In recent years, the use of phase change material (PCM) to improve the output performance of semiconductor thermoelectric generator (TEG) and maintain the long-term operation of TEG has been widely concerned. In view of the current situation that the existing PCM-TEG combination methods are complicated and lack of unified understanding, this paper established a PCM-TEG coupling mathematical model, compared the system performance when PCM is arranged on the hot side, cold side and double sides of TEG, and proposed a skeleton with PCM design and verified its effectiveness. The results show that, through the design of PCM, the output capacity of the TEG can be improved by the device thermal management, which can effectively avoid the failure of thermoelectric devices due to its own heat storage capacity. The skeleton with PCM design is superior to the conventional PCM-TEG system performance. The design of hot-side-PCM-TEG on the double-sides-PCM-TEG on double sides can effectively maintain the stable operation of TEG. Enhancing the heat transfer capacity of TEG on the cold side can make up for the defect of insufficient output performance of hot-side-PCM-TEG. The study results can provide a reference for the next research on the relevant application of PCM-TEG.

Energy conservation and efficiency improvement under the dual carbon background is the first choice for coal-fired power plants to reduce carbon. The energy efficiency parameters of dry electrostatic precipitator (ESP), wet electrostatic precipitator (WESP), auxiliary equipment and dust removal technology route before and after ultra-low emission transformation were analyzed and evaluated, which could excavate their energy saving and carbon reduction space. Before the transformation of ultra-low emission, the annual CO₂ emissions corresponding to the high voltage power consumption of 300 MW, 600 MW and 1000 MW units supporting dry ESP are about 6 000 t, 9 000 t and 14 000 t respectively. In addition, the better the performance of ESP, the higher the corresponding energy consumption and CO₂ emission. After the ultra-low emission transformation, the annual CO₂ emission corresponding to the high-voltage power supply power consumption of the 1000 MW unit supporting the ESP is about 18 000 t, which increases by about 20% compared with that before the transformation, but could be reduced by about 60% through the energy saving optimization. The annual CO₂ emissions corresponding to the high-voltage power supply power consumption of the 300 MW, 600 MW and 1000 MW units supporting the WESP are about 2 000 t, 2500 t and 3400 t, respectively. The low temperature economizer of 630 MW unit could reduce the annual CO₂ emission by about 19000 t, and the phase change condenser of 280 t/h furnace could reduce the annual CO₂ emission by about 8 000 t. Compared with the WESP removal technology route, the flue gas cooperative treatment technology route of 660 MW unit with low-low temperature ESP removal technology as the core could reduce the annual CO₂ emission by about 3 000 t. This paper could provide technical ideas for the carbon emission reduction of subsequent coal-fired power plants.

With the massive access to renewable power generation and the advancement of the marketization process, the development prospects of virtual power plants that can give full play to the value of flexible resources have gradually emerged. In the process of virtual power plant participation in the market, the formulation of its market trading strategy needs to be challenged by the market mechanism. On the other hand, the market trading is closely related to the optimal scheduling of resources. The adjustable capacity of the internal resources, uncertainty, load behavior and other characteristics bring challenges to the development of trading strategy. This paper focused on the challenges and problems faced in the market transactions of virtual power plants, and summarized the market strategies adapted to the market mechanism. The key technologies required to deal with the formulation of the strategies, such as uncertainty handling, bid analysis methods, and virtual plant management methods were analyzed and reviewed, in order to provide a reference and a direction for the future research on virtual power plants.

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.

The development of industry has brought a large amount of CO₂ emissions. In the process of achieving the goal of carbon peak and carbon neutralization, carbon dioxide capture, utilization and storage (CCUS) technology is an indispensable key technology. The carbon capture method with high technology maturity at this stage and great development potential in the future is post combustion carbon capture technology, mainly including solvent absorption, adsorption, membrane method and cryogenic distillation. The development and industrial application of the four most commonly used carbon capture methods were briefly introduced, and the industrial applicability of several methods was analyzed, especially the chemical absorption method and physical adsorption method, which are most widely used in large-scale carbon capture projects currently running. Chemical absorption method, adsorption method and membrane carbon capture technology have great development potential in the future, which can quickly promote the achievement of the goal of double carbon and help the near-zero emission of carbon.

