Viability of producing lignocellulosic biomass in the Cape Winelands District Municipality for bioenergy generation
Thesis (MScAgric (Agricultural Economics)--University of Stellenbosch, 2009.
The growing scarcity of fossil energy, expressed by rising real prices, justifies an investigation into the viability of utilising alternative, sustainable energy sources. Another motivation is to mitigate CO2 pollution resulting from using fossil fuels, causing climate change. Biomass has the potential to become a major global primary energy source during the next century. In South Africa, a limited amount of land is suitable for high‐potential biomass energy sources like sugar cane or grain. Large areas of South Africa are, however, dry and more suitable for woody biomass production. Cultivating trees in short‐rotation‐system plantations provides a sustainable and effective way of producing biomass. The first part of this study investigated the physical capacity of the Cape Winelands District Municipality (CWDM) for woody biomass production in short‐rotation systems, based on a land availability assessment using Geographic Information Systems (GIS). The CWDM comprises about 2.3 million hectares, of which about 175 000 ha with a slope of less than 35% have been identified as suitable for woody biomass production. Within the CWDM, the following land use classes were excluded: nonagricultural land, such as urban areas, bare rock and mines; ecologically sensitive areas; as well as areas with slope gradients that are too steep for biomass production, due to limited accessibility and trafficability. This was followed by an assessment of suitable tree species and their productivity rates – also using GIS with climate data (i.e. temperature extremes, frost and mean annual precipitation) and terrain data. By combining the identified biomass production sites with the productivity rates of the identified species, an annual supply of woody biomass for energy generation at a medium productivity of about 1 412 000 tonnes of fresh biomass is expected, using exotic species like Eucalyptus claducalyx ( and about 1 306 000 tonnes, using indigenous species like Acacia karoo).