energy equality

Using old coal mines for renewable heat

There’s a new development planned for County Durham in the North-East of England. Called South Seaham Garden Village, it will include 1,500 new homes, a village centre with a school, and an innovative district heating system. It will be the first development in Britain to be heated using an abandoned coal mine.

Country Durham is old coal country. There are abandoned mines scattered through the landscape, and that creates opportunities for sustainable heating. Specifically, it is the water in the mines that will be used as a source of heat.

The mines in the area are flooded, and the water is very salty. The Coal Authority, the government body responsible for the environmental legacy of Britain’s coal mining, spotted that this could pose a risk to a fresh water aquifer in the area. If the hyper-saline mine waters were to mingle with the aquifer, it would pollute a source of drinking water for thousands of people. So they built a mine water treatment plant. Powered by a huge solar array, the plant treats hundreds of millions of litres of water a year.

Since this warm water was being pumped up for treatment anyway, heat exchangers were fitted to heat the offices and staff rooms at the site, but there was obviously plenty of capacity for more. Now it will be pumped through a local network to provide renewable heat to the new village. It’s a unique form of geothermal heat, and it will deliver warmth to the new homes at less than the price of grid gas.

“Water in the mines is heated by geological processes, and remains stable year-round” explains Jeremy Crooks from the Coal Authority. “This constantly renewing available, zero-carbon heat resource, can be transferred to a pipe network using a heat exchanger and distributed to nearby homes, and the Seaham Garden Village development will be the first working example of this network.”

An interesting experiment, but one that begs the question of whether or not it could be replicated elsewhere. And the Coal Authority reckon it could. Apparently a quarter of Britain’s homes and businesses are located on or around former coal fields, and there is enough energy in the flooded and abandoned mines to heat all of them. It won’t ever reach that far, but clearly it could make a big contribution to decarbonising our heating needs. And I think there’s something very satisfying about seeing the country’s former coal infrastructure repurposed and redeemed to produce renewable energy in this way.

Interestingly, this could be a technology that reduces inequality too. Lots of towns and villages in Britain were built to serve the mines. When they closed, there was never a replacement source of employment on the same scale, and former coal mining communities have been marginalised and disadvantaged ever since. By being so close to the mines however, these communities would be first in line for low cost, low carbon geothermal heat. It would reduce bills and save money in poorer areas, create jobs, and would see the mines putting cash back in people’s pockets again. That would help to rebalance regional inequalities, and would benefit some of the left behind areas of North-East England or the mining towns of Wales.

South Seaham Garden Village will be an experiment to to keep an eye on.


  1. Oldham, with old coal mines under the town centre, is an obvious candidate for this.
    There is a competing re-use option, isn’t there? Storing carbon dioxide from CCS…

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