Search

ObjectivesWith 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.MethodsFirstly, 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.ResultsThe 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.ConclusionsThis method has guiding significance to the operation strategy of the unit.

Incorporating renewable energy sources into the grid poses challenges due to their volatility and uncertainty in optimizing dispatch strategies. In response, this article proposes a cloud–edge collaborative scheduling strategy for distributed multi-energy systems, operating across various time scales. The strategy integrates day-ahead dispatch, intra-day optimization, and real-time adjustments to minimize operational costs, reduce the wastage of renewable energy, and enhance overall system reliability. Furthermore, the cloud–edge collaborative framework helps mitigate scalability challenges. Crucially, the strategy considers the multi-timescale characteristics of two types of energy storage systems (ESSs) and three types of demand response (DR), aimed at optimizing resource allocation efficiently. Comparative simulation results evaluate the strategy, providing insights into the significant impacts of different ESS and DR types on system performance. By offering a comprehensive approach, this strategy aims to address operational complexities. It aims to contribute to the seamless integration of renewable energy into distributed systems, potentially enhancing sustainability and resilience in energy management. [ABSTRACT FROM AUTHOR]

Copyright of Power Generation Technology is the property of Power Generation Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

[Introduction] With the development of new energy, the influence of new energy uncertainty and time characteristics on power grid is increasing day by day. Traditional new energy indexes are difficult to describe the interaction between power grid and new energy. It is necessary to establish evaluation system and index to quantify the impact of new energy on power grid. [Method] Construct the evaluation system from multi-dimensional and multi-scale and establish new energy output characteristic index, electric quantity characteristic index, peak regulation characteristic index and flexibility demand index to analyze the new energy output characteristics, the relationship between new energy output and electric quantity, the influence of new energy on peak regulation and the influence of new energy fluctuation on power grid at critical moments. Typical scene features were mined by applying indexes from different time scales such as year, season, month, day and hour. [Result] All kinds of indexes of the evaluation system has been calculated by taking the actual wind power, PV power and load in a certain area as an example. The results show quantitatively the influence of regional new energy on power grid and its distribution characteristics at different time scales. The engineering practicability of the proposed index system is verified. [Conclusion] The proposed index calculation method is quick and simple and the physical meaning of indexes is clear and intuitive and helpful to guide the planning and dispatching of new energy.

Incorporating renewable energy sources into the grid poses challenges due to their volatility and uncertainty in optimizing dispatch strategies. In response, this article proposes a cloud–edge collaborative scheduling strategy for distributed multi-energy systems, operating across various time scales. The strategy integrates day-ahead dispatch, intra-day optimization, and real-time adjustments to minimize operational costs, reduce the wastage of renewable energy, and enhance overall system reliability. Furthermore, the cloud–edge collaborative framework helps mitigate scalability challenges. Crucially, the strategy considers the multi-timescale characteristics of two types of energy storage systems (ESSs) and three types of demand response (DR), aimed at optimizing resource allocation efficiently. Comparative simulation results evaluate the strategy, providing insights into the significant impacts of different ESS and DR types on system performance. By offering a comprehensive approach, this strategy aims to address operational complexities. It aims to contribute to the seamless integration of renewable energy into distributed systems, potentially enhancing sustainability and resilience in energy management.

The influence of thermal inertia of the furnace refractory on the peak regulation characteristics of a 300 MW circulating fluidized bed boiler (CFB) was studied by using a numerical calculation method. Based on the actual operation conditions of the boiler, the calculation results reveal that the thermal inertia of refractory is affected by its thermal conductivity and the thickness. Specifically, the thermal inertia of refractory decreases with the increasing thermal conductivity and decreasing refractory thickness. As a consequence, the time that required for the refractory to reach heat equilibrium decreases from 5 812 s to 3 426 s if the thermal conductivity of refractory increases from 1 W/(m⋅K) to 15 W/(m⋅K), while it increases from 3 267 s to 7 771 s if the thickness of refractory material increases from 30 mm to 90 mm. Practically in the presence of the traditional refractory in the CFB dense phase zone, the time required to achieve heat equilibrium state becomes 82, 65 and 60 min when the load of this CFB boiler rises from 50% to 100% with a rate of 1%/min, 2%/min and 3%/min. For a refractory with higher thermal conductivity, the equilibrium response time will be reduced to 65, 46 and 40 min, correspondingly. According to the calculation results, a formula for the heat absorption rate of refractory material was obtained. In addition, the influencing coefficient of the thermal inertia of refractory on coal feeding was also defined and calculated.

