Extract from an article taken from the Shell Foundation:

"If user demand were the sole driver of innovation, the biomass cooking stove would be one of the most sophisticated devices in the world. Depending on which development agency you ask, between two and a half and three billion people - nearly half the world’s population - use a stove every day, in conjunction with solid fuel such as wood, dung or coal. Yet in many parts of the world the stove has barely progressed beyond the Stone Age."

"The World Health Organisation (WHO) estimates that toxic emissions from cooking stoves are responsible for causing 1.6m premature deaths a year, half of them among children under five years old. In China 83m people will die from lung cancer and respiratory disease over the next 25 years, according to a recent report from Harvard University. Research from the University of California, Berkeley, on stoves in India, Guatemala and Mexico has found links between indoor airpollution from stoves and increased incidence of pneumonia, cataracts and tuberculosis."

"After an initial wave of stove design that sought to reduce deforestation through improved effciency, scientists and engineers have turned their attention to stoves that minimise the levels of noxious emissions to which stove users - mainly women and children - are exposed. Crucially, they have also recognised the need to take account of the way in which stoves are actually used."

"Better effciency can reduce emissions, but does not solve the indoor pollution problem. One solution is the 'rocket stove', a simple design that diverts the
smoke outside. Other options include stoves that run on propane gas or pellets, or re?ect solar radiation onto a cooking vessel. But specialist fuels and constrained cooking times can restrict their appeal."

"As well as being effcient, stoves must also meet the conficting objectives of being transportable and being rugged enough to withstand the rigours of daily cooking. Combustion chambers therefore present a "huge materials problem", says Dr Wilson. Mild steel is the natural choice for a stove chassis, but such stoves do not last for more than a few weeks in the field."

"Nickel content alloys are a better choice for durability, but more expensive. For insulating the stoves, ceramic linings are the materials of choice in the lab, but they are difficult to ship and present problems of consistency for mass production. Materials are therefore often limited to those available locally."

"Even if they get the thermodynamics and materials right, designers must also make the devices compatible with local foodstu?s and cooking habits. A lot of the initial stove projects failed this test, says Daniel Kammen of Berkeley’s Energy Resources Group, who has worked on several stove projects in subSaharan Africa. A lack of field testing, he says, meant a lot of stoves were simply unsuited to users’ needs. The difference in cooking styles between countries, he says, can determine how - and whether - a new stove design ends up being used."

"And even the best stoves will always be less effective in the field than they are in the lab, says Kirk Smith, an expert on the impact of stove airpollution on health. In a field where a large number of development projects are chasing small amounts of funding, getting solid data is essential for making the necessary improvements, he says. In parallel with the advances in the stoves themselves, researchers are therefore funding more precise
ways to measure usage and pollution, including the placement of battery powered heat sensors in users’ homes and the use of particulate monitors with data
storage. "You don’t get what you expect - you get what you inspect", says Dr Smith. It is a lesson that many in the field are belatedly learning. "

Read the article in full here

Read the Shell Foundation newsletter - Spring 2009 here