ABSTRACT
Figure 6.1 Stove emissions of one small village in Nepal (Ghusang, just north of the Anapourna mountain range). 6.2 Initial Stove DevelopmentFifteen years ago, I was transforming my household into one which does not require fossil fuels to run. For all functions affordable solutions were available, except for cooking. There were no commercial devices available that could deliver this. My search for these devices brought me in contact with the cooking problems of the two billion people living in developing countries. These problems have not passed unnoticed. Between 1982 and 1992, the Chinese National Improved Stove Program reported the installation of 129 million improved stoves in rural households. This was both in terms of size and in terms of coverage (50%) the largest program to date. Similar programs were rolled out in other Asian and African countries [5]. Still the adaptation is low enough that 2 million people die each year. Apart from these programs there is a community of stove designers, research centers (such as Aprovecho [6], or the clean cookstove research program of the United States Environmental Protection Agency [7]) and disseminators. The latter has culminated into the Global Alliance for Clean Cookstoves. The alliance seeks to mobilize high-level national and donor commitments toward
the goal of universal adoption of clean cookstoves and fuels. Its ambitious goal is to foster the adoption of clean cookstoves and fuels in 100 million households by 2020. It brings together private, public, and nonprofit stakeholders and is currently the prime source for information related to clean cooking solutions and cooperation partners. However, this was not available when I was looking for a solution for my cooking question: Easy and clean cooking without using fossil fuels. Most so-called improved stoves at that time (and still) do had lower emissions and higher efficiencies but very moderately. Being used to cook with natural gas or electricity my standards were very high. Only biogas digester-stove combinations have properties which come close. But living outside the tropics and having no cow available (I live in a city) a biogas digester is not an option. I considered charcoal stoves as inappropriate because most of the energy content of the fuel is lost making charcoal from wood. So the stove had to be wood fueled, needed to burn without smoke and soot, had to have an easy way to regulate fire power, and had to be quick to start up. No stove design using wood fuel which I could find came close. Making use of the Internet and the stove community which was active at that time, it became clear that real advances in stove performance could best be gasifier stoves or fan stoves. The gasifier stoves were pioneered by Dr. Thomas B. Reed. Several different types were constructed. In these stoves clever airflow gasifies the wood first and then burns the resultant gasses. The emissions of such a stove can be very low, but disadvantages are that fuel size and quality is rather critical, stove power regulation is not easy, and the stove is batch fueled. The latter means that fuel is loaded into a cold stove and lit. The stove stays on until the fuel is gone. I personally wanted an easier stove, but I have studied the gasification well, since it can give such low emissions. That is also why there are still avid proponents of this technology such as Paul S. Anderson [8] and why several gasifier stoves are in the market. The most successful gasifier stove is the fan-driven Oorja stove, initially brought on the market by BP but nowadays marketed by Firstenergy [9]. The fuel sensitivity of the stove is circumvented by using standardized pellets and the power control is improved by using speed control of a fan.
