Anaerobic digesters take slurry, grass clippings, food waste and other agricultural products to produce heat or electricity and cut emissions of potent greenhouse gas methane.

Agriculture emits about 7 percent of Britain's greenhouse gases and an industry report last year suggested that anaerobic digestors could cut UK methane emissions from dairy, cattle and fattening pig enterprises by up to 75 percent.

"Anaerobic digestion has a lot of potential, not least because it will help us meet three of our needs at the same time," Benn said, noting it produced renewable energy, reduced emissions of greenhouse gas methane and helped to divert organic waste from landfill.

Germany builds around 1,000 digesters a year and leads the world in the technology with Britain trailing far behind.

Energy Minister Malcolm Wicks told the conference that proposals to build anaerobic digestion plants would receive "the top level of support" under proposed reforms to the government's renewable energy policy.

"Farmers have a vital role to play in the UK in meeting our climate change targets and increasing our energy security," Wicks said.