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An editorial is presented on the winners of the Clean Energy Best Paper Prizes for 2021, which recognize research in clean and low-carbon energy. An overview of the awarded papers such as blockchain technology in energy trading, the design of a solar power station in Sudan, and the performance of a floating photovoltaic system in an Indian reservoir is presented. It further emphasizes the significance of clean energy and the journal's commitment to promote a sustainable future.

The article discusses that Clean Energy and China Energy Group has awarded inaugural Clean Energy Best Paper Prize to ‘Reversible solid-oxide cells for clean and sustainable energy'. The paper is based on the how reversible solid oxide fuel cells when powered by sustainable energy can be used on large scale for transportation sector.

The presence of decentralized production in modern electrical systems precludes traditional automatic generation control (AGC) strategies. Renewable energy production is highly dependent on the environment; for example, photovoltaic (PV) system, but its power generation is very unstable, which makes power grids containing PV systems face greater challenges. In this paper, we propose a PV-grid control method based on self-gain system compensation to reduce the negative effects of large fluctuations and uncertainties in solar energy production. First, the performance characteristics of solar modules are discussed and a multi-region model with a system with high penetration of solar systems is built. The AGC power is then displayed with different power variations according to different maximum power point tracking methods to analyze the uncertainty and variation of the PV output power and its effects on the AGC. We have also developed and implemented a compensation unit to eliminate the negative effects of PV power on AGC. Finally, the proposed method was demonstrated using the load from the example step as a disturbance variable to obtain a dynamic model of a dual-zone switched grid AGC with two PV systems based on a DMPC-distributed model. As a result of the simulation, the proposed method in this paper can guarantee the excellent properties of the dynamic behavior of the AGC system with large variations and high uncertainty of the PV system, and the validity of the proposed method have also been confirmed. [ABSTRACT FROM AUTHOR]

The technique of producing hydrogen by utilizing green and renewable energy sources is called green hydrogen production. Therefore, by implementing this technique, hydrogen will become a sustainable and clean energy source by lowering greenhouse gas emissions and reducing our reliance on fossil fuels. The key benefit of producing green hydrogen by utilizing green energy is that no harmful pollutants or greenhouse gases are directly released throughout the process. Hence, to guarantee all of the environmental advantages, it is crucial to consider the entire hydrogen supply chain, involving storage, transportation and end users. Hydrogen is a promising clean energy source and targets plan pathways towards decarbonization and net-zero emissions by 2050. This paper has highlighted the techniques for generating green hydrogen that are needed for a clean environment and sustainable energy solutions. Moreover, it summarizes an overview, outlook and energy transient of green hydrogen production. Consequently, its perspective provides new insights and research directions in order to accelerate the development and identify the potential of green hydrogen production. [ABSTRACT FROM AUTHOR]

Green hydrogen is considered one of the key technologies of the energy transition, as it can be used to store surpluses from renewable energies in times of high solar radiation or wind speed for use in dark lulls. This paper examines the decarbonization potential of hydrogen for the heating industry. Worldwide, 99% of hydrogen is produced from fossil fuels, because hydrogen derived from renewable energy sources remains prohibitively expensive compared with its conventional counterpart. However, due to the expansion of renewable energy sources and the current energy crisis of conventional energy sources, hydrogen from renewable energy sources is becoming more and more economical. To optimize the efficiency of green hydrogen production and make it more price-competitive, the author simulates a hydrogen production plant consisting of a photovoltaic plant, a power grid, hydrogen storage, an electrolyser, a natural gas purchase option, a district heating plant and households. Using the deep deterministic policy gradient algorithm from deep reinforcement learning, the plant is designed to optimize itself by simulating different production scenarios and deriving strategies. The connected district heating plant is used to map how hydrogen can be optimally used for heat supply. A demonstrable outcome of this paper is that the utilization of deep deterministic policy gradient, over the course of a full year, can result in a competitive production of hydrogen derived from renewable or stored energy sources for the heating industry as a natural gas substitute. [ABSTRACT FROM AUTHOR]

Increasing the application of renewable energy in the power system is an effective way to achieve the goal of 'Dual Carbon'. At the same time, the high proportion of renewable energy connected to the grid endangers the safe operation of the power system. To solve this problem, this paper proposes the application of a copula function to describe the correlation between wind power and photovoltaic power, and reduce the uncertainty of power-system operation with a high proportion of renewable energy. In order to increase the robustness of the model, this paper proposes the application of the conditional value-at-risk theory to construct the objective function of the model and effectively control the tail risk of power-system operation costs. Through case analysis, it is found that the model proposed in this paper has strong practicality and economy. [ABSTRACT FROM AUTHOR]

The development of microgrids is progressing due to intelligent load demands, clean energy, batteries and electric vehicles. The presence of such systems in microgrids causes power balance inconsistency, leading to increased power losses and deviation in voltage. In this paper, a mixed-integer non-linear programming model is proposed for modelling island microgrid energy management considering smart loads, clean energy resources, electric vehicles and batteries. Similarly, a flexible distributed AC transmission system device is proposed to prevent voltage deviation and reduce power losses. A scenario-based multi-objective function has been proposed to decrease energy losses and voltage deviations and energy outages of clean energy resources, reduce emissions from fossil-fired distributed generation and finally decrease load outages to reduce the vulnerability of the islanded microgrid. Regarding the proposed mixed-integer non-linear model and the high number of variables and constraints, a modified evolutionary algorithm based on particle swarm optimization has been proposed to solve the proposed model, which can be more efficient than other algorithms to achieve global optimal solutions. The model presented is implemented on a 33-node island microgrid and the results illustrate that the proposed algorithm and model are effective in reducing energy losses and voltage deviation, as well as reducing the vulnerability of the microgrid. The simulation results demonstrate that the proposed approach can lead to significant improvements in the performance of the microgrid. Specifically, the approach can result in a 27% reduction in losses, a 6% reduction in pollution and a 31% improvement in voltage. Additionally, the approach allows maximum utilization of renewable energy sources, making it a promising solution for sustainable energy management. [ABSTRACT FROM AUTHOR]

