Mayor Boris Johnson is challenging students in Harrow to come up with new and innovative ideas to cut carbon emissions and boost London's green credentials.
The 2013 Low Carbon Prize offers the students the opportunity to win a share of £20,000 to turn their ideas into reality.
This year, 20 of the best runners up will be shortlisted for a chance to win a paid internship with the industrial engineering firm Siemens, who sponsor the award.
London's low carbon and environmental goods and services sector is worth an estimated £27 billion.
The Mayor's Low Carbon Prize, which is open to students at Further and Higher Education Institutes across Harrow, will award cash prizes to help develop the best ideas for reducing carbon emissions from London's buildings, transport and energy infrastructure.
It forms part of the Mayor's commitment to achieve a 60 per cent reduction in carbon emissions by 2025.
Applications will be judged by a panel of experts, including representatives from the Mayor's Office, experts in climate change mitigation and successful business leaders.
The winners will be announced at an awards ceremony at the Siemens Crystal on Thursday 13 June.