Most families in rural China still cook and heat their homes using stoves that burn coal or wood. Coal use in particular leads to high levels of indoor air pollution, and contributes to the poor outdoor air quality in much of China, as well as producing CO2 and other greenhouse gases. Much of the wood comes from unsustainable sources, thus adding to greenhouse gas emissions as well as increasing deforestation.
In 2000, a group led by Pan Shijiao began developing a stove that could burn wood more efficiently, and also burn crop waste – thus avoiding the use of wood or coal altogether. In April 2005 Shijiao set up the Beijing Shenzhou Daxu Bio-energy Technology Company Ltd (Daxu) to commercialise the new stove. The design ensures that the fuel - compressed or loose crop waste or wood - burns efficiently, and that heat is transferred to the pots effectively which allows a meal to be cooked quickly and with minimal smoke.
The Daxu stove has greatly improved the lives of farming families. Its two hotplates allow a stir-fry dish and steamed rice to be cooked at the same time, it reduces the cost of cooking and heating by about 50% and it significantly reduces levels of indoor air pollution. Some models come with a back boiler, bringing running hot water and central heating to rural families for the first time.
As one stove user, Zhang Qinhua put it: "it's much cleaner - my kitchen isn't dirty and smoky like it used to be and we can wash properly now we have hot water - there wasn't much point in washing before anyway because it was so dirty with all the coal dust."
By 2007, 25,000 Daxu stoves had been sold. These sales were supported by subsidies provided by the Yangqing County authorities in a drive to combat deforestation and indoor air pollution in a region with an abundant source of crop waste. There is enormous potential for introducing similar technology throughout China, since over 20 million wood and coal stoves are sold each year.