A solar-powered cardboard cooker which aims to transform the lives of hundreds of millions of villagers in developing countries is the winner of the $75,000 prize in our global competition for innovation to tackle climate change.

The Kyoto Box is targeted at the three billion people who use firewood to cook and has the potential to deliver huge environmental and social benefits. “We’re saving lives and saving trees, “ says Kenya-based entrepreneur Jon Bøhmer. “I doubt if there is any other technology that can make so much impact for so little money.”

The box, which costs about five euros to make, aims to save some of the millions of children who die each year from drinking unclean water by allowing families to boil water and cut the health risks from smoke inhalation. Bøhmer believes it will halve the need for firewood, saving an estimated two tonnes of carbon per family per year, and sparing women from the time-consuming and sometimes dangerous job of gathering fuel.

The Kyoto Box uses the greenhouse effect to cook and can boil 10 litres of water in two hours. It consists of two boxes, one inside the other, with an acrylic cover which lets the sun’s power in and traps it. Black paint on the inner box and silver foil on the outer help concentrate the heat while a layer of straw or newspaper between the two provides insulation.

Bøhmer, is founder and chief executive of Kyoto Energy [www.kyoto-energy.com], a Nairobi-based design and engineering company working on novel energy solutions for the developing world. He plans to use the prize to conduct mass trials in ten countries, including India, Indonesia, South Africa, Kenya, Uganda, Tanzania, Mozambique and Liberia.

He has developed a more robust, longer-lasting cooker in corrugated plastic, which can be mass-produced in existing factories as cheaply as the cardboard prototype, and he intends to produce 10,000 to use in the trials.

The trials will generate data to back an application for carbon credits, the crucial element which will make the project scalable, he explains. He expects each stove to make a yearly profit of 20-30 euros, which will more than cover the manufacturing cost. The surplus will fund production of a suite of other products which offer solar-powered solutions for villagers in the developing world: a torch; a plastic bag which heats and cleans water; and a smokeless cooker which burns biomass.

Bøhmer is quick to point out that this isn’t a charity. “We’re going to make money on this. This is a whole new kind of business. I think Grameen [the celebrated microfinance institution which offers affordable credit to individuals and communities in Bangladesh] has proven that there’s an interesting business at the bottom of the pyramid.”

Kyoto Energy is a real family affair. Bøhmer, a Norwegian, set it up with his Kenyan wife Neema, and has used his own money to fund the project. His father has mobilised support for the project back in Norway and his five-year-old daughter Amina, pictured above, helped build the prototype.

Download a high res picture here.

Read more about the competition and the finalists.