Integrated Carbon Capture and Utilization in the Cement Industry: A Comparative Study

This study analyzes a novel carbon capture and utilization pathway that has been proposed for the decarbonization of the cement sector and compares its performance in terms of carbon dioxide (CO2) emissions to business as usual (BAU) and a carbon capture and storage (CCS) alternative. In the proposed integrated carbon capture and utilization (I-CCU) solution, methanol is produced with hydrogen from an electrolysis plant and with CO2 captured at an oxyfuel cement plant; the oxygen delivered to the oxyfuel cement plant comes from the same electrolysis plant that provides hydrogen, which eliminates the need for an air separation unit (ASU). Due to the high energy demand for electrolysis, the carbon footprint of the solution depends on the carbon intensity of the power grid; any advantage from avoiding an ASU is overshadowed by the energy requirements of I-CCU. Consequently, BAU outperforms I-CCU in geographical regions with specific electricity emissions larger than 0.2 kgCO2/kW h, which corresponds to most of Europe. Furthermore, CCS is practically always a better alternative to I-CCU; only when there is renewable electricity available in abundance, I-CCU is better. Finally, it should be highlighted that using additional low-carbon electricity sources to drive I-CCU is not the most efficient use in terms of emission reductions per unit of low-carbon electricity. While the pursuit of (energy) integration and circularity should always be considered, our work emphasizes the necessity of conducting a comparative analysis, such as that presented here, to guarantee the achievement of the desired objectives.