Wind power generation and solar thermal power generation have complementary advantages in terms of time characteristics, and the heat storage system equipped with solar thermal power station can effectively alleviate the peak regulation pressure and improve the wind power absorption capacity. On this basis, a solar thermal-wind combined power generation system is proposed. The Latin hypercube sampling method is used to effectively reduce the uncertainty of wind power output and solar irradiation intensity. Then, a two-stage double-layer optimal allocation method is proposed to rationally allocate the heat storage capacity. The upper layer model aims to minimize the investment cost of comprehensive operation of the system and the lowest curtailment of the system. The optimal heat storage capacity is determined by a fuzzy multi-attribute decision scheme. In the lower layer model, the operation is optimized with the goal of maximizing the net benefit of the cogeneration system in the scenario. The results show that the optimal heat storage capacity of the heat storage system of the solar thermal power station is 906 MW·h, and the comprehensive operating cost for the optimal heat storage capacity configuration is 2 430 000 yuan. Through the comparison between the results of different scenarios, the curtailment of the system with this configuration method reduces by 69.615 MW, and the net revenue of the system increases by 7.7%.

To improve the control effect of key parameters and energy conversion efficiency of ultra-supercritical coal-fired power generation units during load cycling process, 600 MW class ultra-supercritical coal-fired power generation units are taken as the research objects to carry out modeling and verification. The deviation of key thermal parameters meets the specified range of thermal power simulation standard. The spatiotemporal distribution model of internal heat storage in thermal system of coal-fired power generation units is established, and the water-fuel ratio and flue gas damper opening control logic of the feedforward internal heat storage state of the unit are proposed. The real-time heat storage state of the unit during the load cycling process is fed forward to the flow rate of feed water, coal, and flue gas damper control. The simulation results show that, when the unit load cycling rate varies from 1.0% Pe/min to 3.0%Pe/min within 40%~70% THA load range, the absolute value of the cumulative main steam temperature deviation rate decreases by 27%~31%. The average power generation standard coal consumption rate of the unit decreases by 0.37~0.65 g/(kW·h) during the transient process. The proposed control strategies improve the control accuracy of key thermal parameters and the energy conversion efficiencies of the ultra-supercritical coal-fired power generation units during load cycling transient processes.

Decarbonization in thermal power industry is directly related to the realization of the “double carbon” target, while the circulating fluidized bed boiler has the advantages of wide fuel applicability and can carry out large-scale fuel blending. Biomass fuel is a renewable “zero-carbon” energy source, its blending can greatly reduce the carbon emissions of thermal power plants. Based on the existing circulating fluidized bed boilers and coal-fired conditions, biomass co-firing tests were conducted, and comprehensively evaluation was also carried out on combustion stability, pollutant emissions, and thermal efficiency. The co-firing experiments results showed that, as the co-firing ratio increased, the coal consumption rate per unit of steam production significantly decreased, with stable combustion conditions maintained throughout the process. Under co-firing conditions, the consumption of limestone decreased to approximately 4.5 kg for 1 ton steam production, with SO₂ emissions meeting the standards. Blending raised the furnace temperature, elevated the exhaust temperature, increased the fly ash content, and slightly increased the heat loss. Through regulating the air volume ratio, material layer pressure difference and excess air coefficient, the overall thermal efficiency closely approached the design value. Under long-term operating conditions, the blending ratio of biomass reached about 30%, and the emissions of SO₂ and NO_x were qualified. The tail heat exchanger was not corroded obviously, and the CO₂ emission reduction amount reached about 480 kg for 1 ton steam production.

