Objectives Under the background of the “double-carbon” target, thermal power is facing great pressure to reduce emissions. Thermal power carbon footprint evaluation can directly show the greenhouse gas emissions of thermal power and help tap the potential of carbon reduction. Therefore, the research status of thermal power carbon footprint assessment was reviewed. Methods This paper introduced the main standards and methods for thermal power footprint evaluation, and summarized the thermal power footprint evaluation process. The differences in the evaluation process were reviewed and some suggestions were given. The life cycle is divided into upstream, core and downstream. According to the high concentration of carbon emissions in the core links, the carbon footprint of the construction, decommissioning and power transmission of coal-fired power plants can be ignored in some cases. Conclusions The life cycle of different types of thermal power generation is similar, but the carbon footprint of waste incineration power generation does not include the acquisition process of domestic waste. Regardless of the form of thermal power, in the absence of measured emission factors, it is recommended that the emission factors select the default values of the published standards, literature and databases at home and abroad.

Objectives As an important support for the new power system, hydrogen gas turbines can help reduce carbon emissions and are conducive to grid peak regulation. They are the focus of technological innovation in the global future strategic emerging industries. Many key issues faced by hydrogen blending gas turbine power generation technology from demonstration to commercialization, need to be solved. Methods H-class gas turbines were taken as the research object, and the strategic planning and demonstration projects of hydrogen blending gas turbine power generation in China and abroad were introduced, and the technology routes of H-class gas turbines of major gas turbine manufacturers were compared. The analysis and suggestion was made from four aspects for the scale application of future hydrogen blending gas turbine power generation technology, including hydrogen source, system transformation, emission impact and hydrogen blending power generation cost. Results Renewable energy electrolysis of water to produce hydrogen will be the main source of hydrogen blending gas turbine power generation. In addition, the development of new dry low nitrogen oxide burners, which are suitable for unstable combustion of hydrogen blending, will be the key direction for future hydrogen blending gas turbine system transformation. The higher the hydrogen volume percentage is, the greater the CO₂ emission reduction is. However, the NO _x emission is on an upward trend. Moreover, there is a risk of exceeding the standard value, and the future cost of hydrogen blending gas turbine power generation can reach the same level as the cost of natural gas power generation. Conclusions With the reduction of the cost of large-scale renewable energy hydrogen production, and the implementation of carbon tax and the maturity of hydrogen blending power generation technology, the gas turbine hydrogen blending power generation will gradually enter large-scale application.

Objectives Magnetic confinement fusion is regarded as a critical solution to future global energy challenges. As the central component of magnetic confinement fusion devices, magnets play a crucial role in generating and sustaining plasma stability. A review of the magnetic system structures and specifications in representative magnetic confinement fusion devices worldwide was provided. Methods The technological evolution of fusion magnets was reviewed, from copper-based to low-temperature superconducting, and finally to high-temperature superconducting magnets. The structure and performance parameters of magnetic systems in various typical fusion devices were summarized systematically. Additionally, the technical challenges in magnet development were explored and an outlook on future development trend was offered. Conclusions Advances in magnet technology are vital for enhancing the performance of fusion devices and accelerating the commercialization of fusion energy. With the increasing application of high-temperature superconducting materials and continuous optimization of magnet designs, the practical realization of fusion energy is becoming increasingly feasible.

Objectives Liquid storage and transportation is one of the effective ways to realize large-scale and long-distance storage and transportation of hydrogen and ensure the large-scale application of hydrogen energy. At present, there is relatively little research on the preparation, storage, transportation, and refueling of liquid hydrogen in China. Therefore, the current development status analysis of key technologies in these fields was conducted. Methods The advantages and disadvantages of high pressure gaseous storage, liquid hydrogen storage and solid hydrogen storage technologies were compared. The main liquefaction methods, liquid hydrogen storage insulation technologies and key materials in the process of liquid hydrogen preparation were reviewed. The characteristics of different transportation modes and equipments of liquid hydrogen were analyzed. The construction of liquid hydrogen hydrogenation station was combed, and the liquid hydrogen filling technologies were compared. The main application fields and industrialization modes of liquid hydrogen were expounded, and a statistical analysis of the patent technologies of liquid hydrogen storage and transportation in China in recent years was carried. Results The “neck-stuck” difficulties faced by the development of liquid hydrogen storage and transportation in China and the urgent need for technical research directions were proposed. Conclusions The results can provide reference for the key technology research and equipment development of liquid hydrogen.

Objectives Deep peak regulation of coal-fired boilers is crucial to the stability of the future power system dominated by new energy, but there is a lack of performance and engineering applications on deep peak regulation of 1 000 MW ultra-supercritical coal-fired boilers. In order to improve the deep peak regulation capacity of 1 000 MW coal-fired boilers, a 1 000 MW coal-fired unit of a power plant is selected to carry out a wide-load high-efficiency research. Methods Focusing on the unit load depth peak regulation load of 340 MW, the low-load stable combustion experiment and the denitrification side inlet flue gas test were carried out. In addition, the main operating parameters of the boiler, the temperature distribution of the furnace and the combustion adjustment test on the boiler side were analyzed. The combustion optimization adjustment experiment was carried out on this basis. Results 1 000 MW unit has a deep peak regulation capacity of 34% rated power. The flue gas temperatures of selective catalytic reduction (SCR) denitrification inlet are basically 320-350 ℃, which meet the flue gas temperature requirements higher than 300 ℃. After the optimization and adjustment of the boiler, the modified thermal efficiency of the boiler is 94.09% (increased by 0.94%), and the coal consumption for power supply is reduced by 3.27 g/(kW⋅h). The NO _x at the inlet of SCR denitrification is basically 180-260 mg/m³ (decreased by about 30 mg/m³), and meet the requirements of less than 300 mg/m³. Conclusions The research results are helpful to improve the safety, economy and environmental properties of low-load operation of 1 000 MW coal-fired thermal power units.

