The setbacks of Fonroche, the French geothermal specialist, whose drilling 5 kilometers deep in Strasbourg caused earthquakes in November and led to the shutdown of the project, do not dampen the optimism of the leaders of Celsius Energy.
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Three engineers from the Schlumberger oil services group have just developed a new, much less invasive process for recovering heat from the basement. “ We are not at all on the same technologies. We’re only going to a depth of 200 meters and we’re not going to collect water by fracturing the rock », Explains Cindy Demichel, one of the founders of Celsius Energy, created in 2019 and which already employs 22 people.
The first demonstrator has just been installed in Clamart (Hauts-de-Seine) in front of the campus of the Franco-American group, the sole shareholder of the new company. This 3,000 m² building will be heated in winter and air conditioned in summer, thanks to this system.
Inclined boreholes that take up little space
The main innovation of Celsius Energy is to use a very small floor area. It requires a footprint equivalent to that of a few parking spaces, against half a football field usually to supply a building of this size. “ We need ten times less space », Underlines Cindy Demichel. In conventional geothermal energy, the vertical wells are spaced approximately every ten meters.
The technology deployed by Celsius Energy, inspired by what is done in oil, allows drilling at an angle. Schematically, the installation resembles the frame of an umbrella. The probes, in which a coolant circulates, leave from the same wellhead and dive 170 meters below the surface to recover a heat of between 15 and 20 degrees.
A world first
« It is a breakthrough technology, used for the first time in an existing building in the heart of a city ”, underlines Cindy Demichel. The originality is also in the algorithms to optimize the system, which is coupled with a heat pump.
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« We use the basement as a battery, allowing inter-seasonal storage. We collect the calories in winter to put them in the building, and in summer, we do the opposite », Explains the geologist.
Communities are interested
The leaders of Celsius Energy are targeting the huge energy retrofit market, with a solution they consider very competitive. ” For a cost of 100 € per m², we can divide CO emissions by ten2 of a gas-powered building while a global renovation, by insulating the walls and changing the windows costs 400 € per m² for a reduction in emissions of only 40% “, Details Cindy Demichel, evoking a return on investment” between six and ten years old ».
Celsius Energy hopes to convince six customers in France in 2021. Half of this objective is already on the way to being reached. Communities would also be interested and the leaders of Schlumberger went to present the project to the government, which has great ambitions for the renovation of its own building stock.
Celsius Energy also intends to rely on the network of the oil services group by targeting an international clientele. In the Gulf countries, for example, air conditioning needs are very important and are mainly supplied by fossil fuels.
A welcome diversification for Schlumberger
With this geothermal process, the company created in the XIXe century by the Schlumberger brothers finds a new way to diversify, while the conditions of the oil and gas markets are very difficult.
It is thus working on the construction of a green hydrogen production plant at its Cameron site in Béziers, on the basis of a technology developed by the CEA (French Atomic Energy and Alternative Energies Commission).
In July, Schlumberger announced the elimination of 21,000 jobs worldwide. In France, 400 jobs are affected, or 20% of the workforce, including the closure of the Defense site, according to the plan presented by management at the end of November.