Life cycle based emergy analysis on China's cement production

To evaluate the sustainability of cement production in China, a life cycle inventory (LCI) based emergy analysis (EMA) method was employed in this study. According to Taylor series expansions, uncertainty analysis was also performed in order to improve the accuracy of the results. Direct renewable resources, nonrenewable resources, imported materials and energy, transport of materials, as well as ecological service for emissions dilution and CO₂ uptake were included in this study. The unit emergy value (UEV) of cement was 1.93 × 10¹⁵ sej/t with service and 1.92 × 10¹⁵ sej/t without service, respectively. Uncertainty analysis shows that the GSD² of the total emergy needed for cement production was 1.83. Results also indicate that key factors making dominant contributions to the total emergy needed for cement production were the consumptions of limestone, coal, and electricity. Emergy-based indicators indicate that cement industry in China brought higher environmental burden and is not sustainable. Furthermore, the results suggest that adjusting industrial structure, improving energy efficiency, and applying alternatives to replace raw materials are effective approaches to improve the sustainability of cement industry.