A rocky road: deep geothermal energy arrives at pivotal point in Flanders


Facing earthquakes and the generation of less power than originally thought, the developers of Flanders’ first deep geothermal energy plant are learning the ropes

Climate solutions

The development of deep geothermal energy in Flanders has come a long way, but it has faced ups and downs. While there is concern about the risk of earthquakes in the Kempen, three Flemish entrepreneurs are investing millions in a company that is tapping into the commercial potential of this renewable energy source hidden beneath the Earth’s surface.

After about a decade of research and trials, Vito – the Flemish institute for technological research – has finished building its geothermal power plant at the Balmatt site in Mol, Antwerp province. The installation contains all the necessary technology – like pumps and heat exchangers – to pump up hot water from between 500 and 4,000 metres below ground, extract its heat and re-inject the water back into the depths.

While it’s not easy, nor cheap, the development of deep geothermal energy is a promising domain in the struggle to develop CO2-neutral energy supplies. “Especially when it comes to heating, which makes up about half of our energy consumption,” says Ben Laenen, who leads the deep geothermal energy project at Vito.


The energy extracted from far under our feet can be used to produce electricity as well. Currently, the plant has the capacity to provide the heating for Vito’s buildings (also in Mol) and for those of the neighbouring nuclear research centre SCK-CEN. For this purpose, heating networks have been installed. Vito can also profit from the electricity production at the plant.

The plant is designed to be able to work 24/7, and there are concrete plans to also provide heating to a nearby European school, nuclear waste management plant Belgoprocess and the residential Atoom quarter that is currently being renovated.

However, the project suffered a serious setback at the end of June. A power failure was followed by an earthquake measuring 2.1 on the Richter scale. The earthquake was the result of a sudden release of pressure that had been increasing as cooled water was re-injected.

Since the start of the test phase last year, 265 tremors have occurred, but all of them minor

- Ben Laenen

Residents in both Mol and neighbouring Dessel felt the earth move. “There was at no point any risk involved for the community, and there was no damage,” says Laenen. “The trembling was comparable to what you might feel when a large truck passes your house. Since the start of the test phase last year, 265 tremors have occurred, but all of them minor.”

Still, the earthquake caused quite a stir, so Vito organised an info session with local residents. Vito has also paused its geothermal project to make thorough investigations, fine-tune its monitoring system to limit seismic risks and reduce the pressure resulting from the re-injection of water.

The analysis should be ready by the end of this month, after which Vito’s board of directors will decide on the way to proceed.

Vito also had to rein in its ambitions concerning the development of a large-scale residential heating network by 2022, as its plant currently cannot generate enough power for such an enterprise. “Our original plans for this were probably too ambitious, but the project is still feasible with the right adjustments,” explains Laenen. “We have to keep testing to optimise our production process; you can’t achieve that with only theoretical calculations.”

The potential of deep geothermal energy, in any case, has convinced a trio of entrepreneurs, including the founder of adhesives producer Soudal in Turnhout. Together, the three are investing €3.8 million in Vito spin-off company Hita.

In the coming decade, the company – led by Vito’s former geothermal development manager – aims to develop and market about 10 geothermal energy plants, requiring a total investment of €230 million. The plants would provide enough green power to heat about 40,000 homes and provide electricity to 15,000 homes.

We hope in the long term to be able to set up similar projects elsewhere in Flanders, perhaps near Ghent and Ostend

This could save up to 140,000 tons in CO2 emissions per year. The first plant should be operational in five years, in the region of Turnhout.

Apart from Hita, Janssen Pharmaceutica in nearby Beerse is also preparing its own deep geothermal energy project, for the heating of its own facilities.

The government of Flanders is supporting the geothermal sector with a guarantee scheme for businesses that invest in such projects. If it turns out after drilling that the estimated energy production is not achieved, the government will pay back some of the costs. The companies contribute to the scheme by paying a premium.

Iceland on top

Current geothermal activity in Flanders focuses mainly on the Kempen region, in the north of Antwerp and Limburg, which is no coincidence. It is the easiest in Flanders to drill into because the hardest layers of rock are much lower there than elsewhere.

The area around Mons in Wallonia also offers opportunities, which led to the installation of two plants in the area. “We hope in the long term to be able to set up similar projects elsewhere in Flanders, as well, say in the regions of Ghent and Ostend,” says Laenen. “For that, we have to develop techniques that allow us to extract the heat from rock formations that contain little or no water.”

Deep geothermal energy has already proven its value in several countries. The renewable energy source is used for extensive heating networks in France, Germany and Italy. Thanks to its specific geological location, Iceland is the biggest European pioneer in the application of geothermal energy for heating.

Photos courtesy Vito