Chapter from Annual report 2021.

5 Geothermal Energy

5.1 Preface geothermal energy

Tables 5.1, 5.2 and 5.3 provide an overview of the changes in geothermal energy licences that took place in 2021. Applications that are fully competitive with previous applications are not published in the Government Gazette and do not appear in Chapter 8.5.

Table 5.1 Changes in exploration licence applications in 2021.

*¹ In addition 6 more applications were filed late 2021. These were not yet officially published in the Government Gazette in 2021. These unpublished applications will be included in the 2022 statistics.

Table 5.2 Changes in licenced exploration licences for geothermal energy in 2021.

Tabel 5.3: Wijzigingen in aangevraagde en vergunde winningsvergunningen voor aardwarmte in 2021.

*¹ 2 of these were submitted late December 2020 an were published in 2021.

Changes in the licence position in 2021 of geothermal energy exploration and production licences are listed in the tables of Chapter 8. Figure 5.1 shows the evolution of the Dutch geothermal licence position. In the histogram bar of year 2021 the number of licence applications is presented as well.

Figure 5.1 Number of licences for geothermal energy in force per year. For the year 2021 the number of applications is presented as well.

5.2 Geothermal wells and production installations as at 1 Yesnuary 2022

In 2021 2 geothermal wells were completed (see Table 5.4 and Figure 5.2). These concern wells within the licences Leeuwarden I and Luttlegeest. In 2021 two additional wells became operational for the geothermal production intstallation Naaldwijk Geothermie. This installation now consists of two injection and two production wells, a geothermal quartet.

As at 1 Yesnuary 2022 there were a total of 27 geothermal production installation[3] of which the Mijnwater Energiecentrale Heerlen installation is actually a heat/cold storage facility and as such will not be included in the following overview. The other 26 geothermal installations (will) produce heat from the deep subsurface. In general, these installations are named doublets as they consist of two wells. One well produces warm water from the aquifer and after extracting the heat, the second well injects the cooled water back down into the same aquifer. Nineteen of these 26 geothermal production installations were operational with reference to the fact that they provide (energy) production figures according to art. 111 and 119 of the Mining Decree.

All of the operational installations operate under a formal production licence (as at 1 Yesnuary 2022).

Table 5.4 Geothermal wells completed in 2021.

Figure 5.2 Number of geothermal wells completed (side-tracks excluded) per calendar year and number of installations completed since 2007.

The geothermal heat is produced from depth intervals between 700 and 2800 meter and from various geological units (Figure 5.3a and b). The mid depth of the producing zone is displayed in Figure 5.3 b. Most of the geothermal installations produce heat from the Upper-Jurassic and Lower-Cretaceous strata in the southwest of the Netherlands, 12 installations. Two installations in the southwest of the Netherlands produce from strata of Triassic age. The nine production installations in Noord-Holland, Overijssel and Flevoland produce from Rotliegend strata, whereas two installations in North-Limburg produced heat from Lower Carboniferous to Devonian strata. One geothermal energy production installation in Noord-Brabant produces water from an aquifer pertaining to the Lower North Sea Group.

The heat produced is predominantly used to heat commercial greenhouses. Two projects also supply heat to two distict heating networks for the built environment. Another project is planned to supply heat to a district heating network in an urban area (Figure 5.3 c).

Figure 5.3 a) Stratigraphy of the productive interval, b) Depth to mid of aquifer (certain geothermal production installations have multiple production wells), c) Uses of the heat produced.

5.3 Production of geothermal energy in 2021

Of the 26 geothermal installations (Mijnwater Energiecentrale Heerlen excluded) 19 were operational in 2021 (Table 5.5). The operational installations have submitted the obligatory monthly production figures. Of the 7 non-operational installations 2 were temporarily closed-in and 3 were in the start-up phase. The other two non-operational geothermal energy production installations were shut down in 2018 as a consequence of agreements and safety policy in force. In the course of 2021 one installation was shut down. In addition, there is one installation that was expanded with two operational wells in 2021.

Table 5.5 Geothermal installations.

Figure 5.4 Monthly production of geothermal energy in terajoules and the number of geothermal energy production installations contributing to the reported production (Mijnwater Energiecentrale Heerlen excluded).

Figure 5.4 shows the aggregated production figures of geothermal energy per month in TJ (x10¹² Joule) and the number of installations contributing to the monthly total. Not all installations were operational throughout the year. The cumulative reported annual production is 6.321 PJ (1 PJ = 10¹⁵ J) in 2021 (Figure 5.5).

Figure 5.5 Annual production of geothermal energy (PJ/year) and number of operating geothermal installations.

Small amounts of natural gas are co-produced with the geothermal energy production (Figure 5.6). Under subsurface reservoir conditions (elevated pressure and temperature) gas is dissolved in the formation water and released when the pressure of the production water in the production installation falls below the ‘bubble point’. Table 5.6 gives an overview of the produced geothermal energy, co-produced gas and co-produced oil per year since 2008. Only in one installation oil was co-produced until March 2017.

Figure 5.6 Volumes of hydrocarbons co-produced with geothermal energy. Gas in 1000 Nm³.

Table 5.6 Overview of produced geothermal energy, co-produced gas and co-produced oil.

* Figure derived from: Hernieuwbare energie in Nederland 2013. Statistics Netherlands, The Hague/Heerlen, 2014. ISBN: 978-90-357-1857-9.

- No value reported.

** Adjustment of reported figure in Natural resources and geothermal energy in the Netherlands, Annual review 2016.

*** Correction of co-produed gas compared to previous annual reports.