Flexible methanol and hydrogen production from biomass gasification with negative emissions

Bioenergy plants with carbon capture and storage have been recently receiving attention as negative emission technologies. In this work, a techno-economic analysis of bio-methanol and bio-hydrogen production plants coupled with carbon capture and storage is conducted. The plants include different gasification technologies (direct oxygen-blown gasification and indirect gasification) and different CO2 capture processes (pre-combustion MDEA-based and post-combustion MEA-based CO2 capture) from different streams, to achieve increasing CO2 capture rates at increasing marginal costs. Moreover, an assessment of the economic impact of multi-product plants which flexibly produce methanol and hydrogen is carried out. Overall fuel production efficiencies of between 65.1 and 68.1% have been computed in all cases, showing a little dependency of energy efficiency on the gasification technology and the final product. In methanol production plants, a CO2 capture rate of between 26 and 55%, depending on the gasification technology, can be reached via a pre-combustion capture process at a cost of 41-46 euro per tCO2. In hydrogen production plants, between 64 and 90% capture efficiency can be reached at a cost of 52-56 euro per tCO2. Higher CO2 capture efficiency, resulting in CO2 residual emissions below 2% of the inlet carbon, can be achieved via post-combustion capture with a marginal cost of 98-205 euro per tCO2 and an average cost of 47-77 euro per tCO2. Flexible methanol-H2 production plants result in the highest capex and the highest LCOF. However, when considering the time-dependent H2 market price, the internal rate of return of flexible methanol-H2 plants is slightly higher or slightly lower than that of the corresponding best single-product plant. On the other hand, multi-product flexible plants are never the worst case scenario despite the highest investment costs, thus offering a potential advantage from the financial risk perspective thanks to lower exposure to market price volatility.