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As the penetration of distributed renewable energy gradually increases, prosumer groups in high-altitude areas are being expanded. However, the operation of these prosumers in high-altitude areas faces numerous challenges. To address the issue, this paper proposes a double layer energy cooperation framework for high-altitude prosumer groups, considers peer aggregation and shared composite energy storage, aims to adapt to the trend of diversified energy interactions and improve the economic efficiency, maximize social welfare and ensure the continuous growth of the sharing market of prosumers operations in high altitude areas. To meet the diversified energy interaction needs of prosumers, a composite energy storage provider, an energy aggregator, and a two-stage profit clearing scheme are proposed. Furthermore, the overall benefits of the framework and the impact of profit clearing schemes on fairness under various scenarios are studied, and the comprehensive effects of the double layer energy framework are evaluated. The study results show that compared to independent operation by prosumers, under the guidance of shared electricity prices and composite energy storage providers, the economic benefits, evaluation indicators and energy storage utilization efficiency have all been improved. In addition, compared to other profit distribution modes, the two-stage profit clearing scheme proposed in this paper has higher fairness, which greatly encourages the participation of interested entities in energy cooperation. This study provides a feasible framework for energy cooperation among prosumers, and the framework's effectiveness is well-validated. [Display omitted] [ABSTRACT FROM AUTHOR]

The increasing demand for renewable energy sources has led to the development of HRES that combine multiple sources of renewable energy to provide a reliable and efficient energy supply. However, renewable energy sources typically come with higher costs than conventional energy production methods. Hence, the optimal sizing of HRES is essential to prevent the oversizing of the system while ensuring a reliable supply of load demand, accommodating variations in meteorological conditions and changes in power demand. Numerous research papers addressing the optimal sizing problem are available in the literature. However, none of the mentioned studies take into account the power degradation of all renewable sources. The degradation of renewable sources, such as PV and WT, can have a significant impact on the performance of HRES. The degradation of PV panels can result in reduced efficiency and output, leading to a decrease in the overall energy production of the HRES. Similarly, WT may experience wear and tear over time, leading to reduced performance and output. The reduction in the output of renewables in the standalone system causes an increase in the loss of power supply probability (LPSP). This paper analyzes the optimal sizing of the HRES, considering the degradation of the sources. Further, analysis has also been carried out based on the number of BESS to be added to HRES to meet the derived constraints and their impact on the cost of energy as well. [Display omitted] [ABSTRACT FROM AUTHOR]

The increasing demand for renewable energy sources has led to the development of HRES that combine multiple sources of renewable energy to provide a reliable and efficient energy supply. However, renewable energy sources typically come with higher costs than conventional energy production methods. Hence, the optimal sizing of HRES is essential to prevent the oversizing of the system while ensuring a reliable supply of load demand, accommodating variations in meteorological conditions and changes in power demand. Numerous research papers addressing the optimal sizing problem are available in the literature. However, none of the mentioned studies take into account the power degradation of all renewable sources. The degradation of renewable sources, such as PV and WT, can have a significant impact on the performance of HRES. The degradation of PV panels can result in reduced efficiency and output, leading to a decrease in the overall energy production of the HRES. Similarly, WT may experience wear and tear over time, leading to reduced performance and output. The reduction in the output of renewables in the standalone system causes an increase in the loss of power supply probability (LPSP). This paper analyzes the optimal sizing of the HRES, considering the degradation of the sources. Further, analysis has also been carried out based on the number of BESS to be added to HRES to meet the derived constraints and their impact on the cost of energy as well. [Display omitted] [ABSTRACT FROM AUTHOR]

Innovation and adaptation of renewable energy technologies significantly reduce carbon dioxide (CO2) emissions and increase energy efficiency. Understanding the convergence patterns in renewable energy innovation will enable policymakers to design policies to increase energy efficiency and renewable energy consumption and reduce CO2 emissions. This paper applies the convergence algorithm proposed by Philips and Sul to assess the convergence in renewable energy innovation for 90 countries covering the period between 1993 and 2018. This paper also examines the determinants/factors driving the convergence clubs of the countries using Probit and Logit regression. The convergence analyses suggest that there is no global convergence in renewable energy innovation. Findings highlight two convergence clubs: i) a club comprising more innovative countries and ii) another club that includes less innovative countries. We find that countries with higher income per capita, CO2 emissions per capita, research and development (R&D) investment, better environmental regulations and stronger institutional settings are more likely to be part of the innovative club. Countries should increase their R&D investment and environmental regulations and improve their institutional quality to increase their likelihood of belonging to a more innovative club. Furthermore, less innovative countries could promote policies to transfer renewable energy technologies from innovative countries. [ABSTRACT FROM AUTHOR]

