Abandoned coal mines could be goldmines for geothermal energy


Biden administration recently announced Nearly half a billion dollars from both the inflation reduction and infrastructure laws will go toward clean energy projects in former coal mines. Some sites will have solar farms, but there’s a lesser-known opportunity inside the mines: geothermal energy.

Abandoned coal mines are usually filled with water when mining stops. That water carries heat from the very bottom of the Earth’s surface. People can drill bore holes to bring that heat to the surface, then pass it through heat exchanges and heat pumps in buildings and homes.

The first neighborhood mine-water heating scheme in Great Britain became fully operational at the end of March and will eventually serve more than 1,200 homes.

Gareth Farr, head of heat and by-product innovation at the Coal Authority in Mansfield, England, explained: “Each mineable scheme has its own individual challenges, and the costs involved with drilling bore holes or laying district heat network pipes in the ground Will be.” , “But the expectation is that most of these schemes, if not all of them, will be able to operate at the same or better cost than the traditional fossil-fuel heating schemes we have at the moment.”

Geothermal energy is nothing new, but taking it from abandoned coal mines is not yet common, especially in the United States.

Natalie Krause-Daniels, professor and director of the Environmental Studies Program at Ohio University, and her students are studying abandoned mines in Appalachian Ohio to see which ones are large enough to be used for home heating .

“It’s an untapped energy source that could lower bills, that could make energy more efficient, that could reduce some of the dependence on fossil fuels,” said Daniels, who has been fascinated by coal mines since childhood. .

Geothermal energy from coal mines can be used not only to heat homes and buildings, but also to cool them. This opens up many more opportunities, especially for data centers. They are some of the worst carbon offenders, using vast amounts of energy and requiring thousands of gallons of water to cool themselves. Now, researchers in Scotland are studying how hot air from data centers could be pumped into coal mines and then recovered with water to heat other buildings.

“We can store heat in the mines, and we hope to actually become part of the significant heat storage. Certainly, storage is important for a lot of renewable energy,” Farr explained.

Coal fields run under at least 20 states in the US.

Ohio has more than 4,000 abandoned mines, a treasure trove of geothermal energy opportunity. In 2007, the US Department of Energy reported that the amount of water currently being released from underground coal mines in the Pittsburgh Coal Seam could potentially be used for heating and cooling of approximately 20,000 homes.

So why is it not happening? Krause-Daniels said that while it is a relatively cheap form of clean energy, location and legacy can be liabilities.

“I think some of it is out of sight, out of mind, right? When we look at investment in new technology and clean energy in Appalachia, it’s limited,” Krause-Daniels said.

Coal is controversial, so investors don’t target coal fields, which she says is a mistake.

“In a less predictable climate and a warming world, this opens up an opportunity to turn this legacy, this liability, into a resource,” he said.

CNBC producer Erika Paus contributed to this piece.

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