Techno-economic analysis of promoter-enhanced CO2 capture with electrochemical regeneration: A comparative study with CESAR1 on a CHP plant

Abstract

This study presents a techno-economic analysis (TEA) comparing an alkaline solvent-based carbon capture technology utilizing electrochemical regeneration (ConsenCUS) with a conventional amine-based thermal regeneration approach (CESAR1) when retrofitted to a combined heat and power (CHP) plant to capture 0.45 Mtonne CO₂ annually. The study also investigates the integration of immobilized carbonic anhydrase (CA) as a promoter to enhance CO₂ absorption kinetics in the ConsenCUS system (ConsenCUS-CA). The results demonstrate that CESAR1 has a regeneration energy requirement of 3.23 GJ_th/tonne CO₂, compared with 3.74 GJ_el/tonne CO₂ for ConsenCUS. Meanwhile, ConsenCUS-CA demonstrates significant improvements, including an 18.6% reduction in solvent requirement, a two-thirds decrease in absorber height, and an 18.4% reduction in electrical regeneration energy requirement, resulting in a 14.1% decrease in total capital requirement, a 12.2% decrease in operating cost, and a 22.3% decrease in the cost of CO₂ avoided when using renewable energy. Despite requiring 30% lower capital investment than CESAR1, ConsenCUS-CA incurs up to 23% higher annual operating costs, primarily due to the electricity required for electrochemical regeneration. The impact of regeneration energy sources is also examined. The economic comparison shows that CESAR1, using a natural gas boiler for steam generation, has an €11.38/tonne CO₂ higher cost of CO₂ avoided but a €2.60/tonne steam lower additional steam production cost than ConsenCUS-CA using renewable electricity. The study further examines the impacts of technological learning, electricity price, CA cost and lifetime, CO₂ emission price, discount rate, plant lifetime, and potential performance improvements on the economic viability of the technologies. The findings indicate that, with continued technological development, ConsenCUS-CA could achieve operating cost parity with CESAR1 if its electrical energy consumption is reduced by at least 25%.