“Bioenergy” covers the use of biomass and biomass waste for energy purposes.
Bioenergy is the most widely used renewable energy worldwide and can be defined as “energy contained in living or recently living biological organisms (i.e., biomass)”. Both in Africa and globally there is an increasing demand for food and non-food biomass due to population growth, dietary shifts and the move from fossil-fuel based economies to biomass-based economies. Moreover, the continued use of wood and charcoal for satisfying basic energy needs puts significant pressure on the remaining natural forests and other wooded ecosystems in Africa, also having influences on biodiversity and rural livelihoods. As the demand for bioenergy may create trade-offs between food and non-food biomass production, careful planning and decision-making are required to achieve positive effects from substituting fossil fuels with bioenergy options. Meanwhile, innovative processing and the use of biomass waste can help produce bioenergy without jeopardizing food security and environmental protection.
This thematic area features contributions related to the:
- Biofuels made from crops, such as from corn and oil palms
- Biogas produced from waste products, such as from coffee pulps
- Solid biomass used for energy purposes such as wood, charcoal, bamboo, dung and agricultural residues
Theme coordinator: Raymond Jatta
Kiatkamjon Intani, Sajid Latif, Zebin Cao, Joachim Müller. 2018. Characterisation of biochar from maize residues produced in a self-purging pyrolysis reactor. Bioresource Technology (265): 224–235 pp.
Response surface methodology was used to optimise pyrolysis conditions to produce biochar from maize residues (cobs, husks, leaves and stalks). The aim was to obtain biochar with good potential as an additive for composting. Mathematical models were developed to explain the experimental responses of volatile matter content (VM), ash content (AC), pH and electrical conductivity (EC) to the operating parameters such as temperature, heating rate and holding time. The temperature had the most significant influence on biochar properties. AC, pH and EC significantly increased (p < 0.05) with increasing temperature, while the VM decreased. The holding time showed less effect on the responses, while the heating rate had insubstantial effect. Under the optimal conditions, the husk and leaf biochar had higher AC (11.42 and 26.55%), pH (10.96 and 11.51), and EC (12.37 and 6.79 mS/cm), but lower VM (7.38 and 8.39%) than those of cob and stalk biochar.