Methane production via syngas fermentation within the bio-CCS concept: A techno-economic assessment

Abstract

The study provides a comprehensive approach on assessing the feasibility of a novel process configuration that couples synthetic natural gas (SNG) production via syngas fermentation with carbon capture and storage (CCS). The present research constitutes the first endeavour to examine the techno-economic performance of this sophisticated hybrid SNG+CCS infrastructure. For this purpose, a flowsheet analysis within the Aspen Plus environment served to quantify the material and energy flows and then based on the simulations technical and economic indicators were estimated. A plant processing 6.25 dt/h of virgin biomass yields 1.32 t/h of SNG, achieves 51.2% energy efficiency and stores 2.97 t/h of CO2. The threshold SNG price (NPV=0) for the project to become economically viable is 92.14 £/MWh. A combination of existing policy schemes and the establishment of new instruments that will reward negative emissions has the potential to generate profits. A thorough cost breakdown along with a sensitivity analysis revealed that the process is CAPEX and feedstock intensive while larger plants can reduce the SNG price by about 15%. A stochastic Monte Carlo analysis indicated that even if the project shows promising techno-economic potential without the establishment of a consistent and robust legislation framework there is no realistic prospect for the proposed bio-CCS plant to compete with fossil natural gas.