Evaluation of Miscanthus Gasification and Oxy-Combustion Carbon Dioxide Removal Potential with Carbon Capture Towards Implementation of Bioenergy with Carbon Capture and Storage in England

Abstract

Abstract Bioenergy with Carbon Capture and Storage (BECCS) pathways and supply chain designs are researched broadly and implemented for scenarios as of the IEA's (2021) Net Zero by 2050 report. The Committee on Climate Change (2018a, 2018b) has identified Miscanthus as one biomass type to achieve its negative emission goals and aligned one third of 1.2 million hectares under high level and one third of 0.7 million hectares under medium level of ambition (multi-functional land use) for the cultivation of Miscanthus for BECCS in the UK. In this study the input of 39 t/hr of Miscanthus x giganteus biomass as well as Energy technologies institutes (2015) information on projected distributed BECCS installations in the UK for BECCS were considered to bring up different gasifying agent options for H2 generation through Miscanthus Gasification with pre combustion carbon capture and one configuration for oxy-combustion with post combustion carbon capture for highly efficient power generation. Process simulations with Aspen software were conducted to determine power yields and carbon capture rates of optimized bioenergy with carbon capture value chains, sensitivity analysis were executed in order to optimize the configurations. The aim of the study was to observe how highest achievable power generation efficiencies of H2 generation through gasification of Miscanthus x giganetus compare with oxy-combustion power generation efficiency and how the different pathways influence the carbon capture efficiency. The aim was to inform BECCS implementation decisions with optimum possible H2 and power generation yields as well as their respective carbon capture potential. It was found that under oxygen, air and steam as gasifying agents steam is most effective for H2 generation with 3.1 t/hr of H2 produced under a input of 39 t/hr of Miscanthus input, which generates 35,6 MW of power in a simulated H2 turbine. Under simulation assumptions it captures thereby 55,2 t/hr of CO2 with a carbon capture rate of 99%. Oxy-combustion is more efficient than the gasification pathways in regard of power generation, which is 100,4 MW with CO2 capture of 36,6 t/hr with an carbon capture efficiency of 73,8 %. Concluding oxy-combustion is preferred, if highly efficient power generation is wanted and lower carbon capture rate is accepted thereby. When H2 generation is preferred, steam gasification should be chosen as highest efficient gasification pathway. The exact numbers of power generation as well as carbon capture can be used now to estimate UKs overall power generation as well as carbon capture potential of Miscanthus x giganteus cultivation under different land use scenarios considering land use change effects and biodiversity.