Solar Cooker wins $75,000 prize

Written by adam


The votes are in, and the Kyoto Box solar cooker has claimed the $75,000 prize in the FInancial Times Climate Change Challenge.

> The Kyoto Box uses the greenhouse effect to boil and bake. 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.

The innovation is not the cooker itself, which is a variation of a simple technology that has been around for a long time, but rather the manufacturing process. Each cooker can be made for about $6 out of common materials readily available in the countries in which the cookers will be used. Jon Bøhmer, creator of the Kyoto Box, hopes to distribute them for free using carbon credits as financing. The prize money will fund trials in 10 countries.

I said earlier that the Kyoto Box was my sentimental favorite, and sentimentally I’m glad it won. Two billion people presently use firewood as their main cooking fuel. Better cookers will help to fight waterborne disease and will also help protect women and children from the health risks of smoke inhalation.

I’m still not sure what the climate change impact of the stove will be, though, and I do notice that the expert panel in the Financial Times Climate Change Challenge by a wide margin chose as their favorite a giant microwave oven for making biochar — the innovation that the public liked least. I do wish the Financial Times had done a better job explaining the benefits of these different choices, even if I can’t really argue with the result.

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  1. Eliza Olson

    I think the Solar cooker is brilliant and a real benefit in countries where wood is scare. This could have additional side effects–fewer trees cut down.
    It will be interesting if it will be tested with other materials, eg. recyclables and different materials that are available in different countries.
    This Solar stove could be used by campers in the Americas as well.That would reduce weight and the use of wood and gas for cooking on camping trips.

  2. David C

    How much more efficient would a heat-pump heat exchanger be if you used solar to heat the air around it? I’m tempted to paint mine black for the winter – and then white for the summer.
    Or would the VOC’s from the paint do more damage than any solar benefits?

  3. Linda Huntington

    I believe a drawback is that the solar ovens don’t last long. I remember something like a couple of years or so.
    However, free is free and no firewood means no carbon.

  4. Tim Grant

    The beauty of any simple product, is simplicity itself. The concept is proven and the cost could be further reduced and benefit increased by the use of recycled material. We should (as a collective) be more accepting of the little steps necessary to fix the big problems that face our planet.

  5. Tim Grant

    You make a point about the U.S could make use of the product. I would add that even today
    there are groups around the country that live off the grid. Not only campers need to cook.
    Here in the Southwest some of the Natives live very modestly with no electricity. “Third World” countries are not the only areas that need these types of devices and assistance.

  6. Susan Thompson

    Most of this country thinks in terms of HARD living is only in third world countries!
    Well welcome to AMERICA the first third world country that doesn’t know it.

  7. EM

    The New York Times just had an article about how the black carbon – the soot released from inefficient cookstoves often found in developing countries, as well as other sources – may account for 18% of global warming. Replacing these stoves is, as they say, “low hanging fruit” so why not give it a go? I can tell you that all the old-style stoves and heaters here in Beijing that burn cakes of coal make for some nasty air, indeed…

  8. joanne

    I made a similar solar cooker a couple years ago and often use it here in New England, US. As long as there is 4 hours of full sun, i can cook anything in it. Food doesn’t over-cook in it which is very nice. You don’t have to watch it closely.

  9. Anna

    This type of cooker has been around for many years. I first used one from Kerr Cole solar box cookers in 1982 shortly after moving to Arizona. I’m presently using Global Sun Oven (look it up).
    In my yard I use the cooker for anything which needs long cooking at moderate heat in a covered container. Think slow and moist.
    Solar Cookers International, a non profit organization, has been working at least 20 years to develop, promote and distribute these cookers.
    Their archive contains a wealth of information.
    Another group promoting solar cooking is Solar Household Energy,
    There are many solar cookers available, from the simplest cardboard box to pretty sophisticated village size ovens. There are organizations in place with lots of experience in introducing this new technology in third world countries. None of this needs to be re-invented, just supported.

  10. Alex Kelley

    What a great idea! I’ll be building one of these to use on my roof top deck in downtown Chicago. Summertime BBQ could have some baked beans and apple cobbler to go along with it.

  11. Eliza Olson

    Could someone send me the instructions to build the Solar cooker? I would like to teach my summer day campers how to build one.
    We hold our summer day camps in the Delta Nature Reserve where there is no electricity so it would be great to show and teach the children, especially the older ones how to build and use the cooker.
    Thanks for your help.

  12. Dave

    Let’s see, two coats of paint per year would quickly add thickness to the heat exchanger surface that would impede its efficiency.
    Perhaps a better bet would be two switchable heat exchangers for your air-source heat pump: a black one for winter (placed in the direct sun with reflective enhancements around it) and a white one for the summer time (placed in a shady location out of the direct sunlight).

  13. Frank Deutsch

    Would like to have directions for making this solar cooker. ANyone, please reply.

  14. Jim Banks

    A well built cardboard box cooker that is painted and taken care of (kept out of wet locations) can last more than 10 years.
    I’ve used a cardboard cooker as much as 200 days per year.

  15. Jim Banks

    Excellent plans for solar box cookers are found at
    The most important thing is to get the glass to fit without leaking. A 1/4″ hole can reduce temperatures by 100 degrees.