Two Westcountry schools that have drastically cut their carbon emissions have triumphed in the 10th annual Ashden Awards.

Okehampton College in Devon and St Columb Minor primary school in Newquay, Cornwall, other finalists in the UK, including businesses, local authorities and charities.

All had made significant carbon savings through the use of renewable energy or energy efficiency measures.

Six UK and six international projects were chosen as winners to receive their awards from internationally renowned natural history filmmaker Sir David Attenborough.

Winners received £10,000 or £20,000 to invest in future sustainable energy work.

Ashden Awards for Sustainable Energy were set up in 2001 to champion practical, local energy solutions that cut carbon, protect the environment, reduce poverty and improve people's lives.

Okehampton College has cut its electricity bills by more than half and saving 70 tonnes of CO2 a year by encouraging energy-saving behaviour, replacing 3,000 fluorescent lights, installing cavity wall insulation and using solar PV energy.

The College is working with 11 primary schools by helping them carry out energy surveys and assisting 10 of them to install solar PV.

Future plans include building a mini hydro system using a local stream, as well as two wind turbines, solar water heating and a biomass boiler.

Keith Webber, the school's community technology coordinator, said: "Our approach has been to win hearts and minds through our lessons and community engagement whilst at the same time taking practical measures like installing renewable technologies that are used in teaching a range of subjects."

Sarah Butler-Sloss, Founder Director of the Ashden Awards, said: "We were very impressed with the huge difference Okehampton College's sustainable energy work has made both to the school itself and its 11 feeder primary schools."

St Columb Minor School has raised nearly £120,000 to give its building a green makeover with energy efficiency, a wind turbine, solar PV and solar thermal.

Electricity consumption has fallen by 37 per cent and gas consumption by six per cent.

Pupils make pledges to shrink their carbon footprint and display them around the school. To raise awareness outside the school, Year Six students made a video called 'Making a Difference' giving their views on climate change and featuring the school's use of renewable energy.

Gill Harper, the school business manager, said: "We're learning all the time. There's always something more you can do – that's why we want to network with other schools to share ideas and explore ways to continue to improve the environment and reduce our carbon emissions."