Nantes Métropole's heating network is being deployed to supply more and more homes and public buildings with hot water and heating.
But how does it actually work?
20 Minutes
visited the Malakoff boiler room and explains everything to you.
A huge trench is dug along the street and the pipes now have to be laid.
By this summer, the Semitan workshops and the Bellier hospital in Nantes will in turn be connected to the heating network.
If the inhabitants have been hearing about it for years, in particular with works every summer in this direction, they are rarer to know how this urban network works in practice.
20 Minutes
was able to visit the Malakoff boiler room, one of the most important in the metropolis, and explain everything to you.
What is the heating network?
A pillar of Nantes Métropole's energy policy, the heating network, also known as the district heating network, is different from electricity and gas and aims to be more ecological.
To supply heating and heat water to public facilities (Mandela high school, CHU, Jules-Verne swimming pool, etc.) and condominiums, very hot water (around 100°C) is sent from the boiler rooms in pipes in underground and well insulated steel.
In total, 12% of homes are connected to the Nantes metropolitan area heating network, which extends over 145 km, divided into five sectors.
The most important of these is the Centre-Loire network (more than 86 km), which has a main boiler room (Malakoff) and a smaller one (California in Rezé, which operates only between October and the end of May).
How does the Malakoff boiler room work?
Managed by Erena, a subsidiary of Engie, the Malakoff boiler room produces heat using two main sources of energy: waste from residents, incinerated not far from there in the Prairie de Mauves plant (41%) and wood, which is called biomass (43%).
“These are mainly residues from logging, related sawmills, half of which comes from Loire-Atlantique”, we explain at Erena.
In the big black building that we observe when passing in front of the site, 4,000 m³ of wood are stored, the equivalent of four days' consumption, before being burned.
When the temperatures warm up, like right now, this wing doesn't run every day.
Conversely, for periods of extreme cold,
What is the future of this system?
The deployment of the Center Loire network has quadrupled since 2012 and Erena ensures that there is still “big potential”.
With the explosion of gas and electricity prices, Nantes Métropole (which has the third largest network in France behind Paris and Grenoble) will continue to bet on it, even if the solution is not yet adapted to individual houses. .
“We want to make it a kind of local energy public service, assures Tristan Riom, deputy (EELV) for energy in the city of Nantes.
Wood is the most stable source in terms of price and the heat produced by the incineration of waste exists anyway.
According to Nantes Métropole, the tariffs of the heating network can be 15 to 30% lower than the price of gas.
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Pays de la Loire
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