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Hydrogen fuel cells are characterized by non-pollution, high efficiency and long power supply time, and they are increasingly used as backup power systems in substations, communication base stations and other fields. In this paper, based on the thermodynamic model of the hydride hydrogen storage system, the relationship between pressure, composition, and temperature in metal hydride hydrogen storage is quantitatively analyzed using a PCT curve. The hydrogen fuel power supply is used as the overall backup power supply of the DC system, and the hydrogen-fuel integrated backup power supply is established to realize the uninterrupted switching between the utility power and the backup power supply. Finally, the working process of the backup power supply and the reaction process of hydrogen are analyzed to test the feasibility of a hydrogen fuel cell backup power supply. The results show that the operating current climbs to the end of 80 A under the 5 kW workload demand of the communication equipment. In addition, the hydrogen absorption reaction rate was 0.29 Mpa, and the hydrogen release reaction rate was 0.21 Mpa at a temperature of 291 K. This study has developed a fuel cell backup power system that can provide uninterruptible backup power and has a wide market capacity and application prospects.

BackgroundSolid oxide electrolysis cell (SOEC) offers a promising method for converting H2O into H2 at high temperatures ranging from 600 °C to 850 °C. Glass sealants, which are crucial materials in SOEC, fulfill most criteria for an ideal sealant when appropriate glass components at suitable stoichiometric proportions are selected. Nevertheless, they exhibit certain drawbacks, including limited stability, elevated gas leakage rates, and suboptimal thermal cycling performance during the SOEC operation.PurposeThis study aims to evaluate the performance of Al2O3 added Ba-Si-Ca sealant for SOEC.MethodsFirstly, a new Ba-Si-Ca system sealing glass (glass-P) was developed to enhance its properties, such as the coefficient of thermal expansion, glass transition, and softening temperatures, and a series of alumina additions to glass-P, intended for use as the SOEC sealant, were prepared using curtain coating. Then, the coefficients of thermal expansion of these sealants were evaluated using a thermal expansion instrument. The leak rate of the sealants, as well as the impact of different alumina additives on the material's thermal shock resistance and chemical stability, were assessed via a 1-cell stack measurement for extended SOEC operation. Finally, the elemental distribution of the specimen was observed using scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (EDS).ResultsThe experimental results show that the leakage rate of the glass P-10 sealant is measured at 5.54×10-3 sccm∙cm-1, which is lower than that of glass P. After undergoing ten thermal cycles, the leakage rate of glass P-10 is found to be 2.275×10-2 sccm∙cm-1, lower than that of the others. An open circuit voltage (OCV) of approximately 1.169 V is recorded for glass P-10 after a 1 053-h test.ConclusionsThe addition of alumina to glass P significantly enhances the sealant's thermal stability and gas tightness.

Offshore wind power stands out as a promising renewable energy source, offering substantial potential for achieving low carbon emissions and enhancing energy security. Despite its potential, the expansion of offshore wind power faces considerable constraints in offshore power transmission. Hydrogen production derived from offshore wind power emerges as an efficient solution to overcome these limitations and effectively transport energy. This study systematically devises diverse hydrogen energy supply chains tailored to the demands of the transportation and chemical industries, meticulously assessing the levelized cost of hydrogen (LCOH). Our findings reveal that the most cost-efficient means of transporting hydrogen to the mainland is through pipelines, particularly when the baseline distance is 50 km and the baseline electricity price is 0.05 USD/kWh. Notably, delivering hydrogen directly to the port via pipelines for chemical industries proves considerably more economical than distributing it to hydrogen refueling stations, with a minimal cost of 3.6 USD/kg. Additionally, we assessed the levelized cost of hydrogen (LCOH) for supply chains that transmit electricity to ports via submarine cables before hydrogen production and subsequent distribution to chemical plants. In comparison to offshore hydrogen production routes, these routes exhibit higher costs and reduced competitiveness. Finally, a sensitivity analysis was undertaken to scrutinize the impact of delivery distance and electricity prices on LCOH. The outcomes underscore the acute sensitivity of LCOH to power prices, highlighting the potential for substantial reductions in hydrogen prices through concerted efforts to lower electricity costs. [ABSTRACT FROM AUTHOR]

