Energy Supply Research Articles

Optimal design and thermal performance evaluation of phase change material filling position for solar air collectors

Unreasonable filling positions of phase-change materials (PCMs) significantly reduce the heat storage capacity, heat release time, output temperature difference, heat collection efficiency, and heat peak migration capacity of PCM-based solar–air collectors in building heating systems, thereby affecting the comprehensive heating requirements of building users. To solve this problem and obtain the optimal filling position of the PCM, four PCM filling schemes were designed in this experiment: Type I was a solar air collector with the PCM filled in the upper portion, Type II was filled in the middle portion, Type III was filled on both sides, and Type IV was filled in the bottom portion. Subsequently, the four models were compared. A comparative analysis of the thermal performance evaluation index showed that compared with the other three types of collectors, the heat storage layer of Type I stored 1.505× 106 J of heat in 1.42h, indicating that the Type I solar–air collector had the best heat storage speed rate. When the solar energy supply was terminated, the continuous heat release time of the Type I collector was 13.92h, and the ratio of the heat release time to the non-solar time was 96%. The Type I collector had the lowest output temperature and the slightest temperature fluctuation, which could increase indoor thermal comfort. The average daily heat collection efficiency of the Type I collector was the lowest, at only 38.11%, indicating that the Type I collector has the strongest "peak cutting and valley filling" ability, which allows for transferring more heat for nighttime release. Therefore, filling the upper portion is the optimal filling scheme that can provide technical benefits for the application and development of collectors.

Formation of Energy Supply Systems for Special Economic Zones

Formation of Energy Supply Systems for Special Economic Zones

Techno-economic, techno-environmental assessments, and deep learning optimization of an integrated system for CO2 capturing from a gas turbine: Tehran case study

This study investigates methods to reduce heat losses, CO2 emissions, and improve the overall efficiency of micro gas turbine power plants, considering economic viability as gas turbines are a major component of the global energy supply chain. Heat recovery and carbon capture techniques were employed to achieve these goals. First, a steam Rankine cycle and a greenhouse were designed to integrate with an existing micro gas turbine. Second, the entire system was simulated using thermodynamic, economic, and environmental models. Finally, an optimization process was conducted through a machine learning model using the integrated model. By adding a Rankine cycle, 80% of the heat losses in a traditional power plant were recovered, converted into electricity and cooling, and resulted in a 3% efficiency improvement. Additionally, implementing a CO2 separation and capture unit with utilization in a nearby greenhouse not only enhanced greenhouse profitability but also significantly reduced CO2 emissions into the atmosphere. While the system's cost rate increased by $40/hour, the investment payback period is only 0.97 years. Furthermore, CO2 emission rate was reduced by 15%.

Renewable energy sharing based on the effect of energy supply from energy transportation and storage side on building load demand

Abstract To lower environmental-based operation costs, many literatures studied the relationship between the energy generation side (EGS) and building load (BL) demand side based on solar-based integrated energy systems (SIESs), without directly considering the effect of energy from energy transportation and storage side (ETSS) on BL demand, which may result in waste of solar energy extracted. To enhance energy utilization, this study proposed an analysis method that renewable energy source shares among different buildings was investigated based on the supply relationship between energy from the ETSS side and BL demand side. ETSS included an electric boiler/chiller (EB/C), double-effect absorption heat pump (AHP) and tank. According to the energy sources from ETSS and building loads for a hotel, a residence and a hospital on a heating/cooling day. The proposed analysis method was used to develop the potential of available renewable energy through energy sharing from the perspective of the energy consumption differences of the three buildings. The results presented that the potential of renewable energy utilization was further developed by reasonably operating the use and storage of energy sources from ETSS based on the optimization between energy sources from EGS and building loads. Energy source shares among different buildings with different energy consumption characteristics enhanced energy efficiency according to reasonably change the useable time of energy sources from tanks. When a building required a large number of energy sources, the buildings with low energy consumption directly shared renewable energy without considering the use of energy storage. This study can provide a reference for optimizing the design of integrated energy system (IES)-based architecture with different building loads.

