Scotland evaluates its largest 'water battery': 2 GW pumped storage at Loch Ness

Scottish developer Glen Earrach Energy Ltd (GEE) has announced plans to develop a 2 GW pumped storage hydro station at Balmacaan Estate in Scotland, and recently submitted its scoping request to the Scottish Government's Energy Consents Unit.

If approved, the project would trump SSE Renewables' £1.5 billion and 1.5 GW Coire Glas at Loch Lochy as Scotland's largest hydroelectric project, and overtake the 1,800 MW Dinorwig hydro power project in Wales as the largest hydropower project in the the UK.

GEE's project, nestled next to the famous Loch Ness lake, would leverage a height differential of over 480 meters between the upper and lower reservoirs, and be capable of delivering up to 30 GWh of electricity to the grid, the company said.

GEE estimates the project will represent an investment of more than £2 billion ($2.5 billion) over a six-year period. It will also save the energy grid £2 billion in running costs while reducing the carbon footprint by 10 percent. The developer is working with a group of advisors and experts – including AECOM, Alpiq, Frontier Economics and LCP-Delta – to take the project forward.

Roderick MacLeod, Director, GEE, said in a statement: "Scotland is a leader in wind power, but the wind doesn't always blow when we need the energy most. That's when pumped storage hydro comes in. It is like a giant water battery, storing excess wind power when it's plentiful and releasing it when the wind dies down."

MacLeod added that international experts had identified GEE's pumped storage hydro project as the most efficient in the UK, possibly even Europe. "It will be needed to help Britain get to net zero," he concluded.

In its release, GEE pointed out that "Pumped storage hydro is proven to be the cheapest form of long-duration electricity storage" and described pumped storage projects as "a proven, mature, and reliable technology and has the lowest carbon footprint among long-duration energy storage options."

Loch Ness is no stranger to hydroelectric capacity. The lake serves as the lower storage reservoir for the 300 MW Foyers pumped storage project, which opened in 1975. Another, smaller 5 MW power station nearby provides power for an aluminum smelting plant and the national grid.

A 100 MW Glendoe Hydro Scheme reopened after repairs in 2012, and the government in 2021 approved the 450 MW / 2.8 GWh Red John project, which was subsequently acquired by Norwegian company Statkraft in December 2023.