Gloucestershire-based green energy company Ecotricity is looking to produce gas from grass in its latest renewable energy innovation.

Ecotricity, who pioneered the use of the wind and sun to make green electricity in Britain - has begun construction of a green gas mill, which will make gas from grass.

Its first-of-a-kind gas mill is now being built near Reading in Berkshire. Once fully operational in early 2023, it will provide all the gas needs of 4,000 local homes - every year.

Traditional methods of making green gas involve use of food waste or energy crops, but both have sustainability issues and problems with a lack of scale.

Ecotricity's green gas mill will be fed by herbal lays - a mix of grass and herbs, sown and grown on farmland next to the plant.

Green gas mills do not require agricultural land and do not compete with food production. Costing £11 million to build, Ecotricity's first green gas mill will create 30 jobs and directly contribute £3m into the rural economy.

Ecotricity has also released a new white paper on the potential for Green Gas in Britain. Authored by independent academics from Imperial College London Consultants, the report reveals the potential that a national Green Gas programme would have:

• There is enough grassland in Britain, not involved in food production to provide gas for all homes
• A national programme to achieve this would create 160,000 jobs in the rural economy and contribute £15bn annually
• The UK could make all the gas it needs for home and business use - if meat production was reduced by 10 per cent and land was used to grow grass. Such a reduction would be well under the historical trend and targets set by government advisors to enable transition to net zero
• Green gas made this way can reduce greenhouse gas emissions by nearly 90 per cent when compared to the current use of North Sea gas and synthetic fertilisers. Green gas mills produce a natural fertiliser as a by-product.

The report also highlights the significant shortcomings of the government's national air source heat pump roll-out - its alternative plan for heating homes without carbon emissions.

Ecotricity says such a plan would cost six times as much as a green gas roll out - partly due to the need to triple renewable electricity generation, and significantly upgrade the grid to deliver it.

The plan would also require the scrapping of millions of gas devices - boilers and cookers, as well as the UK gas grid. Currently, it costs £8,000 per home to install a heat pump - which also adds more than 40 per cent to the overall energy bill of each household that uses one instead of gas. The report also flags that heat pumps will not work for 20 per cent of British homes at all - while a further 20 per cent of homes will need significant upgrades.

Ecotricity says green gas can be used to simply replace fossil gas in the grid - far more efficiently, quickly and cost effectively. And it will work for all homes - no exceptions.

Dale Vince, founder of Ecotricity, said: "This report could not be more timely - we're deep into an energy security crisis that has exacerbated an existing energy price crisis - while we urgently need to deal with the role of energy in the climate crisis anyway.

"The answer is not to throw away our national gas grid and the tens of millions of appliances that use it, imposing vast costs on the public - the answer is simply to change the gas we put into the grid. And carry on as normal.

"Green gas is cheaper, faster and far less wasteful than a switch to heat pumps. And it will work for every home - no exceptions. It will give us a more balanced and diverse outcome in terms of energy supply and form an essential part of the smart grid we need - with gas and electricity grids supporting each other, sharing the energy load of the country."

Explaining the process to make green gas, Mr Vince said: "It's pretty basic really - it uses the same kind of process of a cow's stomach which is known as anaerobic digestion where organic stuff breaks down in the absence of oxygen. We've got an industrial version of a cow's stomach. We feed it grass and it feeds us methane. We scrub it up and we put it into the gas grid.

"It's a really neat way to make the gas we need.because we have to get off of fossil gas because of carbon emissions and imported gas because of instability in the world."