Task execution latency minimization for energy-sensitive IoTs in wireless powered mobile edge computing: A DRL-based method

Wireless powered mobile edge computing (MEC) has become a vital component of future 6G networks, offering efficient computational capabilities to internet of things (IoT) devices and ensuring a stable energy supply. In this paper, we propose an innovative design for a wireless powered MEC-assisted energy-sensitive IoT systems. The system integrates wireless power technology (WPT), allowing IoT devices to efficiently perform tasks under wireless power supply without consuming their battery energy. Therefore, we formulate a dynamic computational task execution latency minimization (DCTELM) problem to tackle the impacts of unpredictable energy requirements and potential communication latency on resource allocation. We also analyze the differences between time division multiple access and non-orthogonal multiple access communication protocols. Given the complexity and dynamic nature of this problem, we define it as a mixed integer nonlinear programming problem. To address this problem, we introduced an enhanced deep reinforcement learning (DRL) algorithm. First, the DCTELM problem is transformed into a Markov decision process (MDP), which simplifies the structure of the problem. Then, after determining the offloading decision, we reveal the convex relationship between resource allocation and task latency. Furthermore, the action space of MDP is further reduced, and a multi-head proximal policy optimization (PPO) algorithm is proposed to deal with the simplified MDP problem. This process reduces the complexity of problem solving, decreases the consumption of computational resources. Simulation results demonstrate that our method outperforms other baselines in terms of computation latency, particularly with the introduction of an exploration strategy during the training phase, which significantly reduces task latency.

Theoretical prerequisites for planning the content and focus of training sessions in the pre-season preparation of hockey players

Importance. The rapid growth in the number of student sports teams in recent years has predetermined the issue of combining sports and academic activities. In this regard, the considered aspects of the processes of fatigue and recovery in amateur sports become relevant and require analysis and systematization of the views of domestic and foreign scientists on the issues of localization and mechanisms of development of fatigue, as well as the patterns and time of recovery of the athlete’s body in the process of training activities. The study purpose: analysis and systematization of scientific articles on the problem of fatigue and recovery of the athlete’s body after physical activity, determination of the fundamental scheme for the formation of the content and focus of training sessions based on the analysis of the theoretical component of the problem of fatigue and recovery during physical activity of various nature, direction and magnitude in different types of sports.Materials and Methods. The study is conducted on the basis of studies concerning the problem of interaction of the body’s life-supporting systems in the development of fatigue mechanisms, published in scientific journals, monographs of famous physiologists covering a large time period. The study is based on a systemic-structural approach, which allows, during the analysis of scientific publications, to identify the main patterns of the development of mechanisms and localization of fatigue, to put forward hypotheses regarding the prospects for developing an appropriate scheme for the formation of the content and focus of training sessions, to determine the range of issues that require instrumental confirmation of the recovery time of the athlete’s body during combining various characteristic aspects of loads in the training process. Within the framework of this study, the following research methods are used: scientific and methodological literature analysis, systematization, pedagogical observation, generalization.Results and Discussion. In the course of the study, the main factors are identified that influence the mechanisms of the development of fatigue during work of various sizes and directions, in different intensity zones; The interrelationships of various localization systems and mechanisms of fatigue development, as well as energy supply to support the athlete’s vital activity during physical activity, are revealed. An attempt is made to substantiate the strategy of expediently combining types of training activities, the content and focus of training sessions in the preparatory period of pre-season training for students involved in hockey at Hockey club “Derzhava”.Conclusion. Research prospects include issues of experimental substantiation of the construction of a system of training sessions, taking into account the registration of the main indicators of lifesupport systems, allowing the trainer to expediently distribute and quickly regulate training loads and ensure the effectiveness of recovery processes in the period under study.

Impact of carbon dioxide removal technologies on deep decarbonization: EMF37 MARKAL–NETL modeling results

