• Energy Research

Abstract As the largest producer of coal chemical products in the world, China faces tremendous pressure to reduce its carbon emission. An accurate quantification of the carbon dioxide (CO2) emission of coal chemical industry in China is therefore necessary. However, due to the variety of coal chemical products and limitations of CO2 emission factors, the total CO2 emission of coal chemical industry has yet to be determined. In this study, local CO2 emission factors of coal chemical products in China are published based on first hand data from twenty-three coal chemical enterprises and the total CO2 emission of China's coal chemical industry is extrapolated. The provincial-level spatial distribution of the CO2 emission of coal chemical industry is presented to assist the government in identifying key emission reduction areas. Additionally, scenario analysis of CO2 emission for China’s modern coal chemical industry in 2020 is conducted to determine whether the development of the modern coal chemical industry will have a significant impact on future CO2 emission, as well as the effect of carbon capture, utilization and storage technologies on the reduction in carbon emission. The estimate shows that the total CO2 emission of the coal chemical industry in 2015 was 607 million tonnes (Mt), accounting for approximately 5.71% of China’s total CO2 emission. The figure is higher than the total annual CO2 emission of a country such as Canada (555 Mt) or Brazil (486 Mt). Quantifying the emission of the coal chemical industry is therefore critical to understand the global carbon budget. The spatial distribution shows that Shandong, Inner Mongolia and Shanxi release one-third of the coal chemical industry’s total CO2 emission. Considering the development of the modern coal chemical industry, its CO2 emission is predicted to be as high as 416.52 million tonnes in 2020. However, the CO2 emission could be reduced by 317.98 million tonnes when carbon capture, utilization and storage are applied to process and energy systems simultaneously. This paper quantifies the CO2 emission of the coal chemical industry in China for the first time, identifies key chemical products and the provinces in which they are produced, explores the carbon reduction potential by scenario analysis, and provides specific data to support the assessment of effective CO2 reduction policy.

Coal is the primary energy source in China, and its life cycle inventory (LCI) is widely used as background data for life cycle assessment studies. Previous research indicates that the inventory of coal production varies regionally. However, the development of complete regionalized LCIs for coal production is quite limited. Here, we establish the first provincial-level LCIs of local coal production and market for coal in China, based on a database of 6,122 coal mines and developed models. In the inventory results of local coal production, the coefficients of variation (CVs) of nine indicators exceed 0.5, especially SO2 and particulate matter emission factors (CVs > 1). Compared with that, the interprovincial coal trade homogenizes the provincial production inventory of market for coal relatively, despite four indicators with CVs exceeding 0.5. Therefore, the regionalized inventory with remarkable spatial differentiation can provide more accurate fundamental data for future research such as electricity production. Furthermore, CH4 emissions from coal production account for 24% of China's total methane emissions, highlighting its significance in mitigating global warming. Moreover, through the increasing coal trade, the significant and implicit plunder of water resources from the three coal net-exporting provinces, located in water-scarce areas, should be noted.

Cement is a critical material for urbanization, but its energy-intensive production creates serious potential environmental impacts. As further air pollutant mitigation become more expensive and difficult, ‘co-control’ measure by new energy-efficient technologies is proposed to bring co-benefits. In this study we conducted a cost-effectiveness analysis to evaluate available new technologies in Chinese cement industry. The analysis verified the findings of recent studies that many technologies have huge co-control potential, but we also found the heterogeneity and conflict in different parameters of certain technologies that has not declared by existing studies. The finding indicates the necessity to design the technology promotion roadmap. We obtained a technology promotion roadmap by establishing a multi-objective optimization model and it proves to be the best solution for achieving energy saving, PM2.5, SO2 and CO2 abatement compared to single-objective optimization models. Furthermore, pollutant emissions and energy consumption of the cement industry under four control scenarios are projected for 2010–2030. Under integrated measure scenario combining technology promotion and product structure adjustment, energy consumption will drop back to 2006–2007 level by 2030. The major air pollutant emissions will be ∼44% lower than business-as-usual scenario and the CO2 emission will be reduced by ∼15%. The annual monetary benefit of technology promotion is estimated to be 396.5 billion RMB Yuan in 2030. The findings verify the co-control strategy and update our understanding of new technologies implementation. The technology promotion roadmap and scenario analysis results are supportable for future policy-making of cement industry.

Abstract This study presented a life cycle assessment of the environmental impacts of the production of three crops (rice, wheat, and maize) in the Chaohu Watershed of China. The crop production system involved phosphate rock mining, P fertilizer manufacturing, crop cultivating, and crop processing. Resource depletion, climate change, and eutrophication were examined. The functional unit chosen was 1 ha of cultivated land. The results showed that phosphate rock mining and P fertilizer manufacturing had been the main contributors to P resource depletion, representing shares of 57.40% and 25.86%, respectively. Large quantities of extracted phosphate raw rock and manufactured fertilizer for heavy fertilizer application were identified as the main causes of these effects. Rice crop had depleted the largest share of P resources, as it required the highest level of fertilizer use. Crop cultivation and processing were found to be particularly influential in terms of climate change effects, representing shares of 45.37% and 41.70%, respectively. This had mainly result from high fertilizer and electricity use for crop cultivation and processing, respectively. When processing maize for flour production, higher levels of electricity-producing greenhouse gases were consumed than those consumed for the other two crops. Moreover, crop cultivation accounted for 71.22% of eutrophication processes due to high degrees of fertilizer application even though all three crops exhibit nearly identical eutrophication potentials. In turn, means of mitigating such impacts to increase the phosphorus use efficiency of this system were presented. The limitations of this study must also be examined and studied in the future.

