Toulouse tomato greenhouses heated with waste treated by Econotre

Every year, the 10 hectares of vegetable greenhouses built alongside the Econotre centre are supplied with 25,000 MWh of thermal energy. This recovered heat supplements the 120,000 MWh of electricity already generated by Econotre (equivalent to the consumption of 21,300 homes) by burning 192,000 tonnes of waste.

Sold at €10.13 per MWh, the heat energy halves the energy bills of farmer Gilles Briffaud, the owner and operator of the greenhouses, which will ultimately produce 6,000 tonnes of local tomatoes a year. These favourable conditions have enabled him to extend the greenhouses, which will cover 10 hectares, and create about a hundred local jobs.

Econotre represents 25,000 tonnes of recyclable household waste sorted, 30,000 tonnes of bottom ash recovered, 8,000 tonnes of green waste recovered and 3,500 tonnes of compost produced every year. The centre uses incineration to recover the value from household waste generated by the Decoset municipalities.

This processing method exploits the energy generated by burning the waste to produce electricity and heat. Econotre uses the heat released by burning the waste in ovens to produce electricity with a turbo-alternator. Since 2016, the low-temperature energy still available after combustion has been recovered to supply heat to the vegetable greenhouses built alongside the site, rather than being dissipated in the atmosphere.

"This is a circular economy model," declares Gaël Spitz, the SUEZ director of Econotre. Reusing 25,000 MWh per year saves the equivalent of 2,200 tonnes of oil and 6,000 tonnes of CO2. This has created a new activity that has generated 100 jobs, and the tomatoes are consumed locally."

The Econotre heat network was built thanks to the ambition shared by Decoset, Bessières town hall and Econotre to generate alternative renewable energy to support the energy transition and local socio-economic development. SUEZ experts worked on new high-performance cogeneration technology to make it possible. The result is a first in France.