A plant which generates power from farm and animal waste is being built on a farm in Gloucestershire.
The installation in Cirencester will produce methane-rich biogas which will provide heat and power.
The plant will take chicken litter, pig manure, wheat and corn and generate enough electricity to power 350 homes.
Biogas company Alfagy said the farmers who put up the plant would have the benefit of free heat for animals, grain drying and housing.
Managing director Peter Kindt said: "Two farmers got together and supplied a big digester in which you put animal and farm waste which ferment.
"You capture (the gas), tidy it up and put it into a combined heat and power plant which makes heat and power.
"The [National Grid] buys the electricity from them, which pays back the project costs over time."
He described the plant as a "giant cupcake" with a green membrane on top. Smells would be captured by the digester.
The plant is due to be up and running in December.