Deep geothermal energy is the natural heat found beneath the earth's surface. It comes from the red-hot core of our planet, the friction between rocks and the decay of radioactive elements on the earth's surface. Deep geothermal energy has therefore been around for millions of years and will also remain permanently available in the future.

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Water measuring 125°C

In some places, geothermal energy literally emerges from the earth's crust, such as in Iceland and in northern Italy. In other areas, it is necessary to pump the water up in order to use the heat. In the Campine, water measuring around 125°C can be pumped up from a depth of 3.5 kilometres. Researchers at VITO identified this in the demonstration project on the Balmatt site.

The warm water can be used to heat buildings via a heating network. Water measuring 125°C is also warm enough to supply large complexes such as hospitals, entire residential areas and greenhouses with the necessary heat.

 

How does it work?

The deep geothermal energy from the deep subsoil passes via a heat exchanger, to which the warm water delivers its energy. The cooled water is then injected back into the subsoil. This is carried out via a second well, which is 4,341 metres long but runs at an angle and therefore emerges at a depth of 3,300 metres. This 'geothermal doublet' is an aspect of each geothermal energy plant. It forms a closed circuit, which means that no differences in pressure arise in the subsoil. By connecting the deep geothermal energy plant to a heating network, homes and companies in the area can be supplied.

Green power

Once the temperature of the water is high enough, green power can be generated.  This occurs by converting the geothermal energy into electricity via Organic Rankine Cycle (ORC). VITO will apply this principle on the Balmatt site in Mol.