DEA Evaluation Model Research Articles

The impact of environmental regulation on green investment efficiency of thermal power enterprises in China-based on a three-stage exogenous variable model

Due to the increased frequency of extreme weather events and the implementation of the China’s dual-carbon target, thermal power companies have been under pressure to construct green infrastructure and to actively pursue low-carbon transformation in response to stricter environmental regulations. This research thus selects 30 listed thermal power enterprises in China as study objects and assesses their green investment efficiency in the low-carbon transition process using three-stage DEA evaluation model with environmental regulation as an exogenous variable. Based on this, a benchmark regression model is used to corroborate the relationship between environmental regulation and green investment. Simultaneously, we carry out analysis to compare the correlation between thermal power firms’ green investment efficiency and their focus on green investments. The results show in terms of total efficiency that environmental regulation significantly improves the total efficiency of 80% of thermal power enterprises compared to the absence of this exogenous variable. With the addition of environmental regulation, firms’ total efficiency declines gradually in general from 2018 to 2022, with the mean value of efficiency falling by 0.068. In terms of stage-specific efficiency, the efficiency of the green investment stage of the majority of firms is between 0.3 and 0.6, which is much lower than that of the operational stage and the market performance stage. In terms of sub-indicator efficiency, both green investment efficiency and social donation efficiency among thermal power enterprises show obvious polarization, with 30% of them having an efficiency of 1 and 30% less than 0.1. In terms of green investment focus, thermal power unit renovation has a more obvious role in boosting the green investment efficiency of thermal power enterprises than do wind power and photovoltaic projects. Therefore, both governmental departments and thermal power enterprises need to take active measures in order to achieve green transformation from the perspective of green investment efficiency. Through the segmentation of important projects of green investment, this paper provides a reasonable investment direction reference for the sustainable transformation of China’s thermal power industry. It also provides a rich and novel theoretical basis for the Chinese government to further improve the relevant environmental protection laws and regulations of thermal power industry.

Operation Efficiency Evaluation of the China-Europe Freight Train Based on Grey Cross-Efficiency DEA

The China-Europe Freight Train (CEFT) serves as an important carrier and platform for international economic cooperation and international trade circulation between China and Europe. Since it worked, its actual operation and development have been affected by many factors, but the level of its actual operating efficiency and the main affecting factors of CEFT have been difficult to find, which has severely limited its sustainable development. Therefore, this paper scientifically selected the operation efficiency evaluation indicator system of CEFT and combined grey system theory, cross-efficiency method, and DEA to construct a new DEA evaluation model based on grey cross-efficiency, which can not only overcome the problem of ignoring the relative importance ratings of the evaluation indicator in the general DEA evaluation model and the traditional cross-efficiency DEA evaluation model but also more accurately evaluate the actual operation efficiency of CEFT. At the same time, based on the actual operating data of CEFT from 2011 to 2018 and the above new evaluation models, the CEFT’s operation efficiency was evaluated and tested by examples, showing that on the one hand, the grey cross-efficiency DEA evaluation model can more accurately evaluate the actual operation efficiency of CEFT than other traditional evaluation models; on the other hand, it is found that the “overseas cities,” “operating lines,” and “entry-exit nodes” are currently the main factors that limit the actual operation efficiency of CEFT and indicating improvement direction for the future efficient and sustainable development of CEFT.

Effect of biodiesel ester structure optimization on low temperature performance and oxidation stability

The main shortcomings of biodiesel are related to the low-temperature performance and oxidation stability. Hence, this study proposes to investigate the influence of the oleic acid-based esters with various linear and branched chain alcohols on these two properties of biodiesel. The economic impact of biodiesel with various compositions is also evaluated by means of a mathematical model. The results showed that the longer the carbon chain length of the alcohol component, the better the low-temperature performance of the biodiesel. Hence, the cold filter plugging point and solidifying point of methyl oleate were −19 and −24°C, respectively, whereas the cold filter plugging point and solidifying point of amyl oleate were −36 and −41°C, respectively. The more irregular the molecular structure, the better the low-temperature performance of oleic acid-based lipids. For instance, the condensate point and solidifying point of oleic acid-based esters with branched chain alcohols should be lower than oleic acid-based esters with linear chain alcohols. On the other hand, for the linear esters of oleic acid, the oxidation stability is better as the carbon chain is longer. For instance, the induction period of methyl oleate is 0.07h while for amyl oleate, it is 0.36h, which corresponds to an increase of about 5 times. For the branched esters, although they are sensitive to oxidation, the induction period is higher than that of methyl oleate. Finally, the DEA evaluation model was used to analyze the economic aspects of the resulted biodiesel. The results showed that the addition of ethyl oleate to biodiesel significantly improved the low-temperature performance and oxidation stability of biodiesel with good economic benefits.

Analysis of Interval Data Envelopment Efficiency Model Considering Different Distribution Characteristics—Based on Environmental Performance Evaluation of the Manufacturing Industry

This study utilizes the Data Envelopment Efficiency (DEA) model to assess input–output efficiency from two perspectives. First, not considering the distribution of interval data, we introduce an adjusted parameter to transform interval data to determination data. Second, by contrast, we take into account the distribution characteristics of interval data and test the DEA model with interval data based on linear uniform distribution and normal distribution with uncertainty. Based on the normal distribution DEA evaluation model, this paper aims to evaluate the input–output performance of the manufacturing industry with the constraint of environmental pollution in the Yangtze River Delta (YRD) region, China. Research has shown that the optimal solution of the normal distribution model is better than that of linear distribution. Therefore, it is imperative to adopt an appropriate method to evaluate the energy and environmental efficiency of this region.

On Enterprise Operation Efficiency and Strategic Research Based on Super-efficient DEA

With the rapid development of China's electric power market today, the national provincial electric power companies, which are under the background of the principal-agent framework management, have become the main development pillars of the national electric power companies. These companies are responsible for many important businesses such as electric power market exploitation, power grid construction, electric power operation mode transformation, etc., and they are relatively independent management subject. How to evaluate the performance of provincial companies is always a focus point of the management of the national electric power company. The author tries to improve the C2R evaluation model of the DEA method and construct the super-efficient DEA evaluation model, in order to solve the problem that the sorting and selecting decision cannot be made when there are more than one effective decision unit, furthermore, to apply it to evaluate the operation efficiency of provincial companies and propose measures to improve business performance. The author hopes this can provide good ways of improving the reformation of electric power companies marketization in their reformation process.