December 28, 2009

Solar Cookers: An Essential Tool for Better Health and Economic Benefits

During my travels to developing nations such as Haiti, Peru and Uganda, I witness the challenges and negative impact of cooking with fires fueled by wood or dung. The impact also applies to people who walk long distances to collect wood or spend their limited income on fuel. A solution to satisfying the need for cooking without breathing toxins or wasting time searching for cooking fuel lies within solar cookers. This entry provides a summary of this amazing tool.

"Solar cooking is the simplest, safest, most convenient way to cook food without consuming fuels or heating up the kitchen," according to Solar Cookers International, a nonprofit organization based in Sacramento, California and with an office in Nairobi, Kenya. "For millions of people who lack access to safe drinking water and become sick or die each year from preventable waterborne illnesses, solar water pasteurization is a life-saving skill. There are numerous reasons to cook the natural way — with the sun."

Solar Cooker International explains, "The three most common types of solar cookers are heat-trap boxes, curved concentrators (parabolics) and panel cookers. Hundreds — if not thousands — of variations on these basic types exist. Additionally, several large-scale solar cooking systems have been developed to meet the needs of institutions worldwide."

Box cookers, the most common solar cooker used worldwide, are made of cardboard, metal or plastic, with glass lids and aluminum foil or metal reflectors that trap heat from sunlight inside a sealed, insulated box and cook food in 2-3 hours at 250-350 F. Some box cookers can accommodate multiple pots. There are several thousand box cookers used in India and all solar cookers work with varying degrees of efficiency in hot or cool weather as long as the sun is shining. (Photos courtesy of Solar Cooker International)

Panel cookers incorporate elements of box and curved concentrator cookers. They are small, lightweight, foldable, portable and relatively inexpensive to purchase or manufacture by hand. They work like a crock-pot, with temperatures ranging between 225 and 275 F. Most panel cookers are made from cardboard and aluminum foil and they require a lightweight cooking pot painted black with non-toxic paint. Raw food is placed in the pot, which is put inside a heat resistant plastic bag and placed in the cooker. Panel cookers can cook food in 2-3 hours.

Curved concentrator cookers or "parabolic cookers," cook fast at high temperatures and are excellent for boiling and drying. Especially useful for large-scale institutional cooking, they require frequent adjustment and supervision for safe operation. Curved cookers may be used for indoor cooking by focusing sunlight through a hole in the wall.

Solar Cooker International provides a comprehensive list of health and nutritional benefits of using solar cookers:
  • Moderate cooking temperatures in simple solar cookers help preserve nutrients;
  • Those who otherwise could not afford the fuel to do so can cook nutritious foods — such as legumes and many whole grains — that require hours of cooking;
  • At times many families must trade scarce food for cooking fuel. Solar cooking helps them to keep more food and improve their nutrition;
  • Smoky cooking fires irritate lungs and eyes and can cause diseases. Solar cookers are smoke-free;
  • Cooking fires are dangerous, especially for children, and can readily get out of control — causing damage to buildings, gardens, etc. Solar cookers are fire-free;
  • Millions of women routinely walk for miles to collect fuel wood for cooking. Burdensome fuel-gathering trips can cause injuries, and expose women to danger from animals and criminals. Solar cooking reduces these risks and burdens, and frees time for other activities; and
  • With good sunlight, solar cookers can be used to cook food or pasteurize water during emergencies when other fuels and power sources may not be available.
In addition to the health and nutritional benefits, solar cookers provide a variety of economic benefits. Many poverty-stricken families worldwide spend 25 percent or more of their income on cooking fuel. Sunlight — solar cooker "fuel" — is free and abundant. Money saved from purchasing cooking fuel may be used for food, education, health care, etc. Furthermore, solar cooker businesses can provide extra income. Business opportunities include cooker manufacturing, sales and repair, as well as solar food businesses like restaurants and bakeries.

Benefits to developing governments include reducing imports of — and subsidies on — biomass and fossil fuels. Where forests are disappearing and many people suffer from fuel shortages, solar cookers reduce families' fuel wood needs by 30-50 percent. Electric companies that have trouble meeting peak hour demand because of heavy use of stoves and air conditioners can reduce that demand by promoting use of solar cookers.

I support funding by industrialized governments or nongovernmental organizations to programs that help deliver solar cookers to the world's most vulnerable populations. Not only is delivering solar cookers important, but providing the necessary training to manufacture, use, and repair the devices is essential.

Aaron Rose is an advisor to talented entrepreneurs and co-founder of great companies. He also serves as the editor of Solutions for a Sustainable World.


  1. I appreciate the post about cooking technologies. I spent a summer working on a project buildiing and teaching how to use fuel efficient stoves. I have also worked with a non-profit that had developed a water filter. One of the main problems with these technologies that I saw was the uptake in use. At the end of your post you mention that training is needed. In my experience this is the critical point. As effective and economically beneficial as solar cooking may be, it seems this technology would dramatically change cooking times and practices, all thoroughly embedded in cultural practices. I would be interested to know the training methodologies the organization is using as this, in my opinion, seems like the biggest barrier to its use.

  2. Thank you, Emily, for your comment. In addition to solar cookers, teaching people how to effectively use technology is one of the greatest challenges in the developing world. Too many programs whose goal is to implement a technological service or product fail because of the lack of localized training.