Geothermal energy

By drilling the production and injection wells at an angle, the underground distance between the wells is about 1,500 metres.

Geothermal is a conflation of the Greek ‘geo’ (earth) and ‘thermos’ (heat). It is a renewable energy source that is neither weather- nor season-dependent. 

The subsurface is composed of rock layers that are usually filled with salt water. In geothermal energy production, this salty water, which gets progressively warmer with increasing depth, is pumped up through a production well to a heat exchanger above ground. The heat exchanger extracts heat from the salt water and transfers it to the fresh water flowing through the heat grid. The cooled salt water is injected by an injection well into the rock layers from which it was produced.

Data and information

GDN manages all the data on the Dutch subsurface that oil and gas companies have been collecting for decades. Under the Mining Act, data delivered to GDN is checked for quality, and then added to the database. This public data is published via NLOG. We use this data to locate geothermal energy resources and for the production of geothermal energy, for example. In doing so, we contribute to the development of geothermal energy production and help accelerate the energy transition. 

Research and innovation in geothermal energy

Which technologies are suitable for the production of geothermal energy? And where in the Netherlands is the subsurface most suitable? The Geological Survey of the Netherlands has the necessary expertise and is conducting research on this. 

New technologies can make geothermal energy production affordable, even safer, and more compatible with the environment and the subsurface. For example, we are exploring the possibility of wells with multiple branches. This aims to increase production. 

We can test the developed technologies at the Rijswijk Centre for Sustainable Geo-energy (RCSG). RCSG is a unique innovation lab where geothermal energy innovations can be investigated at full scale.

Subsurface mapped

By mapping the subsurface of the Netherlands, and doing so with increasing detail, we bring the world under our feet into focus. We develop various subsurface models that can, for example, show which strata are potentially suitable for geothermal energy production. The maps and three-dimensional models we can develop, allow viewing the subsurface from all directions. 

Mapping the Dutch subsurface provides the foundation for further research into the potential and optimisation of geothermal energy production. Moreover, it provides insight into the (estimated) opportunities and risks of geothermal energy production. Examples of applications include WarmingUp (research programme), ThermoGIS (using maps), and our advisory role to the Dutch Ministry of Economic Affairs and Climate Policy. 


Besides technical and innovative research, GDN also conducts research on the potential of geothermal energy, based on the geology of the deep subsurface (500 metres to 4 km). ThermoGIS maps the regional potential of geothermal energy. It is a public, web-based geographic information system developed by all expertise areas (four departments) of GDN. 

ThermoGIS is unique in the Netherlands and abroad. It translates geological data and knowledge into a model of the subsurface. ThermoGIS shows the depth, thickness, permeability, and temperature of rock layers in the Netherlands that are considered potentially interesting for geothermal energy production. Based on these properties, ThermoGIS calculates how much geothermal energy could be produced. By considering uncertainties in the models used, a prediction is also made of the probability that a certain power output will be achieved. 

ThermoGIS includes an economic calculation module that calculates the cost of geothermal energy production. These costs can be compared with those of conventional energy. In this way, ThermoGIS not only identifies technical geothermal energy potential, but also its economic potential.

WarmingUp and SCAN

We are one of 38 participants in the WarmingUp collective. This is a partnership that develops applicable knowledge so that collective heat systems are reliable, sustainable, and affordable for the heat transition. One of the themes of the WarmingUp projects is Geothermal energy. This theme aims to accelerate the development of geothermal energy projects in the built environment and their incorporation into collective heat grids.

Together with Energie Beheer Nederland (EBN), we implement the SCAN programme. SCAN explores the opportunities for geothermal energy and investigates where the Dutch subsurface could be suitable for geothermal energy production. SCAN focuses on the parts of our subsurface of which we still have little information. With a better and more complete picture of our subsurface, we can improve the assessment of geothermal energy potential for the Netherlands and increase the chances on the successful implementation of geothermal energy projects.

Advisory role in implementing the Mining Act

The Mining Act is the guiding legislation for geothermal energy production. The competent authority for permits under the Mining Act of the Netherlands is the Dutch Ministry of Economic Affairs and Climate Policy (EZK). GDN advises EZK and the State Supervision of Mines (SodM) on the Mining Act, both when implementing and drafting policy.

Regarding the licencing process for geothermal energy exploration and production, local and regional authorities (municipalities, provinces, and involved water authorities) have an advisory role. They therefore need information and insight into the possibilities of geothermal energy production in their region. GDN supports and advises them on this. 

More information

Do you want to find out more about our research on geothermal energy? Please contact Jan Diederik van Wees via the blue ‘mail directly’ button below.

For more information about ThermoGIS, please contact Hans Veldkamp via the blue ‘mail directly’ button below.

Want to know more about our advisory role regarding the Mining Act for geothermal energy production? Contact Bart van Kempen via the blue ‘mail directly’ button below.

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