Rosny-sous-Bois, Noisy-le-Sec, Montreuil. By summer 2016, these three towns in Seine-Saint-Denis will be powered by the same geothermal network, which is to be called Ygéo. A major project, which will supply heating and domestic hot water to the equivalent of 10 300 residents, corresponding to an energy demand of 103 GWh.
Initial identification
A major project is underway in Seine-Saint-Denis to create a network of geothermal heat can provide three towns (Rosny-sous-Bois, Noisy-le-Sec and Montreuil) with domestic hot water (DHW) and heating by the summer of 2016. An implementation that has, of course, not been decided upon at random. As part of the Regional Climate and Air Energy Plan and geothermal recovery plan in the Île-de-France Region and supported by the ADEME (French Agency for Environment and Energy Management), the General Council in Seine-Saint-Denis commissioned the engineering consultancy firm Sermet to carry out a feasibility study on geothermal energy and to identify which municipalities might be able to meet their energy needs through geothermal energy.
A network of over 10 km
Currently under construction in the town of Rosny-sous-Bois, the geothermal plant will provide a capacity of 10 MW. It will consist of an 1800 metre deep geothermal doublet, the drilling of which has just ended, and heat pumps. Geothermal energy is expected to provide about 60% of the heat; the remainder being provided – particularly in the case of insufficient ambient temperatures – by 8 decentralized gas boilers which are already in operation, thus avoiding the need to construct a backup gas boiler on the site.
How will the production site work? The water used will be drawn at about 2000 metres deep, from ground water in a geological layer dating from the Jurassic period named Dogger. The temperature of this water is between 55 and 85 ° C. Note that this is currently the third largest source of renewable energy in France, after hydropower and biomass. It is a clean, local and renewable energy, which has the potential for non-negligible development for district heating networks, and prospective future laws on energy transition will only serve to encourage people to further tap into renewable energy sources.
10,300 connected homes
After completion (in summer 2016), the geothermal heating network in Rosny-sous-Bois, Noisy-le-Sec and Montreuil should be able to distribute more than 100 GWh of heat per year to 10 300 units in the three municipalities. Compared to a “classic” form of central heating, it will result in 15,800 tonnes less of CO2 being emitted into the atmosphere.
However, the environment is not the only winner: as renewable energy will account for more than 50% of the total energy used in the Ygéo heating network, end-users will benefit from a reduced VAT rate of 5.5% on their heating bills. Furthermore, while energy prices are steadily increasing, the cost of geothermal heat should be increasingly competitive year after year, since it is not subject to fluctuations of markets unlike the price of fossil fuels.
Signed in January 2014, and covering a period of 30 years, the delegation contract awarded the construction and management of the future heating network to Cofely network, a subsidiary of the GDF Suez group. The group has invested some 33 million euros, with the ADEME Heat Fund and the Region Ile-de-France providing further financial backing to the tune of 6.5 million euros.
Image source: Mappy.
