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Soaking up rays

February 3, 2010

Some three billion people worldwide rely on dung, wood and charcoal to cook their food - with catastrophic effects on the environment. Cookers powered by the sun provide a cheap and clean alternative.

Villagers in India learn to use a parabolic cooker
Solar cookers have transformed entire villages in IndiaImage: Elisabeth Pongratz

In the aftermath of the devastating earthquake that hit Haiti recently, thousands of people need food and drinking water. But clean water in particular remains a problem.

The quake damaged water pipes in many places and health experts warn that alternative water sources run the risk of being contaminated by bacteria. Boiled water is the only safe option but cooking involves several hardships in Haiti, because firewood used for cooking fires is either expensive or requires painstaking gathering.

A young girl in Freetown, Sierra Leone carries firewood on her head
In many parts of the world, people walk miles to gather firewoodImage: DW/Schaeffer

"97 percent of the rainforest has disappeared. The women usually spend hours looking for scarce firewood, "said Hans Milchbauer of the EG Solar organization that coordinates solar cooker projects worldwide. The group is now raising funds to send more solar cookers to Haiti.

But it's not just Haiti that stands to profit from the appliances. In many developing countries, solar cookers can potentially raise living standards and help combat climate change. It's estimated that cooking fires fuelled by dung, dry grass, charcoal and, above all, wood are responsible for 17 percent of global carbon dioxide emissions.

Catastrophic health effects

An estimated three billion people are dependent on such fuels but cooking with wood leads to the erosion of forest cover, in turn silting up rivers.

And gathering firewood also involves trudging for miles and consumes time that could be better used to work and earn money. In addition, cook stoves spew soot into the atmosphere, polluting the air. The thick clouds of smog seen over much of South Asia each winter can largely be traced back to open cooking fires, according to a Swedish study.

Worse, the "black carbon," as the soot is known, also has devastating health effects. The World Heath Organization (WHO) estimates that 1.5 million people die each year of respiratory illnesses linked to inhaling wood smoke.

Young girls cooking chapatis in an Indian village
Conventional cookstoves fueled by wood and charcoal have disastrous health consequencesImage: Elisabeth Pongratz

The problem is now seen as a major climate killer and hundreds of organizations, many of them in Switzerland, Austria and Germany, have begun campaigns to distribute solar cookers worldwide. Governments too are pushing the appliances in numerous climate-friendly projects.

But so far, the results have been modest. It is estimated that just one million solar cookers are in use around the world. That's just a drop in the ocean when the Solar Cookers International Association (SCIA) says Asia alone needs some 300 million solar cookers.

"The technology has been refined and the potential to mitigate climate change is huge. But what's missing is a wider acceptance," said Marlies Kees of the GTZ in Germany, a state-backed international organization for sustainable development.

Experts say many of the solar cooker projects lack savvy marketing. But more importantly, changing entrenched attitudes and offering people practical help on the ground remain the biggest challenges.

"People need a contact person, someone who has spare parts and who encourages them to continue using the solar cookers, " said Hans Milchbauer.

He added that too often, people are initially convinced of the cookers but quickly switch back to conventional wood-fired cooking stoves.

A "sun in a box" cooker

Solar cooking technology has come a long way. There are almost 200 different models ranging from large parabolic cookers that use reflectors to concentrate sunlight to a simple solar cooker called a "Kyoto Box."

The Kyoto Box is made from cardboard and can be used for sterilizing water or boiling or baking food. It uses reflective foil and black paint to maximize absorption of solar energy.

Most solar cookers work on basic principles: sunlight is converted to heat energy that is retained for cooking. One or more mirrors or shiny surfaces concentrate sunlight on a dark pot within the cooker. The pot usually has a tight-fitting lid to hold in heat and moisture.

However, the technology doesn’t work everywhere. The cookers cannot be used in places with little sunlight, where cooking is usually done indoors or where there is no acute shortage of firewood.

"In such cases, it probably makes sense to combine solar cookers with energy-efficient ovens for example, " explained Willington Ortiz from the Wuppertal Institute, which researches the use of solar cookers.

A women in Tibet uses a solar cooker to boil water
A woman in Tibet uses a solar cooker to boil waterImage: AP

The appliances work best in regions with high treeless plateaus which receive lots of sunshine. Some 600,000 cookers are in use in the Andes, Tibet, Nepal, Mongolia and parts of China.

A big hit in India

But it is in India where solar cookers have proved to be the biggest hit, according to the SCIA. The Indian government is promoting the use of the cookers, particularly in villages in the countryside, as part of a national solar energy drive.

Solar companies have recognized the huge potential a market like India offers for solar cooking to become a sizeable economic force. The company Gadhia Solar, the world's largest producer of solar cookers, is transforming whole villages in India. One such place in the northern state of Uttar Pradesh has cleaned up its act by completely switching to solar cookers. Some 20 other villages have signaled interest in signing up for similar projects.

Gadhia Solar also builds large solar systems for temples and hospitals. It has set up 18 large solar facilities so far, which combined is estimated to slash greenhouse gas emissions by 4,000 tons by 2012. That is equivalent to the carbon emissions of 3,600 Indians each year.

One of the most promising solar projects in India is the Muni Seva Ashram in the western state of Gujarat attended by hundreds of school children. Food in the school's canteen is prepared entirely in solar cookers.

Experts say this is just the kind of initiative that's needed to push solar cooking into the public sphere.

"It's so important to strengthen the role of solar cooking in schools and universities," said Marlies Kees. "It's going to take a generation to change our behavior. You need to begin with it as early as possible."

Author: Torsten Schaefer (sp)

Editor: Mark Mattox