Multi-energy complementary technology is meaningful for promoting the development of solar energy utilization, and the main novelty of this paper is the proposal of a novel linear Fresnel reflector solar-gas combined (LSGC) system which utilizes the organic Rankine cycle driven proton exchange membrane hydrogen production (PEM-HP) subsystem as well as is designed for generating electricity and hydrogen. By using the Ebsilon, the operation performance and exergy analyses of the LSGC system are launched. The results show that the output power and electric efficiency of the LSGC system are 424.8 MW and 45.4%. The solar field contributes a power of 34 MW. The hydrogen production rate of the LSGC system is 182.88 kg/day. The solar field, GTCC and PEM-HP section can reach the coordinated operation effectively during a long term, revealing the technical feasibility of the LSGC system. The exergy analysis results indicate that the solar field has the second maximum exergy destruction and the smallest exergy efficiency, and the combustion chamber has the maximum exergy destruction. The economic analysis shows that the levelized costs of electricity and hydrogen of the LSGC system are 0.045 $/kWh and 5.67 $/kg. The environment effect evaluation shows that compared with the coal power, the LSGC system can reduce the annual emissions of CO 2 , NO x , SO 2 and dust effectively. Those reveal relatively acceptable economic feasibility and environment protection effect of the LSGC system. [ABSTRACT FROM AUTHOR]

Organic Rankine cycle (ORC) is used for geothermal power generation, and other two derived cycle configurations, parallel double-stage organic Rankine cycle (PDORC) and organic Rankine flash cycle (ORFC), have been proposed to improve the geothermal power generation performance. However, no experimental comparison have been done before. An experimental device that can switch between three cycles was designed and constructed to compare the power generation performance of three cycles. The operational performance of the three cycles at different heat source and heat sink temperatures are analyzed in this paper. The results show that under the heat source temperature of 90 °C and heat sink temperature of 15 °C, the output power of ORFC is 876.59 W, which is higher than that of the PDORC and ORFC. Moreover, the exergetic efficiency is greater than other two cycles due to the smallest irreversible loss of ORFC. The exergetic efficiencies of the ORC, PDORC and ORFC are 31.87 %, 31.32 % and 34.79 %, respectively. The increase of heat sink temperature is beneficial for the isentropic efficiency of the expander, but not conducive to power generation performance and energy utilization. PDORC and ORFC promote the effective utilization of heat source, outputting more power but with a lower efficiency. [ABSTRACT FROM AUTHOR]

Full utilization of the potential regulation ability of flexible loads in an integrated energy system (IES) and expanding its structure for more flexibility via integrating auxiliary devices is the key to realizing its high-efficiency operation and high-proportion renewable consumption. The present paper builds the flexible regulation models of thermal and electrical loads and introduces them to the structure expansion planning of IES. A two-stage stochastic probability optimization method integrating the uncertain operation of introducing flexible loads is then proposed to balance the additional costs of device integration and the benefits of performance promotion. Herein, an enhanced sample average approximation based on a stochastic hierarchy scenario generation method is developed to solve the optimization. The regulation mechanisms of flexible loads and their influence on expansion planning are then analyzed by comparing the optimized results. The results show that the path to decreasing the cost via introducing flexible thermal and electrical loads into optimization is increasing renewable consumption and coordinating an increment in renewable consumption and average electrical efficiency, respectively. The regulation between them has synergism on cost reduction and saturation on increasing renewable consumption. The synergism can reduce the cost by 0.62 %. Besides, there is a synergism between electric boiler integration and flexible loads, which further reduces the total cost of the expanded IES by 24.86 %. [Display omitted] [ABSTRACT FROM AUTHOR]

This paper presents the development of a thermodynamic model for the hydrogen refuelling station (HRS) to simulate the process of refuelling, which involves the transfer of hydrogen gas from a high-pressure storage tank to the onboard tank of a fuel cell electric vehicle (FCEV). This model encompasses the fundamental elements of an HRS, which consists of a storage tank, compressor, piping system, heat exchanger, and an on-board vehicle tank. The model is implemented and validated using experimental data from SAE J2601. Various simulations are conducted to assess the impact of the Joule-Thomson effect and compression on the temperature of hydrogen flow, specifically focusing on an average pressure rate of 18 MPa/min. Furthermore, a comprehensive analysis is conducted to examine the impact of pressure variations in the storage tank (10–90 MPa) and the initial pressure within the vehicle tank (5–35 MPa), as well as variations in ambient temperature (0–40 °C). The study revealed that the energy consumption in the cooling system surpasses the average power consumption in the more advantageous scenario of 60 MPa by a range of 36% to over 220% when the pressure in the storage system drops below 30 MPa. Furthermore, it was noted that the impact of ambient temperature is comparatively less significant when compared to the initial pressure of the vehicle's tank. The impact of an ambient temperature change of 10 °C on the final temperature of a hydrogen vehicle is found to be approximately 2 °C. Similarly, a variation in the initial vehicle pressure of 10 MPa results in a modification of the final hydrogen vehicle temperature by approximately 8.5 °C. [Display omitted] [ABSTRACT FROM AUTHOR]

