| dc.description.abstract | In order to limit the global mean temperature increase, efforts need to be made to reduce greenhouse gas (GHG) emissions. A commonly recognized strategy to reduce GHG emissions is by replacing fossil fuels by renewable energy sources. In this thesis different potential biomass to bioenergy configurations for the Southeastern USA region are explored, and the costs and GHG emissions involved in the bioenergy production are compared to the costs and GHG emissions of the fossil fuels which they can substitute. The feedstocks Loblolly pine and mixed natural hardwood are selected as biomass, and the five conversion technologies pelleting, TOP process, hydrolysis and fermentation, gasification and FT and pyrolysis are selected. The ten configurations produce different bioenergy types which are able to substitute coal, gasoline, diesel or a mix of gasoline and diesel. The costs and GHG emissions for the processes cultivation, harvesting, transport and processing are first calculated separately and after combined to find the supply chain costs and supply chain emissions for each configuration. The feedstock mixed natural hardwood is, under the assumptions made in this thesis, not economically interesting to be used for bioenergy production due to high discounted cultivation costs of 25.81 $/GJ biomass, compared to 1.93 $/GJ biomass for Loblolly pine. Due to the selected management practices the cultivation of hardwood however has no GHG emissions. The costs and emissions involved in harvesting are similar for both feedstocks, and only represent a smaller share in the total supply chain costs and GHG emissions. The costs and GHG involved in the transport of hardwood are higher due to the larger transport distance of the biomass. In the processing costs of the conversion technologies the pelleting and TOP process result in the lowest costs, while fermentation and gasification have the lowest GHG emissions. Two different scenarios’ are applied in order to compare the bioenergy to the reference fossil fuels. First the GHG emission reduction due to the conversion of 1 tonne biomass in the different configurations is calculated finding that the pelleting, and after the TOP process configurations lead to a GHG emission reduction of approximately 1200 to 1500 kg CO2-eq per dry tonne biomass. Following, the cost difference between bioenergy and its fossil fuel reference is divided by the GHG emission reduction of bioenergy compared to the fossil fuel. For the configurations using hardwood this scenario leads to high GHG emission reduction costs due to the high costs of the biomass. For the remaining loblolly pine configurations the pelleting technology leads to the GHG abatement costs. | |