Objectives The effectiveness of cooling technology directly influences the performance and lifespan of gas turbine blades operating in high-temperature, and high-pressure environments. The research status of swirl cooling technology was reviewed, aiming to summarize and evaluate its application in enhancing cooling efficiency and reducing thermal stress, and systematically analyze the basic principle and performance of swirl cooling technology. Methods The review focused on the design of swirl cooling channels, the combined use of swirl and film cooling, and the impact of rotational conditions on heat transfer performance. Results The swirl cooling technology significantly improves blade cooling efficiency and reduces thermal stress concentration. Specifically, reasonable design of swirl cooling channel can achieve uniform distribution of cooling fluid, enhance the cooling effect and prolong the service life of the blade. Conclusions The application of swirl cooling technology in gas turbine blade cooling has broad prospects. Future research should continue to explore the optimized design of swirl cooling technology and its performance under various operating conditions. Additionally, the combination with advanced manufacturing technologies, such as additive manufacturing, can further enhance the design complexity and cooling efficiency of swirl cooling channels, providing reliable support for the efficient and stable operation of gas turbines.

Objectives The mechanism of the impact of carbon capture technology on the peaking capacity of coal-fired power plants was analyzed, and the impact on the carbon capture technology on the power generation efficiency of coal-fired power plants was quantified. Methods A typical coal-fired power plant was used as an example, and a post-combustion carbon capture scheme was selected. The simulation model of the conventional coal-fired thermal power unit and the carbon capture power plant was constructed by EBSILON software. The operation interval of the carbon capture power plant was derived. A comparative analysis of the operation of the carbon capture power plant and the conventional coal-fired power plant was conducted, and the variation in peaking performance was investigated. Results The equivalent output power of the carbon capture power plant decreased by 1%-2%, the net output power decreased by 20%-30%, and the net efficiency of the whole field decreased by 8%-10% compared with the conventional coal-fired power plant. Conclusions The addition of a carbon capture system allows the plant to gain greater downward peaking depth and faster peaking response, although it reduces efficiency.

Objectives Under the background of the “dual carbon” strategic goal, the demand for flexible regulation resources in the power system has significantly increased after the large-scale integration of new energy generation into the grid. At present, the coal-fired power is the main flexible resource on the power side with the ability to scale up peak shaving. Since 2016, the major domestic power generation companies have implemented a certain scale of flexibility transformation of coal-fired power units. Therefore, it is necessary to summarize and analyze the problems existing in the actual operation and maintenance of the unit after flexibility transformation. Methods The technical route, investment cost and actual operation of several coal-fired power units with flexible transformation in a company were statistically analyzed. Results After the flexibility improvement and transformation of the active coal-fired power generation unit, the minimum power generation output of the advanced unit can be reduced to 18%P_e (P_e is rated load) level, the load change rate with 20%P_e~30%P_e can reach 1.8%P_e/min, and an average unit capacity investment is 101 yuan/kW. In addition, under flexible operating conditions, the coal consumption of coal-fired power units after the transformation has significantly increased. Conclusions Suggestions are put forward for the operation, maintenance and further work of coal-fired power units under flexible operating conditions. The research results provide reference and inspiration for the flexibility improvement and transformation of existing coal-fired power units.

Objectives The inlet temperature of gas turbine has far exceeded the allowable temperature of the blade material, so it is very important to develop more efficient turbine cooling technology, especially the film cooling technology. The film cooling in the central region of the turbine blade is usually supplied by the crossflow ribbed passage. Therefore, the research progress of the film cooling in the crossflow ribbed passage in recent years was reviewed. Methods The variations in film cooling performance under different coolant supply modes were introduced. The impacts of rib angle, rib shape, relative position of film holes and ribs, and Reynolds number at the inlet of the crossflow channel on flow and film cooling performance were summarized. The research progress of film cooling hole shape design under the condition of crossflow ribbed cooling air was concluded. Results The internal cooling structures within the crossflow ribbed passage and the Reynolds number at the entrance of the crossflow channel exert significant influences on film cooling performance, while the distribution of cooling effectiveness at the hole outlet downstream is altered during crossflow intake. Moreover, the flow at the hole entrance is influenced by both the relative position of the hole and rib as well as changes in Reynolds number. The asymmetrical spanwise cooling hole and the hole insensitive to the crossflow can enhance the film cooling performance. Conclusions In order to further promote the development of film cooling technology in the crossflow ribbed passage, it is recommended to thoroughly study the relationship between film cooling performance and all influencing factors, and to optimize the design of special film cooling hole suitable for crossflow ribbed inlet.

Objectives In order to provide technical reference and design basis for the research and subsequent upgrade of China’s independent heavy-duty gas turbine, a series of upgrade measures of SGT5-4000F gas turbine were analyzed. Methods Through the collection, organization and performance analysis of relevant literature and data on the SGT5-4000F gas turbine, a series of upgrade measures taken by Siemens to improve the performance of the gas turbine have been summarized since it was introduced to the market in 1996. Results Through the analysis, it can be concluded that Siemens’ upgrade measures include: increasing compressor mass flow, reducing the cooling air and adopting HCO to improve the power and thermal efficiency. The use of premixed pilot and optimization of the main swirler helps to improve the thermo-acoustic stability and reduce NO _x emission. The validated new materials and new casting technologies can be used to improve the durability, life and operational flexibility. Conclusions The above technical upgrade measures can be used as technical reference and design basis for future improvement and upgrade of China’s independent heavy-duty gas turbine and its derivative models.

