The Kyoto Box is a solar-powered cooker made of cardboard that can boil 10 liters of water in two hours and reduce the need for firewood, which will not only enhance the lives of millions in developing countries, it will shave about 2 tonnes of greenhouse gas emissions from the carbon footprints of the families who use it.

Kyoto Box designer Jon Bøhmer; photo courtesy Einar Lyngar. Click for full-sized photo

The Kyoto Box won the FT Climate Change Challenge, a global competition with a $75,000 purse aimed at finding the best innovations to address climate change. The inventor, Kenya-based entrepreneur Jon Bøhmer, will use the prize to fund large-scale trials of the solar cooker in 10 countries.

More than 300 entries were submitted to the contest. A combination of public votes and assessments from a panel of business leaders and climate change experts chose the winner. The Financial Times, HP and Forum for the Future teamed up to create the contest.

The Black Phantom. Click for full-sized photo

The solar cooker, a contraption that costs five euros (US$6.57) to build, consists of two boxes that rely on the greenhouse gas effect. One box rests within the other while an acrylic cover lets in and traps the sun's heat. The inner box is painted black while the outer box has silver foil to concentrate heat. Users can stuff newspaper or straw between the two boxes for insulation.

The Deflecktor. Click for full-sized photo

Other finalists included the Black Phantom, a machine developed by New Zealand-based Carbonscape that turns biomass into charcoal that can be stored underground; the Deflecktors, lightweight covers that fit into truck wheels to improve fuel efficiency; Mootral, a garlic-based feed additive developed by U.K. firm Neem Biotech that reduces livestock methane emissions; and ceiling tiles developed at Longborough University in the U.K. that cool room temperatures without energy.

The Longborough Univeristy ceiling tile. Click for full-sized photo

The Kyoto Box holds the potential to help an estimated three billion people who use firewood to cook, while improving the health of millions of children who lack access to clean drinking water and suffer from smoke inhalation, Bøhmer said.

Bøhmer, the owner of design firm Kyoto Energy, can replicate the solar cooker with corrugated plastic for the same cost for a longer-lasting cooker. He'll conduct trials with 10,000 cookers in 10 countries, including India, Indonesia, South Africa, Kenya and Uganda.

He hopes to use the data from the trials to apply for carbon credits, which could produce an annual profit of up to 30 euros (US$39.47) per stove. He'd use the excess funds to launch other solar products, such as a plastic bag that heats and cleans water, a smokeless cooker to burn biomass and a solar-power torch.