The city's district heating network is the second largest in France after Paris! 185 km of pipes are distributed under the public roads of seven municipalities in the conurbation*, supplied with hot water by one of the five heat production sites in the Metropolis: Villeneuve, Poterne, Athanor, Biomax, and the thermal power plant. from Solvay.
This heat network supplies 46,000 homes, but also the university campus, the University Hospital, the Grenoble Museum, the Grand'Place and Caserne de Bonne shopping centers, and many other public buildings. Biomax, commissioned in 2020, has the particularity of using wood exclusively as fuel (and fuel oil only for the auxiliary boiler): cheaper and more responsible energy for heating this winter.
Heat and electricity
On the scientific peninsula, Stéphane, operations manager at the heating company, begins a visit to the site: “ Here, the wood is unloaded, screened and stripped: large pieces are removed, but also nails and metal parts, before drying the wood to eliminate all the water it contains.. » This wood serves as fuel for the main boiler. The steam produced is used in part to heat network water, and is sent to a turbine to produce electricity. “ Biomax is a cogeneration plant, explains Stéphane, meaning it produces both heat and electricity.. »
The heated water is then sent through steel pipes throughout the district heating network, to serve between 15,000 and 20,000 homes. From the outside, the three large thermal storage towers do not go unnoticed: “ They allow hot water to be stored when there is a surplus, and to discharge it when needed. During peak hours, this avoids starting the auxiliary boiler which runs on oil. » The 214 employees of the Biomax site operate the factory from November to May, and carry out maintenance work the rest of the year.
*Grenoble, Échirolles, Eybens, Gières, La Tronche, Le Pont-de-Claix, Saint-Martin-d’Hères.
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