Efficient full-spectrum solar energy utilization shows great potential to improve solar energy conversion efficiency. In this paper, a spectral splitting concentrated photovoltaic/thermal hybrid system based on a wave-selecting filter-coated compound parabolic concentrator and linear Fresnel reflector mirror field is developed. Optical models to simulate the linear Fresnel reflector have been developed and validated. With the wave-selecting filter coated compound parabolic concentrator, the visible and near infrared spectra transmit onto the photovoltaic cells, while the rest are reflected to the receiver tube. Furthermore, a simplified receiver indoor test prototype is designed to investigate the characteristic of solar photovoltaic module with the spectral filter in the context of the compound parabolic concentrator. The measured I–V curves are compared with the modeled results. Additionally, the thermodynamic performance of the system is analyzed. Parametric studies are performed to investigate the effect of key design parameters including the mirror width, focal length and the radius of the receiver tube on the solar flux density and the exergy efficiency. An exergy efficiency of 35.51% and an optical efficiency of 94.78% are achieved. With a preliminary techno-economic analysis, the levelized cost of the electricity of the system is $0.209/kWh with a payback period of 10 years. [ABSTRACT FROM AUTHOR]

This paper addresses the critical challenge of sizing hybrid renewable energy systems over their lifespan while accounting for uncertainties in energy sources and load demands. By leveraging stochastic programming, we introduce a novel modeling technique that ensures robust optimization without compromising numerical tractability. Unlike conventional methods, which determine system parameters for the entire project duration upfront, our approach enables annual adjustments to the renewable components' sizing. This dynamic strategy alleviates early-stage under-utilization, aligning system capacity with evolving demand patterns. Central to our approach is the reformulation of the two-stage stochastic program as a quasi-optimal control. This reduces the number of optimization variables significantly, simplifying the solution process. Moreover, thousands of constraints are replaced with a system of differential equations, enhancing computational efficiency. By minimizing capital costs and dynamic operating expenses, we achieve an optimal system size. Through a real-world application in a rural area of South Africa, we demonstrate the effectiveness of our approach. The results showed a remarkable improvement in problem-solving efficiency, reduced under-utilization, and heightened adaptability to unpredictable weather conditions. This innovative framework represents a substantial leap forward in hybrid renewable energy systems design, offering a more agile and efficient solution for sustainable energy generation. [ABSTRACT FROM AUTHOR]

Energy is one of the essential components for the social and economic growth of urban and rural communities worldwide. However, the lack of energy supply is one of the most significant challenges facing remote or local communities in Nigeria. Distributed generation systems based on renewable energy, conventional sources, or hybrid resources are possible energy production solutions for these communities. This paper, therefore, focused on providing an energy generation system based on photovoltaics (PV) and diesel generators (DG) for stand-alone applications. A comparative analysis was carried out to assess the impact of control strategies, namely load following (LF), cycle charging (CC), and combined dispatch (CD). The designed energy systems: 60 kW PV, 78.69 kW PV, PV-DG-LF, PV-DG-CC, and PV-DG-CD were simulated using HOMER Pro while technical, economic, and environmental indices were used as performance metrics. Simulation results showed that 60 kW PV generated 84,927 and 75,859 kWh, without and with temperature effect, respectively, with the corresponding unmet electric load (UEL) of 13.8 and 14.2%. The result further demonstrated that PV-DG-LF is the optimal design with the highest renewable penetration of 80.7% and the least annual total fuel consumption (TFC) of 6,594 l. The economic results further confirm the suitability of PV-DG-LF with the lowest fuel cost (FC) and moderate cost of energy (COE) of $219,934 and 0.302 $/kWh, respectively. The PV-DG-LF is found to be more environmentally friendly, with the least annual CO 2 emission of 16,629.652 kg. The study considers veritable strategies to achieve affordable, clean, and reliable energy in line with research efforts on realizing the sustainable development goal (SDG) 7. [ABSTRACT FROM AUTHOR]

