Evolution and projection of CO2 emissions for China's cement industry from 1980 to 2020

Previous studies have estimated emissions from China's cement industry for some specific periods, but a trend analysis of historical emissions has not yet been carried out. Based on changes in clinker quality and developments in energy-saving technologies of different clinker kilns, we calculated carbon dioxide (CO2) emissions due to cement production in China for the continuous period from 1980 to 2014. Our analysis showed that total CO2 emissions from cement production in China were 1270.55 Mt in 2014, which is 18 times higher than that in 1980. There was a slight reduction in the share of emissions from fuel consumption, while the percentage of process emissions rose at a stable rate. The cement emission factor fell sharply from 852.12 kg/t in 1980 to 513.15 kg/t in 2014. Two scenarios were considered to predict future emissions, namely a baseline scenario (BS) and a best practice scenario (BPS). We found that CO2 emissions could be reduced to 856.62957.91 Mt in 2020, which corresponds to a cement output of 1.86 billion tons. This implies that, by 2020, clinker and cement emission factors will fall to 789.11-840.618 kg/t and 460.55-513.15 kg/t, respectively. By 2020, energy efficiency improvements will be the main driver of emission reductions. Our projections also indicated that emission reductions resulting from process improvements would only account for 1.48% of total direct emissions, even under the BPS scenario. Thus, we suggest that the development of alternative industrial byproducts and fuels, substituting for natural resources, should be a main focus of future innovation efforts toward a sustainable cement industry in China.