Besides agricultural substrates, Weltec and Domaix biogas plants will use sludge and food leftovers from schools and company cafeterias must be used for the production of energy. In all four biogas plants, the residual heat will be used in a digestate dryer in order to reduce the amount of liquid manure and market the dried digestate.
The four biogas plants have an efficiency of at least 70 per cent, enabling the operators to benefit from the heat and power bonus, which is up to €0.04/kWh in France.
One plant in the département of Charente will use a 3,000-m³ stainless-steel digester, while the other 600 kW plant in Burgundy, central France, will have two digesters with a capacity of 2,000 m³ each. The two other plants will have an electrical output of 190 kW and 255 kW, respectively. The smaller WELTEC biogas plant in Lorraine comprises a 1,500-m³ stainless-steel digester and will be loaded with cattle manure from the operator's farm as well as whole plant silage and food leftovers. Additionally, the 255-kW plant will utilise agro-industrial waste.