- Réseau de chaleur et de froid
An innovative, modular heating network for Bischwiller
The municipality of Bischwiller in Alsace wanted to install new energy infrastructure in the form of a modular shared heating network. The exemplary public service provided by the district heating network is in keeping with the local approach to sustainability. One of the municipality's flagship measures, the project was completed in just 13 months, ready for its first heating season in winter 2023-2024.
Meeting all the heating needs of Bischwiller
The municipality chose the solution developed by Idex, based on the construction of a new biomass boiler plant and the networking of local districts. For this project, Idex was supported by local companies from the Bas-Rhin region, which demonstrated particularly efficiency in the civil engineering works.
The network now supplies 123 buildings over a distance of 13 km, covering the whole town. This makes it one of the most extensive heating networks in eastern France, supplying heat and domestic hot water to municipal buildings, schools, the local departmental hospital, retirement homes, residential buildings, private homes, a swimming pool, a sports complex, a municipal technical centre, an art centre, a leisure centre, the Oberhoffen-sur-Moder military camp, and the Baumgarten area for mixed-use development (ZAC).
This district covers an area of around 22 ha in the north-western part of Bischwiller. Designed as part of a sustainable approach to urban planning, it comprises 810 homes including 491 flats in residential buildings, 169 intermediate housing units and 70 grouped single-family homes. It was planned with the future heating network in mind.
Low-carbon performance with 96% renewable energy
The heating network produces 24 GWh of heat per year. An interconnection with the local hospital's boiler plant makes it possible to share heat production for greater security. The choice of local, low-carbon energy also guarantees a competitive, stable price for the 25-year concession period. The centralised boiler plant is equipped with two biomass boilers of 3 and 6 MW, as well as a 10 MW gas-fired boiler for continuity of service. With renewable energies meeting 96% of requirements, the network avoids the emission of 8,000 tonnes of CO2 per year, equivalent to 3,500 cars on the road for a year in Alsace. The wood chips required by the boiler plant are purchased locally, helping to develop a local fuelwood activity. The ash from combustion is also used to fertilise the surrounding fields.
To promote energy conservation, Bischwiller shares consumption data with network subscribers, enabling them to adjust their indoor temperature based on their actual needs. This is made possible by the use of hypervision, a function that controls the various connected systems, while monitoring energy production, distribution and demand in real time in order to optimise plant operation.
It’s relatively rare to see a district heating network of this size covering an entire town of 13,000 inhabitants.
Bischwiller rewarded for its commitment to sustainability
The total cost of this energy infrastructure is €18.3 million. The heat fund of the ADEME is providing financial support of €7.7 million, while the municipality is investing €1.9 million.
Bischwiller also raised €228,000 from 99 donors on the Lendosphere crowdlending platform, exceeding the initial target of €200,000. For this participatory financing initiative, the town received the label Financement Participatif pour la Croissance Verte (Participatory Financing for Green Growth), created by the French Ministry for the Ecological Transition. Private investors have the opportunity to invest in a short-circuit ecological project, decarbonising their portfolio at an attractive gross interest rate of between 5 and 6.5% over a four-year period.
Winner of the 2023 Alsace municipality awards in the sustainable development and quality of life category, this infrastructure illustrates Bischwiller's practical commitment to the energy transition. It was also praised by Sylvain Waserman, Chair of the ADEME, at its official inauguration on 26 January 2024. At the same time Idex CEO Benjamin Fremaux expressed his pride in making an active contribution to the energy transition of Bischwiller.
24 GWh of heat delivered
96% of renewable energy
13.5 km for the new network
8,000 tonnes of CO2 emissions avoided