Alternative scenarios


The geothermal power of a doublet can be enhanced in several ways. Two options were calculated in ThermoGIS: by stimulating both wells and by adding a heat pump. A third scenario combines the two options.

This results in four scenarios:

  • Base case
  • Well stimulation
  • Heat pump
  • Well stimulation and heat pump

Well stimulation

The goal of stimulating a well is to decrease the resistance the water encounters while being produced from or injected into the reservoir. Technically, this means that the skin factor of the well is reduced. For the well stimulation scenario in ThermoGIS, the skin reduction was set to a value of 3. In combination with the skin due to the well deviation, this results in a skin factor of -4 for both wells. The CAPEX, which is the cost of stimulation, was then increased by €0.5 million.

Heat pump

The calculation methodology for the heat pump scenario is described on the Heat pumps page.

In the ThermoGIS Mapviewer, the displayed thermal capacity map of the heat pump scenario is based on the total heat output delivered to the end user. This is the sum of the geothermal heat output and the additional heat supplied by the heat pump. As a result, the map shows the actual heat capacity available to the heat consumer.

The economic calculations, however, distinguish between geothermal heat and heat upgraded by the heat pump. In these calculations, geothermal capacity is based solely on the heat extracted from the subsurface. The additional heat generated by the heat pump through the use of electricity is therefore not counted as geothermal capacity. Under the SDE++ categories currently included in ThermoGIS, this additional heat is not eligible for geothermal SDE++ subsidy support*. Nevertheless, the extra heat supplied by the heat pump has an economic value because it replaces an alternative heat source. A value of 28 €ct per kWh has been assumed, based on the cost of an alternative hot water installation. This benefit is accounted for in the system’s operating costs. The electricity required to operate the heat pump and to further cool the geothermal water prior to reinjection is included in the OPEX calculations. For the heat pump, investment costs (CAPEX) of €200 per kW thermal capacity and annual operating costs (OPEX) of €10 per kW have been assumed.

* SDE++ categories that include a heat pump do exist (PBL, 2026), but these are currently not implemented in ThermoGIS.