Dutch municipalities’ keen interest in geothermal energy use

In view of the growing resistance to wind farms and solar fields, many municipalities in the Netherlands are investigating the opportunities offered by geothermal energy. There are still many questions about this sustainable source. It is unclear how much heat can be extracted and whether projects are realistic. And not everyone is happy about this either, so Gemeente.nu.

The Hague, Utrecht and Zwolle, but also Pijnacker-Nootdorp, Nieuwegein and Westland. Just a few of the large group of municipalities that have set their sights on geothermal energy. Energy from the soil, or geothermal energy, is on the rise. According to the sector organization Geothermal Netherlands, there are about twenty places in our country where heat is currently being extracted from the deep subsurface, and that number is increasing rapidly. Dozens of projects are in the pipeline in Brabant, Gelderland, Groningen and North Holland, among others.

The early challenges to geothermal heat ambitions

In 2012, The Hague was the municipal pioneer with geothermal energy. The country’s first geothermal heating plant opened in the residence that year to provide thousands of homes with sustainable heating. However, after years of delays due to technical and financial problems, the green light was only given in 2019 for the actual application in homes. This course illustrates the early challenges surrounding geothermal energy.

Nevertheless, enthusiasm among municipalities continues to increase rapidly. By the end of this year, every municipality must have its Heat Transition Vision ready. Geothermal energy may have a significant share in the natural gas-free heating of houses and buildings, as agreed in the Climate Agreement.

Drilling in testing grounds

In the Natural Gas-Free Neighborhoods Programme, a number of pilot projects are also focusing on the largely untested technology. For example, Pijnacker-Nootdorp has plans to make homes natural gas-free during the redevelopment of the Klapwijk via the existing geothermal heat source of Trias Westland. At the beginning of July, 345 homes in De Lier (municipality of Westland) were connected to this source, which was initially built for local greenhouse horticulture. Zwolle also wants to use heat from the soil in a municipal testing ground.

The ‘exploration’ or the technical search for geothermal energy has been criticized. Supervisor State Supervision of Mines (SodM) insisted that the safety culture at geothermal companies is weak and geothermal energy production itself is still risky. In June , the Court of Audit pointed out that the central government is not protecting drinking water supplies enough against the risks of drilling for geothermal energy. Leaks from geothermal pipes can pollute drinking water layers. Legislation should prevent this in the form of a drinking water prevention ladder .

Much is still unclear about geothermal energy, especially its potential as an ‘energy source of the future’. Much research, including drilling, is needed to gain reliable insight into the depth of strata and the temperature in them. The water permeability of the subsoil is also relevant for geothermal heat extraction. These factors determine how much heat can be extracted and whether projects are realistic.

Disappointing yield

For example, Zwolle had to halve expectations after research from 6.6 to 3.3 MW of sustainable geothermal heat. Nevertheless, the municipality of Overijssel received a European subsidy at the beginning of this year to conduct an exploratory drilling in Zwolle-Noord. The reason for the granting of the subsidy is the use of an even new innovative drilling method for smaller wells. With this technology, the production of geothermal heat from thinner layers of the earth could possibly be doubled, so that smaller geothermal sources can also be made profitable.

The test drilling in Zwolle will start in mid-2022. If this is successful, the city wants to connect the Holtenbroek district to a geothermal network. Agreements have already been made with potential buyers, including two Zwolle housing corporations and a number of educational institutions. After that, the project can expand to other districts. According to alderman Monique Schuttenbeld, the tipping point is at 3800 homes that switch to geothermal energy. For smaller numbers, the business case for the construction of a technical installation cannot be calculated, according to the alderman.

Utrecht promising

Utrecht will be the scoop with the first research drilling from the SCAN program financed by the government (the letters stand for ‘Seismic Campaign for Geothermal Heat in the Netherlands’). The area east of the city seems very suitable, because there are four layers of earth below each other, which run through large parts of the central Netherlands. Drilling near Utrecht can therefore provide useful information for other parts of the country. Geothermal drilling requires a lot of preparation: the drill head can only go into the soil in 2023. The research could take up to a year, alternating between drilling, measuring and testing at a depth of three kilometers.

In a council letter from the end of May, the Utrecht college wrote about the high expectations. Geothermal energy would be the most important potential source of energy to make existing district heating more sustainable. The municipality has been investigating this since 2016. The province is also involved, but the lead is Warmtebron Utrecht , a network of knowledge institutions and energy companies. Twenty locations have previously been examined for their potential for ultra-deep geothermal energy (five to seven kilometres) , seven of which are in Utrecht and two in the adjacent Nieuwegein. Two locations in Rijnenburg and one location in Nieuwegein appear to be the most suitable.

Involve residents

In Nieuwegein, however, there was plenty of criticism from residents, who found the substantiation of the search area insufficient. Once the exact location choice for the SCAN drilling is known, Utrecht will start a participation process. The construction of a drilling rig requires a lot of construction traffic and noise nuisance, while the nuisance is limited during operation. According to the municipality, it is important to involve as many residents as possible in this development.

Source: Gemeente