China will strive to achieve a 'dual carbon' target: 'carbon peak' by 2030 and 'carbon-neutral' by 2060. In this context, improving the efficiency of renewable energy and reducing the use of thermal power are important ways to achieve the target. Clean, efficient and large-capacity energy-storage technology is the key to improving the utilization rate of renewable energy. First, this paper proposes to use compressed-air energy-storage technology instead of the old energy-storage technology to build an economical and environmentally friendly comprehensive energy park capacity optimization configuration model. Second, this paper uses the newly proposed improved chicken swarm optimization algorithm to solve the model, which is more accurate and faster. Finally, this paper analyzes a comprehensive energy park in north-west China. Through case analysis, it can be seen that the average utilization rate of renewable energy can reach 73.87% through the model proposed in this paper, while the average power-abandonment rate is only 9.32%. [ABSTRACT FROM AUTHOR]

In order to deal with the increasingly severe energy shortage problem, to find new energy solutions and to alleviate the dual pressure of domestic energy and environment, building a new type of multi-energy complementary power system has become one of the hot issues in recent years. This paper presents an optimal scheduling model of building integrated energy system (BIES) based on the comprehensive utilization of electricity, heat and gas. Based on the traditional combined cooling, heating, and power (CCHP) system, this model adds wind power and photoelectric renewable energy power generation systems, ground source heat pump system and energy storage system. Then, taking the environmental cost and system operation and maintenance cost as the objective function, it is solved by using the improved multi-objective ant lion algorithm based on differential evolution. Finally, a building in Northeast China is taken as an example to verify the simulation. The simulation results show that the optimal scheduling model of building integrated energy system proposed in this paper can promote the consumption of renewable energy such as wind power and photoelectric, realize the peak cutting and valley filling of power load, effectively reduce the economic operation cost of the system, reduce carbon emissions and effectively solve the problem of environmental pollution to a certain extent. [ABSTRACT FROM AUTHOR]

To provide clean energy at a lower cost to their citizens, all nations of the world are striving to increase their energy production in an environmentally friendly way. Benin has also joined this dynamic by considerably increasing its green energy production efforts in recent years. The country has a huge undeveloped renewable-energy (RE) potential that can contribute considerably to its national energy production capacity. This paper summarizes the current RE situation in Benin and examines its future prospects. The current energy situation of the country is discussed, followed by an examination of its electricity demand-and-supply situation. The country has been found to depend heavily on natural gas and petroleum products from neighbouring countries and has ~41% of national electricity access. However, the government is taking considerable steps to implement RE projects in the country. The study analyzes government targets in the energy sector with existing policies and institutional frameworks. Recommendations are made for the benefit of the government, the private sector and other actors in order to developing the RE potential of Benin. [ABSTRACT FROM AUTHOR]

Due to the fuel security and environmental concerns of traditional energy resources like fossil fuels, grid operators are tending to use renewable energies as the primary energy supply. This paper presents the study of designing, simulation and analysis of a 100-kWp on-grid photovoltaic power plant (PV-PP) in north-western Iran. Accurate meteorological data, satellite images and local knowledge from this region have narrowed down the options to three highly irradiated cities of Maragheh, Mahabad and Khalkhal in this region. PVsyst and MATLAB software are used in this paper to obtain the performance results. Environmental effects and carbon-emission savings from the execution of the proposed PV-PP are also available in this paper. The result of this study shows that PV-PP installation in Maragheh will have higher energy output than the two other cities. This study is insightful for the academics and the grid stakeholders in finding optimal spots in north-western Iran to construct a PV-PP. Also, recommendations are available for future studies. A 100-kWp on-grid photovoltaic power plant is designed in north-western Iran. Accurate meteorological data, satellite images, and local knowledge are used in a simulation to select the best location from among three cities. [ABSTRACT FROM AUTHOR]

During the past few years, Egypt has increased the share of electricity generation from renewable energy sources to achieve the renewable-energy strategy. The Egyptian Ministry of Electricity and Renewable Energy has set an ambitious target to increase the share of renewable energy among the total energy mix to be 20% by 2022 and 42% by 2035. This target will be achieved using several approved policies such as feed-in tariffs, build–own–operate and independent power producers under a merchant scheme. This paper presents a full analysis of wind-potential characteristics at Elkharga Oasis in Egypt based on an actual wind-measurement campaign taken by a met mast at two height levels of 10 and 25 m, respectively. The measurements show an average annual wind speed of 5.72 m/s at 10-m height and 6.53 m/s at >25-m height. The estimated wind speed, however, is 8.38 m/s at 120 m, which is technically convenient to generate electricity from wind energy. In this paper, the wind potential in the area is assessed using the statistical method of the Weibull probability density function. The different methods to estimate the Weibull distribution parameters are presented and the relevant accuracy is verified based on the root mean square error. A techno-economic assessment and selection of the optimal wind-turbine size with ideal micro-sitings are performed using the software package windPRO. Different cases of study for three typical wind-turbine models with various rotor diameters, power capacity, layout configuration and annual yield are assessed at the site. The selection of the most convenient wind turbine is determined based on the IEC 61400 standard criteria and the turbine that produces the lowest levelized cost of electricity. [ABSTRACT FROM AUTHOR]

The core of building energy allocation is to reduce the power load and power consumption through the reasonable allocation of energy equipment, so as to reduce the capacity of the supply side and save investment. In this way, the configuration of energy schemes in data center is conducted in this paper. According to the results of load forecasting, the energy supply scheme of each building in the planning area is determined, including ground source heat pump (GSHP) system, solar water heating system and heat pipe air conditioning system. In addition, feasibility analysis and economic analysis of each configuration scheme are carried out, and the relatively reasonable scheme is selected. It is found that GSHP system can be used in canteen building, solar hot water system can be used as auxiliary for apartment buildings and joint operation of heat pipe air conditioning unit and traditional machine room air conditioning unit is the most economical for data room. Through the research of this paper, a feasible method for the reasonable allocation of energy is provided in the data center planning stage. [ABSTRACT FROM AUTHOR]

The purpose of this investigation is to summarize modular façade construction using renewable energy features in different aspects. Researches done so far primarily focusing on building envelop have shown various constructions of building enclosure without energy usage. This paper mainly focuses on modular façade renovation system programmes of European Horizon 2020 [ 34 ] and IEA ECBCS Annex 50 Prefabricated Systems for Low Energy Renovation of Residential Buildings in terms of construction, material, installation and thermal performance. Four aspects of construction, material, installation and thermal performance are adopted to evaluate these practices. Related website, paper and report from European commission constitute the database providing for review. Final results illustrate that all modular façade systems mentioned above could be classified into three layers: interior; module and exterior layer, taking charge of disparate functions. Both insulation and energy usage achieve the innovative envelop constructions manufacture. Integrating the renewable energy resources utilization technique into insulated building façade system is the core of this innovative projects achievement. [ABSTRACT FROM AUTHOR]

