The removal efficiency of ammonia in denitrification downstream equipment, concentration and distribution mechanism of ammonia in fly ash and slurry were studied under the condition of high concentration of ammonia escaping from denitrification by selective catalytic reduction (SCR) in coal-fired power plants. Through sampling analysis of 350 MW and 600 MW units, the results show that: the escaping ammonia removal efficiencies of air preheater, electrostatic precipitator and wet desulphurization system are 3.37%-6.63%, 75.14%-83.28% and 36.36%-46.38%, respectively. The ammonia removal efficiencies of these downstream environmental protection equipment are high, and the ammonia concentration at chimney entrance decreases obviously compared with that at denitrification outlet. The ammonia content in fly ash is inversely proportional to the particle size of fly ash. Ammonia concentration in desulfurized flue gas increases with the increase of ammonia concentration in original flue gas. The removal efficiency of ammonia in desulphurization system decreases with the increase of slurry pH value. The results have great significance to the units’ environmental protection and economic running.

High temperature solid oxide electrolysis cell (SOEC) is a new type of high-efficiency electrochemical energy transfer device with high energy transfer efficiency, high reaction rate and wide application scenarios. It has enormous potential in the fields including production of low-cost green hydrogen and carbonaceous product with high added values. Nitrogen oxide treatment _{and ammonia synthesis may also be a promising direction of application. SOEC is expected to play an important role in the low-carbon transformation of energy, chemical industry, transportation and other fields. Based on the latest progress of SOEC in the fields of hydrogen production, oil production, nitride treatment and ammonia production, the development status of SOEC was systematically summarized, and the key directions for future development were prospected.}

Solar photovoltaic/thermal (PV/T) technology is the integration of PV modules and solar collectors, which can simultaneously generate electricity and provide thermal energy. The overall efficiency and the space utilization efficiency will be improved simultaneously by the combination of two modules. The types of PV/T technology and related theoretical researches were summarized firstly in this review. By focusing on the heat loss and overtemperature problem of flat-panel PV/T technology, the design progress has been reviewed and analyzed. The state-of-art study on integration of phase change materials with PV/T (PV/T-PCM) technology was comprehensively summarized. The deficiencies in the research and the future development tendency were also prospected in order to provide theoretical guidance for further development of PV/T systems.

Accurate estimation of state of charge (SOC), battery state of health (SOH) and prediction of battery remaining useful life (RUL) of lithium-ion battery are important contents of battery management. It is of great significance to prolong battery life and ensure the reliability of battery system. Researchers all over the world have done a lot of research on battery state evaluation and RUL prediction methods, and proposed a variety of methods. This paper first introduced the definition of SOC and SOH and the existing estimation methods and compared them. Then, the definition of RUL was introduced and the main methods were classified and compared. Finally, the challenges of lithium-ion battery state estimation and RUL prediction were summarized, and the future development direction was proposed.

In the past three decades, China’s power industry has developed rapidly and solved the problem of efficiency and cleanliness to a certain extent. However, the implementation of the “double carbon” target has put forward the requirements of low carbon development for China’s power industry. Improving energy utilization efficiency, increasing the proportion of zero-carbon energy and carbon-neutral energy, and equipping carbon capture, utilization and storage (CCUS) technology are three important ways to achieve carbon emission reduction in the power industry. Based on the carbon neutral formula of power system, the carbon emission reduction history of China’s power industry and the carbon emission reduction contribution of different pathways between 2000 and 2020 were analyzed, and the current situation and routes of CCUS technology development in China were described. The results show that between 2000 and 2011, improving the efficiency of carbon-containing energy utilization made the main contribution to carbon emission reduction in the power industry, and after 2011, the increase of the proportion of zero-carbon energy contributed more to carbon emission reduction in the power industry. To achieve the goal of carbon neutrality in the power industry, CCUS technology is indispensable when the fossil energy cannot be completely replaced. Currently, the high cost and energy consumption of CCUS technology are the main reasons that hinder its promotion. The fuel source capture technology realizes the graded utilization of energy and the enrichment of carbon components, which reduces the energy consumption of CO₂ capture, and the efficiency of fuel source carbon capture system can generally be improved by 5 to 8 percentage points compared with the current mainstream carbon capture technology.