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 cope with the increasing shortage of fossil fuels and a series of threats brought by global climate change, and achieve the goal of “dual carbon”, the proportion of renewable energy such as wind power and photovoltaic power in the grid has been continuously increased. However, the renewable energy power generation is random and uncontrollable, and the access location is scattered, which increases the difficulty of safe and stable operation of the power system. The introduction of virtual power plant (VPP)provides a feasible path for the above problems. The concept and classification of VPP was summarized and expounded. Moreover, the main differences between VPP and microgrid were compared. The existing researches from the perspectives of coordinated control, resource aggregation and optimal scheduling, and participation in the electricity market were analyzed and summarized. Taking the blockchain and digital twin technologies as examples, the applications of digital technologies in VPP were analyzed. Finally, the development prospects of VPP suitable for China’s national conditions and the challenges that may be faced in the future were pointed out.

Accurate power load forecasting is conducive to ensuring the safe and economic operation of the power system. Aiming at the problems of low prediction accuracy and long time consuming of the current prediction algorithms, an improved deep learning (DL) short-term load forecasting model based on random forest (RF) algorithm and rough set theory (RST), namely RF-DL-RST, was proposed. Firstly, based on historical data, the model used RF algorithm to extract the key features that affected the load forecasting. Then, the key features and historical load data were trained as the input and output items of deep neural network (DNN), and the prediction results were corrected by RST. After that, the rough set method was used to revise the prediction results. Finally, the simulation was verified by an example. The results show that the prediction accuracy of the model is higher than that of a single DNN model and a model without RST revised.

Optimizing the controllable load resources of residents on the demand side is a major aspect of virtual power plant (VPP). It is an important means to improve the utilization rate of new energy such as wind power and photovoltaic power, to achieve carbon neutrality. The key to control controllable load is to meet the basic power demand of users, and different users have different power demand. Therefore, an optimal control method of residents’ controllable load resources considering user demand was proposed. Considering the different demand of different users, as an intermediate link between the power grid and the load group, VPP manages the controllable load. Firstly, an improved K-means clustering algorithm for optimal k selection was proposed for clustering. Then, according to the demand difference function to quantify the deviation between the power consumption and the original demand of each group after load regulation, a priority division rule based on the demand difference was proposed. Finally, in the regulation, VPP compensated different costs for different priority groups to achieve the regulation goal of maximizing VPP revenue and minimizing changes in user electricity consumption behavior. The simulation results show that the proposed optimal control strategy can effectively cut the peak and fill the valley of the load curve, and ensure the VPP revenue with less impact on the power demand of users.

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.

In order to promote the utilization of clean and renewable energy such as solar energy and hydrogen energy, and better integrate it with virtual power plant technology, aiming at the coupling system of photovoltaic power station and electrolytic water hydrogen production, the operation mode of large-scale aggregate resources was constructed and the relevant economic analysis considering the initial investment of resources was carried out. At the same time, combined with the analysis of the annual output data of the actual photovoltaic power station project, it was discussed that when this kind of coupling resources were used as virtual power plant resources, while supporting the new power system and promoting the consumption of new energy, it could maintain and continuously optimize its own economy. The operation mode optimization elements, equipment function characteristics and market conditions worthy of attention were pointed out, which provided a reference for related research.

Under the background of energy complementarity and low-carbon economy, virtual power plant (VPP) is an effective carrier for achieving optimal allocation of regional resources and new energy consumption. At the technical level,the CO₂ recycling through carbon capture power plant (CCPP) and power-to-gas (P2G) conversion devices was realized, a CCPP-P2G coupling model was established, and a price based demand response model considering user satisfaction on the load side was introduced. In terms of low-carbon policy, the ladder carbon trading mechanism was introduced into VPP to constrain carbon emissions. Then, with the goal of minimizing the total cost, a low-carbon economic dispatch model for VPP was established. By setting different scheduling scenarios for comparison, the effectiveness of the model in low-carbon economy operation of VPP was verified, and the impact of carbon trading parameters on the carbon emissions and costs of VPP was explored through sensitivity analysis. The results show that the model has guiding significance for VPP low-carbon economic scheduling.

With the gradual increase in the proportion of new energy, energy storage technology, as an auxiliary new energy grid, has attracted wide attention. Hydrogen energy storage and fuel cell technology have been listed as strategic energy technologies in China, and have been actively applied in the market and enterprise development. Hydrogen production from electrolytic water can stabilize the fluctuation caused by the connection of renewable energy to the grid and help the power grid to cut peak and frequency modulation. As a power generation device to improve energy conversion rate, fuel cell has the advantages of low noise and no pollution, it is one of the effective ways to absorb renewable energy. This paper made a comparative analysis of the development status and advantages of the existing energy storage technologies, the key technologies and research directions of hydrogen energy storage system were introduced emphatically, and the commercial development of hydrogen energy storage was prospected.

