Bioenergy with carbon capture and storage (BECCS) is one strategy to remove CO₂ from the atmosphere. To assess the potential scale and cost of CO₂ sequestration from BECCS in the US, this analysis models carbon sequestration net of supply chain emissions and costs of biomass production, delivery, power generation, and CO₂ capture and sequestration in saline formations. The analysis includes two biomass supply scenarios (near-term and long-term), two biomass logistics scenarios (conventional and pelletized), and two generation technologies (pulverized combustion and integrated gasification combined cycle). Results show marginal cost per tonne CO₂ (accounting for costs of electricity and CO₂ emissions of reference power generation scenarios) as a function of CO₂ sequestered (simulating capture of up to 90% of total CO₂ sequestration potential) and associated spatial distribution of resources and generation locations for the array of scenario options. Under a near-term scenario using up to 206 million tonnes per year of biomass, up to 181 million tonnes CO₂ can be sequestered annually at scenario-average costs ranging from $62 to $137 per tonne CO₂; under a long-term scenario using up to 740 million tonnes per year of biomass, up to 737 million tonnes CO₂ can be sequestered annually at scenario-average costs ranging from $42 to $92 per tonne CO₂. These estimates of CO₂ sequestration potential may be reduced if future competing demand reduces resource availability or may be increased if displaced emissions from conventional power sources are included. Results suggest there are large-scale opportunities to implement BECCS at moderate cost in the US, particularly in the Midwest, Plains States, and Texas.

Environmentally friendly amino-acid salt solutions are used for the absorption of carbon dioxide from concentrated flue-gas streams via chemical absorption. Process intensification reduces operating and capital costs by combining chemical reactions and separation operations. Here, we present a new process-intensification approach that combines the CO₂ capture and the amino-acid regeneration steps into a single process carried out in a slurry three-phase reactor. The absorbed CO₂ precipitates as a solid carbonated guanidine compound. The cycle is completed by separation of the solid precipitate to strip the CO₂ and regenerate the guanidine compound, while the liquid solution is recycled to the slurry reactor. The process was studied by modifying a model developed by the authors for a gas-liquid bubble column without the presence of the guanidine compound. The guanidine precipitation reaction was accounted for using kinetic parameters calculated by the authors in another study. The proposed model was implemented by modifying an existing computer code used for the simulation of gas-liquid bubble columns. The calculated results showed that the proposed cycle can significantly reduce energy, equipment, and operating costs and can make an important contribution to developing a competitive cost-effective large-scale process for CO₂ capture.