Thursday, June 13, 2013

Introducing Solar Cooking to the World

Solar Cookers for the World - image courtesy of, more images at:
As we all know, we should end the practices of burning forests and clearing land for farming, for urban expansion and for road construction. Big companies are often blamed for this, but what's often overlooked is the practice of collecting wood for heating and cooking and for making charcoal, which is of particular concern in Africa, where wood provides some 70% of domestic energy

Loss of trees leads to flooding and loss of top soil during heavy rains, and makes the land more prone to desertification, droughts, fires, insect plagues and other natural disasters. 

Burning wood is also bad for our health and for the environment. It releases very fine particles of carbon into the air and those carbon particulates are directly responsible for one million deaths

Furthermore, the practice of burning wood contributes substantially to global warming. 
Smoke particles travel around the globe, landing on deserts, ice and snow, which reduces the Earth's albedo (reflectivity), resulting in more heat absorption and melting of ice, which uncovers further darker soil and in turn causes further global warming. According to the UN Environment Program (UNEP), between 20% and 25% of all annual global CO2 emissions are caused by the practice of burning forests and clearing land for farming. 

All over Asia, Africa and Latin America, you can see women and children scrambling for wood, carrying up to 40 lbs of wood on their heads and backs. They spend many hours daily to collect and carry the wood to their homes, causing deforestation, land erosion and desertification. Estimates are that more than half the woodfires in India are associated with rural cooking. 

Bob Metcalf is a professor of biological sciences at California State University Sacramento. As a volunteer for Solar Cookers International, established in 1987, Bob has helped distributing theCookit foldable solar cooker panel around the world. Bob points out that in many developing countries, such solar cookers can be used 200-300 days a year. 

Bob Metcalf further writes: "Some 2.5 billion people, over one-third of humanity, use wood fire for cooking. In 40 of the world's poorest countries, over 70% of the country's fuel comes from dwindling supplies of wood, or, in towns and cities, from charcoal that was inefficiently made from wood. Tanzania has some 32 million people and over 90% of the country's energy comes from wood/charcoal. That's about 60 million pounds of wood burned to ashes every day!"

Apart from using the Cookit for cooking food, it can also be used to pasteurize contaminated water held in a black metal or glass container and put in the CooKit. Water only needs to be heated up to 149°F (65°C) for five minutes to kill virtually all harmful microbes, such as worms, Protozoa cysts (Giardia, Cryptosporidium, Entamoeba), bacteria (V. cholerae, E. coli, Shigella, Salmonella typhi), Rotavirus and Hepatitis A virus. 

Solar Cookers International also distributes a simple thermometer, called a Water Pasteurization Indicator (WAPI), a clear plastic tube partially filled with a soybean wax that melts at about 70°C (158°F). With the solid wax at the top end of the tube, the WAPI is placed in the bottom of a black container of water that is solar heated. If the wax melts and falls to the bottom of the tube, pasteurization has taken place. The photo below shows the WAPI and Cookit in use in Tanzania. 

Diarrhea kills 1.9 million children under 5 a year, mostly due to drinking contaminated water. In fact, more young children around the world die from diarrhea than from maleria, AIDS and TB combined. Yet, the World Health Organization (WHO) spent less than $10 million on fighting diarrhea in 2004-05, compared to the $217 million it spent on HIV and the $123 million it spent on TB. 

Actually, this relatively small amount of money spent on fighting diarrhea has accomplished a lot. Since the WHO started its program, worldwide diarrhea deaths fell from 5 million in the 1980s to 3 million today, in a large part due to educating people about sanitation and treating dehydration caused by diarrhea with sufficient intake of a drink made from one liter of water, one level teaspoon of salt and eight level teaspoons of sugar. Simplicity sometimes achieves more than building expensive hospitals and administering antibiotics and other drugs. 