Multi-infeed AC-DC hybrid system is the notable form of China’s power grid upgraded because of the distribution of the generation and load. Multiple high-capacity high voltage direct current transmission lines enhance the transmission capacity, while the problem of small signal stability will emerge new features. As the complexity of the power grid increases, the small signal stability problem faced by multi-feed AC-DC power systems becomes more severe, and a specific theoretical analysis is urgently needed. The article introduced the typical structures and characteristics of multi-feed AC-DC hybrid systems. The system dynamic interaction mechanisms and the stability problems under the small signal stability caused by AC-DC system interaction were reviewed. The research methods and their achievements in this field were summarized. The future developing trend of multi-feed AC-DC hybrid system and the challenges were discussed to provide references for related research work at last.

The increasingly frequent extreme weather has a more serious impact on the electro-thermal coupling system. Resilience is a core indicator that measures the system’s ability to withstand extreme events, reduce the impact of failures,and recover quickly. To enhance the ability of the electro-thermal coupling system to withstand extreme disasters,a two-stage three-layer resilience enhancement strategy of combined heat and power-virtual power plant (CHP-VPP) considering thermal inertia was proposed. In the first stage, the system was reconstructed based on the minimum spanning tree theory with the goal of minimizing the cost of tie switches. In the second stage,aiming at minimizing the operating cost,the optimal decisions under the worst failure scenario was formulated based on distributionally robust optimization theory. The column and constraint generation algorithm was used for iterative solutions. A CHP-VPP test system was built based on an IEEE 33-bus system and a 6-node thermal system. The simulation results show that the proposed method can effectively enhance the resilience of CHP-VPP to cope with extreme disasters.

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 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.

With the increase of new energy penetration, the power balance and frequency stability problems brought by its randomness, intermittency and volatility has become increasingly serious. It is difficult to cope with these problems only by traditional centralized power plants. Flexible resources in the power systems should also bear a part of the responsibility for the balance of power and energy. Virtual power plant (VPP) can aggregate a large number of distributed flexible resources with different characteristics, participate in the electricity markets as a whole and accept the dispatch of the grid, and provide important support for the real-time power balance of the power systems. The development of VPPs should be based on a large number of flexible resources, advanced communication and dispatching/control technologies, and efficient business models and good market policies. The operation of VPPs can be attributed to the energy flow of the energy network, the information interaction of the information network and the value transfer of the value network. Therefore, based on the three-layer network architeciture of “energy-information-value”, the operation modes and control schemes of different types of VPPs were analyzed, and the idea of “three flow separation-convergence” for VPP architecture design was proposed. The findings provide useful guidance for the design, construction and operation of VPPs.

Aiming at the multi-objective optimization of boiler combustion system, on the basis of the established prediction model of boiler combustion system, the weighted-particle swarm algorithm and the multi-objective particle swarm optimization (MOPSO) algorithm were used to optimize the adjustable operating parameters of the boiler, which can realize the operating state of the boiler with high efficiency and low NO_x emission. The analysis shows that the operating parameters obtained by the two optimization algorithms are similar, and the trend is consistent with the combustion characteristics analysis and combustion adjustment test results. It indicates that the intelligent algorithm is effective and feasible to optimize the combustion system of the power plant boiler. However, the weighted-particle swarm optimization algorithm has serious subjective dependence. It is difficult to select appropriate weights, and the optimization time is long and the results are few. However, the optimization time of the MOPSO algorithm is far less than the optimization time of the weighted-particle swarm optimization algorithm, the optimization results are more, and the optimization efficiency is higher. Therefore, the MOPSO algorithm is more beneficial to guide the actual operation of the boiler.

The research on the evaluation model of the energy storage power station focuses on the cost model and economic benefit model of the energy storage power station. However, fewer studies consider the social benefits brought by the long-term operation of the energy storage power station. The cost model of energy storage power station was firstly established by considering the construction cost, storage battery rental cost, labor cost, operation and maintenance cost, disposal cost and other costs. Then, the benefit model of energy storage power station was established by comprehensively considering the economic and social benefits. Finally, the comprehensive benefit evaluation model based on the whole life cycle of the energy storage power station was established, and the optimal scale was determined by comparing the comprehensive benefits of the four scale energy storage power stations. This work helps to verify the effectiveness of the comprehensive evaluation model, and provide an intuitive comprehensive evaluation method for the selection of the construction scale of the energy storage power station.

