Abstract

The cement industry is one of the most challenging sectors to decarbonize due to the coexistence of high-temperature thermal demand and process-related emissions from limestone calcination. This study presents an energy and emissions assessment of cement manufacturing based on representative mass and energy balances derived from literature benchmarks and industrial operating data. Typical cement production requires 2.8–3.6 GJ of thermal energy and 80–120 kWh of electricity per tonne of final product, resulting in total emission in the range 500–850 kg CO2/t cement, of which 55–65% originate from clinker calcination. Moving from this baseline, possible decarbonization pathways are evaluated, including energy efficiency improvements, clinker substitution through supplementary cementitious materials use of alternative fuels, electrification, hydrogen utilization and carbon capture technologies. The analysis shows that energy efficiency measures provide relatively limited reductions (10–30 kg CO2/t cement), while alternative fuels and clinker substitution can achieve larger but still partial benefits. Hydrogen emerges as a promising option for decarbonizing the combustion-related share of emissions, with a potential reduction ranging from 50 to 200 kg CO2/t cement, particularly when integrated with oxy-fuel combustion systems. Deep decarbonization ultimately requires carbon capture and storage (CCS), the only technology capable of addressing the substantial process emissions inherent to clinker production and use of hydrogen can be relevant too.

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