Hydroelectric power has been generating clean electricity in the UK for over a century. Pumped storage is now the critical long-duration storage solution for a net-zero grid — and a £20bn+ development wave is underway.
PSH acts as a giant rechargeable battery — pumping water uphill when electricity is cheap, generating when it's expensive. The UK's existing four stations have served the grid for decades. A new wave of gigawatt-scale projects is now in planning.
Scotland's glens and highlands host most of the UK's conventional hydro capacity — much of it built by the North of Scotland Hydro-Electric Board from the 1940s–1960s.
Hundreds of small run-of-river schemes provide clean power to local communities and farms across Scotland, Wales and Northern England. Many are community-owned and provide local economic benefit.
Take water from a river, pass it through a turbine and return it — no reservoir needed. Minimal environmental footprint but output varies with rainfall. Most UK small hydro uses this approach.
As the grid moves to 70–80% renewables, the challenge is no longer generating clean electricity — it's storing it. PSH provides the only proven, large-scale, long-duration storage technology available today. 30+ GWh of new UK PSH is required by 2035 according to NESO modelling.
PSH lacks a CfD equivalent. The UK government's Cap-and-Floor mechanism — consulted on by DESNZ — would provide a revenue floor to attract investment decisions. Coire Glas is the test case for whether this unlocks the pipeline.
Hydro and pumped storage are just two parts of the UK's net zero story.