A more efficient use of China’s coal resources is key to rapidly promoting the growth of the country’s industrializing economy. As such, it is essential that an effective approach for measuring and ...evaluating the current efficiency of coal resources is developed. This paper measures the efficiency of coal resources in 30 provinces in China from 2000 to 2015 using an improved DEA model of Bootstrap, and it uses Tobit regression to analyze the influencing factors on the efficiency of coal resources. The results illustrate that: 1) The proposed approach could significantly improve upon the accuracy of the measurement of the traditional DEA model. 2) The efficiency of coal resources shows an uptrend of fluctuation for the research period. With respect to the influential factors, total coal consumption has the least influence on the efficiency of coal resources. In contrast, local financial science and technology expenditures have greatest influence on the efficiency of coal resources. Among all the influential factors, local financial science and technology expenditures have the greatest negative impact on energy efficiency of coal resources and it is very critical that the government increases investment in scientific and technological investment in the mining industry.
•This paper uses Bootstrap-DEA to calculate the ECR of 30 provinces in China.•The finding that FST has negative impact on ECR is the most serious, particularly for 14 provinces in China.•GDP, IPC and SEC have negative impacts on ECR in 8 provinces.•COC has negative impact on ECR in 6 provinces.•TER and RPY have negative impacts on ECR including in 11 provinces and 9 provinces respectively.
This study investigates the effect of green-bond financing on energy efficiency investment for green economic recovery. The fuzzy Analytic Hierarchy Process (AHP) technique was used to achieve the ...research objective. The study’s findings showed that green bonds are currently the primary financing source for energy efficiency projects, enhancing economic growth by 4.9% and potentially increasing green economic recovery by approximately 17% per annum. The fuzzy analysis technique and alternative models of fuzzy modeling were applied in this study. An alternative to project-based financing is energy performance contracts (EPCs). Green bonds also invest in public and private funds for energy efficiency and economic growth. Alternatively, such bonds may finance environmental initiatives or companies. Testing energy-efficiency projects with low payback rates may be expensive. Expanding the green economy through green bonds is essential for financing to successfully promote energy efficiency finance and green growth. This study also has policy implications for stakeholders.
Information and communication technology supported by the internet has become an important driving force that promotes the intelligent development of environmental governance in China. Using Chinese ...provincial panel data for the period 2006–2017, this study investigates whether the internet has improved China's green total factor energy efficiency (GTFEE) using a dynamic spatial Durbin model, mediation effect model and dynamic threshold panel model. The empirical results indicate that the GTFEE has a significant positive spatial correlation. Internet development can not only directly improve local GTFEE but also improve GTFEE in neighboring regions. After accounting for potential endogeneity, this conclusion is still valid. Meanwhile, internet development can indirectly improve regional GTFEE by reducing the degree of resource mismatch while enhancing GTFEE by improving regional innovation capabilities and promoting industrial structure upgrades. In addition, the regression results of the dynamic threshold model show that there is a nonlinear relationship between the influence of the internet development and GTFEE. Specifically, due to an increase in the degree of labor resource mismatch and capital resource mismatch, the impact of the internet on GTFEE has gradually decreased, and this effect has gradually increased with the improvement of regional innovation capabilities and the industrial structure.
•Green total factor energy efficiency (GTFEE) of 30 provinces in China is estimated.•Influence of internet development on GTFEE efficiency is quantitatively investigated.•A spatial-Durbin model that accounts for potential spatial spillover effects is employed.•Internet development can significantly improve GTFEE, but the relationship is nonlinear.•Resource mismatch, technological innovation and industrial upgrading may affect GTFEE.
The application of a two-phase ejector allows for the mixing of liquid and gas and provides effective heat transfer between phases. The aim of the study is a numerical investigation of the ...performance of a water-driven, condensing two-phase ejector. The research was performed using CFD methods, which can provide an opportunity to analyze this complex phenomenon in 2D or 3D. The 2D axisymmetric model was developed using CFD software Siemens StarCCM+ 2022.1.1. The Reynolds-Averaged Navier–Stokes (RANS) approach with the Realisable k-ε turbulence model was applied. The multiphase flow was calculated using the mixture model. The boiling/condensation model, where the condensation rate is limited by thermal diffusion, was applied to take into account direct contact condensation. Based on the mass balance calculations and developed pressure and steam volume fraction distributions, the ejector performance was analyzed for various boundary conditions. The influence of the suction pressure (range between 0.812 and 0.90) and the steam mass flow rate (range between 10 g/s and 25 g/s) is presented to investigate the steam condensation phenomenon inside the ejector condenser. The provided mixture of inert gas (COsub.2) with steam (Hsub.2O) in the ejector condenser was investigated also. The weakening of the steam condensation process by adding COsub.2 gas was observed, but it is still possible to achieve effective condensation despite the presence of inert gas.
Despite strong political efforts in Europe, industrial small- and medium-sized enterprises (SMEs) seem to neglect adopting practices for energy efficiency. By taking a cultural perspective, this ...study investigated what drives the establishment of energy efficiency and corresponding practices in SMEs. Based on 10 ethnographic case studies and a quantitative survey among 500 manufacturing SMEs, the results indicate the importance of everyday employee behavior in achieving energy savings. The studied enterprises value behavior-related measures as similarly important as technical measures. Raising awareness for energy issues within the organization, therefore, constitutes an essential leadership task that is oftentimes perceived as challenging and frustrating. It was concluded that the embedding of energy efficiency in corporate strategy, the use of a broad spectrum of different practices, and the empowerment and involvement of employees serve as major drivers in establishing energy efficiency within SMEs. Moreover, the findings reveal institutional influences on shaping the meanings of energy efficiency for the SMEs by raising attention for energy efficiency in the enterprises and making energy efficiency decisions more likely. The main contribution of the paper is to offer an alternative perspective on energy efficiency in SMEs beyond the mere adoption of energy-efficient technology.
