In the Kempen, the fourth largest geothermal energy plant in Europe is being built. VITO is working on the second drilling well on the Balmatt site in Mol. Sustainable heat and electricity are within reach.

second drilling well on Balmatt site in Mol

3,610 metres: near the end of 2015, VITO reached a geothermal reservoir in the Kempian soil at that depth. It is the deepest hole ever drilled in Flanders. A geothermal project of such scope has never been seen before in our region. But that is about to change.

“A geothermal energy plant needs at least two drilling wells: one to pump up water, the other to inject it back into the soil,” says Ben Laenen, research leader at VITO.

“The first drilling was a success. Along the way, we encountered a few difficulties, but those provided us with plenty of additional information on the geological situation. Those data are invaluable. Among other things, they allowed us to adapt the route of the second drilling.”

Pump test

After a successful pumping test at the start of this year, the second drilling was started right away. Ben Laenen: “In January 2016, we pumped up water from the geothermal reservoir. The positive results were reason enough to start the second drilling.” That drilling will not be as deep as the first one: ‘only’ 3,300 metres. But because its trajectory is slanted, it will be longer (4,200 metres). Ben Laenen: “Thanks to the knowledge we gathered while drilling the first well, we can now work a lot faster. We hope to finish drilling by the beginning of June 2016. As soon as the second well is operational, we can study the temperature and flow rate during a longer period of time and research all the possibilities of the underground reservoir in full. We are also studying the composition of the water. We may even be able to extract metals and other valuable elements.”

Geothermal plant

Scientists already know that the future plant will offer plenty of opportunities. “Not only do we want to provide heat, we also want to provide electricity,” Ben Laenen says. “For heat, we are installing a heat exchanger. We want to generate electricity with an Organic Rankine Cycle (ORC). The current two wells should be able to provide 12 to 17 megawatts of thermal energy or 1.5 megawatts of electric energy. Enough to deliver energy to 5,000 households and several companies. But our goal is a full energy plant with a maximum of six wells. With those wells, we can generate up to 5 megawatts of electric energy.” VITO’s plans are fully-formed: by summer 2017, the sites of VITO and the neighbouring SCK•CEN and Belgoprocess should be heated with sustainable geothermal heat. “The surrounding municipalities should follow. We want to give companies and families in the area the chance to benefit from this project,” says Geert De Meyer, Business Developer at VITO. “For the heating season of 2017-2018, we have come to an agreement with energy provider  Eandis to build and maintain the heat grid. This will allow us to take the first steps towards rolling out heat grids. These are indispensable to transport the heat efficiently to the consumer. And we are discussing the issue with the municipal governments of Mol and Dessel.”


Strong support at the administrative level is needed to roll out heat grids in the area and fulfil the potential of geothermy. “But we are also telling the story to a wider audience,” says Ben Laenen. “We live in a world in which we are growing more and more dependent on non-renewable fuel sources, with all  of the subsequent environmental problems and price fluctuations. That is why we deliberately invest in education: we are considering opening a visitor centre on the Balmatt site. Today, we already receive plenty of visitors, mostly school groups, in cooperation with Voka Kempen, the GoodPlanet organisation and the province of Antwerp. This spring, the one thousandth student came to visit. Earlier this year, the enthusiasm of teenagers was already apparent during ontSTEMDd!, a musical created by secondary schools in Geel and Mol and performed underneath the drilling tower. Hundreds of children attended a performance and got a playful look at the power of geothermy.

The Kempen first, Limburg next?

Drilling on the Balmatt site only started after careful preparations: geological research which proved that there was geothermal potential in the Kempen. Because researchers suspect that similar potential is hidden in the area of Hasselt, Meeuwen-Gruitrode, Maaseik and Zutendaal, they conducted a seismic campaign in 2015. The results are promising.

“With a seismic campaign, we can chart precisely what the soil far beneath our feet looks like,” says David Lagrou, geologist at VITO. “We work  with acoustic waves. Trucks with a wave generator move past hundreds of receivers, or geophones. These register the reflected acoustic signals. As such, we can create a type of echography of the soil.”

New geothermal projects

Geologists at VITO were looking forthe carbon lime layer, the layer in which the geothermal reservoir in the Kempen was found. “We found it at a depth of 1,000 to 2,500 metres. At a depth of 2,500 metres, we suspect the existence of water with a temperature of 85 °C in the top layer. Togetherwith the municipalities involved, we are studying whether new geothermal projects are possible.” VITO’s know-how on modelling subsurface layers to enable geothermal mining is well-known abroad. At Venlo in the Netherlands, VITO is taking part in a project to heat greenhouses sustainably using geothermy.

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