Using Our Coal Mines to Provide Renewable Energy

By Barry Tylee
The Labour Government has pledged to make Britain self-sufficient in renewable energy and make the UK a world leader in floating offshore wind, nuclear power, and hydrogen. However, it would be overlooking a major source of energy – the old coal mines beneath many of our northern cities, including under Stocksbridge and the surrounding area. All these mines are flooded, the deeper the mine the warmer the water and the more energy that can be obtained via a heat pump. When you think of the effort over many centuries to dig the coal out, leaving large cavities which flood; it’s good to think that this can generate energy once again.  My house has been heated satisfactorily by an air-source heat pump since 2010, even though the building is very old and has solid walls; so, I’m a great enthusiast for these devices, which now have an efficiency of 300% to 500%.
Over the years, the Upper Don Community Energy and its fore runner have tried to encourage local developments over old coal mines to consider this as a source of energy. After all, there are plenty of examples to look at now. including whole towns in Europe, such as, Heerlen in the Netherlands where there’s a hot water network which you can plug your house into. However, it’s difficult to attract finance for such schemes. With regards to large-scale PV and wind turbines, while the capital expenditure is large, the return on the investment can almost be guaranteed as the amount of solar radiation or wind in an area is known with certainty. With regards to mines, if there aren’t open water sources to tap into, then boreholes must be made and this is where the risk becomes large and the outlay costs expensive.  You need the bore holes to hit the desired flooded galleries to avoid the need to drill any more expensive holes. With old mines, where the mapping was maybe inaccurate and used room and pillar mining, a bore hole might just hit a pillar of coal and be useless. With more recent coal fields, the retreat method of mining might mean the mined cavity has subsided so leaving much less warm water.
However, there are still plenty of schemes around the county to show that this works – a new one in the northeast of a partially-community owned mine water and heat network supplying 100 homes, 5 businesses and a green house. The temperature of the mine water here is 16 degrees centigrade, which is much more than annual surface water or air temperature, and which generates much more heat. The capital cost of this is about £8.5M, with a return on the investment of 10%.
I would hope that we can persuade the new Great British Energy to underwrite the risk from these schemes and so make a major contribution to renewable energy throughout the country, and it would be nice to see one heating homes and businesses in the Upper Don!