Objectives With the continuous development of China's new power system, there is a growing integration of new energy sources such as photovoltaic and wind power into the grid. However, this integration has also led to an increase in intelligent control equipment and nonlinear loads, resulting in more complex power quality issues. In order to enhance the power supply quality of the entire power grid and achieve economic operation and efficient development, it is crucial to conduct a scientific and rational quantitative evaluation of power quality. Methods Starting from three aspects of power quality evaluation indicators, weighting methods and evaluation models, the comprehensive power quality evaluation methods were systematically summarized and compared, and the research status of comprehensive power quality evaluation methods was summarized. On this basis, the shortcomings and problems that need to be solved of various existing comprehensive power quality assessment methods were summarized, and the possible research directions in this field were prospected. Conclusions Although many results have been achieved in the research on comprehensive evaluation of power quality at home and abroad, each method has its own advantages and disadvantages, there are still a series of important neglected problems that need to be solved in this field.

Objectives Traditional electric energy storage has limitations in scale, duration, and environmental impact.Moreover, the renewable energy absorption capacity in the microgrid is low, and low-carbon and economy cannot be taken into account in planning. In order to solve the above problems, based on the basic working principle of hydrogen energy storage, hydrogen energy storage was incorporated into the microgrid instead of traditional electric energy storage, and a low-carbon and economic synergy bi-level optimization configuration model of microgrid with hydrogen energy storage was established. Methods The upper-level planning model aimed at minimizing the comprehensive equivalent annual value of the microgrid, based on the joint operation of electricity and hydrogen. The carbon trading mechanism was introduced to plan the capacity of various power generation equipments in the microgrid, which can enhance the low-carbon of the system. The lower-level operation model aimed to minimize the sum of the absolute values of the difference between the new energy output and the load demand. The model also encouraged users to adopt diversified demand-side response behaviors with the goal of accurately tracking the new energy output curve, and feeded back the user’s energy consumption behavior to the upper-level model to optimize the load curve. On the basis of improving the absorption capacity of new energy, the system economy is further improved, deeply exploring the synergy between the low-carbon and economic characteristics of microgrids. Results The simulation results of microgrid in a certain industrial park show that the proposed method yields a planning scheme with excellent low-carbon and economy. Compared with the traditional planning method, the low-carbon and economy are improved by 53.6% and 37.1%, respectively. Conclusions The model presented in this paper not only enhances the capacity for new energy absorption but also further improves the system economic performance. It achieves a synergistic enhancement of the microgrid low-carbon and economy.

Objectives The high-efficiency internal cooling technology of turbine blade is crucial for improving the thermal efficiency of gas turbine. As an important component of the gas turbine, it is essential to conduct research on the cooling performance of rotor blade. Due to significant effect of Coriolis force, buoyancy force, and channel structure on the cooling performance of rotating internal channel of turbine blade, this paper summarized the research status and development trends of rotating internal cooling channel based on these effect factors. Methods A new structural design of rotating internal cooling channels was introduced, and a new rotating internal cooling channel structure suitable for double-walled blade configurations was proposed. Conclusions Double-sided enhanced U-shaped channels can utilize the enhanced heat transfer effect of Coriolis force, resulting in better cooling performance than traditional rotating U-shaped channels. There is a broad room for improvement in the internal cooling of gas turbine rotor blades.

Objectives Timely and accurate detection of power facilities is very important to ensure the reliability of energy supply. However, a single sensor has certain limitations in the detection of power facilities. Therefore, a multi-scale feature heterogeneous image fusion algorithm based on saliency detection was proposed. Methods Firstly, the edge guidance network was used to extract the salient target from the infrared image to generate the salient target mask. Secondly, a specific loss function was established in each region, and the salient target mask was used to guide the network for feature extraction. Finally, a directional heterogeneous fusion method based on feature hierarchy was proposed, which combined the depth features of different scales to minimize information loss. Results Subjective and objective experiments on the TNO dataset show that the algorithm is superior to other methods in most evaluation indicators, which verifies the effectiveness of its application in the field of power facilities detection. Conclusions The algorithm effectively solves the problems of low detection rate and information loss, and makes the detection of power facilities more comprehensive and accurate. It is of great significance to improve the accuracy and diagnostic efficiency of power equipment fault detection.

Objectives The natural draft cooling towers with flue gas injection (NDCT-FGI) is a crucial retrofitting technique for enhancing the efficiency of thermal power plants. However, its operational impacts on existing systems are significant and cannot be overlooked. Therefore, the current status of NDCT-FGI technology and its problems in operation were analyzed, and the countermeasures were put forward. Methods Through comprehensive analysis of the existing research, the causes and formation mechanism of environmental impact, cooling tower corrosion, and deterioration of circulating cooling water quality caused by the technical transformation of NDCT-FGI were discussed. Results The protective distance can be reasonably set by the simulation results of flue gas emission trajectory and pollutant landing concentration by computational fluid dynamics (CFD). Installation of baffles at the tower top can prevent flue gas washdown during the extreme weather conditions. Different anticorrosive coatings are recommended for various parts of the cooling tower to extend its service life. To control and optimize cooling water quality, the advanced water treatment techniques are necessary for optimizing chemical dosing, and the management of effluent and makeup water must be carefully controlled to ensure operational sustainability. Conclusions By implementing appropriate and effective countermeasures, the negative impacts of NDCT-FGI retrofitting can be mitigated, thereby enhancing both the environmental and economic benefits for thermal power plants.

Objectives With the intervention of new energy, the uncertainty and volatility problems of new energy output have been shown. In order to make up for the shortcomings of new energy output, thermal power units have assumed the role of peak regulation. In order to improve the peak-load capacity of thermal power units, the peak-load characteristics were studied. Methods Firstly, a 350 MW heating unit was taken as the analysis object. The simulation software was used to build the thermal system model, and the accuracy of the model was verified. Secondly, with the heat storage system as the auxiliary system, the peak-load capacity of the unit under the condition of meeting the heating demand was studied, and the influence of energy storage units such as heat storage on the peak-load capacity of the unit was analyzed. Finally, the heuristic particle swarm optimization algorithm was used to optimize the operation strategy of the storage tank, and the optimal operation mode of the storage tank changing with the heat load was obtained. Results The peak regulation and heating capacity of the unit can be effectively improved by coupling the storage water tank with the unit, and the operation mode can be determined according to the actual heat load data to maximize the benefit. Conclusions This method has guiding significance to the operation strategy of the unit.

