First study on the characterisation of preferred fuelwood species for various energy applications in Limpopo Province

Globally, approximately three billion people still rely largely on solid biomass fuels, which abound in the majority of the countries, for their domestic energy needs. There are several studies in Sub-Saharan Africa which has been undertaken on physicochemical characterization of solid biomass fuels; however, there are limited scientific studies that were undertaken in South Africa, Limpopo Province, in particular. This study therefore sought to determine the physicochemical characteristics of the predominantly preferred fuelwood species for cooking and heating purposes in rural Limpopo Province. A laboratory experiment was conducted to determine their physico-chemical characteristics. The gross calorific value (GCV) of the studied species ranged from 14.27 to 19.11 MJ/kg, with slight variations amongst them. However, a higher GCV does not necessarily indicate better fuel properties when environmental factors, such as air pollution, are considered. Based on the overall assessment of fuel properties, A. caffra was the most suitable species for fuelwood, followed by O. paniculosa, C. mopane, V. tortilis , and D. cinerea . Additionally, the thermogravimetric analysis (TGA) showed that pyrolysis in all species primarily occurred between 200°C and 420°C. The information about fuel characteristics could be used for assessing woody biomass energy yields potential, to reduce indoor and ambient air pollution and indiscriminate cutting of different tree species for fuelwood, as well as to meet or surpass stringent public health and air quality standards. Furthermore, proximate, ultimate and combustibility value analyses provide important information during assessment of suitability of the woody biomass material as fuel. This study underscores the importance of conducting a comprehensive assessment of woody biomass materials before selecting them as energy fuels, thereby improve fuel quality and combustion processes efficiency, as well as reduce atmospheric emissions.