Biomass syngas can be considered as a supplementary fuel to partially substitute coal, which is beneficial to CO2 emission reduction. For the case study, the influences of co-firing typical biomass syngas (gasification from palm, straw, and wood) with coal on the thermodynamic parameters of a 300 MW tangentially fired boiler are evaluated through a thermal calculation based on the principles of mass conservation, heat conservation, and heat transfer. The effects of boiler loads, biomass syngas species, and consumption rates are discussed. The results show that the introduction of biomass syngas weakens the radiative characteristics of the flame and reduces the furnace exit flue-gas temperature. As 3 × 104 m3 h−1 of wood syngas is introduced, the decrement of thermal efficiency reaches 0.4%, while that of the coal consumption rate is 5.1%. The retrofitting of the boiler was not necessary and the corrosion of the low-temperature heating surface did not appear. The CO2 annual emission reduction could achieve 0.001 to 0.095 million tons for palm syngas, 0.005 to 0.069 million tons for straw syngas, and 0.013 to 0.107 million tons for wood syngas with increasing biomass syngas consumption rates under the full load. Moreover, the main thermodynamic parameters changed more significantly under the low loads. [ABSTRACT FROM AUTHOR]

Copyright of Southern Energy Construction is the property of Southern Energy Construction Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The development and utilization of new energy is one of the biggest issues facing mankind. With the rapid development of new energy, its proportion in the power system is getting higher and higher, which will inevitably lead to the increase of the peak–valley difference of the power grid, resulting in a series of stability problems. The connection of energy storage devices to the power grid can not only effectively utilize the power equipment, reduce the power supply cost, but also promote the application of new energy, improve the stability of the system operation, reduce the peak–valley difference of the power grid, and play an important role in the power system. In this paper, the simulation is carried out in PSS/E, and the excitation model and energy storage model are established based on the user-defined function of PSS/E. The particle swarm optimization algorithm is used to optimize the parameters of the excitation system and the energy storage control system, and the performance difference of peak regulation before and after adding the energy storage model and parameter optimization is simulated and compared. Through simulation, the correctness of the user-defined model of excitation and energy storage and the feasibility and superiority of energy storage participating in peak regulation are verified.

The optimal configuration of the rated capacity, rated power and daily output power is an important prerequisite for energy storage systems to participate in peak regulation on the grid side. Economic benefits are the main reason driving investment in energy storage systems. In this paper, the relationship between the economic indicators of an energy storage system and its configuration is first analyzed, and the optimization objective function is formulated. Then, according to the objective limitations of the energy storage system configuration and operation, the constraints are formulated. A set of typical parameters is selected, and the CPLEX (IBM ILOG CPLEX Optimization Studio) solver is used in MATLAB to solve the optimal configuration results. Several sets of optimization results are obtained by taking different subjective coefficient β values, and the economic and social benefits of the optimization results are analyzed. When the economic benefits of the energy storage system are more important, the value of β needs to be smaller, such as a value of 1000. Conversely, when the peak-regulation effect is more important, the value of β should be larger. Finally, configuration results of the control groups are given, and the effect of optimizing the calculation for improving economic benefits is verified. [ABSTRACT FROM AUTHOR]

Copyright of Power Generation Technology is the property of Power Generation Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract Regarding the carbon neutrality target, the proportion of renewable energy in global energy sources is predicted to increase to 50% by 2050, and the increment in penetration requires fossil fuel power plants to play a key role in grid peak regulation. The integrated gasification combined cycle (IGCC) is a promising peak-regulating method for power grids. However, due to the strong coupling between units, the flexibility of gas turbines cannot be fully utilized in response to power demand. This paper proposed a novel polygeneration system integrating syngas storage, hydrogen production, and gas turbines for power. Through syngas storage, the dynamic characteristic of each unit can be decoupled to take advantage of the flexibility of the gas turbine. Compared to the general IGCC system, the load change rate of the new system could be increased from 0.5%/min to 3-5%/min without altering the dynamic characteristics of the original equipment. The design capacity of the syngas storage tank could be reduced by decreasing the ramp rate of the power generation unit or increasing the load change rate of the gasification and hydrogen production units. For the new 300-MW system, the required syngas storage tank capacity reached only approximately 1872 m3 under storage conditions of 35 bar and 25 °C. Furthermore, the investment in the syngas storage tank only accounted for approximately 6.6% of the total investment cost. In general, the novel system can be more flexibly operated under variable loads with low carbon emissions, which can help to increase the penetration of renewable energy in the power grid.