Objectives In order to master the deep peak shaving capability of supercritical circulating fluidized bed units and scientifically participate in the auxiliary service market, it is necessary to conduct in-depth research on the deep peak shaving performance of existing units. Methods From the three dimensions of safety, economy and environmental protection, 40% and 30% of rated load continuous trial operation, boiler combustion optimization adjustment, boiler efficiency and steam turbine heat consumption rate performance tests were carried out, respectively.More than 10 optimization measures such as single pump operation of feed water pump, pressure curve optimization, boiler oxygen amount, bed pressure adjustment, etc., were implemented. Results The continuous operation of 30% rated load for 12 consecutive days was realized, 40% and 30% rated load depth peak-monasizing the peaks affected coal consumption by about 52%, 72 g/(kW·h), respectively. Conclusions The 350 MW supercritical circulating fluidized bed unit has good deep peak shaving ability. There is no need to transform 30% rated load conditions, and inject oil to stabilize combustion and maintain high efficiency of the boiler. Monitoring parameters for the steam turbine generator unit body, thermal system and auxiliary equipment are normal. The main flue gas pollutants are ultra-low emission.

Objectives The accurate measurement of CO₂ emission is of great significance for carbon reduction and the operation of carbon market. Continuous monitoring technology is an important means of measuring carbon emissions from flue gas of thermal power units. Compared with the accounting method, it has the advantages of less human intervention, high automation, and strong timeliness.The research progress and application status of continuous monitoring technology for carbon emissions was reviewed, aiming to provide reference for the power generation industry to establish a more perfect carbon emission measurement method system and carbon emission data management system. Methods The research progress of CO₂ concentration monitoring technology and flow monitoring technology in flue gas was emphasized. The current application status of continuous carbon emission monitoring technology in thermal power plants in the United States, the European Union and China was analyzed. The comparative research situation between continuous monitoring method and accounting method was discussed. Conclusions The technical challenge faced by continuous carbon emission monitoring technology is the accurate monitoring of flue gas flow rate. There are great differences in the magnitude and accuracy of carbon emissions obtained by continuous monitoring and accounting methods. Based on the current situation of continuous monitoring of carbon emissions in China, it is recommended to improve the relevant policies and standard system as soon as possible, conduct in-depth technological research, and expand technological applications.

Objectives A portable solid oxide fuel cell (SOFC) system includes a gas supply module, a fuel processing module, an SOFC power generation module, a thermal management module, an exhaust treatment module and a control module. There is a complex coupling relationship between the fuel processing module and the SOFC power generation module. Clarifying the coupling characteristics between them is crucial for improving system performance and operating time. Methods The effects of temperature, the carbon-to-oxygen ratio and other factors on the performance of catalytic partial oxidation (CPOx) of propane with Rh as catalyst were analyzed, and the coupling performance of CPOx and SOFC stack was further tested. Results With the increasing of fuel flow rate, the reforming efficiency first increases and then decreases. The most suitable flow rate is 100 or 150 mL/min. An increase in temperature can continuously improve the reforming efficiency, but the improvement in reforming efficiency at high temperatures caused by an increase in temperature gradually decreases. The optimal C/O ratio obtained from the experiment is 1.0. Under the optimal operating conditions, the output power of SOFC stack reaches 8.38 W. Conclusions Under the conditions of propane flow rate of 150 min^-1, carbon and oxygen mole fraction ratio of 1.0, and operating temperature of 800 ℃, the coupling performance between SOFC stack and CPOx is the best, the portable propane power generation system can generate 150 W of power with a volume of 12 L.

Objectives Battery energy storage system is one of the effective means to ensure the reliability of photovoltaic (PV) power generation system and improve the utilization rate of PV power generation. However, there are some problems in the PV-energy storage power station, such as the difficulty of power fluctuation suppression and the unreasonable configuration of energy storage capacity. In order to solve these problems, relevant research was carried out. Methods For energy-based battery energy storage, the characteristics of scheduling mode and autonomous mode were analyzed, and a power-limited suppression strategy of PV-energy storage system based on energy storage operation in scheduling mode was proposed to realize power suppression and reduce the frequency of energy storage charge/discharge switching. The optimization objective of minimizing abandoned power losses in the PV-energy storage system was established, with constraints such as the probability of power fluctuation exceeding the limit. An algorithm was used to solve and optimize the energy storage configuration. Taking the 50 MW Sangzhuzi PV-energy storage power station in Langming, Tibet as an example, the effectiveness of the proposed grid-connected power suppression strategy was validated. Results The proposed grid-connected power suppression strategy can reduce the probability of power fluctuation exceeding the limit from 25.64% to 6.41% without increasing the frequency of energy storage charge/discharge switching. When the probability of grid-connected power fluctuation exceeding the limit is 5%, the optimal configuration for the energy storage system of the power station is determined to be 14.5 MW/94 MW⋅h. Conclusions The proposed power fluctuation suppression strategy and energy storage optimization configuration method can provide technical reference for the optimal design and operation of grid-connected PV-energy storage system.