The beam-down concentrating solar power plant has the advantages of high concentrating ratio, low installation and maintenance requirements, and low pump consumption. Relying on the 50 MW beam-down tower concentrating solar power station in Yumen Xinneng First Power Co., Ltd., the mathematical models of the heliostat field, hyperboloid mirror, receiver, molten salt tank, and power generation cycle are established and verified. The run-test results reveal that, the maximum outlet temperature of the molten salt can be maintained at 559 ℃ for 50 minutes at an average direct normal irradiation of 739.70 W/m². The cosine efficiency, shading and blocking efficiency, shading efficiency of the hyperboloid mirror, and attenuation efficiency of the heliostat field at 12:00 are 0.856 8, 0.999 7, 0.994 1, and 0.974 6, respectively. The average hyperboloid mirror flux density and receiver flux density are 11.3 kW/m² and 400.5 kW/m², respectively. Meanwhile, the power station is maintained for 16 h at the rated generation power of 50 MW. The research has certain reference significance for the operation of a beam-down concentrating solar power plant.

In view of the electricity demand of users and the power generation of renewable energy, an optimal scheduling model of grid-connected wind-optical-battery-waste mine pumped storage combined power generation system is established, with the optimization objective of minimizing the total operating cost of the system. Moreover, the results of the optimal scheduling are measured with the evaluation indexes of the equivalent load variance, the fluctuation rate of the contact line, and the power supply loss rate. The optimal solution is performed using CPLEX solver for the scheduling model. Through simulation on the optimal scheduling models of three different energy storage forms, it is concluded that the total cost of the hybrid energy storage in the form of storage battery and abandoned mine pumped storage reduces by 62.21% and 49.18% compared with that of the battery alone and abandoned mine pumped storage alone, respectively. The optimization results are ranked and evaluated by using the combined entropy weight rank sum ratio method, and the weighted rank-sum ratio of the wind-solar-battery-abandoned mine pumped storage combined power generation system is 0.833, with the highest score ranking. The results show that the proposed model not only improves the operation economy of the system, but also enhances the reliability of the system power supply, which verifies the rationality and effectiveness of the proposed model.

Compressed air energy storage is a new form of large-scale and long-term physical energy storage. Gas storage is a crucial component of compressed air energy storage system. The characteristics of common gas storage devices are summarized, and the underground artificial chamber is discussed in detail. The advantages of underground artificial chamber of compressed air energy storage system compared with other types of gas storage are summarized. The design factors such as bearing structure, sealing system and heat transfer management system of underground artificial chamber are analyzed. The key technologies affecting operation of the underground artificial chamber such as site selection, buried depth and pressure design criteria are analyzed and discussed. The evaluation method and evaluation indexes of the factors affecting stable operation of the artificial chamber are put forward. On this basis, the future development direction of compressed air energy storage underground artificial chamber is prospected, which provides a reference for rational design and stable operation of the underground artificial chamber.

With the rapid advancement of renewable energy power generation, thermal power units need to take on major peaking tasks. Molten salt thermal storage technology, as a prominent method for thermal power peaking, can effectively improve peaking performance of the units. The Ebsilon software is employed to model a subcritical 300 MW unit integrated with coupled molten salt thermal storage system. Considering the operational conditions of supplying industrial steam to external entities, several indexes such as the storage/exothermic thermal efficiency, load variation and thermoelectric conversion rate of three heat storage/exothermic schemes are investigated comparatively. The results indicates that, during the heat storage process, the heat storage scheme 3 (the heat source for heat storage is the main steam, reheat steam and medium-pressure cylinder exhaust, and the exothermic medium-pressure cylinder exhaust goes directly to the condenser) exhibits the highest load variation, reaching up to 102.63 MW. Meanwhile, the heat storage scheme 1 (employing main steam and reheat steam as the heat source for storage) demonstrates the superior thermal efficiency at 28.76%. During the discharge process, exothermic scheme 2 (heat from high-temperature molten salt is used to supply industrial steam and preheat condensate) has the largest load variation, release thermal efficiency, and thermoelectricity conversion rate, which are 34.69 MW, 46.14%, and 59.07%, respectively. This study can provide theoretical guidance for the study of peak performance and thermal economy of thermal power units coupled with molten salt thermal storage system.

