Comparative Techno-Economic Modelling of Large-Scale Thermochemical Biohydrogen Production Technologies to Fuel Public Buses: A Case Study of West Midlands Region of England

Abstract

This work presents techno-economic modelling of four thermochemical technologies that could produce nearly 20,500 tonnes of hydrogen per year from biomass for public bus transport. These included fluidised bed (FB) steam gasification, fast pyrolysis-FB gasification, fast pyrolysis-steam reforming, and steam reforming of biogas from anaerobic digestion (AD). Each plant was modelled on ASPEN plus with and without carbon capture and storage (CCS), and their process flow diagrams, mass and energy balances used for economic modelling. Payback periods ranged from 6.7 to 7 years. For operations with CCS, in which the captured CO 2 was sold, FB gasification gave the lowest minimum hydrogen selling price of $2.84/kg. This was followed by AD-biogas reforming ($3.67/kg), while pyrolysis-reforming and pyrolysis-gasification giving $6.58/kg and $7.49/kg, respectively. Hydrogen selling prices were sensitive to raw material costs and internal rates of return, while revenue from selling CO 2 was very important to make biohydrogen production cost competitive. FB gasification and AD-biogas reforming with CCS could deliver hydrogen at less than $4/kg when CO 2 was sold at above $75/tonne. This study showed that thermochemical technologies could produce cheaper biohydrogen to extend the current use of electrolytic hydrogen-fuelled buses in Birmingham to the wider West Midlands region.