In view of the unstable performance of the cold-end system of traditional power plants and the high annual operating cost, a mathematical model based on the heat, resistance, civil construction and annual operating cost calculation of the direct flow cold end system based on negative digging depth was established, and the cold end system configuration was obtained from different conditions outside the tower. The optimal configuration was used to analyze the effect of cooling water for intlet tower water temperature, coagulator area unit price and condenser negative digging depth on the performance of cold end system. The results show that reducing the cooling water for intlet tower water temperature and condenser area unit price can reduce the annual operating cost of cold end system. The performance parameters of the cold end system with a negative digging depth of 3 to 5 m reach the lager value. Therefore, selecting the cold end system configuration according to different weather parameters outside the tower can improve the operating efficiency of the power plant and reduce the annual operating cost of the cold end system.

As an important part of carbon capture, utilization and storage(CCUS) technology, CO₂ sequestration in saline aquifers is an effective means to achieve the goal of carbon neutralization. Improving the research scheme of CO₂ sequestration mechanism in saline aquifers is of great significance to accurately evaluate the storage potential. The storage mechanism of CO₂ sequestration in saline aquifers was discussed, the commonly used characterization techniques were summarized, the effects of different parameters on sequestration in saline aquifers were discussed, and the future development of this technology was prospected. According to the study of different storage mechanisms, the characterization technology of sequestration in saline aquifers mainly includes reservoir rock characterization, core flooding experiment, solubility experiment, mineralization reaction experiment and so on. The storage potential of CO₂ sequestration in saline aquifers is affected by many parameters, such as the residual water saturation, residual gas saturation, solubility and salt precipitation. Therefore, it is very important to select appropriate characterization techniques to determine the relevant parameters to ensure the accuracy of storage potential evaluation. In addition, the analysis of the whole process storage mechanism and the research of marine CO₂ sequestration in saline aquifers project are the important research direction of this technology in the future.

Proton exchange membrane (PEM) water electrolysis is a green and sustainable method of hydrogen production. The development of efficient and economical electrocatalysts for anodic oxygen evolution reaction (OER) is the key to its large-scale commercialization. Iridium oxide catalysts supported by different manganese based oxide carriers (IrO _x /Mn₈O₁₀Cl₃, IrO _x /β-MnO₂ and IrO _x /α-MnO₂) were prepared by two-step synthesis method, and the content of iridium is about 55%. Compared with the commercial IrO₂ and other noble metal containing electrocatalysts, the synthesized catalysts have lower overpotential and higher current density. The overpotential of IrO _x /β-MnO₂ is only 228 mV at the current density of 10 mA/cm². The specific mass activity of IrO _x /Mn₈O₁₀Cl₃ reaches 916.7 A/g_Ir at 1.53V. The enhancement of OER activity is attributed to the abundant hydroxyl oxygen defects and Ir^III species on the catalyst surface. The rich crystalline-amorphous interface provides a large number of active sites for the reaction. The iridium oxide/manganese based oxide catalysts reported in this paper provide new insights for the development of efficient and economical catalysts for acidic OER.

The new power system with high proportion of new energy and power electronic equipment is an important means to achieve the goal of “double carbon”, but the new power system will also bring a series of unstable problems. In the new power system, grid-forming control technology (GFM) has the characteristics of voltage support and active inertia, which can replace synchronous machine to realize grid support and maintain power system stability. Therefore, GFM has a broad development and application prospect. Based on this, this paper first briefly introduced the topology of energy storage converter, and selected its type according to the control characteristics of GFM technology. After that, a reasonable summary and analysis of the existing control strategies of GFM was made, the current research difficulties, problems and challenges in the development process and the research prospects were put forward, and the ideas for the construction of grid-forming construction were provided.

This paper reviewed the current development research of China’s offshore wind power industry in the field of integrated design of wind turbine, tower and foundation. This paper explored the feasibility of integrated design from the aspects of load reduction optimization technology, structural optimization technology and engineering exploration and application, and discussed the key technologies and implementation methods of integrated design that can be adopted under the optimization goal of lightweight offshore wind turbine support structure. The research shows that China’s offshore wind power industry needs to be gradually implemented from three levels: providing the prerequisites for integrated design, using the technologies that can be adopted at the current stage,and exploring the next research directions. In the context of offshore wind power moving towards grid parity, owner-engineers and third-party certification bodies need to play a greater role in promoting the integrated design method.

