Hydro plants first line of defence in battle to keep Britain’s lights on

In the Welsh and Scottish mountains, a small number of hydro power stations, some of them more than half a century old, have become a first line of defence in the battle to keep electricity flowing around Britain during the coronavirus crisis. Britain’s four “pumped storage” hydro power stations, often referred to as “green batteries”, have played a critical role in helping utility company National Grid address exceptional conditions in the energy system since lockdown. The closure of businesses pushed demand for electricity down by 20 per cent on average in April and May while unusual weather meant the grid was simultaneously flooded with record solar generation and strong output from wind farms.