BackgroundThe performance of solid oxide fuel cells (SOFCs) can be promoted by optimizing cathode materials.PurposeThis study aims to boost the electrochemical performances of cathodes for SOFCs by doping transition metal at the B-site of double perovskite.MethodsFirstly, a series of B-site doped PrBa0.8Ca0.2Co2O5+δ (PBCC) oxides as cathodes for SOFCs were prepared by sol-gel. The effects of B-site doped content and doped elements on the crystalline structure of the cathodes were analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM). Then, the trends of conductivity and thermal expansion coefficient with B-site doped PBCC oxides were investigated. Finally, the electrochemical performances of cathodes with different B-site doped PBCC oxides were tested to find optimal doping element type and content.ResultsTest results show that polarization is reduced and the electrochemical catalytic activity is improved when 5 mol% of Fe is doped on the B-site of the PBCC cathode. Compared to the PBCC cathode, the max power density of the full cell with a 5-mol% Fe-doped cathode increases from 988 mW∙cm-2 to 1 259 mW∙cm-2 at 700 ℃.ConclusionsThe electrochemical performances of SOFCs can be boosted by modifying the B-site of double perovskite using transition metal.

Reversible solid oxide fuel cell (RSOC) has gained widespread attention due to their potential for high efficiency in implementing multi‐energy distributed systems. When high power demand is required, RSOC can operate in the solid oxide fuel cell (SOFC) mode, directly converting the chemical energy from hydrogen or other renewable fuels into electricity. When excess electricity is available, RSOC can operate in the solid oxide electrolysis cell (SOEC) mode, producing fuels through the electrolysis of water or co‐electrolysis of water and carbon dioxide. The reversible operation of RSOC enables the direct conversion between chemical energy and electricity, offering a promising solution for clean and sustainable energy with low cost and high round‐trip efficiency. This paper introduces the research background and working principles of RSOC, provides a detailed overview of the current research status of electrolyte, fuel electrode, and oxygen electrode materials, discusses the optimization design of RSOC stacks and energy utilization strategies in the system. In addition, the future development directions of RSOC were also explored, which is of significant importance for the commercialization of RSOC. [ABSTRACT FROM AUTHOR]

Aiming at the problems that the existing arc suppression cabinet technology cannot adjust the zero sequence voltage flexibly and the control and hardware implementation of active arc suppression equipment based on power electronics are difficult, a new method of voltage arc suppression in the distribution network based on the flexible regulation of the neutral point potential of the new grounding transformer is proposed. From the perspective of the sequence component, the variation law of the neutral point voltage before and after the closing of the tapped grounding branch of the new grounding transformer is analyzed. By selecting the appropriate initial tap position of the tap-to-ground switch, the fault phase voltage is flexibly controlled so that the fault phase voltage is reduced to below the reignition voltage to quickly solve the influence of the single-phase grounding fault, and the risk of non-fault phase insulation breakdown is reduced to ensure the stable operation of the distribution network. According to the ratio of the fault phase current to the zero sequence voltage before and after the gear inputs, whether the arc suppression of the single-phase grounding fault is completed is judged. Compared with power electronic products, the new grounding transformer has the advantages of high reliability, long service life, and low cost and has strong economy and applicability in engineering. The single-phase grounding fault model of the 10kV distribution network is built in the PSCAD/EMTDC simulation environment, and the new method of the distribution network voltage arc suppression based on the flexible regulation of neutral point potential of the new grounding transformer is verified. The simulation results show that the proposed method can effectively reduce the fault phase voltage to achieve the reliable arc suppression of the single-phase grounding fault.

[Introduction] In recent years, the attention paid to the development of energy storage technology and energy storage industry has continued to heat up. [Method] Review of compressed air energy storage technology (CAES) progress and its commercial application scenarios have been summarized in this paper. CAES research teams and their technical characteristics were summarized, which reflected the development direction of CAES technology. Meanwhile, the configuration parameters and operation experience of two commercial CAES power stations (Huntorf station and Alabama station) were introduced. The demonstration progress of various new CAES technologies was also reviewed. These review on CAES technologies, commercial power stations and demonstration stations can provide reference for the development of domestic CAES technology and the development of energy storage industry promoted by national ministries in China. At the end of this paper, the adaptability and application potential of CAES technology were analyzed from three aspects: electricity generation side energy storage, grid side energy storage and user side energy storage. [Result] The two CAES power stations in Germany and the United States have tested the long-term reliability of CAES power plants. The CAES demonstration projects with capacity from 500 kW to 10 MW have been built in China. It indicates that this energy storage technology has achieved breakthroughs from the theoretical research stage to the demonstration verification stage in China. [Conclusion] In the current policy environment, the user-side peak-to-valley electricity price policy is a typical boundary condition for energy storage application scenarios, which can be considered in the application of CAES technology.