This paper examines the MARKAL-NETL modeling results for the Energy Modeling Forum study on Deep Decarbonization and High Electrification Scenarios for North America (EMF 37) with a specific focus on carbon dioxide removal (CDR) technologies and opportunities under different scenario guidelines, policies, and technological advancements.The results demonstrate that CDR, such as bioenergy with carbon capture and storage (BECCS), direct air capture (DAC), and afforestation, are key technologies in deep decarbonization scenarios and account for 40–60 % of avoided carbon dioxide (CO2) emissions annually. From 2025 to 2050, cumulative CO2 abatement by CDR technologies will range from 37 to 47 billion tons (GtCO2), or more than 2 GtCO2 annually by 2050. The potential scale of CDR and its impact depends on the advancement and costs of energy supply and demand technologies, end-use sector electrification, and availability and costs of CDR. Results show that the price of carbon is substantially lower when advanced technologies are available, particularly in the EMF 37 carbon management scenarios [1].While BECCS deployment is likely to be constrained for environmental and/or political reasons, the results display relatively large-scale BECCS deployment. The study found that BECCS could make a substantial contribution to emissions reductions after 2035, and, in the medium term, CO2 sequestration by BECCS will depend on CO2 price; BECCS deployment starts at a carbon price of around $70/tCO2. Long-term CO2 sequestration by BECCS increases in all scenarios, reaching the same annual level of ∼890 MtCO2 by 2050 in net-zero CO2 scenarios. According to the modeling results, DAC acts as a true backstop technology at carbon prices of around $600/tCO2.

Study on the Design of Valve Base Insulation and Power Supply Transformer for High-Voltage DC Circuit Breaker

Abstract High-voltage DC circuit breaker is a key piece of equipment to building DC power grids. DC circuit breakers need to support and isolate from high voltage to ground through valve-based equipment and use valve-based power supply transformer to continuously supply energy to high potential components, the electrical performance of these two equipment determines whether DC circuit breakers and DC networks can be operated safely and reliably. For this reason, this paper carries out the research on the insulation capability of the valve base and the performance of the power supply transformer, such as the design and simulation of electric and thermal fields, as well as the test program. Firstly, the insulation design and simulation study of the valve base as a whole is carried out, and the design optimization of the equipotential scheme of the top homogeneous tubular bus, diagonal pull insulator and hydroelectric pole is completed. Secondly, the design and simulation verification of the thermal field distribution of the energy-supply transformer, the overvoltage between the ends of the output windings and the optimization scheme, and the short-circuit impedance were carried out. Finally, the insulation performance of the valve base, the temperature rise of the energy supply transformer, the overvoltage simulation of the output winding and the short-circuit characteristics were tested. The results show that: after optimization, the maximum field strength of the homogenizer is 2.3kV/mm, and the overall maximum field strength of the valve base is 2.61 kV/mm on the diagonal insulator, and there is no pressure difference between the water circuit and the fittings using the three-pin vertically distributed hydropower electrode scheme; the temperature rise of the supply transformer in the simulation and the actual measurement is 27K and less than 30K; by means of the parallel connection of the MOV, the overvoltage of the output winding of the power supply transformer under voltage impulse is effectively reduced to -1.8kV; the measured short-circuit impedance of the power supply transformer is 69.5%. The optimized design of DC circuit breaker valve base and power supply transformer can operate safely, and effectively support the construction of DC circuit breaker and DC power network.

Partner heterogeneity and driving factors of China’s export embodied energy intensity

Although China’s energy consumption is very high, foreign demand has become crucial factor affecting China’s energy consumption due to exports. A detailed analysis of the embodied energy intensity of China’s exports from the demand side could provide valuable insight into promoting China’s energy-saving development. This paper explores disparities in the embodied energy intensity of China’s exports to different trading partners and the energy supply structure behind these exports. Furthermore, it explores the driving factors of export embodied energy intensity using multiplicative structural decomposition analysis. The results show that China’s export embodied energy intensity to developing countries, such as India, is higher than that of European and American countries; however, a convergence trend has emerged over time. Regarding the driving factors influencing changes in export embodied energy intensity over time, the sectoral energy intensity effect plays a pivotal role in promoting its decline, while the production structure and export structure effects change from inhibition to weak promotion. The adjustment of export structure has significant potential for reducing China’s export embodied energy intensity, especially in emerging economies. Finally, this paper proposes policy directions for collaborative opening up, energy saving, and emission reduction goals.