Hydrogen energy has broad development prospects as a clean, carbon-free, flexible and efficient secondary energy and industrial raw material. Although the technologies of hydrogen production by water electrolysis, hydrogen storage and hydrogen supply have been relatively mature, the technology chain of hydrogen production-storage-supply is still in its infancy. It is of great importance to explore the technology chain in power system for the cooperative utilization of hydrogen energy and traditional electricity. This paper firstly introduced the basic principles, classifications, advantages and disadvantages of the technologies including hydrogen production by water electrolysis, hydrogen storage and hydrogen supply, and summarized the development of hydrogen production by water electrolysis, hydrogen storage and hydrogen supply technologies in the United States, Japan and the European Union. Then, the current status of above technologies in China was analyzed, and three possible application modes of hydrogen production by water electrolysis, hydrogen storage and hydrogen supply in power system in China were discussed. Finally, based on the current situation, the suggestions for promoting the development of hydrogen production by water electrolysis, hydrogen storage and hydrogen supply in power system in China were put forward, which provide a reference for optimizing the development of the whole technology chain of hydrogen energy production-storage-supply-use.

The power balance of the new power system mainly based on new energy is facing an important technical challenge, and the participation of flexible load in power system regulation is an important way to enhance the active balance capability of the new power system. In view of the obvious seasonal and temporal characteristics of the electric and thermal loads, the new energy sources are “extremely cold and hot without wind” and “late peak without light”, and the thermoelectric loads in the new power system show the trend of anti-peak regulation. To address this problem, this paper analyzed the spatial and temporal characteristics and energy-use characteristics of electric and thermal loads, explored their regulation potential, focused on the control scenarios of electric and thermal controllable loads, and systematically gave a flexible scheduling strategy for electric and thermal loads to complete the flexible control and regulation of electric and thermal loads. The results realize the network-load cooperative optimization and flexible scheduling on the whole time scale, and thus verify the feasibility of the real-time participation of telectric and thermal loads in the scheduling of the grid.

The pollution-free characteristics of hydrogen energy make it a necessary means to achieve the goals of “carbon peaking” and “carbon neutralization” in China. With the implementation of a series of related policies, the development of hydrogen energy is to enter the fast lane. Large scale storage and transportation of hydrogen energy with low energy consumption is a technical bottleneck that needs to be solved urgently at present. Hydrogen liquefaction with mixed refrigerant is an effective means to solve this problem. This paper made a statistical analysis of the current hydrogen liquefaction with mixed refrigerants. The basic technical routes of different researchers and the current hydrogen liquefaction process were summarized. Furthermore, the suggestions for the development of hydrogen liquefaction process with mixed refrigerants were put forward, to provide effective support for large-scale storage and transportation technology of hydrogen and accelerate the realization of large-scale commercial use of hydrogen energy.

A model of hundred kilowatt proton exchange membrane fuel cell (PEMFC) combined heat and power system was established in Aspen Plus platform, which was composed of fuel processing unit, heat recovery unit and PEMFC unit. The key equipment model of fuel processing unit was built according to the reaction kinetic parameters, while PEMFC stack adopted the custom model from Aspen Custom Modeler. This paper verified the accuracy of key equipment model and analyzed the effects of operating parameters on system performances under steady-state conditions. The results show that under the operation mode of determining heat by power, the feed of combustion natural gas or the steam-carbon ratio of reforming gas can be appropriately reduced to improve electrical efficiency and exergy efficiency of the system. In addition, the linkage valve on the pipeline from pressure swing adsorption (PSA) to PEMFC can be adjusted to increase the anode inlet pressure of the stack, so as to improve the power generation. However, it is not recommended to increase the cathode inlet pressure of the stack, which will lead to raise of auxiliary equipment power consumption and decline in net power efficiency. When the power is determined by heat, the opposite adjustment method can be adopted, and the exhaust temperature of combustion flue gas and PEMFC tail gas can be reduced to improve the system thermal efficiency. The study results provide reference for adjusting the operation parameters of PEMFC combined heat and power system to achieve appropriate thermo-electric output ratio.

Hydrogen energy is an important part of China's new energy system,and its market scale and application scenarios are also expanding. Under the guidance of various national policies,provinces and cities have issued relevant policies in the fields of fuel cell vehicles and other fields according to their regional characteristics,which has accelerated the pace of hydrogen energy commercialization to a certain extent. In terms of fuel cells and other aspects,this paper sorted out the national and local hydrogen energy policies,and analyzed the application fields of hydrogen energy,the policy points of the future development planning of provinces and cities,and the profit model. Finally,the corresponding suggestions and prospects were given for the current process of hydrogen energy commercialization,which provide a reference for improving the efficiency of hydrogen energy in the future.

