Towards a standard for clean solid-fuelled cookstoves

Worldwide, millions of people with limited access to modem energy sources cook food using a wide variety of solid fuels, primarily biomass. Often the cooking arrangement is no more than three stones supporting a pot; sometimes there is an appliance which may be fashioned from local materials; sometimes there is a fabricated appliance. In most cases the combustion of the fuel exposes the cook and often the whole family to smoke and particulates. The World Health Organisation indicates that this exposure is one of the leading causes of Disability Adjusted Lost Years of life. Many organisations have taken credible steps to alleviate the problem, specifically by supplying improved stove technologies, improved or alternate fuels, or a combination thereof. One of the challenges, however, is that there is no agreement on what the performance criteria should be for a so-called "clean stove" or improved cooking technology. Some have focused on the efficiency of the cooking process, arguing that the use of less fuel for a given duty would inherently lower the risks, implicitly assuming that emissions are an inherent property of the fuel. Some have focused on minimizing the total energy used per task, not the total fuel, treating the leftover charcoal as 'unburned fuel,'similarly assuming that less energy means less emissions. Others have focused on ensuring the cleanest possible bum, often by careful preparation of the fuel, which often leads to the inefficient use of the available fuel resource and rejection by the users. Some have focused on the nature of the fuel, overlooking the fact that emissions arise from the choice of the fuel-stove combination. Moreover, users tend to use what is most readily and most cheaply to hand, and are not readily persuaded to use "better" alternative fuels. In this contribution we seek to explore the range of demands from users, in the hope of finding some common threads which would permit the rational development of standards for clean solid-fuelled cookstoves adaptable to the huge range of fuels and cooking cycles employed worldwide.