Events

This research assesses the comparative environmental profiles of the bioenergy systems - biofuel (cellulosic ethanol) and biomass electricity-derived from switchgrass. Switchgrass cultivation as a dedicated energy crop is an emerging practice. It has high yield with relatively low nutrient requirements and has a great potential to meet future energy needs.

The contribution of this research is twofold. First, the life cycle energy and GHG emissions of individual bioenergy pathways - producing cellulosic ethanol and biomass electricity - are analyzed in greater detail. In contrast with previous studies, we have not just used a single value of input parameters for different life cycle stages, but instead, have assessed the impact based on a probability distribution by incorporating a Monte Carlo analysis. This has helped to address the variability in the lifecycle impacts of bioenergy systems and establishing a range of energy and greenhouse gas (GHG) impacts, rather than previous single-valued estimates. Second, a framework to compare cellulosic ethanol and biomass electricity lifecycle energy and GHG emissions is provided. We propose the criterion for comparison should not be dictated by absolute emissions along a certain bioenergy pathway, such as producing biofuels or biomass electricity. Instead, we consider the savings in emissions from the displacement of fossil fuel by biomass along each pathway. Based on this criterion, we quantify the lifecycle GHG emissions impacts of each pathway, compare them to the reference fossil energy system and compare their land use efficiency.