In order to establish a typical terminal multi-energy complementary system and know the characteristics of different optimal configurations and influence factors of its performance under different optimization objectives, this paper proposed a terminal multi-energy complementary system that integrates solar energy, wind energy and natural gas. The energy flow characteristics were analyzed based on the bus-bar structure, and an integrated optimization model for the design and operation of the system was established accordingly. Furthermore, the effects of optimization objectives and energy prices on the optimal configuration and performance of the system were studied, and the applicable scenarios of typical equipment such as micro-gas turbine, internal combustion engine and absorption chiller were illustrated, as well as the promoting effects of flexible power supply and energy storage device on the consumption of photovoltaic and wind power. The relationship between annual CO₂ emission reduction ratio and fossil fuel saving ratio of the system is consistent, and that between annual cost saving ratio and CO₂ emission reduction ratio is contrary under current technical and economic conditions. The most suitable natural gas price to ensure the applicable downward pressure exists and the effect of peak-valley difference of electricity price on system performance is clarified. The results can provide reference for system integration optimization design and energy price policy formulation.

The multi-energy complementary demonstra-tion projects of wind-solar-water-thermal-energy storage focuses on the development from the power side, and forms a complementary operation mode by using wind energy, solar energy, hydropower, coal to generate electricity. Multi-energy complementarity can effectively solve the problems of wind abandoning, light abandoning, water abandoning and power limiting, promote the absorption of renewable energy nearby, realize the stable delivery of electricity and improve the comprehensive utilization efficiency of energy. This paper summarized the connotation construction principles of multi-energy complementarity, detailed the development status and existing problems of the first batch of multi-energy complementarity demonstration projects, and analyzed in detail the development paths of different modes of multi-energy complementarity projects. This paper focused on the evaluation of wind and solar resources, new energy site planning, total installed capacity and optimal power ratio, optimal allocation of energy storage, coordinated control technology to ensure safety and stability and economic evaluation indicators of the project, so as to extract the general process and development mode suitable for the construction and promotion of multi-energy complementary projects. Finally, some summary and suggestions were put forward from the aspects of top-level design, market mechanism and operation management.

Perovskite solar cells (PSCs) have attracted extensive attentions due to their high-efficiency, simple preparation process and low-cost. The efficiency of the PSCs has increased from 3.8% to 25.7%. So far, more and more studies focus on n-i-p structured PSCs using SnO₂ as electron transport layer. However, its process reproducibility is relatively poor, and efficiency is still low. This report conducted a systematic study of planar n-i-p PSCs, mainly including the selection of transparent conductive oxide (TCO) glass, optimization of preparation parameters and the influence of storage conditions on device performance. Experimental results show that these parameters have an important impact on the device performance. At the same time, it was analyzed by scanning electron microscope, X-ray diffraction, absorption spectrum. The devices achieved an average efficiency of 21.85% and a highest efficiency of 23.47% with good reproducibility under the optimal conditions (Indium Tin oxide substrate, PbI₂ annealed at 70 ℃ for 1 min, standing time after dropping amine salt solution is less than 5 s, and stored in 4.5% humidity environment). This work provides scientific support for the preparation of high-efficiency and repeatable PSCs.

As a green and zero-carbon secondary energy, hydrogen is one of the key carriers for the development of energy transition and has become an important medium for energy interconnection. Hydrogen production by electrolytic decomposition of water is the main way to produce hydrogen in the future, which will promote the adjustment and transformation of energy structure. However, the development and industrial application of hydrogen energy technology in China is still at the initial stage. In addition, there are a lot of problems to be solved in the aspects of hydrogen energy production, storage and transportation, conversion and application industry chain. This paper analyzed the development status of green power hydrogen production technology, hydrogen storage and transportation technology, hydrogen application technology, and studied the typical scenarios of green electricity-hydrogen energy-multi-domain application and the key technologies of network coupling and integration. This work provides indicative ideas for the combination of hydrogen energy production, storage and application technology, and the development of application network in various areas.