Nowadays, the global energy and environmental problems are becoming more and more serious, which promotes the development and utilization of renewable and clean energy in various countries. Intelligent car involves many subjects such as electronic technology, artificial intelligence, automatic control technology, sensor technology and computer technology and has become an important part of the application of artificial intelligence. Solar cell is a necessary part of the normal operation of the solar intelligent car, which can provide clean energy for the intelligent car. In this paper, the image recognition technology is used to design the intelligent vehicle control system. According to the intelligent vehicle path recognition, the scale invariant feature transform (SIFT) algorithm is improved to improve the accuracy of intelligent vehicle recognition. Data fusion is used to process the data detected by multi-sensor, and the running state of intelligent vehicle is studied. An evaluation method of intelligent vehicle navigation parameters based on association rules and belief network is proposed. The maximum power point tracking control is realized by using the interference observation method to ensure that the intelligent vehicle can track the maximum power point of the solar cell. [ABSTRACT FROM AUTHOR]

Due to the slow dynamic power-regulation characteristics of the electrolyser (EL), a novel integrated three-port DC/DC converter topology based on a phase-shifted full-bridge converter and dual active-bridge converter is proposed in this paper. Especially, the proposed converter can achieve a fast auxiliary response to the EL. This topology has the features of single-stage conversion, high system integration and compatibility with multiple operation modes. The operational principles and a hybrid modulation scheme of the proposed converter are analysed in detail. In addition, the power-transmission characteristics of each port and the soft-switching range are researched. On these bases, six operation modes suitable for a hydrogen energy-storage system are designed. The simulation and a 2-kW scaled-down experimental prototype are established to verify the feasibility and effectiveness of the proposed topology in different operation modes. [ABSTRACT FROM AUTHOR]

The outcome of this paper is to suggest an efficient energy-management strategy (EMS) for a direct-current (DC) microgrid (MG). The typical MG is composed of two renewable energy sources [photovoltaic (PV) systems and fuel cells (FCs)] and two energy-storage elements (lithium-ion battery and supercapacitor). An EMS was proposed to ensure optimal bus voltage with a power-sharing arrangement between the load and the sources. As a result, in the suggested DC MG, non-linear flatness control theory was used instead of the traditional proportional-integral control approach. The suggested EMS is intended to supply high power quality to the load under varying load conditions with fluctuating solar irradiation while considering the FC status. To validate and prove the effectiveness of the proposed EMS, a MATLAB® environment was used. In addition, the output power of the PV system was maximized using the particle swarm optimization algorithm as a maximum power point tracking (MPPT) technique to track the MPP of the 3000-W PV system under different irradiance conditions. The results show that the suggested EMS delivers a stable and smooth DC bus voltage with minimum overshoot value (0.1%) and improved ripple content (0.1%). As a result, the performance of the DC MG was enhanced by employing the flatness control theory, which provides higher power quality by stabilizing the bus voltage. [ABSTRACT FROM AUTHOR]

The construction of a new type of power system is a key way to achieve the goal of 'carbon peaking and carbon neutrality'. In the process of developing renewable energy, large-scale wind and photovoltaic power systems replace conventional units, which will have an impact on the stability of the power grid. To eliminate these concerns, this paper proposes a bi-level optimal scheduling model for new-type power systems. The upper level aims to minimize fluctuation of net load, with the consideration of demand response, to smooth the load curve. The lower level takes the minimum operating cost of the new-type power system as the objective function and the most economical scheduling strategy is established. To deal with the uncertainty of renewable energy integrated within the system, the lower model is transformed into a two-stage robust optimization model and solved by applying a column-and-constraint generation method. Finally, a regional power system is selected to conduct a case study comprising 760 MW thermal power, 50 MW·h energy storage, 200 MW wind turbine and 150 MW photovoltaic power. The results show that the constructed two-stage robust optimization model is conducive to establishing the most economical scheduling scheme of the system with an uncertain budget and the minimum operation cost is $45,9031. In addition, demand response and energy storage can reduce peak-to-valley differences in the power system. [ABSTRACT FROM AUTHOR]

Hybrid systems based on renewable energies for the electrification of remote sites controlled by power management systems (PMSs) aim to reduce fossil fuels and increase the efficiency of renewable energy sources to minimize greenhouse gas emissions. The influential role of the PMS contributes to improving the efficiency and effectiveness of these systems by ensuring a balance between the different sources and loads in all operating modes. However, the abrupt transitions between the various operational modes selected by the PMS generate power loss and imbalance. To handle this issue, a fuzzy logic controller (FLC)-based PMS controlling a photovoltaic (PV) and diesel hybrid system with a battery storage element connected to a DC bus is proposed in this paper. The proposed PMS is wholly based on FLC to ensure a smooth transition between the different modes of the system. The success of using the suggested PMS lies in how well the FLC parameters are chosen before the system is processed. For this purpose, the particle swarm optimization algorithm is adapted to tune the FLC parameters. The resulting optimal intelligent PMS is tested and compared with a classical one using comprehensive simulations performed in a Simscape ElectricalTM MATLAB® environment. The obtained results show an overshoot attenuation at the DC-bus voltage of 2% when changing the mode and an improvement in the PV generator efficiency by 99.5%. [ABSTRACT FROM AUTHOR]

Solar photovoltaic (SPV) modules have a low output voltage and are load-dependent. Therefore, it is critical that the SPV system has an adequate DC–DC converter to regulate and improve the output voltage to get maximum output voltage. To meet load requirements, the voltage must be increased, necessitating the use of energy-efficient power electronic converters. The performance of an SPV system coupled to a high-gain quadratic boost converter (HG-QBC) with a load is investigated in this paper. The suggested HG-QBC for the SPV system at a lower value of duty ratio provides high voltage gain with a boost factor of four times. An analytical comparison is carried out with the various existing boost converters in terms of the components and the boost factor. The issue of locating the maximum power generation point from the SPV system is crucial. As a result, choosing an appropriate maximum power point tracker (MPPT)-based technique to obtain the peak power output of the SPV system under the rapidly varying atmospheric conditions is vital. To determine the highest output power of an SPV system, a hybrid-based MPPT with a neural network assisted by a perturb and observe (P&O) technique is proposed. For the HG-QBC, a comparison of the proposed MPPT with a traditional P&O-based MPPT is illustrated. The comparative analysis takes into account rise time, settling time and voltage ripples. The output voltage and power characteristics of the proposed model are analysed under constant and varying irradiation conditions using MATLAB®/Simulink®. The results of a hybrid-based MPPT show that the oscillations are minimum at the maximum power point with fewer ripples of 0.20% and a settling time of 1.2 s in comparison with the other two techniques. [ABSTRACT FROM AUTHOR]

