Bioslurry as a Fuel. 2. Life-Cycle Energy and Carbon Footprints of Bioslurry Fuels from Mallee Biomass in Western Australia

Abstract

This paper reports a life-cycle assessment on energy and carbon footprints of bio-oil/char slurry (i.e., bioslurry) fuel from mallee in Western Australia (WA). The results demonstrate that bioslurry fuels have small energy and carbon footprints, <4% and <3% of the total energy and carbon embedded in the delivered fuels, respectively. The energy consumption and greenhouse gas emissions during the life cycle of these fuels are mainly due to biomass production, harvest, and transport. Considering the carbon sinks because of below-ground biomass and land-use change, the carbon footprints of both biomass and bioslurry fuels are actually negative. While a biomass supply chain delivers biomass fuels with smaller energy and carbon footprints for small bioenergy plants, a bioslurry supply chain achieves better performance for dedicated applications only in large-scale centralized plants situated within a biomass collection area. For co-processing applications in coal-based energy plants distant from the biomass collection area, bioslurry as a fuel achieves more energy savings and carbon benefit at a longer transport distance between the biomass collection area and the coal-based energy plant. However, for both biomass and bioslurry fuels, the energy and carbon footprints are small compared to the embedded energy and carbon in the delivered fuels.