A piezoelectric energy harvester for multi-type environments

Researchers have been studying the harvesting and utilization of mechanical vibration energy in the environment in recent years. Wind energy and water current energy are common energy in natural environment, the composite energy harvesting device that can harvest both wind energy and water energy is rarely reported. In this work, a piezoelectric energy harvester for multi-type environments is proposed, which can be installed in corresponding environments to harvest the wind energy, the water wave energy and the water current energy. In addition, the proposed energy harvesting device can adjust the attitude according to the direction of environmental energy. The energy harvesting principle is discussed and the performance of the device under different working conditions is tested by experiment. In the wind energy experiment, the maximum output power is 21.19 mW at a sustained wind speed of 8 m/s, and in the water energy experiment, the maximum output power is 2.01 mW at a medium infiltration depth and a flow velocity of 0.55 m/s. Finally, functional experiments are carried out to verify that the energy harvesting device proposed in this work can be put into practical use, and has a huge application prospect in long-term energy supply for outdoor microelectronic devices.

Severe compound events of low wind and cold temperature for the British power system

AbstractBritain's power system has shifted towards a major contribution from wind energy. However, wind is highly variable, and exceptionally low wind events can simultaneously occur with cold conditions, which increase demand. These conditions can pose a threat for the security of energy supply. Here we use bias‐corrected wind supply data and the estimated temperature‐related part of demand to analyse events of potential weather‐related energy shortfall based on the historic meteorological record. We conduct sensitivity studies with varying scenarios of Britain's total wind energy capacity and the temperature sensitivity of national demand. These scenarios are estimates for present‐day conditions as well as potential future changes of the power system. We apply a new methodology to estimate the potential severity of an event for the power system, and analyse the atmospheric conditions associated with the most severe events. We find that events of potentially severe shortfall are relatively rare and short‐lived, and often occur with an atmospheric pattern broadly resembling a negative North Atlantic Oscillation. This broad tendency emerges from a wide range of individual daily weather patterns that cause cold and still conditions. With an increase in wind capacity, it is likely that severe events will become rarer, although the most severe days of the record are relatively insensitive to changes in wind supply and temperature sensitivity of demand under our assumptions.

Potential of Hydrogen and Thermal Storage in the Long-term Transition of the Power Sector: A Case Study of China

Hydrogen and thermal storage can reduce cost of long-term and large-scale energy storage with high efficiency and low or even zero carbon emissions. Their potential in the low-carbon transition pathway of an energy system with rapid growth of energy demand, large shifting of energy supply structure and limited investment budget remains unclear. A long-term power generation planning model is proposed in this paper, featuring detailed technical and economic characteristics of hydrogen and thermal storage. The power supply system of China is selected as a case study, due to its urgent need for low-carbon transition and complex spatial characteristics. Results show that the application of hydrogen and thermal storage can benefit the development of volatile renewable power generation technologies, facilitate the transition towards zero or even negative carbon emissions while simultaneously reducing power supply costs. Hydrogen is expected to be mainly produced in spring and consumed in summer while heat is expected to be primarily generated in autumn and consumed in winter. Shifting from thermal storage to hydrogen storage might happen around 2050 in accordance to the low-carbon transition progress.

New strategy for Mg-air battery voltage-efficiency synergy by engineering protective film with cation vacancies on Mg anode surface

Although the Mg-air battery with high theoretical energy density is desirable for the energy supply of marine engineering equipment, its applications remain limited due to the low actual discharge voltage and inferior Mg anode utilization rate. In addition to the microstructure of Mg alloy anodes, the properties of discharge product films are of great importance to the discharge performance. Herein, the discharge behaviors of Mg-Y-Zn alloys are first studied mainly from the perspective of film properties. Through contrastive analysis, it is found that the sufficient Y3+ produced during the discharge process can substitute Mg2+ in Mg(OH)2 to introduce effective cation vacancies. The Mg-Y-Zn anode with profuse cation vacancies in the product film shows a synergy of potential and efficiency, and this can be attributed to an increase in the migration pathway for Mg2+, reducing the diffusion over-potential caused by the protective product film. This study is expected to provide a new strategy from the perspective of cation vacancy design of discharge film for developing high-performance Mg-air batteries.

