Coal power plants in China’s Sichuan province consumed a city’s worth of extra water every day while a summertime 2022 drought was limiting hydropower production, in a vicious cycle that climate analysts worry heightens the risk of water scarcity.

Sichuan’s coal plants used up around 21 million cubic metres of water during June to September 2022 as they ran at full tilt while the hydropower-dependent province was suffering from a drought-induced power shortage, according to climate risk data provider TransitionZero.

The daily excess usage, compared to the summer of 2021, equals the daily water needs of 1.2 million people or 480,000 households, TransitionZero found.

“Coal saved China’s hydro-reliant provinces during this summer’s extreme drought,” the climate think tank said in an article published on Thursday. “But using thermal plants to prop up the grid during dry periods risks exacerbating the problem of water stress.”