Solar water heating systems have been widely used around the world. However, exposure to sunlight can overheat the device, affecting the efficiency and durability of the system. This article proposes an adaptive deck controller that protects the system from overheating without compromising the availability of domestic hot water. Solar water heaters are considered one of the most effective ways to reduce a home's carbon footprint. They are a renewable energy source that reduces reliance on fossil fuels and saves money. Thus, this paper aims to develop a dynamic cover for solar water heaters that prevent overheating using an artificial neural network to optimize the design of control systems. Based on a self-organizing map network, the controller automatically adjusts the temperature of the solar collector through a fabric screen covering the main subsystems, depending on many parameters such as weather conditions, collector temperature and domestic hot water depending on demand. A suggested technique of four different shade percentages (0%, 20%, 25% or 32%) can avoid overheating and maintain the amount of hot water the home needs. Although renewable energy is free, proper controls are required to ensure maximum efficiency or proper use. In addition, the control of renewable energy leads to longer service life. [ABSTRACT FROM AUTHOR]

Solar energy is environmentally friendly technology, a great energy supply and one of the most significant renewable and green energy sources. It plays a substantial role in achieving sustainable development energy solutions. Therefore, the massive amount of solar energy attainable daily makes it a very attractive resource for generating electricity. Both technologies, applications of concentrated solar power or solar photovoltaics, are always under continuous development to fulfil our energy needs. Hence, a large installed capacity of solar energy applications worldwide, in the same context, supports the energy sector and meets the employment market to gain sufficient development. This paper highlights solar energy applications and their role in sustainable development and considers renewable energy's overall employment potential. Thus, it provides insights and analysis on solar energy sustainability, including environmental and economic development. Furthermore, it has identified the contributions of solar energy applications in sustainable development by providing energy needs, creating jobs opportunities and enhancing environmental protection. Finally, the perspective of solar energy technology is drawn up in the application of the energy sector and affords a vision of future development in this domain. [ABSTRACT FROM AUTHOR]

In the era when renewable energy resources are advocated, traditional fuels still account for a dominant proportion. During coal exploitation, coal dust explosion has been one of the most common and serious disasters. Nevertheless, the generated dust can suspend in the air, further leading to a secondary explosion. However, there are limited studies focusing on the propagation characteristics of secondary explosion induced by coal dust. Therefore, this paper aims to detect coal dust explosion in a pipe network and investigate the secondary explosion caused by the first explosion. In specific, this paper numerically analyzed the propagation characteristics of first and secondary explosion of coal dust in aspects of flame temperature, airflow rate and CO mass concentration. The results indicate that the maximum flame temperature of the secondary explosion of coal dust could reach up to 4500 K, which was more intense than the first explosion. After the secondary explosion, the air velocity witnessed a significant increase, compared with the first explosion, but the air velocity at the linear section of the pipe network witnessed the highest because of the air supplement at two sides. Different from the highest CO concentration at the ignition area in the first explosion, the CO concentration in the secondary explosion source area decreased rapidly and the maximum CO concentration appeared in the flame front. Moreover, because of enough oxygen supplement, the explosion reaction was much more sufficient, so that the maximum CO concentration was less than that in the first explosion. [ABSTRACT FROM AUTHOR]

Between 2010 and 2020, the U.S. coal industry experienced a 50% drop in production, employment, and active mines, driven by regulatory factors and technological innovation in alternative energy sources. We study the impact of this energy transition on household employment, wages, migration, and home ownership in affected communities. Compared to non-coal-producing, resource-rich counties, coal-producing counties experience 6% and 4% drops in employment and wages, respectively, during this period. Economic mobility and access to banking services significantly moderate these real effects, suggesting a potential role for finance to shape the industrial and economic changes associated with climate transitions. (JEL G20, G50, J61, Q55, Q58) Authors have furnished an Internet Appendix , which is available on the Oxford University Press Web site next to the link to the final published paper online. [ABSTRACT FROM AUTHOR]

In view of the continuous increase in the proportion of renewable energy connected to the grid in China and the increasing peak-to-valley difference in electricity demand on the power grid, this paper proposes a high-temperature thermal-storage combined-cycle power-generation system. Using Thermoflex thermal simulation analysis software, a high-temperature thermal-storage combined-cycle simulation analysis system model was established, and the influence of different initial temperatures and pressure ratios on the combined-cycle system was analysed. Sensitivity analysis of factors such as electricity cost, annual operating hours, initial equipment investment, unit efficiency and other factors that affect the net income of the system was carried out. According to the current power-peak-shaving auxiliary service market in China, it is pointed out that high-temperature thermal-storage combined-cycle projects must be profitable and obtain good economic benefits. The results obtained, on the one hand, provide suggestions for the flexibility and transformation of current gas-fired steam generators for peak shaving and, on the other hand, provide references for the subsequent development of high-temperature thermal-storage combined-cycle demonstration projects. [ABSTRACT FROM AUTHOR]

