The coal mines may be closed, but gas is still slowly escaping from the coal seams. It may come to the surface along natural or artificial shafts, fault lines, during a mine collapse or through permeable rock. For safety reasons, this flammable and explosive gas is therefore regularly released from disused mines in a controlled manner.

The gas from mines consists mainly of methane, a greenhouse gas which is 28 times more harmful where global warming is concerned than CO₂. Already today, methane is used to generate electricity or grey hydrogen, which means from fossil fuels. Not exactly environmentally friendly! The production of green hydrogen by electrolysis using renewable electricity, on the other hand, guzzles heaps of energy and is very expensive.

Materia Nova is working on a new process: extracting green hydrogen from the gas from mines using so-called plasma pyrolysis. The advantage is threefold: no more methane leaks, lower energy consumption than with electrolysis and, in addition to hydrogen, it generates solid carbon, much sought after by industry. Now the search is on to find out which mines in Wallonia are suitable for the capture of gas.