The proliferation of charging stations entails multiple challenges for power systems. In this regard, the installation of photovoltaic-battery systems may help to mitigate the negative effects of charging points. However, such assets should be carefully planned, paying attention to economic aspects, principally. Most of existing works optimize the photovoltaic-battery system in charging infrastructures taking a representative-space of the involved variables (e.g. photovoltaic potential, charging demand or energy prices). However, this approach tends to ignore low-probable scenarios. Thus, the best-case scenario for charging demand (i.e. that for which the highest charging profit is accessible) may not be included in the analysis and therefore such demand could be not attended properly, thus losing this monetary opportunity. This paper focuses on this issue and questions if considering the best-case scenario into planning photovoltaic-battery systems for charging stations is worthwhile or not. To this end, a novel best-case-aware planning tool is developed, including the best-case scenario through a novel chance-constrained formulation. The overall problem is then decomposed into a master-slave structure by which the economy of the system is optimized together with the number of scenarios for which the best-case profile can be attended. A case study serves to validate the developed tool and shed light on the questions arisen in this work. In particular, it is checked that considering the best-case scenario into planning tools is questionable from a monetary point of view. Nevertheless, its inclusion unlocks some collateral advantages such as incrementing the users' satisfaction or reducing the grid-dependency. [ABSTRACT FROM AUTHOR]

With the growing share of the climate-sensitive renewable energy market supply in China, estimating future energy drought risk (ED) is essential. In this paper, based on CMIP6, energy demand and power generation are estimated from 2023 to 2100 under SSP2-4.5 and SSP5-8.5 climate scenarios, and ED is defined from high demand (HD), low wind-solar generation (LWS), and residual load (RL). The results show that the ED exacerbation is relatively high under the SSP5-8.5. Between 2023 and 2100, the duration and severity of HD and RL notably increase, while LWS changes are relatively weak. We find that HD and RL exhibit high summer risks in the south and high winter risk in the north. The return periods vary significantly and extends over time in most regions. Moreover, there are few ED when the installed power generation capacity (IPGC) is increased. When the IPGC increases by 2%–5%, the LWS will decrease at least 20%–72%. With a 10% increase, the LWS will be mitigated by at least 80%, whereas the mitigation for RL is limited, approximately 3–17% at different rates. This work performs the first evaluation of future ED and provides the useful references for risk mitigation in China based on CMIP6. [ABSTRACT FROM AUTHOR]

The aim of this paper is to analyze through simulation how the energy efficiency of a single electrolysis stack at various loads is affected by shunt currents and to determine the energy-optimal load distribution between lines in a multiline electrolysis system under various magnitudes of shunt current losses. A dynamic energy and mass balance model of an industrial 3 MW , 16 bar alkaline water electrolyzer (AWE) process was developed using MATLAB. The optimization goal is to determine the power supply for each AWE line so that it can meet any hydrogen demand while minimizing the global specific energy consumption (SEC). The Particle Swarm Optimization (PSO) algorithm is used to minimize the objective function. According to the results of the single stack investigation, shunt current reduction could significantly improve the energy efficiency of partial-load operation. In addition, the optimization study revealed that whenever two or more lines are required to run in order to satisfy the hydrogen demand, the global SEC is minimized when the lines operate at equal loads. [ABSTRACT FROM AUTHOR]

The hydrogen compressor is a key component in the refuelling station. As one type of hydrogen compressor, the ionic compressor applied in the refuelling station is essentially a liquid piston compressor. The structure and operating condition would significantly influence the system efficiency of the liquid piston compressor. This paper investigated the impact of three key operating factors on the compressor performance of a novel embedded two-piston compressor, based on which the optimal operating values were identified by the Taguchi method when the hydrogen was compressed from 12 to 45 MPa. It was revealed that the movement time ratio of Piston A was the dominating factor for the power consumption and specific consumption while the upward time ratio of Piston B was the most influential parameter for the mass delivered. The optimal combination was 0.4 for the movement time ratio of Piston A, 0.45 for the upward time ratio of Piston A and 0.5 for the upward time ratio of Piston B. Under the predicted optimal operating conditions, the lowest specific energy consumption was obtained as 2733.75 kJ/kg. [ABSTRACT FROM AUTHOR]

In this study, the optimization of a multisource hybrid photovoltaic (PV)/Wind/Diesel/Fuel cell (FC) system is performed to meet three realistic loads demand for heavy, medium and small activities observed at Figuil, Cameroon. This paper also examines and compares the techno-economic viability of an off-grid hybrid PV/Wind/Diesel/FC, PV/Diesel/FC and Wind/Diesel/FC systems in terms of net present cost (NPC), cost of energy (COE) and environmental emissions. The effectiveness of different evolutionary algorithms employed in the designing problem of the various hybrid systems is also investigated. The results revealed that, for maximum loss of power supply probability (LPSP) of 5% and minimum renewable energy fraction of 85%, the PV/Wind/Diesel/FC system is economically the best choice for supplying the three types of non-domestic loads demand with corresponding NPC, COE and LPSP values of 159319.4$, 1.087$/kWh and 0.0397 for heavy activity; 150185.8$, 1.753$/kWh and 0.0411 for medium activity; and 144588.0$, 2.384$/kWh and 0.0288 for small activity, respectively. The results also demonstrated that, in terms of pollution emissions minimization, the PV/Wind/Diesel/FC configuration is a preferable option, with an overall yearly CO 2 emissions of 2946.1 kg, 2043.6 kg and 1504.2 kg corresponding to an annual total fuel consumption of 1115.9L, 774.1L and 569.8L for heavy, medium and small activities, respectively. [ABSTRACT FROM AUTHOR]

