A System for Sharing Household Heat Is Growing Beneath France – Next City

If you live in the United States, your home is likely heated by a boiler or stove – a small personal power plant in your basement that chugs heat just for you. There are millions and millions of these heaters that heat individual apartments individually. It’s a very inefficient system. In fact, it’s not a system at all.

In most cities and suburbs, these boilers and ovens run on natural gas, a fossil fuel that is often referred to as “clean” even though it emits carbon dioxide. The US is burning more and more of it to stay warm. In New York City, for example, 42 percent of carbon emissions come from natural gas boilers. Finding cleaner, more efficient ways to heat our homes is imperative.

One solution could be across the Atlantic in the suburbs of Paris, where a huge, shared heating source meanders underground and pumps climate-neutral heat into the houses from deep within the earth – a sustainable system that everyone can use.

An extensive solution

France committed itself in 2015 to be carbon neutral by 2050. Reducing heating emissions indoors would be critical to achieving this goal. The roadmap to get there relied in part on geothermal heat distributed to homes and buildings in suburban Paris via an unusual network known as remote energy.

Remote energy systems produce hot (and sometimes cold) water in a central location and then route this water through underground pipes to buildings for either heating or cooling. This eliminates the need for individual boilers and reduces CO2 emissions, as generating heating and cooling in one central location is more efficient than generating one building at a time. The French plan takes this model and makes it even more sustainable by generating the heat with a green energy source: geothermal energy.

Geothermal energy draws water from deep in the ground, where it has been naturally warmed by the earth, making it a climate-neutral source of energy. “In France we know that there are mainly three major regions that have excellent geothermal resources,” says Alexis Goldberg, head of the district heating market at ENGIE Solutions. “Ile-de-France, Grand est Alsace in the east of France and Aquitaine in the south-west of France.”

ENGIE settled in Île-de-France, where the Paris metropolitan area is located, to test the feasibility of its project. Two of the most notable projects in Île-de-France were joint ventures: one in Bagneux and Chatillon and the other in Arcueil and Gentilly. The Arcueil and Gentilly project, which was launched at the end of 2015 – shortly before the Paris climate negotiations – supplies around 7,500 buildings with geothermal energy. At that time, this project was supposed to show how home heating emissions can be reduced by up to 60 percent. This project has since expanded significantly to supply three-quarters of all buildings in these suburbs. The district heating systems in Bagneux and Chatillon are similar in size and provide heat to over 40,000 people in this district.

Share costs

The project was not without its challenges. One of the big ones was that even in densely populated Île-de-France, geothermal springs can be a long way from the homes they are supposed to heat. This requires lengthy distribution systems before the hot water even reaches the area and disruptive road excavation to lay the pipelines themselves. Neither of these two challenges makes this type of project impossible, but they make it expensive. Even with more than seven million euros in subsidies from the French environmental management agency, it was too costly for a municipality to pay for it on its own.

In order to keep costs manageable, the suburbs started working together and formed joint ventures that reduced construction costs. This fits well with the remote energy model itself, which is based on the idea that sharing a resource, and not everyone doing their own thing, leads to better results. The system was developed in cooperation and enables the hot water to pass through several communities to individual buildings.

“Sometimes only a quarter of a city [can] Get some renewable energy, but you can do it with a great district heating [system] If you have the resource like in Île-de-France, ”says Goldberg.

Although most of their indoor heating is sourced through new and more sustainable means, chances are most customers won’t even notice the switch. Jean-Baptise Sivery, deputy director of network heating sales at DALKIA, a subsidiary of Électricité de France, says that remote geothermal energy is often connected to buildings where the existing gas boiler is located. This not only makes it easier to connect to existing buildings, but also makes heating seamless on cold winter days. If the temperature drops so far that geothermal energy is no longer viable – at most a third of the year – the gas boiler automatically maintains the flow of heat.

In fact, the only real change residents might notice is that their wallets have gotten a little heavier. French subsidies for renewable energies, together with the even distribution of construction costs over 30-year contracts, reduce energy costs by up to five percent.

The savings in CO2 emissions are even more impressive. According to Sivery, for every equivalent unit of fossil energy used to maintain the district heating system, four equivalent units of green geothermal energy are generated.

News of these successes has spread to communities across the Paris Basin. In 2019, the municipality of Champs-sur-Marne successfully financed an investment in the development of geothermal district heating. “[There’s] A real conscience from the citizens to really proactively support the ecological change in France, ”says Goldberg.

There is no better example of this public proactivity than the proposed geothermal district heating system for the Olympic and Paralympic Village Paris 2024. The geothermal heating and cooling of the Olympic Village is a testament to France’s commitment to renewable energy. It is also a vision of what is to come for the country’s prospects for green energy. If the Olympic project is successful, it could trigger geothermal district heating projects across the country.

In an August press release, Wilfrid Petrie, Executive Vice President of ENGIE Solutions said that “Geothermal energy is therefore honored to become an Olympic energy for athletes.” Perhaps, in addition to all the medals they receive in France, the athletes are also interested in renewable energies.

This story was originally published in Reasons to Be Cheerful and appears here as part of the Solutions Journalism Network’s SoJo Exchange, a nonprofit dedicated to rigorous reporting on responses to social problems.

Chad Small is a New York City-based freelance reporter primarily an environmental reporter for Blavity: Politics. He is also a Finance Solutions Fellow of the New Economies Reporting Project of the New Economy Coalition. His coverage is primarily concerned with the economic, social and health effects of environmental racism in the US and throughout the African diaspora.

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