The Telegraph
Grass-powered gas to heat homes for the first time
Telegraph reporters – February 26, 2023
Grass-powered gas is set to heat thousands of homes for the first time in the coming weeks.
Green energy firm Ecotricity is expected to begin supplying 5,300 homes from its plant near Reading in April.
Research has estimated that the grass biogas can reduce greenhouse gas emissions by nearly 90 per cent.
It is hoped the scheme can be scaled up to supply fuel to more homes around the country.
The £11 million mill uses bacteria to break down grasses and herbs, which absorb carbon dioxide while growing, in an anaerobic digester.
This produces biogas which is then “scrubbed” to remove some carbon dioxide and upgraded to biomethane for use in the gas network.
An organic fertiliser, which is intended to help grow more grass, is also produced.
Hopes for expansion
Homes in Berkshire will be supplied through the distribution company Southern Gas Networks.
Ecotricity owner Dale Vince hopes to expand across the country, building mills which minimise the use of fossil fuels while avoiding damage to the environment, and boost energy security.
Mr Vince, 61, said: “We are ready to go and once the gas supply company’s measuring and checking equipment is in place we expect to start in April.”
Green gas has previously been made from food waste or “high energy” crops such as maize, but both face sustainability issues and problems with a lack of scale.
Maize, for example, is fertiliser-hungry, attracts birds that struggle to survive in it, and is harvested around autumn, leaving topsoil run-off.
“Our mix of grass with herbs and clovers makes carbon neutral gas, pulling carbon out of the atmosphere,” said Mr Vince. “It’s a cycle of carbon rather than a net emission.
“When you burn fossil fuel it’s carbon from millions of years ago that gets released into the atmosphere.
“We’re buying the grass from farmers. Instead of them using it to grow for animals, they’re selling it to us.
“It’s better for farmers, they get a better price and more security because animal agriculture is a super marginal business. It only exists with massive subsidies.”
Reduce greenhouse gas emissions by 90pc
On average, the amount of grass being used initially could be cultivated every year from around 3,000 acres to provide over 48 million kWh of gas, while saving nearly 12,000 tonnes of carbon dioxide emissions – but the ultimate goal is to expand on a national scale.
A report by Imperial College Consultants estimated the UK has 6.46 million hectares of suitable grassland not involved in food production, enough for 5,400 green gas mills to provide up to 236.5TWh – sufficient to heat 98.8 per cent of British homes if made energy efficient.
The research estimated that gas made from grass can reduce greenhouse gas emissions by nearly 90 per cent when compared to the current use of North Sea gas and synthetic fertilisers.
The report also said the Government’s national air source heat pump roll-out – its alternative plan for heating homes without carbon emissions – would cost six times as much as a green gas roll out and would not be possible in 20 per cent of British homes.
That plan would also require the scrapping of millions of boilers and cookers, as well as the UK gas grid.
Project will supply 5,300 homes
Asked about Ecotricity’s biomethane project, a Department for Energy Security and Net Zero spokesman said: “Initiatives like this show how the UK is leading in the development of innovations in green technologies that can help increase our energy security, tackle climate change and bring down people’s bills.”
Southern Gas Networks said: “We’ve partnered with Ecotricity to deliver a biomethane to grid project at a site in Farley Hill near Reading. The project will supply 5,300 nearby properties with renewable green gas for heat and power, helping to reduce each household’s annual carbon emissions by an equivalent of 2.2 tonnes.
“Our role is to commission the gas entry unit infrastructure at the plant. This equipment will measure the flow of gas into our network and ensure it meets the required specification. Approximately 700m3 of biomethane-powered renewable energy will be injected into our local intermediate pressure network every hour.”
A National Gas Transmission spokesman: “Biomethane will play an important supporting role in the journey to Britain achieving net zero.”