A refined dynamic liquid dehumidification model for the packed dehumidifier considering time-varying thermal mass of the desiccant

Liquid desiccant dehumidification technology is a promising, energy-efficient dehumidification approach. It can flexibly adapt to variations in renewable energy supply and users' demands, making it an inherently dynamic process. However, optimizing this process from a dynamic perspective is often neglected. This is mainly due to the challenges in establishing a dynamic dehumidification model, where the desiccant’s thermal mass and heat and mass transfer coefficients should be time-dependent. In this paper, a refined dynamic dehumidification framework using the finite difference method is developed, where governing equations for the mass and species conservations are rebuilt taking the thermal mass and desiccant concentration as time-dependent variables. Auxiliary equations determining evolutions of the desiccant’s thermal mass and heat and mass transfer coefficients are derived based on the continuity equation and analogy method, respectively. Subsequently, the experiments are carried out and serve as a benchmark to check the simulations. It suggests the simulated results using the refined model align well with the experimental data and demonstrate around 50% better predictive accuracy compared to the existing method, indicating the feasibility of the refined model. The refined model also contributes to rapid adaptation of the dehumidification process to meet specific needs. In a specific case, this could result in energy savings of 60% for the regeneration of the desiccant solution. This study provides a reference for quantifying evolutions of the liquid desiccant's thermal mass based on an understanding of the physical process. It lays a solid foundation for modeling the dynamic dehumidification process at the design stage and assists in operating an energy-saving dehumidification system.

Integrative multi-omics analysis reveals the underlying toxicological mechanisms of enrofloxacin on the growth of wheat seedling roots

The continuous release of antibiotics into agroecosystems has raised concerns about the potential negative effects of antibiotic residues on crops. In this study, the toxicological effects of enrofloxacin (ENR) on wheat seedlings were analyzed using a combination of morpho-physiological, transcriptomic, proteomic, and metabolomic approaches. ENR inhibited the growth of wheat (Triticum aestivum L.) roots and induced oxidative stress. In particular, ENR downregulated the oxidative phosphorylation pathway, while it enhanced glycolysis and the tricarboxylic acid cycle, thereby regulating the balance of intracellular energy metabolism. In addition, sustained exposure to excessive reactive oxygen species (ROS) resulted in an increase in reduced glutathione (GSH), a slight decrease in ascorbic acid (AsA), and a significant decrease in the ratio of GSH to oxidized glutathione (GSSG), which imbalanced the AsA-GSH cycle. In addition, the resulting increase in abnormal proteins triggered ubiquitin-independent proteasomal degradation pathways. Further, an increase in abscisic acid (ABA) and a decrease in jasmonic acid (JA) and its derivatives alleviated the inhibitory effect of ENR on the growth of wheat roots. In conclusion, direct damage and signaling by ROS, hormonal regulation, a decrease in the GSH to GSSG ratio, and insufficient energy supply were identified as key factors for the significant inhibition of wheat root growth under ENR stress.

Efficient reduction of power losses by allocating various DG types using the ZOA algorithm

The continuous challenge of ensuring energy supply is a significant concern. Traditionally, utilities have addressed increasing load demands by building new central power plants or expanding existing ones. However, these methods are time-consuming and costly, providing only short-term solutions. Additionally, power plants are often far from load centers, resulting in higher power losses during long-distance transmission. The integration of distributed generation (DG), characterized by smaller scale and lower capital costs, with nearby consumers can effectively address these challenges. Due to the significant influence of DG penetration and their specific locations on the distribution system's performance, this study offers a novel Zebra Optimization Algorithm (ZOA). The suggested ZOA is used to optimize the capacity and position of various DG units connected to a radial distribution system to reduce power losses and study the stability of the system after DG allocation using the Voltage Stability Index (VSI). The evaluation is conducted using the IEEE 33-bus test system, considering various scenarios including single and multiple DGs of different types. The results demonstrate that in the best scenario, the ZOA can reduce losses by up to 94.25 % and improve the VSI from 0.69643 to 0.9605. These findings highlight the superior performance of the ZOA over other techniques in optimizing DG placement and sizing for power system performance.

The carbon footprint of health care delivery in Western Australia's public health system

