Determining the most sustainable lignocellulosic bioenergy system following a case study approach

Abstract

The paradigm shift from fossil to renewable energy sources is driven, largely, by a growing sustainability awareness, necessitating more sophisticated measurements in terms of a wider range of criteria. Technical efficiency, financial profitability, environmental friendliness and social acceptance are some of the aspects determining the sustainability of renewable energy systems. The resulting complexity and sometimes conflicting nature of these criteria constitute major barriers to the implementation of renewable energy projects.The Worcester biomass procurement area in the Western Cape Province, South Africa, is used as a case study. It provides a blueprint for measuring the impacts of lignocellulosic bioelectricity systems – using life-cycle assessment (LCA), multi-period budgeting (MPB), geographic information systems (GIS) and multi-criteria decision-making analysis (MCDA), among others – and for prioritising the relevant criteria to determine the most sustainable technological option.Following the LCA approach, 37 plausible lignocellulosic bioenergy systems were assessed against five financial-economic, three socio-economic and five environmental criteria. On translating the quantitative performance data into a standardised ‘common language’ of relative performance, an expert group attached weights to the considered criteria, using the analytical hierarchy process (AHP). Assuming the prerequisite of financial-economic viability, the preferred option comprises a feller-buncher for harvesting, a forwarder for biomass extraction, mobile comminution at the roadside, secondary transport in truck-container-trailer combinations and an integrated gasification system for the conversion into electricity. This approach illustrates how to internalise externalities as typical market failures, aiding decision makers to choose the most sustainable bioenergy system.