Ministers are hailing a “massive boost to green growth and green jobs” with the launch of eight renewable electricity projects.

By 2020, they claim, the schemes will generate £12 billion of private sector investment and create or support 8,500 jobs.

The projects will also add 4.5 gigawatts of power to the UK’s energy mix – about four per cent of capacity or enough power for three million homes.

Energy and climate change secretary Edward Davey said: “These contracts for major renewable electricity projects mark a new stage in Britain’s green energy investment boom.

“By themselves they will bring green jobs and growth across the UK, but they are a significant part of our efforts to give Britain cleaner and more secure energy.”

The projects are expected to reduce harmful emissions by 10 MtCO2, compared to fossil fuels.

The renewable electricity sector has more than doubled since 2010. This growth is expected to continue and by 2020, 30 per cent of electricity will come from this source, say ministers.