Bioenergy potential from invasive alien plant biomass in South Africa

Abstract

South Africa's natural resources are severely impacted by invasive alien plants (invasive alien plants) that cover about 18.2 million ha with a mean density of 8.2%. The distribution of these plant invasions, together with information of biomass yields of biomass, were used to estimate the total accessible woody biomass of invasive alien trees to be 167 million tonnes (dry). The biomass can be used to produce wood-based fuels (wood pellets, torrefied wood chips and pellets, charcoal, or bio-syncrude) for co-firing with coal at power stations without major capital investments or modifications. If approximately half of the total invasive alien plant biomass is used for co-firing over a twenty-five year period, Eskom's annual coal demand will be reduced by almost 3% and 964 MW of biomass-to-electricity will be added to the national electricity supply mix. These bioenergy opportunities often struggle to be financially feasible due to the significant costs to access, harvest, store and transport the widely distributed and varied invasive alien plant biomass and will likely require coinvestment through public-private partnerships. Linking the government's land user incentive programme with an private sector activity, such as biomass to electricity, has the added benefits of providing jobs in the public works sector, stimulating rural development, reducing carbon emissions, increasing water availability, and helping to steer South Africa towards a Green economy and a more sustainable development path.