Solar farms are becoming a crucial part of the renewable energy mix. Yet, the literature has not reported a generalized approach to its design. In this regard, this paper attempts to provide a detailed plan of a 5-MW grid-connected solar farm. In addition, the procedure to analyze the land footprint of the solar plant is also developed. At first, the main components of the solar farm are selected qualitatively. Then, using an excel spreadsheet, the sizing of photovoltaic (PV) array, inverters, combiner boxes, transformers, cables and protection devices is carried out. Finally, the land footprint analysis of the proposed solar farm was carried out mathematically. The proposed solar PV power plant comprises 13 490 numbers of PV modules with a 365-W rating. Nineteen numbers of PV modules will constitute a string. One hundred forty-two numbers of strings will be connected to an inverter of 1 MW rating. The energy output from five such inverters will be fed to the nearest electric substation using a transformer of 1 MVA capacity. The DC and AC cables having a voltage drop of less than 1% are selected. The inter-row distance and ground coverage ratio (GCR) are estimated as 1 and 0.78 m, respectively. The required number of mounting module structures is found to be 710. The proposed solar farm's total land use requirement is ~43768.41 m2 (around 3 acres). It was observed that the sizing of solar plant components mainly depends on the electrical parameters of the PV module and inverter selected by the designer. Similarly, the land use requirement is influenced by the inter-row distance and PV site layout. This research is expected to streamline the different approaches of solar farm design, which will be beneficial to energy professionals and policymakers. [ABSTRACT FROM AUTHOR]

Continually increasing demand for energy, coupled with the need for clean environment, has made it mandatory to fall back on efficient conversion of energy from renewable sources. Wind energy is one of the most viable sources of renewable energy. A wind turbine blade, shaped as an airfoil with a streamlined cross-section, can be graded for its aerodynamic efficiency in terms of lift-to-drag ratio. Optimal design and analysis of blades with different airfoil sections is critical for efficient energy extraction. In this paper, computational fluid dynamics (CFD) is used to predict the aerodynamic efficiency of wind turbine blades. To set the basics right, a detailed review of aerodynamics of the 2D airfoils are undertaken: (a) NACA4412, (b) NACA23012 and (c) NACA63215 airfoils. Additionally, a numerical study on structural analysis for a 1-kW horizontal-axis wind turbine blade using finite element analysis (FEA) to assess the initial failure of NACA 63215 airfoil internal structure after optimization was conducted. In the internal structure of the blade, a single spar was included to make the structure more efficient in bending. Structural optimization resulted in bringing the weight down from an initial weight of 5.6 kg to a final design weight of 1.1 kg, i.e. a net saving of more than 4 kg. In addition stress levels in the model also improved with the failure indices turning toward unity. Optimized structural thicknesses in terms of glass fiber-reinforced plastic (GFRP) layers were found within safe limits. From FEA study and based on the von Mises stress distribution on the pressure and suction sides of wind turbine blade from root to tip, the initial failure was found to occur in the overlap edge of root region when the equivalent stress reached to the ultimate stress of the tip region. It was found that a well-designed GFRPs wind turbine blade is very efficient compared with metals/alloys. [ABSTRACT FROM AUTHOR]

The integration of various types of renewable energy sources and storage systems into power system increases the complexity of the conventional power system, necessitating a comprehensive optimal power flow (OPF) analysis with multiple and/or competing objectives. From this viewpoint, the paper proposes optimal utilization of different power system entities, by solving the OPF problem using the heuristic particle swarm optimization technique. The proposed methodology optimizes the power flow of a complex, nonlinear hybrid power system to fulfill several objectives, viz. line loss minimization, cost minimization and profit maximization under varying environmental conditions and system attributes. A modified IEEE system replacing conventional sources with renewables and storage system is considered for study. Results corroborate the effectiveness of the strategy. [ABSTRACT FROM AUTHOR]

This paper presents the purpose, advantages, system constitution, operation method and estimation results of using hydrogen storage in a small-scale electric power (off-grid) system when renewable energy sources are introduced. It is assumed that all electricity is supplied from renewable energy sources without using a diesel generator that requires fossil fuels. In other words, for a small-scale electric power system on a remote island, a power-supply system comprising a photovoltaic power-generation system, storage battery, hydrogen-production system, storage tank and a fuel cell is considered. The condition under which the total construction cost is minimized by considering the equipment capacity, operation method of the battery and fuel cell as parameters is investigated. The results demonstrate that the construction cost can be reduced by applying the method of surplus magnification and hydrogen storage. The initial cost is ~70% when hydrogen storage is added as compared with the case in which a storage battery alone is used. Such a cost-effective system can contribute to Japan's self-reliance with regard to the energy sector in the future. [ABSTRACT FROM AUTHOR]

Renewable energy sources cannot guarantee long-term and stable output supply when they are given energy consumption at the load end. At the same time, traditional solar and utility power supply systems cannot guarantee the priority of using solar energy to generate electricity, which has certain limitations. In this regard, an energy control strategy for achieving smooth and no backflow switching and prioritizing the use of clean energy solar energy under a joint power supply system of a solar power grid and a municipal power grid is proposed, which is used for a conventional combined power supply system of a contactor switching circuit. A topology of low voltage power grid is proposed, which effectively reduces the impact on the solar power grid and the municipal power grid during the system switching process combined control mode for controlling the current phase and repetitive control at the output end of the solar power grid in the combined power supply mode, and adding a feedforward control method for the grid voltage is adopted to ensure that the solar grid and the municipal power prioritize the use of clean energy solar energy and, at the same time, ensure the maximum utilization of solar energy. This paper chose the combined power supply system with the solar power grid and the municipal power grid as the object of this research. The topology structure and controlling strategy of the power supply system were comprehensively and deeply researched, and on this basis, the combined power supply system prototype was designed on the foundation of DSP28335 and CPLD. Moreover, hardware parameters are designed in the system, and an energy management optimization algorithm based on the system is developed on the corresponding experimental platform. The experimental results show that the proposed energy control strategy can effectively reduce the impact on the solar power grid and the municipal power grid during the system switching process, ensure that the solar power grid and the municipal power grid have no backflow combined power supply and give priority to the use of clean energy solar energy. [ABSTRACT FROM AUTHOR]

In this paper, the energy models of six hotels were compared. Food and beverage (F&B) service demands the highest amount of energy (over 50%), followed by the hot water system. A regression analysis revealed that, among 31 different characteristics, the revenue per available room, the pool volume, the number of diners and the mean number of guests per occupied room can explain the total energy demand of the studied hotels. The possibility of including photovoltaic solar energy could increase the renewable contribution of the energy mix by 8–30%, but this highly depends on the available surface for this installation in each hotel. [ABSTRACT FROM AUTHOR]

