‘Hollow Mountain’ hydro power plant expansion put on hold

The operator of an underground power station at Scotland’s “Hollow Mountain” has put on hold its plans for a major expansion of the site.

Renewables developer Drax had proposed building a new hydro-electric facility next to its existing complex inside Ben Cruachan, near Dalmally in Argyll.

But it said the costs of the project had risen and it would not be bidding for UK government support at this time.

The company said the expansion could potentially go-ahead in the future, “subject to an appropriate balance of risk and return”.

The existing underground power station was opened by Queen Elizabeth II in 1965.

At the time, it was the first large-scale reversible turbine storage energy project of its kind in the world.

It is housed within a huge cavern dug out inside Ben Cruachan, which is nicknamed Hollow Mountain because of the project.

Drax had proposed investing £500m in the construction project over seven years.

Last year, it completed initial design and engineering work for a 600MW expansion of Cruachan.

The company said: “Drax believes that the Cruachan II project is well aligned with the long-term system need for flexible generation and energy storage and, given its location, is well placed to support system constraints between Scotland and England.”

It added: “Drax remains committed to disciplined capital expenditure which seeks to balance the risk and return of individual projects against other uses of capital, to maximise value.”

Scenes for Star Wars series Andor were filmed at Cruachan.

The makers of the show said the underground power station – and its 316m (1,037ft), 46m (15ft) long dam – had the look it had been aspiring to capture for an episode called The Eye.

Production designer Luke Hull told BBC Scotland News in 2022: “If you look at the dam, it looks like Darth Vader’s mask.”