Health systems have a dual imperative to take action on climate change. First, they must develop climate resilient health services in response to the direct and indirect impacts of climate change on health. Second, they must reduce their own carbon footprint since health systems are a significant contributor to global greenhouse gas emissions. An environmentally-extended multi-region input-output analysis was carried out, incorporating National Accounts data for Australia and annual expenditure data from WA Health for financial year 2019-20. Expenditure data were categorised to one of 344 economic sectors and by location of the provider of goods or services purchased. WA Health contributes 8% of WA's total carbon footprint, driven by expenditure on chemicals (23.8% of total), transport (20.2% of total), and electricity supply (19.7% of total). These 3 sectors represent 63.7% of WA Health's carbon footprint, but only 10.8% of its total expenditure. Reducing emissions related to health service provision in WA will require a holistic approach that leverages carbon footprinting insights and integrates them into organisational decision-making across all health programs. The high carbon-intensity of the transport and chemicals sectors supports previous research calling for a reduction in unnecessary pathology testing and the transition to delivery of non-urgent health care via sustainable models of telehealth. The impact of WA's size and location presents challenges, with a predominantly non-renewable energy supply and reliance on transport and supply chains from other states adding significantly to emissions. The study received funding from the Australian Research Council, The University of Sydney, and the WA Department of Health. The full list of funding information can be found in Acknowledgements.

Assessment of bioenergy plant locations using a GIS-MCDA approach based on spatio-temporal stability maps of agricultural and livestock byproducts: A case study

Addressing the global challenge of energy sustainability and global directives on farming emissions, the United Nations, the European Union, and China have led with strict targets for clean energy, renewable share growth, and carbon neutrality, highlighting a commitment to collective sustainability. This work is situated within the ambit of the Sustainable Development Goals (SDGs), advocating for a transition towards renewable energy sources. With substantial and accessible bioenergy resources, notably in Hubei Province, China, biogas technology has emerged as an emission-cutting solution. This research, focused on the Jianghan Plain, employs an integrated approach combining spatial analyses with machine learning tools to evaluate crop yield stability over two decades, with the aim of maximising the biogas yield from agricultural byproducts, i.e., crop straw and livestock manure. Using Multi-Criteria Decision Analysis (MCDA), which is informed by grey-based DEMATEL, 9 constraints and 13 environmental, social, and economic criteria were assessed to identify optimal sites for biogas facilities. The findings underscore the significant bioenergy potential of agricultural byproducts from the plain of 6.3 × 1012 kJ/year at an 11.4 kJ/m2 density. Stability analyses revealed consistent biomass availability, with rice in Gongan and Shayang and wheat in Jiangling being the primary contributors. Through the MCDA, 45–66 optimal biogas plants were identified across 4 critical counties (Zhongxiang, Shangyang, Jingshan, and Yichen), balancing the energy supply and demand under various stable scenarios. Furthermore, this study demonstrated the criticality of moderate biomass stability for stakeholder consensus and identified areas of high stability essential for energy demand fulfilment. Theoretically, this study offers a practical model for bioenergy resource exploitation that aligns with global sustainability and carbon neutrality goals to address the urgent need for renewable energy solutions amidst the global energy crisis. Practically, this study sets a precedent for policy and planning in environmental, agricultural, and renewable sectors, signifying a step forwards in achieving environmental sustainability and an energy-efficient future.

Environmental Degradation and its Effects on Health in Bangladesh

This study aims to analyze the impact of environmental degradation on health using the Autoregressive Distributed Lag (ARDL) method with data from 1976 to 2020. The primary focus is on the influence of CO2 emissions on life expectancy in Bangladesh, evaluating the short-term and long-term relationships among key variables such as CO2 emissions, urban population growth (UPG), money supply (M2), and renewable energy consumption (REC). The study employs unit root tests, including the Augmented Dickey-Fuller (ADF) and Phillips-Perron (PP) tests, to determine the stationarity of the time-series data. Results indicate mixed integration orders, necessitating the use of the ARDL bounds testing approach to confirm cointegration. The findings reveal that CO2 emissions have a significant negative effect on life expectancy, while M2 and REC exhibit varying impacts. The ARDL model confirms a long-term relationship between the variables, with a significant speed of adjustment towards equilibrium. Diagnostic tests validate the model’s robustness, ensuring no issues with heteroskedasticity, autocorrelation, or model misspecification. The study underscores the importance of effective governance in mitigating the adverse effects of environmental degradation on health, advocating for stricter environmental regulations and improved public health policies. These findings have significant implications for policymakers aiming to enhance public health outcomes amidst growing environmental challenges..

Harvest Ocean Energy Based on Airborne Wind Energy Systems

Two thirds of the earth's surface is covered with water. Up to now, the huge amounts of energy available there have mainly been utilized in coastal areas only. The aim of this work is to show how autonomously operating Airborne Wind Energy Systems (AWES) can make a significant contribution to the global energy supply.