Decarbonization of cement production in a hydrogen economy

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The transition to net-zero emission energy systems creates synergistic opportunities across sectors. For example, fuel hydrogen production from water electrolysis generates by-product oxygen that could be used to reduce the cost of carbon capture and storage (CCS) essential in the decarbonization of clinker production in cement making. To assess this opportunity, a techno-economic assessment was carried out for the production of clinker using oxy-combustion in a natural gas-fueled plant coupled to CCS. Material and energy flows were assessed in a reference case for clinker production (oxygen from air, no CCS), and compared to oxy-combustion clinker production from either an air separation unit (ASU, 95% O2), or water electrolysis (100% O2), both coupled to CCS. Compared to the reference, air-combusted clinker plant, oxy-combustion increases thermal energy demand by 7% and electricity demand by 137% for ASU and 67% for electrolytic oxygen. The levelized cost of oxygen supply ranges from $49/tO2 for an on-site ASU to pipelined electrolytic O2 at $35/tO2 (200 km) or $13/t O2 (20 km). The cost of clinker for the reference plant without CCS increases linearly from $84/t clinker to $193/t clinker at a carbon price of $0/tCO2 to $150/tCO2, respectively. With oxy-combustion and CCS, the clinker production cost ranges from $119 to $122/t clinker, reflecting a breakeven carbon price of $39 to $53/tCO2 compared to the reference case. The lower cost for the electrolytic supply of by-product oxygen compared to ASU oxygen must be balanced against the reliability of supply, the pipeline transport distance and the charges that may be added by the hydrogen producer.