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.

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.

Based on the demand of China to achieve carbon neutrality and zero carbon energy architecture by 2060, this paper studied the future energy system and the realistic path of energy transformation in China. Combined with the trend of energy technology development and the actual situation of China’s current energy system dominated by fossil energy, the hard constraints of China’s energy transformation were analyzed. By comparing and studying the feasibility, the main challenges of different technology options for carbon neutrality energy solutions, and the global energy development trend, this paper deduced the realistic path of realizing carbon neutrality energy architecture and zero carbon energy transformation in 2060 under the premise of ensuring national energy security. Finally, the key technologies and the policy measures were put forward, which should be promoted to build a novel energy system with renewable energy as the main body for the future.

Offshore wind power is a kind of green energy, which has attracted more and more attention. The anti-corrosion technology of offshore wind power facilities has become a current research hotspot. This paper first expounded the corrosion mechanism of equipments in the marine environment, and then introduced the commonly used anti-corrosion technologies for offshore wind power facilities, including the anti-corrosion coatings, cathodic protection, reserved corrosion allowance method, etc. Then, combined with an example, the anti-corrosion technology of thermal spraying and mineral grease coating in the new anticorrosion method in splash area were introduced emphatically. Finally, it briefly described the anti-corrosion detection and maintenance means of wind power facilities. It also introduced the corrosion protection methods used in Guishan wind power project in Zhuhai, Guangdong, which has been built into grid connected power generation in China, in order to provide some suggestions for improving the anti-corrosion level of offshore wind power.

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.

Virtual power plant has become an important means to promote the construction of new power system and achieve the goal of “double carbon”. The intelligent operation management and control platform of virtual power plant effectively realizes the management and monitoring of flexible and adjustable resources in virtual power plant. The intelligent operation management and control platform of virtual power plant was described from the perspective of system framework and comprehensive functions. Firstly, the energy ecosystem of virtual power plant was analyzed and summarized based on framework of operation management and control, and market participation of virtual power plant. The intelligent operation management and control platform of virtual power plant was analyzed based on characteristics of platform system framework and platform structure framework. Then, the comprehensive functions of intelligent operation management and control platform of virtual power plant were analyzed from three aspects of functional structure blueprint, functional physical structure and functional scenario application.

In order to achieve carbon peaking and carbon neutrality goals, the power system presents the trend of extensive access of multiple power sources. A multi-power coordination bi-level optimal operation model was proposed. In the upper level model, photovoltaic, gas turbine, energy storage and other power sources were aggregated into the virtual power plant, and the overall dispatching cost of virtual power plant was minimized through optimization. In addition, the conditional value at risk theory was adopted to measure the risks in view of the uncertainty of photovoltaic output. The lower level model was the system clearing model, which took the minimum total cost of the system as the optimization objective. It can consider the virtual power plant, thermal power units and diesel units to participate in the bidding, and output the actual bidding capacity of the virtual power plant back to the upper level, so that the virtual power plant can adjust the power output according to the actual bidding capacity. In order to solve the constructed model, Karush-Kuhn-Tucker (KKT) condition and strong duality theory were used to transform the bi-level model into a single-level model. Finally, an example was given to verify the validity of the model, the results show that the coordinated operation of multiple power sources can effectively reduce the operating cost of the system and improve the consumption rate of renewable energy.

To achieve the carbon emission reduction target, the use of biomass to replace traditional energy is a key measure. The gasification process in the biomass gasification coupled power generation system was modeled and analyzed by Aspen Plus. The influence of equivalence ratio and ambient pressure on the composition of syngas gas was investigated, and the variation law of calorific value and energy of syngas was discussed based on the calculation results. The results show that the volume fraction of H₂ shows a monotonically decreasing trend with the increase of the equivalence ratio, from 19.47% to 5.19%. The CO volume fraction reaches a maximum value of about 22% near the equivalence ratio of 0.3. The volume fraction of CH₄ shows a monotonically decreasing state with the increase of equivalence ratio, from 1.3% to 0. Relying on the results of theoretical research, the gas calorific value curve shows the same change rule as CO and H₂, and reaches the highest value when the equivalence ratio is 0.3. In the range of 0.3-0.35, the overall change is not obvious and then declines. Considering the energy brought into the furnace and the sensible enthalpy of the gas, a synthesis gas energy evaluation method of calorific value + sensible enthalpy was proposed, which reaches the maximum value when the equivalence ratio is about 0.35.

