Just 10 years ago, 40% of the UK's energy came from coal. Today, the country has only two remaining coal plants and plans to end coal-fired power by the end of 2024. Already closed coal mines have filled with water due to sump pumps being switched off, and are becoming potential sites for geothermal energy.

With about a quarter of UK homes situated above abandoned mines, the UK Coal Authority sees huge potential. It’s now looking into 70 projects that would use the water warmed underground to heat buildings above.

Why This Matters

Mine water heating could help decarbonize the UK's heating sector, which consumes about half of the country's energy, 70% of which is provided by gas. But natural gas will need to be phased out in order to hit net-zero emissions by 2050. Using mine water would provide a neutral energy source, which will be especially important in light of the EU's plans to create a carbon market for heating. The switch could be, as the BBC writes, "a serendipitous circle of history" where the coal industry's "extractive past could be repurposed for a greener, cleaner future."

Energy Switch is Also an Economic Opportunity

The mine complex in the coastal town of Seaham is closed, but it's one of the places moving forward with a second act for the abandoned mine. A new development in the town will be the UK's first district heating plan to use mine water energy, which will be both more climate-friendly and cheaper than gas. There's hope that the innovative approach to heating will bring new investment and jobs to the area, which has struggled to recover economically from the pit closures decades before.

A similar situation is playing out in Spain: in the Asturias region, the last coal pit closed in 2018 and mine water now heats various buildings, including a hospital and a university.

"Geothermal energy has given a second life to our coal mines," María Belarmina Díaz Aguado, the Asturias's director of energy, told the BBC. "We're developing an entirely new business model, one related to pumping water and all the technical expertise that involves."

Quitting the Final 1.8%

Last year, Great Britain went two months straight without coal power for the first time since the late 1800s. Last year, only 1.8% of UK electricity came from coal, part of a ramp down over the past decade. Of the two remaining plants, one has not announced plans to close and just secured a contract through 2022, two years before the government's pledge to end coal power by 2021.