Political flexibility brings about trade-offs for policy-makers aiming to support the deployment of renewable energy sources (RES). On the one hand, it allows incorporating new information on ex ante uncertain benefits and costs of RES policy. On the other hand, it may deter RES investments. This paper scrutinizes how these trade-offs play out economically and politically when RES policy-makers choose the degree of flexibility as well as the instruments to implement flexibility. The analysis builds on a theoretical framework distinguishing between flexibility by design and by adjustment. It is complemented by a discussion of three case studies: RES support schemes in Germany and the United Kingdom, and the EU Emissions Trading Scheme. Theoretical as well as empirical results suggest that the politically chosen degree of flexibility by policy design may be sub-optimally low. In contrast, flexibility by policy adjustment is often excessively high. [ABSTRACT FROM AUTHOR]

This paper compares the historical development of innovation systems related to biogas and improved cooking stove technologies in Rwanda and Kenya by applying the 'functions approach'. It argues that the accumulation of functions in these four renewable energy technological innovation systems (TISs) differed substantially. We find that the accumulation of TIS functions at early stages of development is determined more by national and international contextual factors than by specificities related to technologies or internal dynamics (interaction of functions). Further examination of the functional patterns of TISs suggests that differences in the accumulation rates of functions explain the differences in diffusion rates, with broader and more balanced TIS functional accumulation being related to higher diffusion rates. The paper concludes that systematic support, including well-directed international development assistance, would enable the development of mature and balanced TISs that nurture the diffusion of renewable energy technologies. [ABSTRACT FROM AUTHOR]

Conventional approaches towards energy-system modelling and operation are based upon the system design and performance optimization. In system-design optimization, the thermal or mechanical characteristics of the systems providing for the heat or electricity demands were derived separately without integration with the energy source and without interaction with demand, which results in low-efficiency energy performance. This paper presents a key review on the integration of biomass-powered combined heat and power (BCHP) systems in district-heating systems as well as coupling with thermal-energy storage. In BCHP design, the appropriate sizing of the associated components as part of the district-heating system is very important to provide the optimal dispatch strategy as well as minimized cost and environmental impact while it co-operates with thermal-energy storage. Future strategies for the feasibility, evaluation and integration of biomass-powered energy systems in the context of district systems are also studied. [ABSTRACT FROM AUTHOR]

The increasing global energy and environmental problems are encouraging to the development and utilization of renewable and clean energy in various countries. Wind power is one of the major source in large-scale renewable energy applications. However, the frequency regulation becomes a critical issue while the technology is spreading. Research on the frequency modulation (FM) technology of wind turbines and its control strategy for future power grids become significant. The paper proposes a novel coordinated frequency control strategy with the synchronous generator to solve the unmatched state between the output power of the doubly-fed wind turbines (doubly-fed induction generators) and the grid frequency, combined with the frequency response characteristics of the synchronous generator. The FM coordination strategy is formulated by the modulation coefficient from current wind speed and operation mode of each wind turbine. By coordinating the FM output of the doubly-fed wind turbine and the synchronous generator within the allowable range of frequency deviation, it will achieve the dual goal of reducing the frequency regulation pressure of the synchronous generator and indirectly reducing the abandoned wind volume of the wind turbine. The simulation is carried out on the MATLAB/SIMULINK platform. The results show that the presenting variable coefficient frequency modulation strategy could significant smooth the wind power fluctuation, and allow the reserve power of the doubly-fed wind turbine can fully engaged in frequency modulation which will reduces the frequency modulation pressure of the synchronous generator in the system. [ABSTRACT FROM AUTHOR]

Renewable energy systems are considered essential green energy technologies that could replace a considerable proportion of the current fossil fuel-based electricity generation systems; hence the interest in these technologies is on the rise. However, due to the intermittence nature of most of the renewable energy sources, in particular wind and solar, there are major concerns with the large integration of these technologies in many of the current grid systems. This paper presents a parametric analysis of sizing a large-scale energy storage system that may help to stabilize energy supply based on large-scale grid integration in Suez area in Egypt. The system is based on a Compressed Air Energy Storage, which has the ability to accommodate a large volume of energy from large-scale wind energy integration to the Suez electricity grid system. The paper analyses the characteristics of Suez grid system and the expected wind generation, based on the current integration projections. The results show how compressed air energy storage could add value to the installation of large-scale wind farms in the Suez area in Egypt and indicate the technical ability and successful operation of the proposed system under certain circumstances of the Suez weather conditions. [ABSTRACT FROM AUTHOR]

Hydrogen has gained enormous relevance due to its lower carbon footprint and its potential role in balancing energy supply and demand. It is being considered as a sustainable substitute for conventional fuels. The generation of hydrogen using renewable energy sources is still in development, with a significant challenge lying in the efficient and safe storage of hydrogen due to its low energy density. This challenge hinders the widespread adoption of hydrogen. Compression and liquefaction methods of storage face issues of losses that reduce their effectiveness. The technology for hydrogen storage has advanced significantly in the past few years, driven by recent enhancements in synthesizing carbonaceous materials with hydrogen storage capabilities. This article critically reviews novel carbonaceous materials for hydrogen storage, including biochar, activated carbon, carbon nanotubes, carbon nanocomposites, carbon aerogel, fullerenes, MXenes, graphite, graphene and its derivatives. Effective hydrogen adsorption using microporous materials, such as activated carbons, is crucial, sparking interest in economically viable options for hydrogen storage. Despite this, a significant amount of work still needs to be accomplished before the potential and advantages of the hydrogen economy can be fully realized and utilized by manufacturers and academics. [ABSTRACT FROM AUTHOR]

Renewable energy has penetrated power grid enterprises on a large scale. Due to the intermittency and volatility of renewable energy generation, it is necessary to build new flexible grid-side resources to ensure the safe and stable operation of the power grid, which will cause great pressure on cost allocation for power grid enterprises. This article considers four types of flexible grid-side resources and constructs a dual-level configuration optimization model for flexible grid-side resources under the penetration of renewable energy. Based on the configuration results, the cost scale of flexible grid-side resources is estimated and an improved ancillary service cost allocation model based on the Shapley value method is proposed to smooth the allocation of ancillary service costs in the cost of flexible grid-side resources between the two main bodies of renewable energy and load. The calculation results show that, when the penetration rate of renewable-energy power is 30% and 35%, respectively, the cost of flexible grid-side resources is 9.606 billion yuan and 21.518 billion yuan, respectively. The proportion of ancillary service costs allocated to load is relatively high—about five times that of the ancillary service costs allocated to renewable energy—and the higher the penetration rate of renewable energy, the higher the proportion of ancillary service costs allocated to renewable energy. [ABSTRACT FROM AUTHOR]

