In the underground garage of a Swiss residential development, Enerdrape's geothermal panels are changing how buildings manage energy. We spoke with Margaux Peltier, co-founder and CEO of EPFL spin-off Enerdrape, about how the solution transforms overlooked spaces into efficient sources of heating and cooling. With installations expanding across Switzerland, Enerdrape is offering a practical path toward cleaner energy in urban environments.
Margencel is a development like many in Switzerland. Located directly at Aigle (Vaud) railway station, it is advertised as close to Lausanne and Sion. Five floors in shades of grey and green, about 100 apartments with 250 tenants, and just over 5,000 m2 of commercial space. The first tenants moved into the development, built by a local real estate company, in 2020. A Migros and a Raiffeisen branch are situated on the ground floor.
Margaux Peltier has been here many times, but mostly in the underground garage. The CEO of EPFL spin-off Enerdrape points to the pipes under the ceiling, which runs through both garage levels: “They connect geothermal panels over an area of 330 m2.”
It’s a pleasant 20 degrees outside and Margencel does not need to be heated or cooled. However, if the daytime temperature falls below a threshold, in this case about 15 degrees, the geothermal system switches on automatically.
A heat pump connected to Enerdrape’s system transfers the absorbed heat to the building’s heating system in winter. At the height of summer, the system works in reverse: the heat from the building is fed into the underground garage’s water circuit and the panels release it into the ground via the concrete.
The second law of thermodynamics states that heat always flows from a warmer to a colder body; thus, the ground can be used to heat in winter and cool in summer. “The crucial factor,” says Peltier, “is that the temperature in the building’s underground structure is a constant 12 degrees.”
„I hope that our heat exchange panels will become the solar panels of the future.” — Margaux Peltier
Until now, heating and hot water at Margencel have been generated exclusively using natural gas. “Our system will reduce consumption by 20%,” explains Peltier. In absolute terms, the saving amounts to 15,000 m3 of natural gas, plus the lower electricity requirement for air conditioning in summer.
The use of geothermal energy is increasing in Switzerland. Geothermal plants already cover around 5% of the national heat demand – and this figure is rising (see box). Currently, heat is tapped mainly from the ‘shallow’ area down to 400 metres, either via probes or water circuits in the foundations of buildings such as Terminal E at Zurich airport.
The Laboratory of Soil Mechanics at EPFL has been researching such geostructures for about 20 years under the direction of Lyesse Laloui. Civil engineer Peltier was also working in this field when she came to Switzerland from Monaco to study in 2011. Her master’s thesis focused on the behavior of heat exchange between air, concrete and soil in geostructures.
“But in the long run,” she says, “it was too theoretical for me.” She conducted a small market survey and discovered that the construction industry was open to geothermal energy without probes – and thus without drilling – and that in addition to systems for new builds, it was also looking for solutions in building renovation.
Peltier discussed the issue with Laloui and her master’s thesis supervisor, postdoc Alessandro Rotta Loria. They proposed the development of easy-to-install heat exchange panels for retrofit applications.
“The two of them were there,” recalls the young entrepreneur, “and they encouraged me to take the lead.” Peltier was not yet 30 at the time, but she took the plunge. In 2021, the team obtained the Venture Kick funding to start Enerdrape and moved into offices in the EPFL Innovation Park.
200 panels provide cooling and heating in the Coop store in Renens.
Since then, the founders have overcome a double challenge: first, the design of the pipe system, now patented, in metal panels that are just a few centimeters thick; second, the development of an installation method that reliably generates the heat output promised to the customer.
The first customer was Coop, Switzerland’s largest retailer, which is pursuing ambitious sustainability goals. The company’s properties, including almost 1,000 supermarkets, will be heated without fossil fuels by 2035. At Coop Supermarché in the Lausanne suburb of Renens, it was not possible to sink geothermal probes and there was also no access to the district heating network. This is why, according to Coop, it was looking for “innovative solutions”: 200 panels have been installed in Renens.
The heat exchangers are produced in northern Italy by a metal construction company that Peltier came across on the internet. Until a few weeks ago, communication was purely virtual. Now, she has visited Italy and discussed deepening the partnership with her supplier.
At today’s gas prices, Enerdrape’s system will break even after 12 to 15 years, with a practically maintenance-free service life of half a century. Peltier has so far persuaded three customers in Switzerland with this argument and pilot projects are underway in Spain, France and the US.
In the first few years, Enerdrape was financed through funding from foundations and the innovation support agency Innosuisse. A first equity round followed at the beginning of 2024, with the venture capital arm of energy supplier Romande Energie, VC firm Apres-demain and a private individual investing a total of CHF 1.3 million in the cleantech startup.
The number of venture capital investments in Swiss geothermal startups can currently be counted on one hand. But that could change: US startups Dandelion and Fervo Energy attracted mid-double-digit million amounts in their last financing rounds.
Every now and then a car drives past in Margencel’s underground garage. The panels and pipe system under the ceiling attract no attention. For Peltier, this is one of the main advantages of the Enerdrape solution, in contrast to wind and solar installations in the landscape: “Our system is invisible.” In addition, the underground system provides a constant supply of energy, day or night, winter or summer.
“I hope that our heat exchange panels become the future solar panels,” says Peltier. It should become a matter of course that underground car parks and other subterranean infrastructure near residential areas are upgraded to thermal power plants. “I just hope,” she adds, “that it does not take as long as it did with photovoltaics.”
Heat from the depths
“When it comes to energy, everyone talks about electricity, nobody talks about heat. Yet we use half of our energy consumption to provide heating and process heat, mostly with fossil fuels,” says Cédric Höllmüller, co-director of Geothermie-Schweiz. He is convinced that geothermal energy can play a decisive role in the Swiss energy mix of the future. Last year, heat from the ground replaced 460,000 tonnes of crude oil.
The most important contribution is made by geothermal probes. As of today, well over 20 million linear metres have been installed in Switzerland (see table above). Switzerland is less advanced in the area of deep boreholes up to 5,000 metres, which are used specifically to search for underground hot water streams. Investors are wary of the risk of not finding hot water in sufficient quantity and of local resistance from the population. Currently, only the two plants in Riehen BL and Schlattingen TG supply hot water from the earth’s mantle. A dozen other projects, mostly in French-speaking Switzerland, are in the implementation or planning phase.
This article was first published in the
TOP 100 Swiss Startup Magazine 2024.