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.

In order to obtain the online monitoring information of boiler furnace temperature field in thermal power plant quickly and accurately, a temperature field reconstruction algorithm of acoustic tomography (AT) based on deep neural network (DNN) was proposed. After normalizing the measured values, combined with principal component analysis (PCA) dimension reduction, a fully connected network was constructed to distinguish the peak type. Moreover, DNN and BP neural network were built to predict the normalized slowness value and its maximum value, respectively. Finally, the temperature field distribution was reconstructed. Four typical temperature field models were simulated by using this method. The results show that the reconstruction quality of DNN algorithm is better than that of Tikhonov regularization algorithm and conjugate gradient algorithm. In addition, the average relative error and root mean square error of reconstructed image are less than 0.36% and 0.85% respectively.

The shaft seal heater is a heat exchange device in a steam turbine, which plays an important role to the performance of the shaft seal system. Based on limited data, a method for calculating the relevant parameters of the shaft seal heater was proposed by using an iterative algorithm. The algorithm was validated by comparing the calculated basic heat transfer parameters of the shaft seal heater with the results from Aspen Plus software. The discrepancy is within 0.4%, which validates the iterative algorithm presented in this paper. Taking the practical application of the combined cycle steam turbine unit of Huaneng Beijing Thermal Power Co., Ltd. as an example, the liquid phase and gas phase flow at the outlet of the shell side, under the condtion of inlet parameter change, were calculated by using this method. Moreover, the correlation model between the fluctuation of import parameters and the heat transfer parameters of the heater was established to verify the effectiveness of the method.

Chemical absorption method is one of the most widely used technologies to capture CO₂ from flue gas of coal-fired power plants, but it has problems of low absorption capacity and high regeneration energy consumption. Therefore, it is one of the current research focuses to develop a new efficient CO₂ absorbent to replace the traditional monoethanolamine (MEA) absorbent..To study the CO₂ absorption and desorption performance of aminoethylpiperazine (AEP)+sodium glycinate (SG) complex solution with different proportions, 30%MEA was used as a reference standard. By adding different additives to adjust the pH value of the solution, the regeneration performance of the absorbent was improved. According to the absorption capacity, absorption rate, desorption capacity, desorption rate, absorption-desorption cycle performance and regeneration energy consumption of the absorbent, 35%AEP+5%SG+1% citric acid was selected as the best compound absorbent. The results show that the ratio of 35%AEP+5%SG+1% citric acid absorbent CO₂ absorption is 3.70 mol/L, desorption capacity is 3.55 mol/L, desorption rate is 96.05%, unit regeneration energy consumption is 136.75 kJ/mol. Compared with 30%MEA, the absorption capacity is increased by 1.18 times, desorption capacity is increased by 2.17 times, desorption rate is increased by 30.93%, and regeneration energy consumption is decreased by 33.90%. After 10 cycle tests, the compound solution has good cycle stability and good regeneration performance, and has potential application value.

Focusing on the goal of carbon peak and carbon neutrality, the low-carbonization of the whole link of energy power system (i.e., source-network-load-storage) faces new requirements and challenges. The high proportion of renewable energy generation has become an inevitable trend. Considering the impact of the uncertainty of renewable energy generation on the safe and stable operation of the power system, the use of virtual power plant (VPP) with multi-energy complementary characteristics is a favourable way to solve this problem. Therefore, an optimal scheduling strategy of multi-energy complementary VPP was proposed. Firstly, taking into account the coupling relationship between multiple energy sources, a VPP operation mechanism that takes into account the entire source-grid-load-storage chain was constructed. Secondly, according to the proposed operation mechanism, a multi-energy complementary optimal dispatching model with low carbon economy as the goal was proposed to promote the consumption of renewable energy by coordinating the dispatching of various types of devices. Finally, the effectiveness of the proposed strategy was verified by simulating and analyzing a reference case of a multi-energy complementary VPP including renewable energy generation in a region.