As a new type of energy storage device, lithium ion capacitors not only have high energy density, but also have excellent power density and long cycle life. They have great application potential in high-power and long-life application scenarios. Firstly, this paper theoretically analyzed the reasons for the energy limitation of electrical double-layer capacitors and the performance improvement of lithium ion capacitors, and then compared and discussed the performance differences between lithium ion capacitors and electrical double-layer capacitors. Finally, the application potential of lithium ion capacitors in intelligent instruments, automotive energy conservation and emission reduction, new energy vehicles and renewable energy power generation and power storage was briefly analyzed. The results provide a theoretical basis for further improving the energy density of lithium ion capacitors, and point out the direction for the application of lithium ion capacitors.

The wide application of wet desulfurization technology makes the desulfurization efficiency reach more than 90%, but the high moisture content of flue gas after desulfurization increases the possibility of smog formation. The spray tower was the main body of research, and the three-dimensional steady-state numerical simulation of gas-liquid two-phase flow field in the tower was carried out based on Fluent software. The results show that the spray droplet diameter plays a key role in flue gas condensation and dehumidification. The smaller the droplet diameter, the larger the gas-liquid two-phase contact area, the more obvious the heat transfer effect. If the droplet diameter is less than 700 μm, the flue gas temperature drop above 6 K can be achieved. When the inlet flue gas temperature is in the range of 319-335 K, the ratio of condensed water caused by this temperature is basically unchanged. The spray droplet velocity has an integration effect on the flue gas flow field. Choosing the appropriate droplet velocity can reduce the flue gas reflux area, and improve the space utilization rate in the tower. When the droplet velocity increases to 40 m/s, the temperature drop of outlet flue gas can increase by about 1.9 K.

Aiming at the problems of difficult manual selection of features, cumbersome classification steps and low accuracy in traditional power quality disturbance classification methods, a disturbance classification method based on particle swarm optimization (PSO) and convolutional neural network (CNN) was proposed. Firstly, the one-dimensional time series of power quality disturbance signals were converted into two-dimensional matrices with equal rows and columns by using the reshaping function, and these two-dimensional matrices were properly divided into training data set and test data set. Secondly, the classification model of power quality disturbance was built based on CNN. Thirdly, the PSO algorithm was used to optimize the parameters of the classification model, and the trained data set was used to train the optimized power quality disturbance classification model. Finally, the trained power quality disturbance classification model was tested by using the test data set, and the class results of various power quality disturbances were obtained according to the output labels. Simulation results show that the classification model can extract the characteristics of power quality disturbance data by itself. Compared with other power quality disturbance classification models, this method has higher classification accuracy for power quality disturbance signals.

Wet electrostatic precipitator (WESP) is a fine treatment equipment for the treatment of coal flue gas. Taking a 660 MW ultra-low emission unit as the research object, the multi-pollutant removal performance and energy efficiency parameters of WESP were tested and analyzed systematically. The removal efficiencies of particulate matter, fog drop, SO₃ and Hg of WESP were 81.12%, 75.60%, 76.13% and 53.08%, respectively, and the power consumption was 402.6 (kW·h)/h, which met the design requirements. The emission mass concentration of each pollutant were 4.20, 17.25, 9.80, 4.08×10^-4 mg/m³, respectively, the emission factors were 13.76, 56.49, 32.10, 1.34×10^-3 g/(kW·h),respectively, the specific power consumption was 1.48×10^-4 (kW·h)/m³.The energy consumption for particle removal per unit mass was 22.87 (kW·h)/kg, which was in the industry average level. This study can provide reference for the subsequent pollutant reduction and energy efficiency control of coal-fired power plants.

Natural gas combined cycle (NGCC) has the characteristics of clean, high efficiency and strong variable load capacity under certain load range. The integration of NGCC unit with carbon capture system is an important way to achieve carbon emission reduction. A 884 MW natural gas combined cycle which consists of two gas turbines, each of which is equipped with a heat recovery steam generator in International Energy Agency (IEA) report was taken as the reference system, and the system was modeled and verified by Ebsilon software. Based on the principle of energy cascade utilization, the following four different integration schemes of NGCC unit with carbon capture system were proposed. Steam extraction from the IP/LP crossover and the condensate is returned to the deaerator, steam extraction from the IP/LP crossover and the condensate after heat exchange is returned to the deaerator, steam extraction from the IP/LP crossover and the condensate is returned to the condenser, steam extraction from the IP/LP crossover and addition of a new turbine while the condensate after heat exchange is returned to the deaerator. The thermodynamic performance of four different integration schemes is further analyzed, and the energy penalty is 6.67%, 6.59%, 6.81% and 5.46%, respectively. It can be seen that the proposed scheme 4 can effectively reduce the energy penalty.

