Techno-economic assessment of hydrogen production based on dual fluidized bed biomass steam gasification, biogas steam reforming, and alkaline water electrolysis processes

Abstract

In this paper, three CO2-neutral H2 production processes were investigated. The three employed technologies were dual fluidized bed (DFB) biomass steam gasification, biogas steam reforming (BSR), and alkaline electrolysis (AEL) powered by renewable electricity with their necessary downstream separation and purification process steps. Aspen Plus process simulations were carried out in order to calculate the mass and energy balances of the three processes. In addition, a techno-economic assessment was carried out for a fictitious business producing H2 at a rate of 90kgh−1 in Austria in 2016. This assumption was used so that the economic feasibility of these investigated processes could be directly compared.The simulation results show that the DFB biomass steam gasification process has a higher H2 conversion rate (51.4%) but a lower fuel based H2 production efficiency (38.9%) than the BSR process (27.2% and 47.0%, respectively). Moreover, the alkaline electrolysis process shows the highest energy based H2 conversion efficiency at about 66%.The results of the economic assessment show that the DFB biomass steam gasification process has investment costs of 12.1 MEUR followed by the biogas steam reforming process with investment costs of 9.9 MEUR. The alkaline electrolysis process has investment costs of 4.4 MEUR. However, the after tax H2 break-even price of the DFB process is the lowest with 0.148EURkWh−1. The BSR process has an after tax H2 break-even price of 0.152EURkWh−1 and the AEL process has an after tax H2 break-even price of 0.191EURkWh−1. The net present value (NPV) calculations reveal that the BSR process has the highest NPV, followed by the AEL process and the DFB biomass steam gasification process. However, the NPV of all three processes are very similar. In general, all three H2 production processes perform at the same level based on the results of the process simulation and the chosen economic assumptions.