Objectives The absorption and regeneration properties of different formulations of methyldiethanolamine (MDEA) mixed with different diamines were studied. Methods In the simulated flue gas environment with 12% CO₂ and 88% N₂, MDEA was used as the main agent, while ethylenediamine (EDA), 1,3-diaminopropane (DAP), N-methyl-1,3-propanediamine (MAPA), aminoethylethano-lamine (AEEA), N,N-dimethylethylenediamine (DMEDA) and 3-dimethylaminopropylamine (DMPDA) were added as activators, respectively. Under a total amine concentration of 40%, the chemical absorbent was configured with mass ratios of main agent to activator of 1∶1, 2∶1 and 3∶1, respectively. The absorption rate, regeneration rate and circulation capacity of different absorbers were determined by comparing bubble absorption and oil bath regeneration experiments. Results MDEA-EDA system has the best absorption property when the mass ratio of MDEA to EDA is 1∶1. The MDEA-DMEDA system has the best regeneration property when the mass ratio of MDEA to DMEDA is 2∶1, with a circulation capacity reaching 1.7 mol/kg. The overall properties of MDEA-AEEA system are optimized when the mass ratio of MDEA to AEEA is 1∶1, with a cycle capacity reaching 1.49 mol/kg. Conclusions The research results can provide a theoretical basis for the formulation optimization of mixed amine solutions in industry.

Objectives The main issue in the current rational optimization of integrated energy systems is to adopt technological means to improve energy conversion efficiency, reduce system energy waste and regional environmental pollution, in order to scientifically coordinate the optimization goals of economic, stability, and low-carbon operation of the integrated energy system. To this end, a low-carbon optimization strategy for a carbon capture and storage (CCS)two-stage power to gas (P2G)integrated energy system based on scenario generation and information gap decision theory (IGDT) was proposed. Methods At the technical level, by finely modeling the two-stage conversion from power to gas, the efficiency of hydrogen energy utilization was improved, and a combined heating and power (CHP)-CCS-P2G coupling model was established. At the market mechanism level, a tiered carbon trading model was introduced to reduce CO₂ emissions in the system. Finally, based on the IGDT, an optimization scheduling model was constructed for different risk preferences. Results Taking a typical integrated energy system as an example, the simulation results show that the proposed model can improve the wind and solar energy consumption rate, achieve low-carbon, economic, and stable operation of the system. Conclusions This optimization strategy can effectively help decision-makers develop scheduling plans under risk avoidance and risk pursuit strategies based on their risk preferences, achieving a balance between system uncertainty and economy.

Objectives With the implementation of the national “Dual Carbon Strategy” (carbon peak and carbon neutrality), it is anticipated that the existing coating structures may not meet the requirements of future gas turbine thermal protection coatings. The concept of a new type of environmental/thermal barrier coating (E/TBC) structure with high temperature corrosion resistance has been proposed to meet the demand for thermal protection coatings in hybrid hydrogen combustion engines. Methods The development history and research status of thermal barrier coating (TBC), environmental barrier coating (EBC), thermal/environmental barrier coating (T/EBC) and thermal and environmental barrier coating (TEBC) were reviewed and analyzed from the perspective of thermal protection coating materials and coating structures. Moreover, the gap between the above coating structures and the requirementsof thermal protection coating for mixed hydrogen gas turbines was investigated. Results It is reasonable to superimpose the function of EBC onto the thermal protection coating of current mixed hydrogen gas turbines, thereby forming a new type of E/TBC structure with high temperature corrosion resistance on the high-temperature alloy substrate. Conclusions Through the preliminary test, it is proved that the new E/TBC structure is suitable for the thermal protection coating requirements of mixed hydrogen gas turbine against high temperature water oxygen corrosion, and it is pointed out that the theory and application research of this new E/TBC thermal protection coating should be vigorously carried out.

Objectives The localization of core components of heavy-duty gas turbines holds significant importance for technological innovation, industrial upgrading, and even national security. As a typical hot-end component of heavy-duty gas turbines, the performance of the turbine first-stage rotor blade directly determines the efficiency and reliability of the gas turbine. Therefore, the structure of the first-stage turbine blades of a certain heavy-duty gas turbine was optimized. Methods By increasing the number of bamboo nodes in the blade body, the blade cooling hole structure was optimized, and the thermal barrier coating was used to improve the blade coating. The temperature, stress distribution and aerodynamic efficiency of the blades before and after optimization under the service condition of the blade were compared and analyzed by fluid calculation and finite element calculation. Results Heat transfer efficiency inside the blade is enhanced by optimization of turbulent structure. Under the condition of the same inlet pressure of the cooling air, the surface temperature of the optimized blade is reduced by more than 50 ℃. Since the shape of the blade is not changed, there is little influence on the aerodynamic efficiency. Compared with the blades without optimization, the maximum equivalent stress and equivalent total strain of the optimized blade during service are significantly reduced. Conclusions By optimizing the cooling structure and upgrading the protective coatings, the reliability of the blades in high-temperature can be significantly improved. The research results provide a theoretical basis for the localization of gas turbines.

Objectives Considering the difference of primary frequency regulation ability of wind turbines under different wind conditions in wind farms, the evaluation method of frequency regulation capability of wind turbines was optimized on the basis of sag control and inertia control strategy. Methods An improved multi-unit frequency modulation reference power cooperative control strategy was proposed. Results The introduction of multi-unit cooperative control method can effectively improve the distribution of frequency modulation reference power among units, thus effectively adjust the degree of each unit participating in the primary frequency regulation of the system. An improved cooperative control strategy was introduced on the basis of inertia control and sag control. According to the operation state of the unit under the actual wind condition, the reference power of the unit which can effectively participate in the primary frequency modulation was evaluated. The introduction of frequency modulation capability coefficient can realize the energy distribution of the reference value of frequency modulation power among units. Conclusions The cooperative control strategy can effectively protect the speed of wind turbine and improve the frequency response of power grid.