In order to achieve the goal of “carbon peak, carbon neutrality” and build a safe, stable, green and low-carbon modern energy system, lithium-ion batteries have attracted much attention as a typical electrochemical energy storage device. How to ensure the safe and stable operation of the power stations has become the primary issue with the scale of newly installed capacity expanding. Therefore, from the perspective of cell materials, aiming at the existing problems of commercial lithium battery separators, the work of intelligent separators in recent years was reviewed, including the modification of polyolefin separator materials, the design of new intelligent separator structures and the development of high temperature resistant polymer materials. The importance of developing high-safety separator materials was emphasized. Finally, the future research on separators of liquid and solid batteries was prospected, in order to provide a reference for further optimization and design of high-safety energy storage materials.

In order to solve the problem that the current domestic and foreign electrical calculation methods have too high requirements for the input parameters of the planning power grid, the predicted load of the plot was transformed into the electrical calculation load, and the realization method of spatial distribution of the future load of the plot was proposed. On the basis of studying the classical reliability formula, the concept of comprehensive failure rate was proposed. Moreover, a more practical reliability engineering calculation formula was given, which simplifies the use conditions of the classical formula. The core algorithms of electrical integration calculation (including power flow, short circuit, reliability and N-\mathrm{1} verification), load forecasting and load space allocation algorithm were applied in the grid planning project of Dezhou Jinghua. The results show that the engineering implementation method is accurate and fast, and can meet the needs of power grid planning.

CO₂ mineralized all-solid waste alkali-activated cementitious materials can not only realize the storage of CO₂ mineralized, but also shorten the curing cycle of alkali-activated cementitious materials and improve their compressive strength. It is a promising way of CO₂ capture and utilization. The effects of the ratio of alkali-activated cementitious materials, mineralized curing pressure and mineralized curing time on the carbon fixation rate and compressive strength of CO₂ mineralized cementitious materials were studied. The results show that the calcium carbide slag as alkali activator is more suitable for mineralization curing, and the sample with the highest Ca/Si ratio has the best carbon fixation ability under the same curing condition. Increasing the curing pressure and curing time of CO₂ can improve the properties of the samples. Physical and chemical characterization test results show that, the microstructure of the mineralized samples is more compact than that of the natural curing samples, and the calcite-type calcium carbonate produced in the curing process is helpful to increase the compressive strength of the material. The research results provide basic data and reference for the development of CO₂ mineralization curing technology of all-solid waste alkali-activated cementitious materials.

The efficient and comprehensive utilization of solar energy is of great significance for the sustainable development of energy and the realization of the strategic objectives of peak carbon dioxide emissions and carbon neutralization. Firstly, focus on the two main solar energy utilization modes, photovoltaic and photothermal, we systematically introduced the main types, research status and development trend of photovoltaic technologies, as well as the current situation and development trend of thermal power generation, building heating and refrigeration, seawater desalination and industrial heating in photothermal utilization. Then, we discussed the basic principles, main types and research progress of photovoltaic/thermal integration technology, especially the integration technology combined with the phase change heat transfer mode, was systematically introduced. Finally, several flexible "photovoltaic +" solar energy utilization technologies were introduced briefly. Photovoltaic, photothermal, photovoltaic/thermal integration and "photovoltaic +" technologies are still in a period of rapid development, have huge application potential and breed a large number of new technological growth points. These technologies are of great significance to solve the energy and environmental crisis and maintain the sustainable development of human society.

The wind-solar-load correlation model is the basis for accurately evaluating the reliability of offshore wind power-photovoltaic-energy storage grid connected system. To solve the problem of high-dimensional wind-solar-load correlation modeling, a hybrid time-varying Copula model based on vine structure was proposed. By combining the actual wind farm output, photovoltaic power station output and grid load data, eight wind-solar-load combined Copula models were established, and the proposed model had more advantages than other models by using two common evaluation criteria of optimal model. Taking the measured data of wind farms and photovoltaic stations in Shandong province as examples, eight groups of models were analyzed and compared in IEEE-RTS79 system with wind farms and photovoltaic stations. The results show that the proposed Copula function model can more accurately describe the multi-dimensional wind-solar-load correlation. However, other existing models underestimate the impact of the wind-solar-load correlation on system reliability. After adding the energy storage device to the test system, other models also have deviations in the selection of the optimal wind-solar installed capacity ratio, the selection of storage power station capacity and the evaluation of power fluctuation.

