Quantification and comparison of the economic and GHG performance of biomass supply chains

Abstract

There is a widespread scientific consensus that global climate change is caused by the increased levels of anthropogenic greenhouse gasses (GHG). Biomass use is seen as an important GHG mitigation option. However, the use of biomass will not by default generate a significant and timely GHG emission reduction compared to the fossil reference. The GHG emission reduction potential has recently been questioned with the inclusion of carbon stock change and land-use change emissions in the total GHG balance. For large-scale utilization of biomass the economic performance is an important driver. Namely, the production of biobased electricity, fuels and chemicals should be able to compete economically with fossil equivalents. In short, important topics for research are: 1) The methods used for the quantification of the economic performance and GHG emission reduction potential of biomass use, 2) Regional specific case studies for the economic performance and GHG emissions of large-scale production of electricity, fuels and chemicals. In this thesis the case-studies are executed for the wood pellet production in the Southeastern USA, mainly for overseas electricity production, and the sugarcane - ethanol production in Brazil. These regions have the potential to significantly expand their production in the coming decades, by the expansion of the cultivation area, improvements in agricultural or industrial yield and the introduction of new industrial processing pathways and value chains. The main results of this research highlight four main messages: First, the carbon debt payback times and offset parity points can be shortened by choosing smart management strategies and maximizing carbon displacement effects of harvested wood. The carbon displacement due to wood use for wood products or bioenergy is an important carbon pool, especially for longer model periods. Important to note that, the total wood volume yield is not per se the best criterion for the selection of the best plantation management strategies to accumulate carbon in- and outside forestry plantations. The second message is that the ethanol production costs in Brazil can be reduced considerably in the coming decades. Overall, total cost reduction found in this study are 48%, 41%, and 53% for first generation, integrated first-and-second generation and second generation industrial processing. These cost reduction arise from (combined) use of improved biomass yield, increase in sugar content, use of optimized technology, collection and use of trash, increase in industrial efficiency and upscaling of the industrial facility. Another key message is that the direct land use change GHG emissions can affect the GHG emission intensity of ethanol production both positively and negatively. Therefore, the location of land use changes for biomass cultivation highly affects the GHG performance of biomass supply chains. Biobased chemical production can be profitable and can achieve significant GHG emission reduction – but picking winners is complex. This is due to the fact that a) the best-performing product strongly depends on the chosen metric, and b) the ranges found in the production costs and GHG emissions are very large, especially for PDO and succinic acid, independent of the chosen metric.