The Big Green Challenge Fund was offered by NESTA and supported by the Mirror, and received applications from 350 community groups involving thousands of people across the UK implementing renewable energy and efficiency measures. The winners were selected from 10 finalists and were judged on their achievements in CO₂ reductions; the innovative nature of their initiatives; the longevity and scalability of their project; and their level of community engagement.

“Whilst Copenhagen showed just how difficult it is to reach consensus amongst governments, the Big Green Challenge shows how local efforts can triumph,” says judging chair Lord Puttnam. “When people are empowered and are given intelligent support, they can make the world of difference in the fight against climate change.”

The winners include:

• Isle of Eigg where an entire island community is working to reduce carbon emissions by generating renewable electricity and installing solar panels, to producing local food and developing low-carbon community transport schemes. The community has reduced its CO₂ emissions by 32% in the past year.
• Low Carbon West Oxford, an environmental project featuring community-owned renewable energy initiatives which have has reduced CO₂ emissions by 28% across 55 homes.
• The Green Valleys community renewable energy scheme in Wales which reduced CO₂ emissions by 20% across 155 homes and four community buildings, and the installation of a number of hydroelectric projects.
• Household Energy Service, a free environmental survey service for residents in Shropshire, which has reduced CO₂ emissions by 10% through the provision of a home energy auditing service carried out by community volunteers.
• The emissions reductions will treble over the next three years, exceeding the UK's reduction target of 34%.

“The Big Green Challenge has shown that communities are a vital force in solving some of society's biggest problems,” adds Jonathan Kestenbaum of NESTA. “We can no longer afford to pay lip service to the importance of local solutions - now is the time to support communities to make a real difference.”

The awards are designed to demonstrate whether a challenge prize could unlock the imagination of communities in responding to climate change through implementing renewable energy and efficiency measures. NESTA developed a rigorous target and evaluation mechanism, and the Big Green Challenge has attracted international interest in how to stimulate civic action, including from the X Prize Foundation in the USA.

Three projects (Green Valleys, Isle of Eigg, Household Energy Service) each received £300,000; the runner-up Low Carbon West Oxford received £100,000.

The initiative reached individuals and groups that grant-led initiatives cannot reach, explains the final report, with 40% of applications from groups that are not registered charities, companies or public bodies. More than one-third of applications came from groups without a previous focus on environmental issues, and 60% of the communities expect to achieve multiple outcomes, rather than the single outcome focus that is more typical of government campaigns.

NESTA is the largest independent endowment in Britain, with a mission to support innovation that will drive economic recovery and solve social challenges. The Big Green Challenge was launched in October 2007 and, from the 355 applications, NESTA selected 100 which received support to develop their ideas into detailed plans.