Belgium’s first deep geothermal power plant

For a number of years now VITO, the Flemish Institute for Technological Research, has been investigating deep geothermal energy’s potential as a sustainable energy source. VITO chose ENGIE Fabricom to build and maintain Belgium’s first ever deep geothermal power plant, which will open its doors in Mol in mid-2018.

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Geothermal energy is older than you think

‘Geothermal’ means ‘heat of the earth’ (from the Ancient Greek ‘γη’ (ge), meaning earth, and ‘θερμος’ (thermos), meaning heat). To use this heat, the hot water found deep underground is pumped to the surface using wellbores before being reinjected into the subsoil. The idea may seem new but it absolutely is not. Native Americans were already using hot water sources for purification rituals and to boil food 10,000 years ago. Italy has been generating electricity using terrestrial heat since the early 20th century.

A green, inexhaustible and continuous energy

Hearing the term ‘green energy’ immediately makes you think of wind and solar power. However, geothermal energy is also a renewable, environmentally friendly and widely available energy source. It can help to stabilise energy prices and reduce our dependence on other countries to supply us with energy. As the hot water circulates in a closed system, its resources are virtually inexhaustible. It also generates energy without emitting any pollutants and, in contrast to wind and solar power, does not depend on the weather.

Anyone wishing to enjoy these benefits must study the financial feasibility and yield of deep geothermal energy, which requires significant initial outlay but subsequently generates low operating costs.

The new deep geothermal power plant in Mol will allow VITO to investigate in real conditions the technical issues, economic feasibility and potential of geothermal energy in Flanders.

A promising pilot project

VITO launched the project in 2015 following its acquisition of the former Balmatt site in Mol in 2007. Two wells (one running 3,610 m deep, the other 4,341 m deep) were drilled in 2016. The pumping test showed that the flow and temperature of the water were sufficient to achieve the project’s aims, so the green light was given to begin building a deep geothermal power plant on the site.

In plain terms, the water pumped to the surface is lying within a deep layer of limestone at a temperature of around 130°C. After passing through the power plant’s heat exchanger, this water is reinjected into the subsoil, where it is reheated naturally, thus restarting the cycle.

Generating both heat and electricity

VITO is working on the principle that, working continuously, the plant’s two wells have a thermal potential of approximately 10 MWth and an electrical potential of around 1 MWe. This will be the first deep geothermal power plant in the Benelux to generate green heat and electricity. A full geothermal power plant (with five or six wells) could generate up to 4 MWe, making Mol one of Europe’s top 10 deep geothermal power plants.

Guiding the energy transition

VITO chose ENGIE Fabricom to build and maintain the surface facilities, a task perfectly aligned with the ENGIE Group’s strategy, which is firmly focused on renewable energies. Construction of the facilities is scheduled to begin in January 2018, with commissioning planned for August that same year.

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