Effect of installed capacity size on environmental efficiency across 528 thermal power stations in North China

Ecological risk assessment of heavy metals in bottom ashes generated by small-scale thermal treatment furnaces for domestic waste in villages and towns of China

Small-scale Solid Waste Thermal Treatment (SSWTT) is prevalent in remote Chinese locations. However, the ecological threats associated with heavy metals in resultant bottom ash remain undefined. This research study scrutinized such ash from eight differing sites, assessing heavy metal content, chemical form, and leaching toxicity. Most bottom ash samples met soil contamination standards for development land (GB36600-2018). However, levels of As, Cd, Cr, Cu, Ni, Pb, and Zn in some samples exceeded agricultural land standards GB15618-2018) by 1591%, 64,478%, 1880%, 3886%, 963%, 1110%, and 2011% respectively. Additionally, the As and Cd contents surpassed the construction land control limit value by 383% and 13% respectively. The mean values of the combined oxidizable and residual fraction (F3 + F4) for each heavy metal in all samples exceeded 65%, with Cr, Cu, Ni, and Pb reaching over 95%. All sample leaching concentrations, obtained via the HJ/T 299 procedure, were less than limits set by the identification standards for hazardous wastes (GB5085.3-2007). However, only the leaching concentrations of three samples via the leaching procedure HJ/T 300 met the "Solid Waste Landfill Pollution Control Standard" (GB 16889-2008). The results indicate that the location and type of SSWTT equipment play a crucial role in determining an appropriate solution for bottom ash management.

Assessing the environmental performances of waste-to-energy plants: The case-study of the EMAS-registered waste incinerators in Italy

This study evaluated the environmental performances of 15 Italian waste incineration (WI) plants registered to EMAS. From the EMAS Environmental Statements, the validated data related to 5 environmental aspects (emissions to air, energy consumption/production, waste production and reagent consumption) and 24 key indicators were analyzed to describe and assess the environmental performances of the plants in 2017-2019 in relation to the best available techniques associated emission levels (BAT-AELs) and other sectorial reference values. All air pollutants' average concentrations resulted significantly below the upper BAT-AELs, the majority under the lower BAT-AELs, with an overall slightly decreasing trend (-4.6%). The specific productions of bottom and other ashes were steady over time and just above the lower characteristic values. The specific energy consumption was higher than the average European performance and stable over time, while the specific reagent consumption was harder to evaluate, with results varying for the different reagents. An evaluation of the influence of the WI plants' characteristics on the environmental performances was also performed considering 13 different parameters (e.g., flue gas cleaning technologies, waste treatment capacity, etc.). A correlation analysis highlighted the positive influence of the pre-dedusting stages on overall emissions, specific reagents consumption and specific waste production, and of the plant size on the specific energy production. This study demonstrated that EMAS can provide a tool to evaluate the environmental performances of WI plants and compare different installations using certified data. It also highlighted the excellent performances of the Italian WI plants registered to EMAS compared to the sectorial references.

Determinants of load capacity factor in South Korea: does structural change matter?

By likening biocapacity and ecological footprint, the load capacity factor follows a specified ecological threshold, permitting for an in-depth analysis of ecological damage. It can be seen that as the load capacity factor is reduced, the ecological damage intensifies. Until now, scholars have used carbon dioxide, ecological footprint, nitrogen oxide, sulfur dioxide, and other indices to objectively examine ecological problems. The utilization of these metrics can cause the supply side of ecological concerns to be overlooked. To make up for this weakness, this paper evaluates the impact of structural change and trade globalization on the load capacity factor. The research also considers other drivers of load capacity factors such as economic growth and energy. We utilized the nonparametric such as nonparametric causality and quantile-on-quantile (QQ) regression approaches to scrutinize these interconnections for South Korea between 1970 and 2018. The findings from the QQ approach disclosed that in the majority of the quantiles, the influence of economic growth, structural change, energies (renewable and nonrenewable), and trade globalization mitigate the load capacity factor. Moreover, the nonparametric causality test divulged that in variance and mean, all the independent variables can predict the load capacity factor. Policy proposals for South Korea's sustainable development are offered based on the findings.

CO2 Reduction Potential from Efficiency Improvements in China’s Coal-Fired Thermal Power Generation: A Combined Approach of Metafrontier DEA and LMDI

Among the G20 countries, China is the only country to experience an increase in electricity generation from coal-fired thermal power plants from 2019 to 2020. This study aims to develop an analytical framework combining metafrontier data envelopment analysis with the logarithmic mean Divisia index for a detailed decomposition analysis of ‘mass-based’ energy-related CO2 reduction potential through efficiency improvements in coal-fired thermal power plants in China. The results show that inefficiency in power generation can be largely attributed to differences in the location of power plants and the production scale. Moreover, the impact of regional heterogeneity on the changes in power generation efficiency is more notable for the small–medium power plants in the northeast region than the large power plants in the western region in China. However, when focusing on the mass-based CO2 reduction potential associated with the regional heterogeneity, its positive effects in the western region for the large power plants are 6.2 times larger than that in the northeast region for the small–medium power plants. These results imply that an analysis that focuses only on the efficiency score would ignore the production scale of coal-fired thermal power plants and thus would fail to properly evaluate the environmental impacts associated with efficiency changes.

