Earthworks and deep foundations have started for a new biomass and heat recovery plant behind the Trousseau university hospital in Tours, Energynews reported on 9 November. The plant will feed Énergie Verte, the district heating network of Tours Métropole Val de Loire, and its biomass boiler is rated at 21 MW. The buildings and equipment go up between this autumn and spring 2027, followed by tests; the biomass equipment is due to be commissioned in October 2027.
The network is not starting from zero. The hospital connection is finished and the pipes are already filled with water, one hospital building is connected, and two substations for the new Trousseau hospital are to be commissioned in the coming weeks. Today the network has 10 MW of subscribed capacity. From 2027 it is to be extended to new customers in the metropolitan area.
What the network will look like when it is built out
- 25 km of heat network, plus 1.5 km of cooling network for the hospital
- areas served: Tours Sud, Chambray-lès-Tours, Saint-Avertin and Joué-lès-Tours
- a mix of 90% renewable and recovered energy: 78% biomass and 12% waste heat, with natural gas kept for back-up and emergencies
- 16,767 tonnes of CO2 avoided per year, according to the project backers
The operator has signed a charter on wood energy and biodiversity and says it will favour local biomass. The stage was presented by the president of the metropolitan authority, the regional director of ADEME Centre-Val de Loire and the president of Coriance. The article does not give the investment, the number of connected homes or where the recovered heat comes from.
A hospital on both sides of the meter
The detail that stands out is the 1.5 km of cooling network next to the heat network. A hospital needs chilled water all year for operating theatres, imaging and server rooms, and heat for sterilisation and hot water at the same time. Serving both from one energy centre opens the door to heat recovery between the two, but it also means two sets of substations in the same plant rooms, with different temperatures and different water quality.
For a hospital, the substation is the part of the network that the facility manager actually lives with. A plate heat exchanger that can be opened and cleaned in a planned window, without draining half the building, is worth more there than a few kilowatts on paper. The same question came up in Joigny last week, where 69 substations are planned for a much smaller town.
Sources: Energynews, Energynews (French edition)
