Stroud-based green energy company, Ecotricity, fears its latest wind park could be its last.

The company has today turned on its new three windmill site at Alveston, South Gloucestershire, next to the M5 motorway. It will provide enough electricity to power more than 3,000 homes for the next 30 years, with no pollution. The project, in development for over a decade, received overwhelming support from the district council and local community alike.

But Ecotricity founder Dale Vince thinks it could be the company's last onshore wind park, due to changes in government policy.

He said: "It's always great to build another wind park and put it into operation. This one is a little bittersweet because without a change of government, or government policy, this could be the last one built in England. Current government policy, to prevent new wind parks in England makes no sense and is a political choice - because onshore energy isn't just good for the environment, it makes good economic sense too."

A new report from the Energy and Climate Change Intelligence Unit (ECIU) think tank supports the widespread view that new onshore wind energy development in the UK is an economic opportunity as well as environmental. They estimate the current government policy could add over £1bn to our energy bills over the next four years, because onshore wind is cheaper than other sources of power which the government backs financially, like nuclear, biomass and offshore wind generation.

Ecotricity has 25 wind parks with over 70 windmills and a capacity of around 90MW - enough to generate almost a quarter of all electricity used by Ecotricity's 200,000+ customers.

When Ecotricity switched on its first windmill 21 years ago, less than three per cent of the UK's electricity was renewable, and this now sits 25 per cent. One of the obstacles to greater levels of renewable energy on the grid is the ability to store electricity, which has been commercially difficult until now. Recent advances in battery technology made by the global take-up of electric cars make this now possible.

In the last couple of weeks, Ecotricity have been granted planning permission to build one of the country's first grid scale battery storage projects on the Alveston site. The 10MW project will share the grid connection with these three new windmills, making better use of the available capacity - and enable Ecotricity to balance variations between supply and demand each half hour of each day.