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 over 22,000 tonnes/year of hydrogen from biomass for >2000 public transport buses in West Midlands region, UK. These included fluidised bed (FB) 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 5.10 to 7.18 years.  For operations with CCS, in which the captured CO2 was sold, FB gasification gave the lowest minimum hydrogen selling price of $3.40/kg. This was followed by AD-biogas reforming ($4.20/kg), while pyrolysis-gasification and pyrolysis-reforming gave $4.83/kg and $7.30/kg, respectively. Hydrogen selling prices were sensitive to raw material costs and internal rates of return, while revenue from selling CO2 was very important to make biohydrogen production cost competitive. FB gasification and AD-biogas reforming with CCS could deliver hydrogen at less than or around $4/kg when CO2 was sold at above $75/tonne.  This study showed that thermochemical technologies could produce biohydrogen at competitive prices to extend the current use of electrolytic hydrogen-fuelled buses in Birmingham to the wider West Midlands region.