Benchmarking the Environmental Performance of Clinker Production: A Life Cycle Assessment Based on Real Industrial Data

The cement industry is one of the largest industrial sources of anthropogenic carbon dioxide (CO2) emissions, with clinker production representing the most energy- and carbon-intensive stage of cement manufacturing. Life cycle assessment (LCA) is widely used to quantify the environmental impacts of clinker production and to support benchmarking of energy use and greenhouse gas emissions. However, plant-level benchmarking studies based on real industrial operational data remain limited, and the relationship between energy efficiency improvements and overall climate change impacts is not always clearly resolved. In this study, the environmental performance of clinker production at a representative integrated cement plant is assessed using a cradle-to-gate LCA approach. The analysis is based on real industrial operational data and uses a functional unit of 1~t of Portland cement clinker. Life cycle inventory data are compiled for raw material inputs, energy consumption, and direct CO2 emissions, and the results are benchmarked against a harmonized literature-based reference dataset. Global warming potential (GWP) is evaluated using IPCC 100-year characterization factors. The results show that the case-study plant exhibits lower thermal energy demand (3162~MJ/t clinker) and electricity consumption (52.23~kWh/t clinker) compared to the literature benchmark. Despite these improvements in energy-related indicators, the total GWP of clinker production at the case-study plant (1010~kg~CO2-eq/t clinker) is comparable to the benchmark value (995~kg~CO2-eq/t clinker). Contribution analysis indicates that process-related CO2 emissions from limestone calcination dominate the total GWP, accounting for approximately 73\% of total emissions. These findings demonstrate that improvements in energy efficiency alone do not necessarily translate into proportional reductions in overall climate change impacts for clinker production. The study highlights the importance of harmonized benchmarking and underscores the need for mitigation strategies that directly address process-related emissions in order to achieve substantial reductions in greenhouse gas emissions in the cement industry.