Lyon: dives into the third district cooling network

The Nelson Mandela esplanade, in front of the departmental archives, baked under the heatwave sun on June 17th. But thirteen meters below the yellowed grass produces a buried factory whose roar does not reach the surface, cold to air-conditioned the offices and the Part-Dieu shopping center. Welcome to the Mouton-Duvernet power plant, a 1,600 m2 bunker filled with an intertwining of metal houses. This knot of pipes, deserted, controlled from the headquarters of Surville, feeds fifteen miles of pipes below the business district and refreshes one million square feet.

In the midst of a heat wave, Dalkia, the operator of this district cooling network since its inception in 1971, praises the energy and environmental benefits of the new Mouton-Duvernet power plant, launched in 2019, with geothermal technology unique in France.

My water at 10 ° C

Here, Dalkia uses mine water pumped at 10 ° C in the LPA parking lots to avoid flooding by rising groundwater: a so-called “fatal” energy, recycling cold that would be lost without this use. This makes it possible to drop to 4 ° C in buildings’ cooling circuits without heating – and damaging – the environment.

“To produce cold, we produce heat, it is inevitable,” recalls Gérald Campbell Robertson, CEO of the dedicated subsidiary Energie Lyon Métropole. “The least efficient installations release it into the air and contribute to heat islands. Centralized systems that pump cold into the surface water level at 15 degrees, return hot water to it, and cause the temperature to rise up to 25 ° C, ”he says. “Not only is the system losing efficiency, but it is disrupting groundwater ecology.”

ice basins

With mine water at 10 ° C, ELM achieves a yield “two to three times higher” and “helps to cool the surface water level by releasing water there at 12-13 ° C”, confirms Dalkia’s representative. And energy efficiency is at its highest: the plant uses 1 KWatt of electricity to produce 7 KWatt of cold. Especially because ice basins allow to keep the excess cold produced at night, to discharge it during the day on top of high heat.

Currently, this 35 GWh network is the second largest district cooling network behind the La Défense district. The latter is connected to the Seine when Marseille takes the cold in the sea. With a € 30 million investment in Mouton-Duvernet and in a kilometer of further pipeline, Part-Dieu is calibrated to triple its distribution in 2027.

“The least bad air conditioning”

This new technology will be implemented from August “in another Lyon network in the 15 GWh Gerland district”, announces Philippe Guelpa Bonaro, Vice President of Greater Lyon for Energy. This is the result of a change in Dalkia’s public service delegation on Lyon district heating – renewed in 2017 until 2041.

The factory is housed under the skate park, in the basement of a former Michelin factory. Cité Scolaire Internationale, Boehringer Ingelheim, the IARC and the WHO are gradually joining it. An investment of 18 million euros for 7 kilometers of pipes and 300,000 m2 of offices working on pumping water from the Rhône.

“The district cooling network is the most efficient system,” says Jérôme Aguesse, Regional Director of Dalkia. “But more conditions are needed to implement it: a source of cold for production and a high density of tertiary buildings to make the heavy investment profitable”, at the expense of the operator. The business model is based solely on subscriptions. Especially since Ademe, which subsidizes the heating network, does not support cold. “A mistake” according to him because it is “the least bad of air conditioning solutions”. There are about 850 heating networks in the country, up to 32 cooling networks.

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