Geothermal energy plays a significant role in meeting the energy demand and achieving the decarbonization transition. To break through the technology bottleneck of traditional EGS and guide large-scale and efficient exploitation of hot dry rock (HDR) geothermal, this paper performed hydraulic fracturing simulation experiments with real fractured-subsequently-filled HDR formation rocks focusing on the effects of confining stress and temperature on breakdown pressure, fracture pattern and fracture permeability. Results indicated that a higher temperature and a lower confining pressure resulted in a smaller breakdown pressure and a larger fracture permeability. Additionally, the hydraulic fractures always propagate along the backfill, which is independent of temperature and stress conditions. Finally, based on the structural characteristics of natural deep HDR mass and the research results, the Filled Fracture - based Enhanced Geothermal System (FF-EGS) was proposed for fractured-subsequently-filled HDR geothermal mining. FF-EGS is a disruptive breakthrough in the field of HDR geothermal development technology. The results are expected to provide theoretical guidance and technical support for large-scale, efficient and low-cost construction of high-permeability HDR reservoirs, and also provides the possibility for large-scale commercial utilization of HDR geothermal resources. [ABSTRACT FROM AUTHOR]

In this era of global warming the importance of climate risk cannot be understated, and finding ways to reduce climate risk is a topic worthy of study. In this paper, we innovatively examine the role of renewable energy technology innovation on climate risk in China. In addition to their linear relationship, we also investigate the asymmetric and heterogeneous impact, detect the impact channels, and find that (1) increased renewable energy technology innovation can effectively alleviate the climate risk situation. Accordingly, the development of renewable energy technology innovation can make a significant contribution to CR abatement. (2) Pronounced impacts of renewable energy technology innovation on climate risk can be observed in the higher quantiles (75th and 90th) of climate risk. (3) Renewable energy technology innovation is a powerful weapon for eradicating climate risk in provinces with a higher level of government fiscal expenditure. And (4) renewable energy technology innovation has an impact on climate risk by facilitating energy consumption efficiency, which is a necessary mediator. These conclusions inspire us to put forward several corresponding policy implications for better climate risk governance and renewable energy technology innovation development. [ABSTRACT FROM AUTHOR]

To achieve the goal of "carbon peaking and carbon neutrality", China is vigorously developing renewable energy. This paper aims to examine the major contributors to regional inequality in renewable energy consumption by analyzing the 30 provinces in China. We have analyzed the inequality of China's renewable energy consumption with Dagum Gini coefficient, and then use the Generalized Divisia Index Model (GDIM) to decompose the influencing factors contributing to the inequality of renewable energy consumption. The main conclusions are summarized as follows: First, renewable energy consumption was higher in the western region than in the central and eastern regions, and the regional inequality in renewable energy consumption have increased over time. Second, the study reveals that inter-group disparity is the primary source of regional inequality in renewable energy consumption in China. Third, at the national level, the results of the GDIM decomposition show that economic development continues to rely on fossil energy consumption, which negatively impacts the low-carbon transition of energy. Given China's complex geographical conditions, it is crucial for different provinces to develop their own strategies for renewable energy development, taking into account unique resources and challenges. [ABSTRACT FROM AUTHOR]

Data analysis is one of the most important tools that can contribute to unveiling critical relationships. Econometric approaches are evolving continuously, while older methods although are not completely abandoned, they may be used vis-à-vis the new ones for comparison purposed. This special issue has called for papers that have used novel research methods in a panel data framework for the studying and modelling renewable energy use and management. This special issue is useful for readers because it provides them an overview of the those novel methodologies employed in the field of renewable energy economics and econometrics. [ABSTRACT FROM AUTHOR]