Determinants of technical inefficiency in China's coal-fired power plants and policy recommendations for CO2 mitigation

This study applies data envelopment analysis (DEA) to estimate the technical efficiency (TE) and CO₂ emission reduction potential of 1270 coal-fired power plants in 28 Chinese provinces and municipalities. The large dataset used in the study includes 727 combined heat and power (CHP) plants and 543 thermal power plants. Results show an average TE score of 0.57 for the CHP power plants and 0.58 for the thermal power plants, suggesting a significant potential to reduce coal consumption in both types of coal-fired plants. Total CO₂ emission reduction potential was estimated to be 953 Mt-CO₂, or 19% of the total CO₂ emissions of China's electricity and heat producing sectors, indicating that China's coal-fired power plants have a significant potential to mitigate CO₂ emissions through technological improvement. In the second stage of the study, a Tobit regression analysis was conducted to identify the determinants of TE. Factors such as the plant's annual operation rate and capacity utilization rate were found to be significant influences. Based on our results, we propose that the Chinese government create a power distribution structure that generates electricity using technologically efficient equipment in areas rich in coal resources and distributes the generated electricity to other areas of the country.

The influence of physical exercise on college students' mental health and social adaptability from the cognitive perspective

BACKGROUND

the relationship between physical exercise (PE) and mental health (MH) had been an important research topic in exercise psychology. With the development of society, the increasingly fierce social competition had put forward higher and higher requirements for college students' social adaptability (SA). As members of the new era, college students were expected to not only have innovative knowledge concept, solid knowledge foundation, and healthy psychology, but also have the ability to adapt to the changes in the environment, know how to get along with others, and deal with problems alone.

OBJECTIVE

this study aimed to evaluate the PE, MH, and SA of college students, and to analyze the internal relationships among PE, MH, and SA.

METHODS

based on questionnaire survey, college students were randomly selected for investigation and the data were statistically processed.

RESULTS

there were significant differences in the MH of students of different genders, majors, grades, and origins. There was a significant difference between the amount of exercise and the MH of college students. The amount of exercise was positively correlated with the MH level of college students, and there was also a positive correlation between PE and MH. The SA of the physical exercisers was average, but the SA of the non-physical exercisers was poor. There was a significant difference between the SA of the physical exercisers and the non-physical exercisers. There were significant differences in the SA between physical exercisers and non-physical exercisers of different genders, majors, grades, and origins. Physical exercisers who participated in team sports were more socially adaptable. There was no significant difference in the SA of physical exercisers of different genders, majors, and origins, and the SA of senior students was stronger.

CONCLUSIONS

PE had a positive effect on college students' MH and social adaptation ability. Colleges and universities could improve their MH and social adaptation ability by arranging appropriate PE.

Sustainable Performance Analysis of Power Supply Chain System from the Perspective of Technology and Management

The power industry is an important strategic industry that has effectively advanced the rapid development of China’s economy. However, this rapid development has created significant environmental problems and does not support the sustainable development of the ecological environment and economy. This study evaluated and analyzed the sustainable performance of China’s inter-provincial power supply chain systems (PSCSs), and developed policy recommendations for further developing China’s power industry based on the research results. For PSCSs with internal subsystems, this study first developed a non-radial two-stage model, and proposed steps to solve the model; then, this study applied the proposed model to empirically analyze China’s inter-provincial PSCSs. The empirical analysis yielded the following key research findings. Firstly, for the study period, China’s power industry had a low overall performance, and PSCS performance varied significantly across different regions. Secondly, the average meta-frontier efficiency (ME) of PSCSs in high-income regions was the highest; the average ME of PSCSs in middle-income regions was the lowest. This is consistent with the environmental Kuznets curve hypothesis. Thirdly, this study found that the PSCSs had effective management and technical systems in Qinghai and Guangdong. The PSCSs in other regions need improvements to mitigate either inadequate management, inadequate technology, or both.

Decomposing CO2 emission changes in thermal power sector: A modified production-theoretical approach

Carbon emission from the thermal power generation sector is one of the main contributors to global warming. It is critical to objectively evaluate the influence of relevant factors on carbon emissions, which may be beneficial for the implementation of policies and the formulation of development plans. However, the current decomposition approach based on production-theoretical decomposition analysis (PDA) and weak disposability may cause deviation on potential emission reduction. This paper proposes a modified PDA model under the assumption of semi-disposability and decomposes the carbon emission changes of China's thermal power generation sector accordingly. The results show that provinces, which have the highest non-disposal degrees during the study period, are mostly located along the east coast of China. The growth in installed capacity is identified as the largest contributor to the increase in national carbon emissions, while the decrease in capacity utilization rate significantly benefits the carbon emission reduction. A cluster analysis is also conducted to give policy implications for provinces with similar characteristics. Compared with traditional methods under strong and weak disposability assumption, the proposed model shows great advantages in identifying the potential emission reduction and reflecting the real production process, which makes it more suitable for decomposing the changes of carbon emissions and other environmental pollutants.

Dynamic environmental efficiency analysis of China's power generation enterprises: a game cross-Malmquist index approach

Since the power unbundling reform in 2002, China's power industry has been a typical sector moving towards marketization. The supply-side structural reform that began in 2015 has intensified the competition among China's power generation enterprises. In this context, this paper combines a data envelopment analysis (DEA) game cross-efficiency model with the Malmquist index approach to investigate the dynamic environmental efficiency of China's power generation enterprises in a competitive market. Furthermore, the system generalized method of moments (SYS-GMM) is employed to analyze the influences of factors on the dynamic environmental efficiency. The results show that: (1) Compared with the basic DEA Charnes-Cooper-Rhodes (CCR)-Malmquist index model, the DEA game cross-Malmquist index approach can enhance the discrimination among the decision making units (DMUs). (2) The change in the overall dynamic environmental efficiency of China's power generation enterprises mainly comes from the catch-up effect, while technological progress has not played a role as significant as expected. (3) The installed capacity growth rate, implementation of carbon emission trading pilots, economic growth rate, and enterprise ownership all affect the dynamic environmental performance of China's power generation enterprises during the study period.