Objectives In order to promote the efficient utilization of energy storage and user-side resources and improve the level of clean energy consumption, a multi-area interconnected integrated energy system planning model considering cloud energy storage was proposed. Methods On the basis of establishing the energy router model of the regional integrated energy system, a virtual energy router model considering electricity/heat/gas cloud energy storage was proposed. Aiming at the problem that cloud energy storage and integrated energy system belong to different investment entities, considering the limitation of the investment return period of cloud energy storage, a dual-subject two-stage planning model was proposed. In the first stage, the grid, equipment capacity and cloud energy storage price were planned. In the second stage, the operation strategy of the integrated energy system was optimized. Aiming at the high complexity of multi-energy flow grid planning, a pre-screening algorithm based on minimum spanning tree was proposed. Results The example analysis results of a three-park integrated energy system planning show that the proposed model is helpful to improve energy efficiency, reduce carbon emissions, and improve the economic benefits of interconnected integrated energy systems. Conclusions The research reveals the potential of collaborative planning between cloud energy storage and multi-area integrated energy systems, and provides reference for the in-depth application and commercial promotion of multi-type energy storage in the energy field.

Objectives Under the background of the “dual carbon” target, the safety and economic problems of peak shaving caused by the construction of high wind power penetration system are urgent to be solved. Methods By using the solution of peak shaving and valley filling of battery energy storage system, a peak shaving optimization control method for zinc-bromine flow battery (ZBB) energy storage taking into account both technology and economy was proposed. According to the actual battery device, the structure analysis and the mathematical model construction of ZBB energy storage were carried out. Considering the technical effects of peak shaving, and taking the minimum standard deviation of load curve after peak shaving as the objective function, a bidirectional optimization control strategy for energy storage considering peak shaving effects was proposed. On this basis, according to the time of use (TOU) policy of the power grid, taking the technical and economic optimization as the objective function, an economic model of energy storage peak shaving based on the TOU price mechanism was proposed, and the optimal power timing results for energy storage were obtained. Finally, taking the load and wind power data of a certain area in Northeast China as an example, the effectiveness of the proposed strategy was verified by comparison. Results Compared with the original load, the proposed strategy reduces the daily average load peak-valley difference and peak-valley difference rate by 35.973% and 34.205%, respectively, and improves the peak shaving economic optimization by 5.582%. In addition, the problem of wind curtailment in the power grid is alleviated. Conclusions The proposed strategy achieves a certain peak shaving effect while maintaining a good peak shaving economy throughout its life cycle.

Objectives The existing hybrid energy storage system control strategy finds it difficult to maintain the state of charge (SOC) within a reasonable range while also meeting the advanced charging and discharging needs due to future wind power fluctuations. Therefore, a new advanced fuzzy control strategy for hybrid energy storage systems was proposed, which takes into account the smoothing of future wind power fluctuations. Methods Firstly, the wind power needing to be smoothed by different types of energy storage devices was decomposed using the ensemble empirical mode decomposition (EEMD) method. Secondly, the power correction parameter was adjusted according to the SOC and power saturation level of the hybrid energy storage system to correct its output power. Thirdly, the wind power prediction algorithm was used to obtain the predicted value of wind power in the forward-looking cycle. The advance charging and discharging parameters were adjusted to correct the output power of the energy storage system based on the wind power fluctuations in the forward-looking cycle and the over-advance control theory. Finally, taking the actual data of a wind farm as an example, the validity of the proposed forward-looking fuzzy control strategy was validated through simulation. Results The proposed control strategy can not only reduce the over-limit probability of wind power grid-connected fluctuation, significantly reduce the deviation between the total output power and the target power, but also maintain the SOC of the hybrid energy storage system within a reasonable range. Conclusions This strategy can provide a useful reference for research related to smoothing wind power fluctuations.

Objectives In order to solve the shortcomings of the traditional preventive maintenance method of air preheater in large thermal power unit, a general mode of predictive maintenance based on digital twin was proposed, and the digital twin system of air preheater was constructed based on digital twin technology. Methods The proposed system included physical entity of rotary air preheater, real-time data acquisition and analysis module, digital twin model construction module, thermal parameter state monitoring, rotor thermal field video and thermal deformation visualization and ash accumulation prediction module. By the real-time acquisition of temperature parameter state and video data, and through the temperature field, video image, air leakage calculation and other modules, the calculation of thermal parameters and the prediction of ash accumulation were realized. At the same time, the 3D configuration screen was used to display data in real time, continuously optimize the accuracy of thermal parameter calculation and ash accumulation prediction, and realize the automatic optimization of soot-blowing strategy. Results The proposed scheme realizes the state monitoring and dynamic control of the thermal calculation process of the air preheater, and solves the problem that the ash accumulation factor of the rotary air preheater in the existing power station affects the safe and reliable operation of the thermal power unit. Conclusions Through engineering testing of actual units, the proposed scheme effectively improves the operation and maintenance efficiency of the air preheater of thermal power units, verifies the feasibility of the proposed method, and provides technical support for the development of smart power plant systems in future.

Objectives In response to global climate change, China has committed to achieving carbon neutrality by 2060, which will inevitably bring strategic transformations across various industries and present an opportunity to develop new quality productive forces. This paper analyzes the potential transformations driven by China’s carbon neutrality goal from the perspective of technological innovation. Methods This paper investigates the main challenges China faces in achieving carbon neutrality, discusses the relationship between carbon neutrality and the development of new quality productive forces, and highlights research directions in zero-carbon energy supply, fossil resource utilization, and CO₂ capture and utilization. Conclusions Achieving carbon neutrality in China requires large-scale development of new energy and advanced transformation and upgrading of traditional industries, especially the fossil resource utilization. It also requires continuous scientific and technological innovation and application, as well as breakthroughs in disruptive technologies. The successful realization of carbon neutrality also relies on CO₂ capture and utilization.

