With a $5, solar-powered, cardboard cooker.
The Kyoto Box consists of two cardboard boxes, one nestled inside the other, and a clear acrylic top. One of the boxes is black, the other is lined with metal foil. Together, they can cook food or boil 10 liters (about 2.6 US gallons) of water in 2 hours.
The box is targeted at about 3 billion people in developing countries who burn firewood to cook. It will be given away free.
"The prize is just what's needed to get this project off the ground," said Jon Bohmer, the Kyoto Box's inventor.
Organized by Forum for the Future and the Financial Times, and sponsored by Hewlett-Packard, the 2009 contest drew almost 23,000 visitors to its web site. Thousands of people voted for the Kyoto Box, which beat out nearly 300 other entrants. In addition to the popular vote, a panel of 8 judges assessed each entry.
Other finalists in the contest were:
- A feed additive that reduces methane produced by cows and sheep
- Hollow tiles cooled by evaporation, which would replace air conditioners
- Covers for truck wheels that cut drag, reducing fuel use
- A giant industrial microwave that fixes carbon in organic material as charcoal.
In the end, the simplest invention caught the public's imagination and took first place.