In this paper, a CdTe photovoltaic double-skin ventilated window integrated with vacuum glazing (VPV-DSV) is proposed. The mathematical model of VPV-DSV was developed and validated through tests in Hefei, China. Annual energy performance and the economic analysis of the VPV-DSV was evaluated and compared with the other two PV-DSVs and an insulating glazed window (IG) under climate conditions of five selected cities, including Changchun, Hefei, Kunming, Shenzhen, and Shijiazhuang. Moreover, effects of window design factors, including the window-to-wall ratio, PV coverage, and pillar spacing of the VG, were explored. Results indicated that: (1) the VPV-DSV produced the best energy saving results and the least energy consumption. (2) NECs of the VPV-DSV in the five cities above was 955.05 kW•h, 464.31 kW•h, 110.66 kW•h, 53.71 kW•h, and 443.14 kW•h, respectively. (3) Due to high cost of the VG, the VPV-DSV only had the best economic performance in Shenzhen and the NPV was 3931.47 CNY. (4) The WWR and PV coverage had obvious impacts on the overall performance of the VPV-DSV, while the pillar spacing only had a more significant impact on the air conditioning energy consumption. [ABSTRACT FROM AUTHOR]

Sustainable development has many dimensions, such as clean energy, green growth, and sustainable industry. Green finance has a key role in realizing these targets. The core focus of the existing paper is to demystify the influences of green finance, green energy on environmental dynamics in Malaysia covering the timeframe from 1990 to 2018. To this end, we employ the QARDL technique to peruse the effect of green finance, renewable energy, and economic growth on CO 2 emissions and ecological footprint separately. By doing so, we crosscheck the empirical outcomes and inspect the consistency of the analysis. Firstly, empirical results show that the ecological footprint model yields similar results to the CO 2 emissions model in terms of statistically significant quantile ranges and the magnitude of the coefficients. According to the overall results, GDP increases environmental degradation while green finance and renewable energy have a mitigating role. Finally, we confirm a significant EKC hypothesis for Malaysia. Based on these findings, we recommend Malaysian policymakers focus on energy efficiency, realize financial reforms and promote green energy through the financial system to achieve the 2050 net-zero emission target. [Display omitted] [ABSTRACT FROM AUTHOR]

The structure of the blade's leading edge significantly affects the centrifugal pump as turbines (PATs) performance. This paper has attempted to investigate the hydraulic performance and pressure pulsations characteristics of PATs with bionic tubercle leading edge impellers by numerical calculation and experiment methods. The results showed that the bionic tubercles structure at the leading edge of the blade does not change the PAT's best efficiency point and helps improve the energy recovery efficiency under all operating conditions, especially with efficiency increased by 6.04 % under the over-load operation condition. Moreover, the bionic tubercles structure at the blade's leading edge can improves the impeller's local flow characteristics and effectively reduces the amplitude of dominant frequency in the main domains of PATs. The maximum reduction amplitude of pressure pulsations in the impeller with the bionic tubercle leading-edge under 0.7 Q b , Q b , and 1.3 Q b operating conditions is 29.8 %, 23.3 % and 61.1 %, respectively. This research provides a reference for the use of bionic blades to improve the energy recovery efficiency and operation stability of PATs. [ABSTRACT FROM AUTHOR]

The structure of the blade's leading edge significantly affects the centrifugal pump as turbines (PATs) performance. This paper has attempted to investigate the hydraulic performance and pressure pulsations characteristics of PATs with bionic tubercle leading edge impellers by numerical calculation and experiment methods. The results showed that the bionic tubercles structure at the leading edge of the blade does not change the PAT's best efficiency point and helps improve the energy recovery efficiency under all operating conditions, especially with efficiency increased by 6.04 % under the over-load operation condition. Moreover, the bionic tubercles structure at the blade's leading edge can improves the impeller's local flow characteristics and effectively reduces the amplitude of dominant frequency in the main domains of PATs. The maximum reduction amplitude of pressure pulsations in the impeller with the bionic tubercle leading-edge under 0.7 Q b , Q b , and 1.3 Q b operating conditions is 29.8 %, 23.3 % and 61.1 %, respectively. This research provides a reference for the use of bionic blades to improve the energy recovery efficiency and operation stability of PATs. [ABSTRACT FROM AUTHOR]

Green financing is essential because it guarantees that initiatives that seek to reduce the world's reliance on fossil fuels receive the necessary funding to be successful. Green financial metrics can be simultaneously made possible by specialized technological innovation and natural resource rent, thereby encouraging the adoption of sustainable energy. In this paper, we investigate the mediating mechanisms underlying the relationship between green financial indicators and renewable energy consumption RNEC and we contribute to the ongoing discussion surrounding this relationship. Our observational example is derived from data collected for 66 countries between 2004 and 2019 using a panel threshold regression model defined with the difference generalized method of moments (GMM). We find that green funding initiatives have accelerated the adoption of renewable energy sources by encouraging increases in the proportion of renewable energy in the fuel supply. Multiple analyses of reliability corroborate the existence of this link. Green funding has been shown to have an encouraging effect on the transition to renewable energy, and our findings indicate that technological advancement and natural resource leasing serve to mitigate this effect. To assist policymakers in reducing the world's reliance on polluting energy, our study demonstrates how green financial markets can be established through improved technological innovation and natural resource management. [ABSTRACT FROM AUTHOR]