The construction of anti-disaster backbone grid is of great significance to enhance the power supply capacity of power system under extreme natural disasters. Comprehensively considering economy and reliability, a planning method for anti-disaster backbone grid was proposed. The economy and reliability of the planning scheme were expressed as the strengthened cost and the benefit from loss reduction in life cycle. The objective function was to maximize the unit benefit from loss reduction of the original grid caused by the unit strengthened cost of backbone grid. Taking the network connectivity and safe operation of power system into account, a planning model for anti-disaster backbone grid was established. The model was solved by the improved crisscross optimization (ICSO) algorithm to find the optimal planning scheme. Finally, the effectiveness of the proposed method was verified by the simulation analysis of the IEEE 30-bus system.

Under the carbon peak goal and carbon neutral vision, offshore wind power has made great progress in China in recent years. The current development status and future planning of offshore wind power in China were analyzed, and the installed capacity of offshore wind power, new models and adopted technical routes were summarized. The paper focused on the basic type, anti-corrosion technology, and operation and maintenance technology of offshore wind power. The floating offshore wind power was the focus of basic type research. The operation and maintenance inspection and operation and maintenance management system was the focus of wind power operation and maintenance technology research. By analyzing the development status of offshore wind power, the main technical routes and advanced achievements of each technology were sorted out. Finally, based on the current domestic technology development status and demand, the future development trend of China’s offshore wind power was prospected.

In the projects of combined heat and power, the application of large capacity heat storage can improve the flexibility of power system operation control, so as to enhance the system ability to absorb wind power. To study the necessity of heat storage tank configuration, a cost-benefit model of heat storage tank configuration for thermal power plants was established, and the total revenue of heat storage tank configuration for thermal power plants was calculated by substituting the parameters obtained from the electrothermal comprehensive dispatching model of power systems with heat storage. The simulation example was solved by the mathematical programming solver GUROBI in MATLAB. The simulation results show that there is an optimal capacity of heat storage system to make the overall efficiency best and the model can effectively analyze the necessity of heat storage tank configuration in thermal power plants.

In the context of the global low-carbon transition, low-carbon and zero-carbon technologies such as hydrogen and ammonia are gradually gaining popularity, and are considered to be one of long-term technological choices for tackling climate change. Focusing on the strategic requirements of realizing the carbon neutrality target, this paper sorted out the characteristics of ammonia fuel, discussedits advantages, opportunities and challenges as a zero-carbon fuel, and analyzed the experience and enlightenment of developing ammonia industry in other countries. The research believes that ammonia fuel is one of the important zero-carbon energy sources under the background of carbon neutrality, and it has wide application prospects in fields of industry, electric power, and transportation. It is suggested that China should consider the development pace of global “ammonia economy”, deploy the “green ammonia” industry timely, and promote the pilot demonstration and application of ammonia fuel.

Distributed energy storage (DES) is a key component in smart distribution networks and microgrids. As one of the current disruptive technologies, artificial intelligence (AI) is expected to change the traditional modeling, analysis, and control methods of DES and make DES more intelligent. The development of the AI application in the field of power systems and the applicability of the modern AI methods in DES were briefly reviewed. Then, the AI application directions and the related research trends in three DES of different scales, micro-grid, smart building, and vehicle-to-grid (V2G), were considered. Finally, the future development of AI in DES was presented, in order to provide useful reference for intelligent research and development of distributed energy storage

Chemical looping combustion has the advantages of inherent CO₂ separation and significantly reducing the NO _x production. The circulation reactors are the core site for oxygen carrier redox and fuel conversion. The current research status of chemical looping combustion pilot systems was analyzed from three aspects of reactor type, solid material circulation mode and design theory. At present, chemical looping combustion pilot plants with heat input of 10~3 000 kW have been established in the world, and the technical readiness level is sixth. The mainstream technical route of chemical looping combustion is that the air reactor and fuel reactor both adopt the fluidized bed. The system circulation flow rate of the chemical looping pilot plants is generally lower than 25.5 kg/(m²·s), which makes it difficult to achieve self-heating operation. Finally, we introduced the latest progresses including the theoretical research, the development of a high-efficiency carbon stripper, the design of a high-flux circulating flow rate chemical looping combustion unit, and the reactor system design, etc.

