Power and Methanol Production from Biomass Combined With Solar and Wind Energy : Analysis and Comparison

Sammanfattning: The purpose of this work is to investigate the feasibility of an integrated system consisting of biomass-based power generation built-in with carbon capture technology combined with a water electrolysis unit operated by solar cells and wind turbines to produce fuel through the methanol synthesis process. The configurations are examined both technically and economically to determine their feasibility, and subjected to sensitivity analysis to determine their economic viability and optimum performance. Each integrated system has the same subsystems configuration including electrical power generation, electrolysis unit and solar/wind renewable electricity input. Three main system configuration variations for carbon extraction from biomass feedstock have been evaluated, based on pre-CCS in the form of integrated biomass gasification combined cycle (IGCC), in-situ CCS represented by Oxy-fuel combustion concept, and post-CCS via exhaust gas treatment, assuming the same access to woodchip feedstock.Two important substances for methanol production are carbon dioxide coming from biomass and hydrogen supplied by water electrolysis based on intermittent renewable energy sources. Coil evaporation system to provide CO2 separation would perform differently in each system; oxy-fuel, pre-CCS and post-CCS alternatives. Meanwhile, H2 supply is provided by the electrolysis process using water supply and electricity produced from solar and wind power. In addition, the effect of location and uncertainty factors is discussed among the sensitivity studies. The technical analysis shows that with 5 ton/hour of biomass feed, each system configuration could produce up to 5.8 t/h of methanol. On the other hand, the economic analysis shows LCOE of Oxy-fuel and the IGCC approaches the lowest possible to 0.086 €/kWh and 0.1060 respectively; while for the gasification process 689 €/ton methanol is produced. The interest rate risk can deviate from the energy cost up to 16% higher when the interest rate is increased from 8% to 9%.