Abstract Eco-efficiency is an instrument for sustainability analysis, indicating how efficient the economic activity is with regard to nature's goods and services. This paper conducts an eco-efficiency analysis for regional industrial systems in China by developing data envelopment analysis (DEA) based models. Using real data of 30 provinces in China, an empirical study is employed to illustrate the pattern of regional industrial systems' eco-efficiency. The results indicate that Tianjing, Shanghai, Guangdong, Beijing, Hainan and Qinghai are relatively eco-efficient. The results also show that, provinces with higher level GDP per capita will have higher eco-efficiency relatively with an exception of Hainan and Qinghai. The study provides deeper insights into the causes of eco-inefficiency, and gives further implications on environmental protection strategies in China. In the article, we also discuss the advantages and disadvantages of using DEA in eco-efficiency analysis and areas that require further work are presented.

China has enacted a series of policies and regulations that require manufacturers to reclaim and recycle obsolete refrigerators to mitigate the life cycle environmental impacts and to improve resource efficiency. However, it is not clear whether the environmental benefits of recycling refrigerators can be balanced with the emissions from the reclamation and recycling processes. To address this issue, environmental impacts of recycling refrigerators under different scenarios were quantified through a comparative life cycle assessment. The data were mainly acquired from a large professional refrigerator recycling company. The CML 2001 method built in the GaBi software (Version 6.0) was used to quantify the environmental impacts. The result shows that the environmental benefits brought about by recycling mainly come from the resource and energy savings in the upstream production, such as in the high impact polystyrene recycling (22.17%), the steel recycling (23.94%), and the copper recycling (8.10%) phases. Compared to railway, motor is a more environmentally friendly transportation for refrigerators. Recycling refrigerators increase the ozone layer depletion potential because the crushing process inevitably releases the CFC-11. The environmental impacts of transportation may exceed the environmental benefit of recycling refrigerators. This study will be useful for manufacturers to design new recycling networks from the life cycle and environmental impact perspectives.

Significance The biogeochemical cycle of phosphorus (P) has been massively altered in China, challenging its food security and causing eutrophication of freshwaters. This study shows, for the first time to our knowledge, how P cycling in China was intensified in the past four centuries to sustain the increasing population and its demand for animal protein. Our analysis also reveals the spatial disparity of its concomitant eutrophication impact. The findings advance the knowledge base needed for closing the P cycle to sustain future food production and maintain healthy rivers, lakes, and oceans.

To mitigate serious air pollution, the State Council of China promulgated the Air Pollution Prevention and Control Action Plan in 2013. To verify the feasibility and validity of industrial energy-saving and emission-reduction policies in the action plan, we conducted a cost-benefit analysis of implementing these policies in 31 provinces for the period of 2013 to 2017. We also completed a scenario analysis in this study to assess the cost-effectiveness of different measures within the energy-saving and the emission-reduction policies individually. The data were derived from field surveys, statistical yearbooks, government documents, and published literatures. The results show that total cost and total benefit are 118.39 and 748.15 billion Yuan, respectively, and the estimated benefit-cost ratio is 6.32 in the S3 scenario. For all the scenarios, these policies are cost-effective and the eastern region has higher satisfactory values. Furthermore, the end-of-pipe scenario has greater emission reduction potential than energy-saving scenario. We also found that gross domestic product and population are significantly correlated with the benefit-cost ratio value through the regression analysis of selected possible influencing factors. The sensitivity analysis demonstrates that benefit-cost ratio value is more sensitive to unit emission-reduction cost, unit subsidy, growth rate of gross domestic product, and discount rate among all the parameters. Compared with other provinces, the benefit-cost ratios of Beijing and Tianjin are more sensitive to changes of unit subsidy than unit emission-reduction cost. These findings may have significant implications for improving China's air pollution prevention policy.

The estimate of future obsolete streams is one of the crucial issues for the establishment of an efficient waste collection and recycling system in China. Due to low availability of reliable data, information on discarded household appliances (HAs) is deficient in China. This study adopts a stocks-based prediction model based on material flow analysis. The model firstly models the lifetime distribution of HAs, and then the future stocks of HAs are extrapolated. By determining the initial year of calculation, the model makes a prediction of future obsolete HAs in China in the time period from 2010–2030. The results show that the discarded amount of the five major kinds of HAs will increase from 130 million units in 2010 to 216 to 221 million units by 2020, and 259 to 282 million units by 2030. A total of 4370 to 4528 million units (149 to 155 million tonnes) of obsolete HAs will be generated in China over the next 20 years. Urban households will generate significantly more obsolete HAs (about 2619 to 2723 million units) than rural households, mainly due to the difference in their HAs possession levels. Thus recycling capacity must increase if the rising quantity of domestic obsolete HAs is to be handled properly. The results of this study can help to develop the collection and recycling systems and facilities needed for the obsolete HAs generated in the future. From a methodological perspective, the stock-based model provides a suitable tool to predict the generation of discarded HAs in the future