites EOIs for Scottish hydro station

The new 600MW pumped storage hydro station will be located in Ben Cruachan – Argyll’s highest mountain – and will more than double the capacity of the existing facility to 1.04GW. 

The new plant, which could be operational in 2030, will act like a giant water battery. It will use reversible turbines to pump water from Loch Awe to the upper reservoir on the mountainside to store excess power from wind farms and other low carbon technologies when supply outstrips demand and then use the stored water to generate renewable power when it is needed.

The works include the construction of a new intake structure within an operational upper reservoir connected via new hydraulic tunnel systems to the powerhouse complex excavated in quartz dolorite rock 400m below ground level.

The powerhouse will be a series of underground caverns containing reversible pump-turbines, motor-generators and associated equipment including transformers and switchgear. A new tailrace tunnel will be constructed from the powerhouse to a new outfall structure in an existing lower reservoir. A vertical ventilation shaft from the powerhouse will connect to an expanded existing above ground sub-station complex.

A new 1.45km main access tunnel will link the powerhouse to a new jetty constructed along the lower reservoir. Forming the main access tunnel portal will require the diversion of a trunk road.

The construction spoil will be taken out through the mountain to the jetty and stored prior to off-site removal. New administration and workshop buildings will be built on the jetty. Existing access roads will be upgraded together with the construction of new roads as required.

The contract notice is expected to be published in October and construction will start in Q4 2025.