More than eight million people live and work in London. A cultural, sporting and financial capital, Europe's largest city is also looking to be a world leader when it comes to sustainability and energy efficiency.
Authorities have set ambitious environmental and energy usage targets. They hope to slash carbon emissions by 60 percent by the year 2025, while Boris Johnson, the Mayor of London, wants to ensure that a quarter of London's energy is supplied from "decentralized sources."
The energy sector thrives on new ideas, and the Mayor of London's Low Carbon Entrepreneur competition, sponsored by Siemens, has been seeking out the city's brightest students and their innovative energy ideas.
"The incredible students behind these green innovations are the future leaders who will be powering London's booming green economy," Johnson said.
Here, we look at this year's finalists, including the winner. Will their ideas help ensure a sustainable future for London?
By Anmar Frangoul, special to CNBC.com