The differential gear train is a common component in wind turbine gearboxes. Investigating the dynamic performance of the gear train is crucial for improving its transmission capabilities. Unlike planetary and compound gear train, there has been relatively little research on differential gear train. Additionally, transmission efficiency is a critical performance metric for gear train, while addressing volume constraints remains a significant challenge in gear research. Currently, there is a lack of relevant research on dynamic transmission efficiency and precise volumetric modeling for differential gear train. Therefore, this paper introduces a high power density design approach for the differential gear train, utilizing the analysis of its dynamic performance. Practical application is demonstrated through two examples. In the first example, the system achieved a 26.32 % reduction in power loss, a 35.44 % decrease in volume, and a maximum root mean square reduction of 12.4 % in component vibration acceleration. In the second example, the system achieved a 19.21 % reduction in power loss, a 41.07 % decrease in volume, and a maximum root mean square reduction of 103.4 % in component vibration acceleration. This research establishes a solid foundation for improving dynamic performance, reducing energy consumption, and minimizing volume in helical differential gear train. [ABSTRACT FROM AUTHOR]

This paper proposes two magnetic multistable (tristable and quadstable) mechanisms to enhance the energy capture performance of point absorber wave energy converters (PAWECs) for low-amplitude waves. Accordingly, two mechanisms consisting of several coaxial magnetic rings are designed based on the superposition effect of magnetic fields. Compared with conventional magnetic bistable mechanisms, the proposed tristable and quadstable mechanisms feature lower potential barriers and greater distances between two outermost potential wells, facilitating the occurrence of large-amplitude interwell motions in low-amplitude waves. A mathematical model is established using the Cummins equation and equivalent magnetic charge approach to depict the dynamic behavior and performance of PAWECs. The energy capture performance and average annual output power of PAWECs with tristable and quadstable mechanisms are evaluated for regular and irregular waves. The findings demonstrate that the two mechanisms significantly improve the energy conversion efficiency, enhancing their robustness against low-amplitude waves and damping detuning. The design concept of nonlinear multistable PAWECs using the superposition effect of magnetic fields provides a promising alternative for exploiting wave energy resources with low energy densities. [ABSTRACT FROM AUTHOR]

Limited attention has been devoted to the harvesting of underwater solar energy for underwater or near-water energy use scenarios. This paper proposes an underwater linear-focusing solar concentrating photovoltaic, which holds the potential to energize subaquatic devices or cater to the electricity needs of islands and coastal regions lacking adequate electricity and terrestrial resources. It mainly encompasses a novel designed underwater solar concentrator with a satisfactory light interception angle and the photovoltaic module. To determine the concentrator's optical performance, optical simulations are conducted. The results illustrate that within the incident angle of 20°, the concentrator can 100% intercept the incident light and has an energy concentration ratio greater than 2.37. Besides, a theoretical model and an experimental setup with solar cells' areas of 0.006 m2 are developed to study its electrical performance. Its electrical efficiency is found to be 12.60% at 0 cm depth and 6.56% at 100 cm depth. Additionally, the greater the water turbidity, the greater the decrease in its electrical efficiency as the water depth increases. At the water depth of 100 cm, the electrical efficiency decreases by 84.27% as the water turbidity increases from 0 NTU to 15 NTU. This work demonstrates the practicality and validity of the underwater solar concentrating photovoltaic technology. [Display omitted] [ABSTRACT FROM AUTHOR]

Liquid air energy storage (LAES) is a promising energy storage technology for its high energy storage density, free from geographical conditions and small impacts on the environment. In this paper, a novel LAES system coupled with solar heat and absorption chillers (LAES-S-A) is proposed and dynamically modeled. A power-speed control system is established for this system. Two operating control strategies are developed for the solar heat collection process. The transient characteristics of the novel system during the start-up, load-up process and encountering different disturbances are investigated. Besides, the dynamic responses when the waste heat is used for producing heating energy are also studied. The results indicate that the power-speed control system can guarantee a very short equilibrium time and a very small overshoot. The energy efficiency of the LAES-S-A system is 65.84 %, while that is 75.32 % when the waste heat is used for producing heating supply. When a disturbance occurs, the equilibrium times of the absorption chiller, air turbines and heating device are 1500 s, 40 s and 38 s, respectively. Compared with the absorption chiller, the heating device can better cooperate with the air turbines. The results can provide a reference for future studies. [ABSTRACT FROM AUTHOR]

