Bioenergy potential from invasive alien plants: Environmental and socio-economic impacts in Eastern Cape, South Africa

Abstract

South Africa's natural resources and ecosystems are negatively affected by Invasive Alien Plants (IAPs). We used a life-cycle approach to assess the environmental and socio-economic impacts of using IAPs for electricity generation in South Africa or exported and used for electricity generation in the Netherlands. Supply chain greenhouse gas (GHG) emissions of electricity from IAPs pellets, excluding land use change-related GHG emissions, are 31.5 gCO2eq MJ−1 for electricity generation in South Africa and 31.2 gCO2eq MJ−1 for electricity generation in the Netherlands. An additional 3.9 gCO2eq MJ−1 is accounted for if emissions of land use change are included and land is rehabilitated to its natural state. The removal of IAPs results in water savings when considering any potential land use transition, ranging between 1,263 mm year−1 for annual cropland to 12 mm year−1 for dense forest. The supply chain costs of pellets are 5,344 ZAR Mg−1 (285 € Mg−1) delivered at the power plant in South Africa and 2,535 ZAR Mg−1 (159 € Mg−1) delivered at Rotterdam port. Direct full-time jobs generated from removing IAPs up to the conversion-factory-gate are 604 FTE year−1 for South Africa and 525 FTE year−1 for the Netherlands. There are clear trade-offs between environmental and social benefits and costs. There are generally net carbon losses when considering the land use transitions after IAP removal, even when land is rehabilitated to its natural state. Using IAPs for electricity can be a valuable strategy for South Africa to generate employment, conserve water resources and reduce GHG emissions.