The underground plant is one of just four pumped storage hydro power stations in the whole of the UK – playing a critical role in stabilising the national grid.

Since its opening by Queen Elizabeth II on 15 October 1965, Cruachan Power Station has powered homes and businesses across Scotland. Cruachan stores excess power from the grid and then generates it back into the system when it is needed like a giant water battery.

Thousands of people participated in the construction of the power station. Those who took part in the drilling, blasting, and clearing of rocks from inside the mountain earned the affectionate nickname of ‘Tunnel Tigers.’ Since its completion, generations of schoolchildren have ventured into the underground facility to see where the Tigers once roared through granite to build this iconic piece of Scottish engineering.

Six decades on from its opening, its current owners Drax are investing £80 million to upgrade and refurbish the plant. Once completed in 2027, the plant will be able to generate even more power, making it even more important to the country’s national grid.

Ian Kinnaird, Drax’s FlexGen assets director, said: “As we have celebrated Cruachan’s diamond anniversary throughout the year, I have heard from so many people who have a special place in their heart for this unique power station. Each year at our award-winning visitor centre we encounter people who have wonderful stories and memories of working at the site or passing through on a memorable school trip.

“Drax believes Cruachan has a bright future as well as a history and a legacy to be proud of. We are investing £80 million in upgrading and refurbishing the plant so it can play a role in stabilising the national grid for many more decades to come.”

The upgrade project will see the generating capacity of two of the plant’s four units increased to raise the facility’s total generating capacity to 480 MWs.