This paper presents a piezoelectric energy harvesting device with anti-interference capability. The device utilizes magnetic coupling between the magnet at the tip of the piezoelectric cantilever and the alternating magnetic field surrounding power lines to efficiently harvest energy. Three piezoelectric cantilever structures are designed to optimize energy harvesting efficiency and space utilization. The impact of magnet interaction on the energy harvesting performance is investigated through theoretical analysis and experiments. The results demonstrate a decrease in the natural frequency of each piezoelectric cantilever due to magnet interaction. Frequency compensation techniques are applied to improve the overall output of the device. The anti-interference capability of the harvester is thoroughly evaluated, showing stable output even under random acceleration and the ability to withstand external interference. Additionally, the device successfully powers a wireless temperature and humidity sensor, validating its potential for self-powered wireless sensing nodes in grid monitoring systems. [Display omitted] [ABSTRACT FROM AUTHOR]

This paper investigates the transesterification of waste cooking oil using TiO 2 , CuO, and GO as catalysts in solar plain and helical glass microreactors. Catalyst properties were determined through XRD, SEM, and FT-IR analyses. Response surface methodology was employed to optimize biodiesel production, with GO catalyst and helical microreactor proving most effective due to their unique geometry. The highest biodiesel purity was achieved with GO at 99.98%, followed by TiO 2 at 95.78% and CuO at 93.55%, all with a 3% catalyst dose, 200 s residence time, and oil-to-methanol volume ratio of 2. The study utilized solar energy and glass microreactors, resulting in a 94% reduction in energy consumption. [ABSTRACT FROM AUTHOR]

Saudi Arabia plans to shift a large portion of its domestic energy production away from fossil fuel towards solar energy by 2030. Yet, the solar energy pool is mainly targeting photovoltaic technology. This study analyzes the potential of cleaner energy production from solar energy using concentrated solar power technology. First, different locations for concentrated solar power technology deployment are assessed based on potential development opportunities, solar resources, and infrastructure. Second, the paper assesses the performance and financial feasibility of four concentrated solar power technologies using the capacity factor, levelized cost of energy, and energy yield. The analysis indicates that all the considered locations are suitable for concentrated solar power technologies with a preference for the NEOM city located in the northern region of Saudi Arabia. The simulation results revealed that solar tower technology produces the highest energy yield of 2738 kWh/kW. The levelized cost of energy for the four technologies varies between 14.54 and 22.67 ¢/kWh, with linear Fresnel demonstrating the lowest and parabolic trough exhibiting the highest levelized cost of energy. [ABSTRACT FROM AUTHOR]

Identifying the research topics of China's energy transition policy and predicting future research trends are crucial for policymakers to make informed decisions and advance the energy transition. This study applied the Latent Dirichlet Allocation (LDA) to extract 26 major research topics from the 13,976 abstracts of Chinese policy research papers in web of science (WOS), conceptualized the five most popular topics and used the ARIMA model to predict trends over the next 36 months. The results show that except for Economic and Environmental Impact of Renewable Energy Consumption (Topic13), which will first experience unanticipated fluctuations and then show strong growth capacity, all other topics will continue to remain positive growth trend. Research and Development (Topic3) is driven by the urgency of China's energy transformation. Economic and Environmental Impact of Renewable Energy Consumption (Topic13) is driven by the potential for the development of renewable energy. Economic Impact of Climate Change (Topic26) is driven by the climate change debate. Economic Growth, Urbanization, and Energy Consumption (Topic7) is driven by a discussion of their relationship and the mechanisms influencing them. Regional Efficiency and Productivity Analysis (Topic19) is driven by regional differences in China's energy policies. [ABSTRACT FROM AUTHOR]

This paper presents a model for optimizing the life cycle economic and environmental impacts of a hybrid renewable energy and battery storage system – as energy supply technologies (EST) for off-grid farms. Micro-hydropower and photovoltaics represent the primary renewable energy (RE) sources, with batteries and a diesel generator considered as possible back-up systems. A modified Non-dominated Sorting Genetic Algorithm II (NSGA-II) was developed and applied to a case study farm in Southern Spain and provided different EST solutions to optimize a design based on economic (life cycle costing or LCC) and environmental (life cycle assessment or LCA) constraints. The results highlighted that cases with a strong dependence on batteries could achieve minimum costs and lower impacts for climate change and energy resources (non-renewable fuels). In contrast, the optimal system for minimizing the consumption of material resources (metals/minerals) resulted in higher fuel use, which was up to 25% more expensive. The optimal EST solutions used up to 37% of the total energy generated; however, the results were sensitive to energy production-demand distributions. This methodology can help identify the most cost-effective solutions with the lower environmental impacts for decarbonizing the agricultural sector. [Display omitted] [ABSTRACT FROM AUTHOR]