Due to factors such as coal quality and combustion, coarse fly ash particles in flue gas of coal-fired boiler can easily cause varying degrees of wear and tear on tail flue and denitrification catalysts. An “A-V-T” type pre-removal structure for coarse particle fly ash before denitrification is established using the flue from the economizer outlet to the denitrification system inlet of a 300 MW unit as the research object. The structure is composed of “A-type baffle enrichment + V-type high-efficiency ash collection + T-type coarse ash channel” and is placed in a large cross-section low flow velocity flue at the economizer outlet. The influence rules of different particle size distribution trajectories, removal effects and resistance before and after the arrangement of the coarse particle fly ash pre-removal device are studied through numerical simulation, and engineering application is conducted to verify the effectiveness. The numerical simulation results indicate that, the use of coarse particle removal technology has little effect on flow field state of the original system at flue gas side. As the particle size of fly ash increases, the removal rate of fly ash increases. The removal rates of fly as particles with size of 50, 200, 500, and 1 000 μm are 12.15%, 59.40%, 87.01%, and 93.62%, respectively. The removal efficiency for coarse particles with size of 200 μm and above is 85.15%. The overall ash collection rate is 15.50%, with an additional resistance of 78 Pa. For this 300 MW unit, the tests after retrofitting show that, the removal rate of coarse ash particles with size of 200 μm and above is 83.96%, the overall removal rate of ash is 14.91%, and the net increase in resistance is 73 Pa. The experimental results verify the rationality of the numerical simulation results.

Flow batteries are considered as one of the most promising technologies for large-scale energy storage, due to their inherent safety, long cycle life, environmental friendliness and robust scalability. As the key material of flow batteries, electrodes have a significant influence on battery performance. The research advancements of electrospun carbon nano-fiber electrodes in flow batteries are reviewed. The fabrication principles of electrospun carbon nano-fibers and their influence on the critical fabrication parameters are elucidated. It provides a comprehensive review of preparation methods for electrospun carbon nano-fiber electrodes with controllable structure and chemistry, properties and their effect on battery performance, including microstructural modulation of carbon nano-fibers, heteroatom doping, and catalytic modification. The key of electrode optimization is synergies between electrochemical activity and mass transport of electrodes, which are associated with the active areas and chemistry properties. The microstructure and surface properties of fibers can be controlled by strategies involving fiber porosity or new structural designs. Doping heteroatoms and introducing catalysts can increase the active area and hydrophilicity of the electrodes to promote the electrochemical activity of the electrodes. Lastly, the challenges and future developments of the electrospun carbon nano-fiber electrodes from laboratory preparation to scaling-up are outlined.

For the integrated energy system composed of photovoltaic power generation, energy storage battery storage and discharge, and coal-fired heating boiler and cogeneration, the power and heat power systems operate in isolation. To analyze the relationship between the information interaction and economic coordination and dispatch of the integrated energy system, by using the J.F.Benders mixed variable target decomposition method, the physical model of the cogeneration photovoltaic storage thermal power system is decomposed according to the main thermal system and the power subsystem. The information interaction between the sub-objectives is analyzed by the objective function and the system boundary conditions, and the mathematical model of the coordinated scheduling operation of photoelectric consumption and storage and cogeneration is obtained. The protection information is isolated and redirected, and the multi-dimensional variable problem of mixed integer programming is iteratively calculated by Gurobi solver. Based on the case of the integrated energy system, three operating conditions under different load requirements of power and heat are analyzed, and it is found that, the economic benefits of the thermal power operation system are synergistic and complementary, and the information interaction expands the space for photovoltaic consumption. The net load of the system reduces by 13.63% on average, the interactive power loss decreases by 9.480 7 million yuan/year, and the energy utilization efficiency rises by 4.48 percentage points, which shows that this model can serve the economic coordination and scheduling optimization and energy efficiency improvement of the integrated energy system.