Under the carbon trading mechanism, virtual power plants (VPP) aggregating distributed energy resource (DER) to participate in electricity market (EM) trading will help new energy consumption and improve environmental benefits. This paper constructed a multi-agent VPP model including wind turbine, photovoltaic power, controllable distribution generation, stored energy, and flexible load, and formulated bidding strategies for each entity participating in the electric energy market (EEM) and peak regulating market (PRM). The EEM and PRM examples showed that participating in peak regulating bidding by VPP could achieve the maximum benefits of VPP and reasonable distribution of the interests among DER members. Moreover, this paper introduced the carbon trading mechanism, analyzed the correlation between changes in carbon trading price and wind and solar consumption rate, carbon emissions and VPP benefits, and further explored the impact of carbon sink resource trading on electricity price, output and energy demand change rate. It provided a basis for the ecological protection compensation mechanism of carbon sink value, and also provided a reference for the price transmission effect of carbon market (CM) on EM under the coordination of electricity-carbon market and the optimization design of CM price mechanism.

China is vigorously developing hydrogen energy and actively realizing the “3060” carbon emission target. It is estimated that China will become one of the largest producers and consumers of hydrogen energy. The resource endowment and economic development of Chinese provinces are different, so the inter-provincial energy cooperation is particularly important. In order to study the feasibility of inter-provincial supply of green hydrogen energy, including the technical feasibility of hydrogen energy transportation, the total cost of ownership (TCO) model of inter-provincial transportation of hydrogen energy was established by using the TCO theory. On this basis, the case study of hydrogen production in Jiangxi province for Guangdong province was analyzed. After model calculation, the cost of hydrogen energy from Jiangxi to Guangdong was found to be 31.9 yuan/kg, which is equal to the local price of hydrogen energy. Meanwhile, the main factors affecting the price of hydrogen energy from other provinces were summarized. It is found that the electricity cost of hydrogen production accounts for 42.38% of the cost of hydrogen production. This research results provide a solution for the supply of green hydrogen energy in China, and also provide a new idea for constructing a new energy transportation channel.

In order to ensure the water production capacity of the seawater desalination system under the low load condition of the generator units, and improve the economy of the whole plant, four dual-purpose power and water plant units were taken as examples. The thermodynamic modeling of the four units was carried out by EBSILON software, and the accuracy of the model was verified. The steam sources meeting the conditions of sea fresh water production were analyzed, and three steam extraction schemes meeting the conditions of low load were put forward. Based on the classical theory of thermodynamics, the thermodynamic model was used to demonstrate and analyze the three steam extraction schemes. Moreover, through the comparative analysis of the coal consumption and transformation cost of the three steam extraction schemes, the optimal low load steam supply scheme was obtained. This study has a certain guiding significance for the power plant energy saving and emission reduction and improvement of the economic efficiency of power plant operation.

Aiming at the high energy consumption of coal fired units integrated with post-combustion CO₂ capture systems, a carbon capture system integrated with membrane condenser based on the recovery potential of low-grade heat in flue gas by membrane condenser was proposed. Based on the chemical process simulation software Aspen plus and Tarong conventional carbon capture system as a reference, a comparative analysis was conducted on the changes in cold and hot load of carbon capture before and after the membrane condenser was used for process transformation, providing a basis for the design and operation of the device. When the carbon capture rate is 90%, the regeneration energy consumption of the new system is reduced to 4.275 MJ/kg CO₂ compared with 4.341 MJ/kg CO₂ of the conventional carbon capture system. Changing the key parameters of the new system, it is found that when the flue gas temperature and CO₂ capture rate of the inlet and outlet of the membrane condenser are constant, the recovery rate of flue gas water increases and the regeneration energy consumption decreases. When the outlet flue gas temperature, flue gas water recovery rate and CO₂ capture rate of membrane condenser are constant, the inlet flue gas temperature increases and the regeneration energy consumption decreases. In addition, the cooling load decreases with the increase of water recovery and increases with the increase of heat recovery.

This paper analyzed the localization status of key components and systems in offshore wind turbines such as blades, spindles, electrical systems, and control systems.In view of the localization weaknesses existing in the components and systems of offshore wind turbines, the localization of blades, main bearings, converters and programmable logic controller (PLC) was carried out by using the ideas of theoretical analysis, material/component selection, component development, test verification and overall assembly, and 5 MW offshore wind turbines were assembled with the developed localization components and systems. The localization rate of the unit was more than 95%. The results show that most of the components and systems of offshore wind turbines have the conditions for localization, but some technologies, such as blade design, still rely on imports, and a few core components are still missing in China.

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.}