Thousands of British homes could soon be heated by, among other things, cow manure after the Health and Safety Executive (HSE) agreed to relax regulations controlling renewable gas plants, the Telegraph reported.
Industry experts say that biomethane, produced by the anaerobic digestion (AD) of food and plant waste, crops, slurries and sewage, could make a significant contribution to Britain’s gas needs.
The biogas has a higher oxygen content than conventional North Sea gas, and safety regulations have so far prevented it being carried in the pipeline network for fear it could cause corrosion and lead to explosions.
Instead, gas from AD plants is generally burnt to produce electricity, with just one commercial-scale plant supplying gas into the grid.
The Poundbury plant, opened by biomethane advocate Prince Charles on his estate in Dorset last year, had to gain special exemptions.
But the HSE has concluded the higher oxygen content is safe and relaxed the rules, to make it “easier, quicker and less costly” for AD plants to supply gas to the grid.
The change is a “significant milestone”, reducing financial risk for developers, according to Anaerobic Digestion and Biogas Association (ADBA) chief executive Charlotte Morton.
Up to 40 new biomethane plants were likely to link up to the grid over the next two years and could produce enough gas to heat 128,000 homes, she said.
National Grid has estimated renewable gas could eventually meet up to 50 per cent of the UK’s residential gas demand and says the cost compares well to other green technologies such as wind farms.
AD technology has long been used by the water industry to treat sewage, but has enjoyed rapid growth in the power sector in recent years thanks to subsidies from the Government. There are now more than 100 plants, with AD generating more UK electricity than solar panels, ADBA says.
New “renewable heat” subsidies have also driven interest in plants to inject gas to the grid. Ms Morton said that to speed up the industry’s growth, ministers should ban food waste being sent to landfills, and councils should collect it separately, securing supplies for the plants.
Other challenges remain. For example, energy bills for households downstream from AD plants may have to be adjusted to reflect the lower energy content of the biogas.