In April, on the occasion of the 20th anniversary of the PRO-SUD syndicate, the 11 member municipalities signed a letter of intention to work together to decarbonise the Minett UNESCO Biosphere. Heating remains one of the main sources of carbon dioxide emissions into the atmosphere. To reduce emissions in this specific area, energy retrofitting of homes and other buildings is a good option. Another option is to use the earth’s heat to heat buildings in the cold season through geothermal energy.

What is geothermal energy?

Geothermal energy is heat that is stored in the earth’s crust and can be used. Basically, this energy can be used for heating or cooling. Geothermal energy can also be used to generate electricity or for combined heat and power generation.

Geothermal energy is a renewable energy source that can help us transition to a more sustainable way of life. There is a continuous transfer of heat from the liquid core of our planet to its surface. This transfer and radiation from the sun have been key facts for life to develop on Earth.

The temperature of the soil increases with depth, on average by 30 degrees per kilometre. However, this temperature gradient can vary regionally. To use geothermal energy, the heat must be brought to the surface through boreholes. This can be done either directly below the surface or in deeper layers. Boreholes deeper than 400 metres are referred to as middle depth geothermal energy.

In order to make use of this form of energy, certain geological conditions must be met, such as hydrothermal reservoirs or hot rock formations that can be found close to the earth’s surface.

The Minett could benefit from this energy source

In 2015, a study showed for the first time the potential of middle-depth geothermal energy in Luxembourg. However, there is still a lack of reliable data, even though geothermal energy could be a sustainable source of heat for entire neighbourhoods to be built on brownfield sites in the coming years. These include the “Nei Schmelz” district being built in Dudelange and the “Metzeschmelz” district planned between Esch and Schifflange.

However, in order to confirm the potential and make a concrete inventory of the real geothermal conditions in our region, the subsurface of our region must be examined in detail. This is the only way to identify the areas where the use of medium-deep geothermal energy seems to make sense.

An initial local analysis was carried out in 2018. A test well drilled to a depth of 430 metres provided geothermal data for a specific site in the south of Luxembourg. A regional analysis of the potential of medium-deep geothermal energy in our region will now be carried out in the coming weeks. This will involve a seismic survey of the region to determine the optimal location for further test drilling (which can be up to 2000 metres deep). After these wells are drilled, it will be known if and where the Minett subsurface has enough energy to sustainably supply our region in the future.

Study to start this November

On three selected routes in the basin of Rumelange, which is probably the area with the greatest potential for geothermal energy, a specialised company will use geophones and vibrating trucks to get a detailed picture of the ground beneath our feet and reveal the potential for geothermal energy between Esch in the west and Dudelange in the east.

For more details on the project, click on this link or watch this explanatory video.