Geothermal energy

Knowledge about the subsurface and groundwater plays an important role in the development of geothermal systems. The temperature increases with depth, so the deeper the better. However, the subsurface needs to be sufficiently permeable to remove the hot water. The deeper you drill, the greater the costs and the risks. We can help you make an initial scan of the financial and technical potential of geothermal heat or geothermal energy at your location or in your municipality. We can also help you to evaluate existing plans and initiatives and to carry out a risk analysis.


The deeper you drill, the higher the temperature becomes. In The Netherlands, every kilometer the temperature increases by approximately 30 degrees, this is the temperature gradient. At a depth of 3 kilometers you will find water of around 100 degrees. Geothermal systems are open systems at depths of more than one kilometer that make use of permeable reservoir rock.

Geothermal systems are usually called doublets, which consist of an extraction well and an injection well, approximately 1 to 2 kilometers apart. The heat from the hot pumped-up water is extracted via a heat exchanger at the surface and the cooled formation water is then injected back into the same deep layer. The lifespan of such a doublet is around 30 years.


In addition to the financial risks, there are also other risks. One of the greatest risks is the pollution of groundwater through leakage of the formation water. During drilling, gas can also be encountered, or a high pressure can unexpectedly be found in the drilled layer. In addition, there is a chance that earthquakes will be induced, especially when drilling near fractures or in seismic areas or when water is injected under high pressure.

All kinds of measures can be taken to limit the impact of these risks. Seismic monitoring is sometimes used to be able to intervene in the event of earthquakes. The casings can be double-walled or with stainless steel to limit the risk of leakage due to, for example, corrosion.