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New geothermal heating project targets deeper depths in Paris area

Bobigny geothermal project scheme (source: Sipperec)
Alexander Richter 19 Dec 2019

A new heating project has been kicked off by a local syndicate targeting deeper geothermal resources below Paris with the goal to provide heating to more than 20,000 households.

A new geothermal heating project has been kicked off in Bobigny and Drancy in the greater Paris region (northeast) in France.

The Syndicate called Sipperec (Syndicat intercommunal de la périphérie de Paris pour les énergies et les réseaux de communication) will be targeting a layer called “Triassic”, at a depth of 2,100 meters where the water is warmer, with the target of heating up to 20,000 homes.

Drilling of the four wells began on November 21. Bobigny and Drancy will soon bring a source of renewable energy from Ile-de-France. The Genyo geothermal network will see the light of day there by the fall of 2020 under the impetus of Sipperec (Paris inter-municipal union for energy and communication networks). Thirty kilometers long, it will supply the equivalent of 20,000 homes with heat (buildings, social housing, equipment).

This December 3, some 550 meters have already been dug underground in the first production well, wedged between rail and road, not far from Bergère park. The huge machine is about to repeat its performance a few meters further, on a second well. On site, around thirty technicians, under the supervision of the SMP company, ensure the progress of the site: analysis and recycling of the sludge which fluidizes the drilling, casing of the hole, consolidation with cement. Four months of work will be necessary: ??the drilling will indeed descend beyond the dogger, the underground layer located 1,600 meters deep in which the water is usually captured.

Sipperec decided to experiment with an extraction in the Triassic layer, at 2,100 meters deep. “As the water is naturally warmer when it comes from the Triassic – at 80 degrees against 60 – the operating costs will then be lower” explains Rémy Houret, project manager, heat network engineer. Once brought to the surface, water is not immediately usable as a heat source. It must go through a heat exchanger, then be heated by heat pumps. Extracting hotter water therefore guarantees lower energy costs. “We can even hope for the key, lower rates for the user” says Jean-Christophe Lagarde, MP and former mayor of Drancy. Who sees more than one advantage: “stable prices, which will not suffer from the vagaries of the price of oil or gas, and will benefit from VAT at 5.5%”. Drancy, which is turning the page on fossil fuels for the first time, even hopes in the long term to see two new districts served, e.g. 10,000 additional homes. “We are going to force new projects to switch to geothermal energy” warns the mayor.

Technological innovation

Sipperec, it hopes to gain other benefits from this technical feat. “The operation of the Trias is a technological innovation, which, if it is successful for the first time in France, will open up new horizons in terms of geothermal energy”, assures Jacques JP Martin, president of Sipperec. In particular, it would allow exploration in the west of the Ile-de-France region, where the water extracted from the dogger does not reach a sufficient temperature to be exploited. Today, two thirds of the Ile-de-France wells are therefore concentrated in the east, south and north. Going to conquer the west, via the depths, will however require the green light from the State and the mining authorities.

The experiment is of great interest to Ademe and the Region, which are funding 17 and 4 respectively of the 78 million investments planned. Sipperec puts almost 50 million on the table. Drancy hopes to see the metropolis of Grand Paris also enter the round table. 58% of the sum will be allocated to drilling work. For this first, Sipperec has chosen to retain the contracting authority. “In any case, there will be no failure, because if the operation of the Triassic fails, we have planned the possibility of withdrawing into the dogger” explains Julien Taris, the general manager of Sipperec. Bobigny will be heated by geothermal energy from 2020, and Drancy in 2021.

Source: Les Echos