The traditional estimation methods tend to result in biased energy efficiency estimates due to the exclusion of heterogeneous production technology. Taking this factor into account, this study uses ...the metafrontier method combined with the stochastic frontier analysis (SFA) to analyze energy efficiency performance of the industrial sectors in China’s 30 provinces during 1997–2016. This study measures energy efficiency by considering the technological gap that can be regarded as a discrete source of energy inefficiency. Different from the traditional classification of different regions in China, we divide regions into three groups by using the cluster analysis based on the indicator of energy intensity. The empirical results are summarized as follows: first, the traditional pooled estimation method, which ignores the technological gap of the industrial sectors among different regions, tends to overestimate energy efficiency performance; second, energy efficiency and technological gap ratios (TGRs) of the industrial sectors are distinct among China’s regions; and the industrial sectors of the eastern region maintained higher energy efficiency and TGRs due to more advanced production technology; third, in general, the average score of industrial energy efficiency of China was only 0.4396, implying that there’s still plenty of room for energy efficiency improvement.
•Applying SFA method with metafrontier to analyze industrial energy efficiency.•Considering technological heterogeneity in energy efficiency measurement.•The traditional pooled estimation tends to overestimate energy efficiency.•Regional differences exist in industrial energy efficiency and TGRs.
Dielectric materials with high power density, fast charge and discharge rates, and high energy-storage density are urgently required due to the rapid development of hybrid vehicles and pulse power ...boosting technology. In this work, the novel environment-friendly (1-x)(Ba0.8Sr0.2)TiO3-xBi(Zn2/3Nb1/3)O3 (0.04 ≤ x ≤ 0.16) (1-x)BST-xBZN ceramics were designed and synthesized by traditional solid-state reaction method, exhibiting ultrahigh energy efficiency and super stability against temperature. The results show that the recoverable energy density (Wrec) and the energy efficiency (η) of the (1-x)BST-xBZN ceramics are increase sharply then decrease slightly with increasing of x value. The 0.88BST-0.12BZN ceramic demonstrated a recoverable energy density of ≈ 1.62 J/cm3 and an extreme high energy efficiency of ∼ 99.8 % at 225 kV/cm at room temperature. These extreme high efficiency and high breakdown strength would make (Ba,Sr)TiO3-based lead-free ceramic systems might be good candidate for high power energy-storage applications pulsed power systems.
The household sector is one of the most energy-intensive sectors in Europe, and thus a focal point for reducing greenhouse gas emissions associated with energy consumption. Energy efficiency is ...considered a key measure to reduce household energy consumption, but several factors could lead to an underinvestment in energy efficiency. This is the so-called energy efficiency gap or paradox. The factors in question are grouped under market failures (including informational failures), behavioural failures and other factors. Various policies can be used to address these failures and promote the adoption of energy-efficient technologies, including energy standards and codes, economic incentives and information instruments. This paper reviews the empirical evidence to date on energy efficiency policies and discusses their effectiveness. On the one hand, command and control instruments seem to be effective policies, but they have to overcome several barriers. In the case of price instruments, subsidies and taxes do not seem to be effective while rebates present mixed results as they sometimes are effective and in other cases, they could present significant shortcomings. Finally, the effectiveness of informational policies is not always ensured as they depend on the country, sector and product category. Information feedback tools also seem to be effective as they work as a constant reminder of energy-efficient behaviour. Some limitations of energy efficiency policies are also identified, such as the difficulties of implementing codes and standards given that a minimum level need to be achieved, differences in the effectiveness of rebate programmes and non-conclusive results in regard to the effectiveness of monetary energy efficiency labels.
Considering the flexibility and adjustability value of integrated energy system (IES) with flexible energy units and multivariate adjustable load in urban energy market, this paper proposes a ...two-stage energy management method of heat-electricity integrated energy system (HE-IES) considering dynamic pricing of Stackelberg game and operation strategy optimization. Firstly, a general comprehensive energy efficiency considering the exergy properties of electric and thermal energy is established, on this basis, this paper put forward a two-stage energy management framework considering interactive relationship between energy service provider (ESP) and users. Secondly, a two-stage energy management model is established to improve the energy efficiency and operation economy of the system, which includes the multi-objective optimization model of day-ahead scheduling and Stackelberg game dynamic pricing model of real-time energy management based on the source-load interaction optimization for hybrid energy. Finally, in order to illustrate the effectiveness of the proposed energy management method in improving system energy efficiency and operation strategy, a typical HE-IES consisting of 6 users and 1 ESP is chosen to simulation. The simulation results demonstrate that the proposed approach can not only enhance renewable energy utilization and reduce the cost of both ESP and users, but helpful to promote the benign interaction between energy equipment and load in IES, which could improve the energy efficiency of system operation.
•The Hybrid energy conversion framework of integrated energy system is established.•A two-stage energy management model is constructed.•In the first stage, IES operation optimization based on economy and energy efficiency is implemented.•In the second stage, optimization strategy of users participating in game optimization guided by ESP is implemented.
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