Enerdrape or geothermal energy without drilling

Ten blue and white striped posters appear to serve as billboards in a parking lot in Sébeillon, Lausanne. They don’t make noise and give a little color to the concrete. If we take a closer look, we’ll see that they are trapped in metal plates connected by tubes and sensors. The message they convey concerns the heat of underground car parks that can be sustainably recovered to heat a building. And for good reason: they are indeed an example of next-generation drill-free surface geothermal energy provided by an EPFL spin-off, Enerdrape.

In the energy transition, these panels are the prototypes of a “new tool in the toolbox” of the energy matrix, according to Margaux Peltier, director of Enerdrape gathered on site. They can contribute up to 60% to the heating of a property, or its cooling in the summer, and can be implanted in basements, by placing solar panels in the basement, at an additional marginal cost close to free, depending on the company.

A solution that reinforces energy autonomy

Its explosive potential and simplicity earned Enerdrape the SUD Prix, organized by the The weather and delivered on May 5, and should allow this year to raise 2 million francs to enter the commercialization phase, the company hopes. The rise in the price of hydrocarbons and the lack of security of supply in this area make this renewable solution even more interesting, which reinforces energy autonomy.

“Our panels work on the same principle as a geothermal probe: they extract heat from the concrete or from the air, which heats the water within a closed circuit of tubes that passes through them and feeds a heat pump, but without drilling because it does not take energy from the depths”, explains the director. The water thus gains an average of 5 degrees, enough to generate good heat pump performance.

The origins

It all started at the EPFL Soil Mechanics Laboratory, with academic research with conclusive results, led by Margaux Peltier, doctor in mechanics Alessandro Rotta Loria and professor Lyesse Laloui. A series of awards led the first to turn these studies into an entrepreneurial adventure to prevent “one more good university solution from ending up in the drawer”, she says. The Frenchwoman took entrepreneurship courses, developed a prototype, was left behind because of the pandemic. Enerdrape Sàrl – an Anglicism that mixes energy and curtains (curtain) – was, however, registered with the Vaud Commercial Register in spring 2021, hired its first employees during the summer and benefits from an EPFL patent license.

“Our solution complements intermittent power sources,” says Margaux Peltier. It does not compete with solar panels, because they are not placed on roofs, and it produces the same amount of energy day and night, because the heat is constant in the basements. It competes with gas, which is more powerful, but pollutes more and costs more in the long run.”

The efficiency of the system depends on the building that benefits it: 1 mtwo of the panel will heat less than 2 mtwo surface area if old and poorly insulated, but 5 mtwo if it meets the latest standards. The installation depends on a pump to circulate the water, but producing 4 to 5 times more energy than the electricity it consumes.

“I really like the idea of ​​exploring the energy potential of underground buildings,” says Eric Plan, secretary general of the organization CleantechAlps and member of the Prix SUD jury. “Geothermal energy is today the poor relative of the energy transition and Enerdrape’s technology allows it to be put back in the debate”, he observes.

The start-up found a subcontractor in Italy capable of producing its slates in quantity. They are lighter than their photovoltaic cousins, free of rare metals and easy to install. Enerdrape wants to expand its sales force, looks for installers to install its panels and discusses with the first customers, in Switzerland and abroad. The market is huge, according to Enerdrape, which estimates the surface of underground car parks in Europe at 50 million m².

“Great potential”

“Enerdrape has an innovative approach and great potential. Any start-up remains at risk in the early years as there are many limits such as time, human and financial resources. But Enerdrape has a good project-team-market alignment, which it is important to continue to consolidate in order to realize its potential”, said Caroline Coquerel, coach accredited by Innosuisse, who follows Enerdrape.

Enerdrape is now working on lighter panels, 8 kg against more than 15 kg of Sébeillon, optimizing the performance of the installations and the connections with the heat pumps, namely placing the panels closer together.

“The challenges to contain climate change are immense, but when I see solutions emerging, I feel more confident,” says Margaux Peltier. “We must, however, accelerate its deployment and quickly,” she concludes.

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