Objectives The randomness and volatility of distributed power generation poses significant challenges for the voltage control in active distribution network (AND). In this context, there is an urgent need for an efficient voltage control strategy to ensure the safe operation of ADN. Methods Based on the deep reinforcement learning method, a voltage control strategy for double-layer regional distribution networks was proposed. First, based on the adjustment characteristics of voltage regulating equipment and the complexity of controllable elements, a regional coordinated control area and a local autonomous control area were designed for the radiating grid structure of the ADN, and the voltage control model of each area was constructed. Then, the model was solved by deep Q-Network (DQN) algorithm and deep deterministic policy gradient (DDPG) algorithm to achieve the purpose of tracking voltage changes in real time, and effectively solve the voltage control problem during the operation of the ADN. Finally, the method was verified by IEEE 33-bus simulation examples. Results The DQN algorithm and the DDPG algorithm were used to solve the control variables in the coordinated control region and the local autonomous region respectively, realizing real-time decision-making of voltage regulation in the ADN system, and solving the problems of bidirectional flow of ADN power flow and complex and changeable voltage. Conclusions The proposed control strategy has obvious effect on controlling voltage deviation, and has strong accuracy and practicality.

Objectives As the proportion of renewable energy in power grids increases year by year, the volatility and uncertainty of the grid are significantly heightened, posing challenges to the safe operation of distribution networks. To address the issue of distributed network reconfiguration in high-proportion renewable energy grids, this paper proposed an online rolling optimization framework. Methods The framework utilized a distributed consensus protocol to obtain network topology and node operation information. It can enable automatic reconfiguration in the event of N-1 and N-2 line failures, allowing the distribution network to automatically restore normal operation without the need for additional external triggering signals, thus ensuring economic operation of the grid. Additionally, a rolling optimization method was employed to handle grid fluctuations caused by the high proportion of renewable energy, and generative adversarial network (GAN) technology was used to generate new data, which combined with historical data. It can help to achieve high-precision forecasting of grid operation data. Results The proposed method can achieve automatic economic optimization and self-healing in normal, single-point failure, and two-point failure scenarios. Conclusions This method provides an effective solution for ensuring the safe operation of distributed networks in high-proportion renewable energy grids.

Objectives It is important to improve the processing ability of uncertain parameters in power planning. Methods A robust power planning model based on cardinality constrained uncertainty set under carbon trading condition was proposed. To reduce the degree of uncertainty, the uncertainty scenario set with cardinality constraints was constructed, and then the concept of “uncertainty budget” was introduced to redefine the best and worst scenarios. Based on duality theory, the robust model with max-min-max three-level programming structure was transformed into equivalent mixed-integer linear programming, which was solved by Baron solver in GAMS. Results The cost of carbon trading can promote a lower proportion of thermal power generation and a higher proportion of renewable energy generation. When the uncertainty budget is larger, the objective function value is lower, and the decision-making style is more conservative. Conclusions The power planning strategy based on robust optimization under carbon trading conditions can improve the ability to handle uncertain parameters. The planning results are robust and feasible, providing decision support for decision-makers in situations of information uncertainty.

Objectives The advanced exergoeconomics analysis method based on exergetic analysis development can refine the economic costs of splitting system components and deeply explore the underlying reasons for the formation of economic costs. Methods Combining advanced exergetic analysis, advanced exergoeconomics analysis method is used to split the costs of the components in the gas-steam combined cycle power generation system into endogenous, exogenous, avoidable and unavoidable costs, and calculate them. Results Under the design conditions, the avoidable loss in the combustion chamber in the combined cycle power system is the largest, which is 28.41 MW, accounting for 26.55% of the combustion chamber loss. Based on the results of the analysis, different improvement measures are proposed for the turbine to reduce the endogenous and exogenous losses of the system. The largest share of the annualized cost of the system is the endogenous avoidable portion, and the bottom-cycle improvement is prioritized highest for the high-pressure cylinder, followed by the low-pressure cylinder. The exogenous share of annualized costs in the combined cycle power system is 80.59%, of which the exogenous avoidable portion is 40.04%. Conclusions The findings of the study can provide the system with a multifaceted energy efficiency evaluation perspective and an improvement direction to optimize the cost.

Objectives This research aims to investigate the operational mechanism of a coal gasifier within an integrated gasification combined cycle (IGCC) power plant, with a focus on analyzing and optimizing key operational parameters. Methods A steady-state thermodynamic model of the gasifier was developed using Aspen Plus. The model’s accuracy was validated by comparing its simulation results with published data. A sensitivity analysis was then conducted to assess the impact of key gasifier parameters. Results The thermodynamic model demonstrates the suitability for simulating steady-state coal gasification processes. The model exhibits high accuracy, simplified structure, and efficient computational performance. Conclusions The sensitivity analysis reveals that the oxygen-to-coal ratio holds the most significant influence on the coal gasification process. Both insufficient and excessive oxygen levels result in a reduction of syngas active ingredient production. The optimal oxygen-to-coal ratio for the Shell gasifier model is determined to be approximately 0.85. Water-to-coal ratio also plays a critical role in the gasification process. When sufficient energy is present within the gasifier, increasing the water input leads to higher water content in the syngas, potentially increasing hydrogen concentration. However, excessive water input under energy-constrained conditions can decrease the effective composition of the syngas.

Objectives The lithium-ion capacitor (LIC) composite cathode materials with both high mass activity and high volume activity were designed. Methods By scanning electron microscope, transmission electron microscope, Kanta fully automatic specific surface and pore size analyzer, and four-probe tester, the micromorphology, stacking mode, contact mode and interface characteristics between particles were analyzed for the impact of conductivity and electrical properties of composite electrodes. Results Mesoporous activated carbon (MC) and monodisperse graphene/single-walled carbon nanotube hybrid (GNH) were mixed, followed by compressing tightly to prepare the lithium-ion capacitor cathode material. GNH were uniformly wrapped around the surface of MC particles with face-to-face connection, which increases the contact area. Then, the even 3D conductive network constructed by GNH among the individual MC particles provided high electrical conductivity and accelerated electron conduction. In addition, GNH were located at the high ion concentration side due to their exohedral surface structure. Meanwhile, a contact potential difference effect existed between GNH (the easy conductive one) and MC (the poor conductive one). This produced rapid ion and electron dual transport channels at the interface between GNH and MC, and boosted ion diffusion in the porous structure inside MC particles. It will help avoid the loss of capacity from slow ion diffusion at higher current densities. Conclusions The addition of 5% GNH brings about outstanding rate performance, and higher mass and volumetric energy density, but does not reduce the packing density.