Pyrolysis is a thermal conversion process in the absence of air to derive energy components from the residues. Renewable-energy technologies will play a major role in addressing future challenges related to environmental safety and energy security. One of the many easily available renewable energy sources is biomass—an organic material that is thought to be carbon-neutral. Pyrolysis technology is a thermochemical process that can be used to produce useful products from biomass, such as biochar, bio-oil and combustible pyrolysis gases. The structure and relative product yield are impacted by the pyrolysis method employed. This article evaluates different approaches for biomass pyrolysis. Fast, slow and advanced pyrolysis methods using various pyrolyser reactors have been studied in the literature and are provided to increase the variety and use of these methods in upcoming studies and research. Slow pyrolysis can lead to increased ecological well-being, as it increases the amount of biochar produced using auger and rotary-kiln reactors. Rapid pyrolysis, mainly in fluidized-bed reactors with bubbling and rotating circulation, can be used to obtain bio-oil. Advanced pyrolysis methods offer a good probability of yielding great prosperity for specific applications. The selection of a pyrolysis process is based on the required output in terms of solid, liquid and gaseous fuels, and the parameter plays a crucial role in the pyrolysis performance. [ABSTRACT FROM AUTHOR]

The Water Hub Project at the Three Gorges, also known as the 'Sanxia Project', now provides more than 1 billion kilowatt-hours of electricity daily to 10 provinces in eastern China. Facing rising energy demands and climate change, despite being the largest hydroelectric power station in the world, this project may still not live up to the vision of the inventor of hydroelectric power, Nikola Tesla, when he said: 'Electric power is everywhere present in unlimited quantities and can drive the world's machinery without the need of common fuels.' Hydrovoltaic technology, invented by Prof. Wanlin Guo of Nanjing University of Aeronautics and Astronautics (NUAA), aims to generate electricity through processes such as evaporation and the motion of water droplets on synthetic nanomaterials. National Science Review recently invited Prof. Guo for an in-depth interview to discuss this exciting new technology and how it may represent the next great opportunity to transition from fossil fuels to renewable energy sources. [ABSTRACT FROM AUTHOR]

The depletion in non-renewable energy sources and a fast-growing population in Bangladesh are exacerbating the already existing energy scarcity, highlighting the need for an efficient and robust renewable-energy supply chain. The primary goal of this study is to evaluate the most optimized renewable-energy supply chain based on natural resource availability and government policies of Bangladesh. In the present study, four renewable energy resources, including solar, biomass, wind and hydropower, are studied and nine subcriteria are defined under four primary criteria for each supply chain. Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) and VIseKriterijumska Optimizacija I Kompromisno Resenje (VIKOR) are multicriteria decision-making approaches used in this study to compare and choose the best renewable-energy supply chain. The relative significance of four supply-chain criteria for primary renewable energy in this study, namely energy procurement, production, operations and maintenance costs, and social and environmental impact, is gathered via a survey. The results of this research, supported by a comprehensive sensitivity analysis, indicate that hydropower is the best renewable-energy supply chain, followed by wind as a compromise solution, biomass and solar. The study also demonstrates that no energy source can satisfy all supply-chain criteria alone; each resource is better for a specific criterion—solar is better for procurement, hydropower is significant for production and wind is remarkable for operations and social impact. Therefore, to maximize output, renewable energy sources must be integrated. From Bangladesh's perspective, for the first time, by using TOPSIS and VIKOR together, this study offers significant insights to establish an efficient and sustainable renewable-energy supply chain for practitioners, academics and policymakers. [ABSTRACT FROM AUTHOR]

At present, industrial development is heavily dependent on traditional fossil energy, which has had an increasingly serious impact on the environment. Clean and renewable energy has received extensive attention and its proportion in daily life has gradually increased. As a clean and renewable energy source that is not affected by changes in weather and seasons, geothermal energy has developed rapidly in recent years and has received increasing attention. According to reports, the total installed capacity of geothermal power generation in the world in 2020 was 15 950 MW—an increase of ~27% over 2015. At the end of 2019, the total installed capacity for global geothermal direct use was 107 727 MW—an increase of 52.0% compared with 2015; the total annual energy use was 1 020 887 TJ (283 580 GWh)—an increase of 72.3% over 2015. Through the investigation of geothermal power generation technology in recent years, the characteristics and shortcomings of various power generation methods are analysed. At the same time, this review analyzes the characteristics of geothermal energy and other renewable-energy (solar energy, water energy) coupling power generation, and analyzes the principles and characteristics of geothermal energy and various new-energy coupling power generation methods. Through investigation and analysis, this review provides a complete understanding of various geothermal power generation technologies and provides insights into the future development direction. [ABSTRACT FROM AUTHOR]

This paper presents a detailed energy analysis of a 37-year-old house, located near Porto, Portugal. The current situation leads to overheating in the Summer and low temperatures during the Winter, causing high levels of discomfort to the occupants. With the aim to improve the overall comfort, several passive/active solar systems were proposed, and a complete energetic analysis was made. The only air conditioning system used in the house is a wood-burning fireplace that distributes warm air through the rooms. During the Summer, no air conditioning is used. Throughout the year, comfortable conditions are not achieved for the occupants. Building energy requirements for the household in the cooling and heating seasons were quantified. The study was extended throughout a whole year: for the heating season and for the cooling season. Also, indoor temperatures were calculated through numerical simulations. The household and its components were modeled with the TRNSYS 17 program. The results show that the integration of passive and active solar systems, guarantee an improvement in comfort and energy savings. The amount of energy required by the household is covered, to a very significant extent (approximately 71%), by energy from renewable sources. The renewable sources considered were solar energy and biomass. As passive measures, a change of the windows and the increase in wall insulation were considered. For the solar active systems, the application of solar thermal collectors for Domestic Hot Water (DHW) and photovoltaic collectors for electricity generation at the household were analyzed. The consumption of biomass in the burning fireplace was also assessed. [ABSTRACT FROM AUTHOR]

