Using Geothermal to Create Heat from Water in Abandoned Coal Mines

Climate Change Environment

            Heerlen           Gaining context for organizing in Heerlen Nord, we of course walked through kilometers of the neighborhood with more to come, but I also heard and watched a presentation on the history of the Limburg region and Heerlen as a central part of the Parkstad area.  The timer clicked through various occupation periods from the Romans to the French, Spanish, Austrians, and finally as part of the Netherlands. First, they had come for the richness of the soil, but they stayed for coal, the “black gold.”  The government announced the closure of the mines in the mid-60s, putting 60,000 out of work over a decade, and the last mine was shut in 1974.

Something popped up a couple of times, I had realized.  In Heerlen, they were now heating some buildings and had plans for much more by piping up water from the now flooded mines.  I was curious how that worked, especially since it seemed a paradox:  an alternative fuel that was by byproduct of coal, perhaps the worst agent of climate change since the Industrial Revolution began in Britain.

The force behind this novel heating system was geothermal energy.   When the mines were working, the pumps were constantly pushing water out of the pits and galleries, so the coal could be extracted.  When the mines closed, water filled up these areas and was naturally warmed by the earths geothermal energy.  Heerlen was an innovator in figuring how to take advantage of this phenomenon.

In 2003, the municipality of Heerlen decided to drill a number of exploratory wells in the mines as part of sustainable energy production. It soon became clear that the mine water could be used to heat and cool buildings in a sustainable manner. Heerlen started a successful initiative with this principle: the Mine Water Project. Five wells were drilled which are connected to each other via a main pipeline to supply and drain water. In the city of Heerlen, 50,000m2 of floor space in buildings was connected to the world’s first mine water power plant.

Now, that’s very interesting!

All of this work in Heerlen by the city led to the creation of a social enterprise called Minewater in order to scale up the early indications of success.  They explain that

When a building is cooled, it simultaneously delivers residual heat back to the network and vice versa. With the district heating network, the cycle of heat and cold supply to buildings is closed. The energy is exchanged via underground basements containing the heat exchangers and pumps. The water in the mines now functions more as a large thermal battery than only as a green energy source. In this way, CO2 emissions from the connected buildings can be reduced by up to 65%. In this way, the company provided 200,000m2 of building space with heating, hot water and cooling by 2018.

The small city of Heerlen has come a long way since the Romans, but as my high school Latin teacher used to constantly remind us Mater artium necessitas, which in English has become “necessity is the mother of invention,” and in Dutch has become the underground heating and cooling system from the geothermal action on water in the old coal mines.