Friday, December 3

The end of geothermal energy in Strasbourg is not on the program


The Reichstett-Vendenheim geothermal power station on November 18, 2020. – G. Varela / 20 Minutes

  • Micro earthquakes have been felt in recent weeks in the Strasbourg metropolitan area.
  • These latest seismic events, which worry the population and the authorities, are the result of tests imposed on the company Fonroche Géothermie which operates the deep geothermal site in Reichstett-Vendenheim.
  • A new test protocol will be put in place, which will help delay, at least until the summer of 2021, any possible operation of the plant.

The Reichstett-Vendenheim deep geothermal site has been in turmoil for a year now. However, the wedding promised to be good for the company Fonroche Geothermal who operates the site. Until November 12, 2019, when an earthquake of 3.2 on the Richter scale shook the Strasbourg metropolitan area. Since then, it is the uncertainties, the shutdown of the plant and the mini-earthquakes that have punctuated the life of geothermal energy north of Strasbourg in recent weeks. Do you think you see mini-cracks on your tiling and hope for the permanent cessation of operation of the site? Well, you might as well say it right away, the end of geothermal energy in this area of ​​the agglomeration is not for tomorrow, quite the contrary.

Even if the test protocol launched in mid-October is suspended, because of the mini-earthquakes recorded in recent weeks, a new protocol would already be in the pipeline. However, it will “not be able to start before the start of next year and again, after validation by a committee of experts,” predicts Fonroche.

“An ubiquitous situation”

Not really good news for the operator and even arouses a bit of misunderstanding. On Wednesday, the general manager of the plant, Jean-Philippe Soulé, without wanting to clear customs, however marked the tracing tests launched in mid-October 2020. Tests imposed on the company to find the causes of … the first earthquake, that of 2019 While Fonroche maintains that it was not at the origin of it in the Strasbourg area, the company admits without any problem that the latest micro-earthquakes are indeed linked to the power plant. Problem, they are, according to the operator, the result of these tests imposed and of which “industrially, they do not need. “

The Reichstett-Vendenheim geothermal power station on November 18, 2020. – G. Varela / 20 Minutes

“We are in an ubiquitous situation, regrets Jean Philippe Soulé. It is the protocol for stopping the injection of water that caused the seismic movements. You have to maintain a certain constant pressure in the fault, otherwise it will deform, shrink and create jerks. We are not at all in the conditions of a normal operation of an active plant, where the pressure is constant. We need to establish a new protocol. “

No problem, the specialists are ready to review their copy with the aim that the seismic activity remains below the thresholds of human perception. A new protocol should therefore be put in place, with levels of different injection flow rates, “step by step, to stabilize the seismicity until reaching 250 m3 per hour”, explains Jean-Philippe Soulé. A first objective to be achieved, even if it means “extending the injection stages over several weeks, months.” “

“In 50 years we will have forgotten the wasted months”

A first threshold that still sounds like a concession for the operator because to be as profitable as expected, the plant must reach 450 m3 per hour. “But that’s for afterwards, we are no longer in this objective, sighs Jean Philippe Soulé. We are for the moment in the understanding of what happened, to define the levels and the level of exploitation. And things will change as water flows more easily through faults over time. The permeability of the rock improves and we can gain in flow. The important notion, continues the director, is that we are in investments over 50 years. It is necessary to relativize. By then we will have forgotten those months lost at launch. “In the meantime, Fonroche does not expect the site to be operated before the summer of 2021. A lot to see coming …


Reference-www.20minutes.fr

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