In the context of Great Britain, onshore wind provides the most cost-effective method of renewable electricity generation. However, projects often face opposition to development based on social issues, and there are concerns that existing geospatial modelling approaches fail to fully integrate these effects into their assessment. Building upon previous statistical analysis, this paper presents a geospatial multi-criteria decision analysis that integrates the technological, legislative and social constraints to determine suitable sites for onshore wind turbine development in Great Britain. The findings suggest that the capacity estimates for wind are less than 5% of what was previously estimated, yet opportunities remain for further exploitation of this resource. [ABSTRACT FROM AUTHOR]

The Cost of Energy Review recommended that, in the face of radical technical change, government should: move towards an Equivalent Firm Power capacity auction, integrating the renewables; establish independent public system operators at the national and regional levels; and move towards an economy-wide carbon price. These have met resistance from vested interests, in defence of the economic rents that have accumulated from the dense web of interventions that have accumulated. The paper shows that the first two of these reforms are nevertheless inevitable with active demand, storage, and decentralized generation technologies inverting the old assumptions of passive demand, no storage, and ever larger-scale generation that have underpinned the electricity industry for the past century. Delay in implementation means continued excess costs of energy and delays innovation. [ABSTRACT FROM AUTHOR]

It is now over 20 years since the seminal paper on energy law as a discipline was published. The aim of this article is to review what currently constitutes energy law after this 20-year hiatus. There are two main ambitions of this article, which we hope will have a similar impact on the field. The first is to develop for scholars and practitioners a view of what constitutes energy law--and to make this accessible to both law and non-law energy scholars. The second is to advance a set of core principles that guide energy law, in essence a treatise for energy law. We advocate for a paradigm shift in our current understanding of what constitutes energy law. We advance that it should revolve around this set of guiding principles; however, we acknowledge that to some degree it is perhaps not a paradigm shift due to the current absence of any core principles of energy law. Nevertheless we argue that in our advancing of a guiding set of principles we set out a new path for the study of energy law and thus we aim to change what constitutes energy law and challenge the assumptions of existing researchers as globally society moves towards a transition to low-carbon economies. [ABSTRACT FROM AUTHOR]

In this paper, we present the design and evaluation of Watt-I-See (WISE), a tangible interactive installation aimed at probing awareness in two target audiences (children and adults) about renewable energy resources that could inform eco-feedforward strategies. Our system combines a tangible interface representing five different energy sources, with a set of Lego™ blocks used to manipulate different weather conditions that affect the available energy mix. Through the evaluation of WISE, our main goal was to expose users to the effort necessary to produce the energy used in our day-to-day lives. We evaluated the installation separately for children and adults. The focus on children was due to their importance in the overall household consumption and their role in future scenarios where consumers will have to adapt to the availability of renewable energy sources. The focus on adults was to observe the impact of such information in their decision making regarding their routines. Our findings highlight the success of the interface in engaging children and adults, creating awareness between weather conditions and energy production and the fossil-fuel energy baseline in the grid. Overall, the study highlights the importance of providing a close point-of-interaction feedback as it enables a better understanding of energy-related decisions, reactions, and availability of resources. [ABSTRACT FROM AUTHOR]

Large-scale deployment of the renewable energy system in India is required to achieve a target of 175GW of green electricity by 2022. Higher educational institutes with a lot of free areas can play a vital role in reducing the conventional energy consumption and carbon footprint. The main aim of this paper is to locate and analyze the feasibility of developing 100% solar PV based academic campus at MANIT - Bhopal, India. Annual electricity consumption of MANIT, Bhopal is analyzed and accordingly 5MW capacity solar PV based captive plant is proposed. Free open space area of the campus including rooftop area is inspected through geographical coordinates utilizing the NASA surface meteorology data and Google SketchUp. The performance of the proposed solar campus is analyzed using PVSyst and Solar Advisory Model (SAM) software. The proposed plant at MANIT campus can generate around 8000MWh per annum of electricity to meet the 100% energy requirements of the campus with the annual reduction of 73 318.0 tonnes of carbon footprint. Development and promotion of such sustainable green concepts will be a significant step towards transforming the academic campus into an energy efficient and environmentally sustainable community. [ABSTRACT FROM AUTHOR]

Background: The aim of this study was to estimate the carbon footprint and financial cost of decontaminating (steam sterilization) and packaging reusable surgical instruments, indicating how that burden might be reduced, enabling surgeons to drive action towards net-zero-carbon surgery. Methods: Carbon footprints were estimated using activity data and prospective machine-loading audit data at a typical UK inhospital sterilization unit, with instruments wrapped individually in flexible pouches, or prepared as sets housed in single-use tray wraps or reusable rigid containers. Modelling was used to determine the impact of alternative machine loading, opening instruments during the operation, streamlining sets, use of alternative energy sources for decontamination, and alternative waste streams. Results: The carbon footprint of decontaminating and packaging instruments was lowest when instruments were part of sets (66-77 g CO2e per instrument), with a two- to three-fold increase when instruments were wrapped individually (189 g CO2e per instrument). Where 10 or fewer instruments were required for the operation, obtaining individually wrapped items was preferable to opening another set. The carbon footprint was determined significantly by machine loading and the number of instruments per machine slot. Carbon and financial costs increased with streamlining sets. High-temperature incineration of waste increased the carbon footprint of single-use packaging by 33-55 per cent, whereas recycling reduced this by 6-10 per cent. The absolute carbon footprint was dependent on the energy source used, but this did not alter the optimal processes to minimize that footprint. Conclusion: Carbon and financial savings can be made by preparing instruments as part of sets, integrating individually wrapped instruments into sets rather than streamlining them, efficient machine loading, and using low-carbon energy sources alongside recycling. [ABSTRACT FROM AUTHOR]

The study focuses on the transition from conventional energy sources to sustainable renewable energy (RE) in Palestine, particularly in the West Bank and Gaza Strip. The research aims to understand the relationship between key factors and residents' willingness to invest in the RE sector, with a specific focus on the impact of education. Using the unified theory of acceptance and use of technology, the study analyzes data from 400 residents through a questionnaire and employs ordinary least-squares regression analysis with Eviews 12. The key findings indicate that residents' inclination to invest in RE is significantly influenced by factors such as resource availability, knowledge level and power outages. Moreover, the study suggests that educated residents are more likely to invest in RE when factors such as knowledge, effort expectation, enabling conditions and resource availability are relatively high. The conclusion emphasizes the importance of policymakers' allocating sufficient funds to research and development to promote technological innovation in RE sources, thereby enhancing the population's energy efficiency. [ABSTRACT FROM AUTHOR]