Plant + Boom = Boat + Vroom

Abstract

This thesis compares the performance of hypothetical biorefineries in Brazil and Scandinavia that produce biofuel for use in large marine vessels using one of three thermochemical technologies—hydrothermal liquefaction (HTL), fast pyrolysis with hydrodeoxygenation (FP), and gasification with Fischer-Tropsch synthesis (GFT)—and one of ten lignocellulosic residues from forestry and agriculture. The biorefineries were modeled using black-box mass balances for biofuel production and electricity and heat cogeneration. The results of this model, along with local costs factors, were used to estimate the economic performance of biorefineries in each country where each feedstock is available. Estimates of capital expenses, operating expenses, and annual earnings were used to calculate the minimum selling price of the biofuel, which is used as an indicator of economic performance. The environmental performance of each combination was estimated using the indicators of life cycle greenhouse gas emissions, sulfur dioxide emissions, nitrogen oxide emissions, and non-renewable energy use. The economic and environmental indicators for each feedstock-technology-country combination are compared to each other and also compared to reference values for other marine emission-reducing technologies, including liquid natural gas, emission scrubbers, and soy biodiesel. The results are subject to sensitivity analysis to determine the influence of uncertainty of capital costs, feedstock costs, biorefinery scale, biorefinery siting, biorefinery configuration, biofuel yields, biofuel blending, and environmental impact allocation. The biofuels modeled in this study have significantly lower life cycle greenhouse gas and sulfur dioxide emissions and non-renewable energy use than those of heavy fuel oil, but have higher life cycle nitrogen oxide emissions, due to the lower quality of the fuel produced and combusted. Economically, none of the biofuels are competitive with current fossil fuel prices when estimated with the scale and cost factors in this study. The feedstock-technology-country combinations with the lowest minimum biofuel selling price, when considered as a ratio to the current local price of marine gas oil, are the hydrothermal liquefaction of barley straw in Sweden, and the fast pyrolysis of corn stover and rice residues in Brazil. Each of those combinations has a minimum biofuel selling price ratio of 3.2 times that of marine gas oil. Performance trends between technologies and feedstocks are weak, and superior economic performance does not correlate with superior environmental performance.