As a clean energy power generation technology, photovoltaic generation has the characteristics of low carbon, green and environmental protection. More and more countries pay close attention to it, more than one megawatt demonstration projects of grid photovoltaic power station has been commenced or built. In order to study interconnection characteristics of large-scale photovoltaic power station better, reduce the effects of photovoltaic power station to the grid, we need to set up photovoltaic power station simulation model. However, the model of photovoltaic power station is complex, the speed of system simulation become slow after establish. In this paper, a real-time digital simulator based on the photovoltaic power station equivalent method will be given, through the proposed hierarchical equivalence method can simplify the process of equivalent of photovoltaic power station, shortening the period of equivalent model, and can be carried out in the process of each layer of the equivalent model accuracy validation, improve the accuracy of the equivalent model.

Summary: With a high proportion of variable renewable energy integration, accurate forecasting approach is of vital importance in ensuring the reliable and economic operation of power system. Therefore, in this article, a novel method for predicting photovoltaic (PV) power generation based on convolutional neural network (CNN) is proposed. Analytical models of PV systems are formulated, thereby providing physical knowledge about the relationship between PV output and critical meteorological features. To explore the nonlinear and time‐varying properties of PV output, CNN is adopted in this article, which matches the patterns of similar days. Case studies based on realistic datasets in Australia demonstrate that the forecasting performance for solar power can be effectively improved by taking advantage of the proposed CNN‐based learning method. [ABSTRACT FROM AUTHOR]

According to the energy policy, which encourages local consumption of photovoltaic (PV) energy, the energy sharing among neighboring PV prosumers is proved to be a more effective way compared with independent operations of each prosumer. In this paper, an energy storage (ES)-equipped energy-sharing provider (ESP) is proposed to facilitate the energy sharing of multiple PV prosumers. With the help of the ESP, the autonomous PV prosumers can be formed as an energy-sharing network, and the energy-sharing activities can be categorized as direct sharing and buffered sharing. First, with the assistance of the ES, a day-ahead scheduling model of the ESP is built to increase the operation profit and improve the net power profile of the energy-sharing network, which considers the uncertainty of PV energy, electricity prices, and prosumers’ load via stochastic programming. Moreover, to further increase the energy sharing, a real-time demand response model based on a Stackelberg game is presented to coordinate the energy consumption behavior of prosumers by using internal prices. Finally, through a practical case study, the effectiveness of the method is verified in terms of improving the economic benefits and PV energy sharing. [ABSTRACT FROM PUBLISHER]

According to the feed-in tariff for encouraging local consumption of photovoltaic (PV) energy, the energy sharing among neighboring PV prosumers in the microgrid could be more economical than the independent operation of prosumers. For microgrids of peer-to-peer PV prosumers, an energy-sharing model with price-based demand response is proposed. First, a dynamical internal pricing model is formulated for the operation of energy-sharing zone, which is defined based on the supply and demand ratio (SDR) of shared PV energy. Moreover, considering the energy consumption flexibility of prosumers, an equivalent cost model is designed in terms of economic cost and users’ willingness. As the internal prices are coupled with SDR in the microgrid, the algorithm and implementation method for solving the model is designed on a distributed iterative way. Finally, through a practical case study, the effectiveness of the method is verified in terms of saving PV prosumers’ costs and improving the sharing of the PV energy. [ABSTRACT FROM PUBLISHER]

Commercial building microgrids will play an important role in the smart energy city. Stochastic and uncoordinated electric vehicle (EV) charging activities, which may cause performance degradations and overloads, have put great stress on the distribution system. In order to improve the self-consumption of PV energy and reduce the impact on the power grid, a heuristic operation strategy for commercial building microgrids is proposed. The strategy is composed of three parts: the model of EV feasible charging region, the mechanism of dynamical event triggering, and the algorithm of real-time power allocation for EVs. Furthermore, in order to lower the cost of computation resource, the strategy is designed to operate without forecasting on photovoltaic output or EV charging demand. A comprehensive result obtained from simulation tests has shown that the proposed strategy has both satisfactory results and high efficiency, which can be utilized in embedded systems for real-time allocation of EV charging rate. [ABSTRACT FROM PUBLISHER]

This paper proposes a comprehensive solution methodology for the pricing difficulty when Lagrange multipliers are not unique. A linear optimization model is proposed to solve the congestion-related pricing difficulty. The objective function of the model is set to be minimizing the congestion surplus. In addition, an incentive-based allocation approach is incorporated in the solution procedure for cases when no marginal participant exists. The unique pricing solution obtained through our methodology can achieve proper reallocation of the undetermined surplus. Further, we discuss the reference bus independence property of the proposed pricing methodology. Numerical results are provided to fully test the proposed methodology. Other possible solutions are also presented for comparison. [ABSTRACT FROM PUBLISHER]