Wood pellets in Mozambique : an alternative to charcoal and firewood for cooking in Mozambican households

Abstract: Consistent with the rest of the world, Mozambique has an increasing demand for energy to satisfy its growing population. The excessive use of firewood and charcoal for household cooking has resulted in various problems such as deforestation and respiratory disease from indoor pollution. This study has investigated possible benefits of wood gasification stoves (WGS) and wood pellets as a sustainable alternative to charcoal and firewood in traditional stoves for cooking in peri-urban Mozambican households. The company Philips has developed a WGS designed for burning biofuels, which uses a built-in fan for increased air flow. At the time of the study this was considered the most suitable stove of this kind on the market. The cooking performance of wood pellets and two other reference fuels (birch wood and torrefied bamboo pellets) were evaluated in the WGS using two international standardized tests, i.e. the Water Boiling Test and the Controlled Cooking Test. The tests were performed in a controlled environment, as well as in the field in the Matola Rio area in southern Mozambique. Wood pellets had a shorter boiling time and higher efficiency than the two other fuels, but using bamboo pellets resulted in lower fuel consumption. Adjusting the stove, however, decreased the fuel consumption for wood pellets. Through experiments a proper air flow adjustment for the stove was found so that the stove can be compatible with wood pellets. The best setting in this study for the chosen wood pellet was decreasing the primary air flow by simply rotating three of the lower tiles in the combustion chamber and keeping the secondary air flow the same as factory setting. The change in stove setting caused the pellets to burn with lower flames and less smoke than before the adjustment. The boiling time increased compared to the basic factory adjustment, but there was a positive effect on ease of use and fuel consumption.