Solar cookers can easily be made locally, all it takes are materials that are cheap and widely available, such as cardboard, aluminum foil, heat-resistant plastic bags, etc. Here are some plans how to make solar cookers:

Below, a photo of a more sophisticated solar cooker

Between 1992 and 2001, some 2,350 solar cookers were distributed in Kakuma Refugee Camp and other localities in Kenya. Furthermore, I read that there are over 100,000 solar cookers in use in both India and China. Here's a country by country report with information on the use of solar cookers in each country.

Some 1.9 million children under 5 are killed by diarrhea a year, mostly due to drinking contaminated water. An article in Time quoted World Health Organization (WHO) figures says that 3 million people a year still die from diarrheal complications, including 1.9 million children under 5, or 17% of the estimated 11 million deaths in that age group.

Wikia says that an estimated 1.5 billion cases of diarrhea occur each year, resulting in the death of nearly 2 million children. Worldwide, about 1.3 billion people do not have access to safe drinking water, including nearly half the population of sub-Saharan Africa, where there is an abundance of sunshine for solar cooking of food and pasteurization of water. 

The 2007 UN Millennium Development Goals Report says: The health, economic and social repercussions of open defecation, poor hygiene and lack of safe drinking water are well documented. Together they contribute to about 88% of the deaths due to diarrhoeal diseases (more than 1.5 million) in children under age five. Infestation of intestinal worms caused by open defecation affects hundreds of millions of predominantly school-aged children, resulting in reduced physical growth, weakened physical fitness and impaired cognitive functions. Poor nutrition contributes to these effects. As the intensity of infection increases, academic performance and school attendance decline substantially. Intestinal worms can also lead to anemia which, for girls, increases the risks later of complications in childbirth.

Apart from the environmental damage, the practice of burning wood to boil water and cook food also causes many health problems, including respiratory diseases and injuries from burns and fires. 

It's good to avoid the use of biomass, dung, charcoal and fossil fuels for cooking and for lighting. Kerosene is also frequently used as fuel, and kerosene lamps alone cause substantial indoor air pollution and health problems, reason for parallel programs to replace them. In 2008, in a comment on LED lights, I wrote about the mission of D.light to replace kerosene lights used by the estimated 1.6 billion people around the world without electricity. Kerosene lanterns cause thousands of fires and burns each year, release CO2 and their air pollution causes acute lower respiratory infections, one of the biggest killers among children under 5 in India. 

Various initiatives such as the Clean Energy Ministerial now supports the efforts to replace kerosene lanterns with solar LED lights, and they should do more to support solar cooking, as well as biochar, as also discussed at the Biochar Economy blog.


Saving Africa's forests, the 'lungs of the world' - by Michael Fleshman

The Solar Cooking Archive

The Other Carbon: Reducing Black Carbon's Role in Global Warming - Wired

The Energy Crisis on a Global Scale - by Bob Metcalf

Cookit foldable solar cooker panel

Water Pasteurization

Water Pasteurization Indicator (WAPI)

Buy a WAPI

Oral rehydration

A simple solution - Time Magazine,9171,1543876-1,00.html

Solar Water Disinfection

Solar cooker

Solar Cookers International

Wednesday, September 21, 2011

Welcome - This blog contains the post "Introducing Solar Cooking to the World", originally posted in February 2008 by Sam Carana, with many comments following soon after posting. Some further figures were added in a 2010 comment.

The original post and comments can be found here:

The use of solar cookers could be encouraged through feebates, such as imposing fees on burning fuel (i.e. fossil fuel, biomass, dung, charcoal, etc.) and using part of the revenues for rebates on sales of solar cookers.

Parts of the revenues could also be used to fund rebates on electric appliances (stoves, fridges and heaters) as well as lights. Furthermore, parts of the revenues could be used to support the shift to clean and safe ways to produce electricity.

In parallel, fees on engines could generate funding for rebates on the batteries and motors in electric vehicles. Having an electric vehicle parked close to their house will allow a family to use the battery for powering lights, appliances and equipment such as TVs and computers.

The image below illustrates this further.

Image from: Towards a Sustainable Economy