In order to further analyze the consumption problem caused by regional photovoltaic power generation, the actual output data of typical photovoltaic power plants in Gansu province was used as an analysis sample to study the output characteristics of regional photovoltaic power generation. The output characteristics of a single photovoltaic power station was considered, and the seasonal and weather characteristics of photovoltaic daytime output was analyzed. Considering the cluster characteristics of photovoltaic power generation output, the volatility, correlation and simultaneity rate among different photovoltaic power plants were analyzed. The research results show that the overall photovoltaic output level in Gansu province is relatively high, but there are certain regional differences. Daily output is cyclical, while fluctuations are random. The output of regional photovoltaic power plants is correlated. Compared with the output of a single photovoltaic power station, the output of regional photovoltaic power plants has been reduced at the same time, and the impact on the grid when connected to the grid is reduced, which can improve the occurrence of “photovoltaic abandonment phenomenon”. The proposed quantitative analysis index for photovoltaic power generation output characteristics provides ideas and methods for regional photovoltaic power consumption analysis, and provides a reference for the formulation of photovoltaic power generation development plans.

Global climate change is the biggest threat to the sustainable development of human, and controlling CO₂ emissions is a major measure to deal with climate change. As a negative emission technology, the direct air capture (DAC) can capture CO₂ emitted from distributed sources, such as transportation, agriculture, forestry, and construction industries. The performance and cost of DAC materials are the most important factors that determine the widespread application of DAC technology. This paper reviewed the current research and development status of DAC materials. The performances, advantages and disadvantages of chemical absorption materials, chemical adsorption materials, physisorption materials and multifunctional carbon capture materials were summarized. The techno-economic analysis of different DAC materials was carried out. It is pointed out that the development of carbon capture materials with low cost, high capacity, high selectivity, and high stability is the key to realize the large-scale application of DAC technology.

With a large number of distributed energy resources connected to the grid,virtual power plants as a distributed energy management technology have received a lot of attention because of their flexibility,efficiency and sustainability. This paper briefly discussed the background of virtual power plants, analyzed the hot directions and emerging directions in virtual power plants,and introduced the composition and structure of virtual power plants. According to the different goals and functions of virtual power plants,virtual power plants can be divided into mission-driven virtual power plants, economy-driven virtual power plants and hybrid driven virtual power plants. On this basis, the different operation modes and different solution methods of different types of virtual power plants were further discussed. Finally,the future development prospects of virtual power plants were prospected.

Hydrogen energy storage is an important support for promoting global green low-carbon transformation and realizing “carbon neutrality” goal. After the “double carbon” goal was put forward, hydrogen energy storage has become a hot topic of social concern. The safety of hydrogen energy storage is one of the problems that must be focused on and solved first. Safety problems in four stages of hydrogen production, hydrogen storage, hydrogen transport and hydrogen use were summarized and analyzed, including hydrogen leakage and diffusion, hydrogen combustion and explosion, compatibility of hydrogen with metals. At the same time, the current status and development of hydrogen leakage detection sensor technologies were analyzed, and the urgent problems and future development directions of hydrogen leakage detection technologies were pointed out.

In order to study the change rule of coal consumption of cogeneration units under different heating load distributions in the whole working condition, and realize the goal of deep energy saving and carbon emission reduction in power plants, two 630 MW cogeneration units were taken as the research objects. The EBSILON software was used for modeling, and the different heating load distribution schemes of single and double units were studied and analyzed based on the Freuger formula and the principle of caloric method. It is found that there is a critical heating extraction steam flow point in the influence of thermoelectric load change on coal consumption of a single unit. When the heating flow is less than the critical point, the greater the electric load, the higher the thermal efficiency of the units. When the heating flow is greater than the critical point, the smaller the electrical load, the higher the thermal efficiency of the units. For two operating units, when the heating load is distributed centrally to one unit, the coal consumption of the whole plant under different working conditions is the least, and the energy saving effect is better. It is of great significance to find the best way of heat supply distribution to reduce the coal consumption of power plants, save energy and reduce emission and respond to the national “carbon neutral” policy.