The biomass cogeneration plant operated by Dalkia provides part of the heating and electricity for Rennes using wood.


C. Allain / 20 Minutes

  • The Rennes biomass cogeneration plant has been supplying electricity and heating to the southern districts of Rennes since 2013.

  • Several sources questioned the local supply of Dalkia, an EDF subsidiary that operates the plant.

  • The operator ensures that the radius of 100 km around Rennes is respected and that the local resource is privileged. 

Doubts were allowed, the communication was so discreet.

After refusing our interview request in October, Dalkia officials finally agreed to answer our questions about the supply to their biomass plant in Rennes.

Installed on the edge of the southern bypass, the factory has seen its chimney spit out a light white smoke for several weeks.

During this winter period, the plant burns wood to provide heating to the equivalent of 20,000 households in the southern districts of Rennes.

An ecological choice thanks to its sustainable supply, but also economic since it allows to break away from the fluctuating price of imported gas.

On paper, the picture drawn up by the EDF subsidiary seemed idyllic.

At the end of the year, however, several voices were raised to ask the operator for guarantees on the origin of the burnt wood.

The contract signed in 2013 with the state was clear.

All the wood burned in the plant had to come from a geographic area within 100 kilometers of the plant.

A commitment that several sources questioned.

According to the annual report sent in 2019 by the EDF subsidiary to the Regional Department for the Environment, Planning and Housing (DREAL), “100% of the supply was within the 100 km radius. in 2019 ”.

This figure was reached for the second consecutive year, after a 2017 financial year closed at 99.7%.

During the first three years of operation of the cogeneration plant, which provides heating and electricity, the figure was 96.6%, according to the same report.

"Transporting wood, storing it ... All that is very expensive"

In addition to this written report submitted to the State, the DREAL conducts site visits every year to verify the origin and quality of the material burned on site.

"Dalkia respects the specifications, there is no doubt about it", we specify.

These comments are confirmed by the director of the power plant Frédéric Blandin.

“Since the site opened, everything has been checked.

Our supply plan is submitted to the prefecture and has always been validated ”.

The director specifies that Bois Energie France, the EDF subsidiary in charge of supply “always favors the closest resource.

Transporting wood, storing it… It's all very expensive ”.

From January to July 2020, the average supply was 46 kilometers and 86% of the resource came from a radius of less than 75 kilometers.

With 109,800 tonnes burned in 2019, or twenty trucks per day, the Rennes boiler room is by far the largest in Brittany.

According to its director, its opening in 2013 would have enabled the wood industry to become sustainable.

“When we started, the foresters weren't organized at all.

By providing them with a long-term contract, they were allowed to invest in equipment.

Producing wafers is expensive, ”explains Frédéric Blandin.

To gain transparency, the site manager wants to open his factory more to visitors, when the health situation allows.


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  • Planet

  • Reindeer

  • electricity

  • Heater

  • energy

  • Forest

  • Wood

  • EDF