Technoeconomic Analysis of a Hybrid Biomass Thermochemical and Electrochemical Conversion System

This study explores an integrated biomass conversion system based on a common fast pyrolysis step and two subsequent bio-oil upgrading pathways. The two options are bio-oil thermochemical upgrading to drop-in transportation biofuels through hydrotreating and hydrocracking, and bio-oil electrochemical conversion for electrical power generation using a direct bio-oil fuel cell method. The technoeconomic performances of biomass-to-biofuels and biomass-to-electricity pathways are first examined individually, and then integrated for the analysis of a hybrid biomass conversion system. A biomass facility of 2000 tonnes per day is investigated as a baseline. The minimum fuel-selling price (MFSP) is estimated to be $2.48 per gallon, with biomass feedstock and other operating costs as major contributors. A very high minimum electricity-selling price (MESP) of $5.36 per kWh is projected based on the current laboratory-scale fuel cell configuration. Sensitivity analysis reveals that the effective reactant content in bio-oil, the degree of oxidation, and the fuel cell system efficiency play key roles in the MESP. The estimate can be reduced to $0.96 per kWh if target values of the three parameters are met. The results of the hybrid system suggest that the MESP can be reduced substantially from $0.96 to $0 per kWh when the hybrid system increases the bio-oil fraction for biofuel production from 0 to 75.8%, given a biofuel MFSP of $3 per gallon.