Abstract
Biomass (roundwood, agricultural residues, forestry residues, organic municipal waste) has the largest carbon reserve with potential to replace unsustainable fossil energy sources. Furthermore, off grid communities produce significant amounts of loose biomass through agricultural and forestry activities. These include maize stalks, tobacco stalks, ground nut leaves and stalks, tree leaves, elephant grass etc. These are traditionally burnt in fields after harvesting. In addition, annually, forestry residues such as elephant grass, yellow thatching grass, dry tree leaves etc. are destroyed in perennial veld fires. Such loose biomass can be harnessed for cooking and heating and thus minimise the use of round wood, which results in defor! estation that cause desertification if not done sustainably. The major challenge in harnessing energy from loose biomass is their low energy density. This can be overcome by developing loose biomass briquetting technologies. This paper reports on the development of loose biomass briquetting technologies at the University of Johannesburg over the past five years. These include shredding, pre-treatment, compaction, off grid solar drying, and combustion. Briquetting required the selection of good feed stock and binders. Cow dung and cactus leaves were found to be good binders producing briquettes with good combustion behaviour. The developed loose biomass briquettes were tested for moisture content, energy content and combustion behaviour and were found to be adequate for domestic cooking and heating requirements.