Objectives Distributed photovoltaic power prediction is of great significance for the operation and scheduling of photovoltaic power plants. Point prediction methods are difficult to comprehensively describe the uncertainty of distributed photovoltaic power. This article proposed a distributed photovoltaic power interval prediction model based on complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN) and sparrow search algorithm optimized least squares support vector machine (SSA-LSSVM). Methods Firstly, the photovoltaic sequence was broken down into multimodal components through CEEMDAN, and then the high-frequency non-stationary components obtained from the first decomposition were decomposed twice. Secondly, sample entropy (SE) was used to reconstruct all components into trend and oscillation components. Then, the point prediction values of the two components were obtained through SSA-LSSVM. Finally, the probability density estimation was performed on the point prediction error of the oscillation component, and the stacked point prediction value was used to obtain the overall prediction interval result. Results The interval prediction model proposed in this paper has higher interval coverage and narrower average interval width. Conclusions Adding secondary modal decomposition to distributed photovoltaic power data processing and combining sample entropy to reconstruct its sub-sequences can effectively reduce the complexity of the original prediction components and improve the accuracy of model prediction.

Objectives The enrichment of heavy metals in desulphurization sludge of coal-fired power plant is significant, so it is necessary to reduce the content of heavy metals in desulfurization sludge. Methods This paper put forward the idea of solidifying heavy metals in desulfurization sludge with fly ash from power plants and compared with common curing agents. Results Among cement, fly ash, chelating agent DTC (dithiocarbamate) and chelating agent TMT-15 (trisodium thiocyanate), fly ash has the best solidification effect on lead in desulfurization sludge. The solidification efficiency of different fly ash and desulfurization sludge is between 40% and 100%. The mechanism analysis shows that, similar to cement, the chemical composition of fly ash mainly contains SiO₂, Al₂O₃, CaO and Fe₂O₃, etc., which can react with desulfurization sludge to generate hydration products such as hydrated calcium silicate C-S-H and ettringite, etc. It is beneficial to the solidification of heavy metals. The products can adsorb heavy metals such as lead. Conclusions It can be seen that adding a certain proportion of fly ash into the desulfurization sludge of coal-fired power plants can realize the solidification and stability of lead, which provides a method for reducing the desulfurization sludge from dangerous solid waste to general solid waste.

Objectives The influence of different placements of phase change heat exchangers on the phase change process was investigated, and the simplified mode of multi-tube heat exchangers was further analyzed. Methods Based on the enthalpy-porosity method, a calculation model for the melting and solidification process of the shell-and-tube paraffin heat exchanger was established, and the phase change process of paraffin outside the single-tube was investigated under horizontal and vertical placements. The effects of single-tube heat exchanger and multi-tube heat exchanger with straight and staggered rows on the melting and solidification process were compared, respectively. Results Full melting time of horizontal single-tube heat exchanger is 18% shorter than that of vertical, but the difference of full solidification time between the two is not significant. Unlike the melting process, the solidification process uses heat conduction as the main mode of heat transfer, so it is relatively slow, and the full solidification time is increased by more than 20% compared to the same period of full melting time. The time required for the melting and solidification process of multi-tube heat exchanger is slightly longer than that of the single-tube heat exchanger, but its increase in time is not more than 10%, and its melting and solidification rate curve is basically consistent with that of single-tube. Through further study, it is found that when the volume of paraffin wraps around each tube in the multi-tube heat exchanger and the wrapping method is the same, different arrangement methods of the multi-tube heat exchanger would not affect the melting and solidification process. Conclusions Compared with the vertical placement, the horizontal placement can effectively enhance the melting rate of paraffin outside the single-tube, and the enhancement effect of the melting process is more obvious than that of the solidification process. In addition, when analyzing the performance of the melting and solidification process of the multi-tube heat exchanger, the single-tube or part of the periodic tube can be used for simplification.

Objectives Compressed air energy storage (CAES) is a new type of energy storage system that utilizes the mutual conversion of electrical energy and compressed air potential energy to balance the fluctuation of power grid. The accumulation of relevant experience in the construction and operation of CAES power station is of great significance to the development of CAES technology. In view of the low efficiency of information transfer between the designer and the site, the difficulty of construction control, and the difficulty of overall project process supervision, a whole-process intelligent system suitable for CAES power station was proposed. Methods Firstly, the construction process of CAES power station was analyzed and its engineering characteristics were found out. Secondly, based on the whole process from design to operation and maintenance of CAES power station, the whole process intelligent construction system of CAES power station was constructed in space and time dimensions. Finally, in the design stage, the key techniques such as forward design drawing were proposed. In the stage of equipment manufacturing, the key technologies such as virtual pre-assembly of equipment were proposed. In the construction stage, the key technologies such as 5D construction management were proposed. In the operation and maintenance stage, the key technologies such as data delivery oriented to operation and maintenance were proposed. Results The verification results of a 300 MW CAES demonstration project show that the construction of the whole process intelligent system of CAES power station is reasonable, and the application of key equipment and software provides technical support for the project. Conclusions Through the intelligent system of the whole process of CAES power station and its key technologies, the interworking chain of each stage of power station construction is opened, and the information management of the whole life cycle of CAES power station is realized.