Due to the increasing penetration of renewable energy, the problem of curtailing wind and photovoltaic is becoming more and more prominent. Peak regulation market is established for renewable integration in China. Owing to the flexibility in demand side, the aggregator is able to participant in the peak regulation market. For this purpose, this paper aims to derive an optimal scheduling and offering strategy for the aggregator in the peak regulation market. The proposed strategy applies information gap decision theory (IGDT) to deal with the uncertainty of the market clearing price. First, the aggregator’s deterministic strategy is given which considers two types of load: temperature control load (TCL) and electric vehicle (EV). And based on IGDT, the robust strategy and the opportunistic strategy are presented. Then, in order to further reduce the profit loss caused by the forecasted error of the market clearing price, the step offering curve is developed. Finally, the results of case studies validate the effectiveness of the proposed strategy.

Based on the intermittent output and inverse peak regulation characteristics of wind power, a multisource peak regulation transaction optimization model that considers the feasibility of combining thermal power, energy storage, and demand response for both power generation and consumption is proposed in this paper. First, a multisource peak regulation transaction cost model is established by considering flexible load participation in peak regulation and price- and incentive-based demand responses. Subsequently, with the objective of minimizing both the peak regulation cost and wind curtailment rate, a reduced half gradient membership function is selected to transform the multiobjective model. Finally, by analyzing the roles of the different subjects in multisource peak regulation transactions, a compensation mechanism based on the Shapley method is designed, and a local power grid in northeast China is chosen as the simulation object. The results show the following: (1) When the thermal power generators (TPGs) transit from regular peak regulation to deep peak regulation, the wind curtailment rate decreases by 5.10%, and the peak regulation cost increases by $ 0.793 × 106. This indicates that the peak regulation cost of the TPGs and the income of the on-grid wind power need to be balanced. (2) When the energy storage and the demand response are combined for peak regulation, both the peak load regulation cost and wind curtailment rate reach the optimal values, decreasing by $ 0.642 × 106 and 5.72%, respectively, showing cooperative optimization. However, the TPGs require a higher regulation cost, whereas the other subjects achieve incremental benefits. (3) The compensation mechanism assists each subject in obtaining incremental benefits depending on the contribution rate. With the strengthening of the peak regulation of the TPGs, more energy storage and demand response output are introduced to meet the urgent peak regulation requirement, which leads to increased regulation revenue and optimal dispatching. In summary, the proposed transaction and compensation mechanism of multisource peak regulation can be used to balance the peak regulation ability and contributions of different subjects and establish the optimal peak regulation scheme.

In the response process of rapid peak regulation and frequency regulation of coal-fired units, quickly controlling the steam temperature within a reasonable range is one of the difficulties in the field of automatic control. Due to the large inertia and large delay characteristics of steam temperature, the conventional cascade control often fails to achieve better control results. Meanwhile, advanced algorithms such as model prediction and neural networks are affected by non-linearity, measurement uncertainty and time-varying characteristics of temperature object, which limits their application in actual control. This paper proposed a hybrid control model based on cascade and local Smith prediction. The accurate local Smith prediction model was obtained through parameter identification method, and the steam temperature control strategy based on the hybrid structure was constructed and applied in the 1 000 MW ultra-supercritical boiler desupercritical water system. The results show that the method is efficient, easy to use and stable, which can effectively improve the performance of steam temperature control and achieve good control effects.

This paper takes the ultra-supercritical unit as an example to introduce the basic principle of the overload valve and summarize the experience in its design and selection. Besides， it compares and analyzes the design load point selection of the overload valve and the capacity of the overload valve participating in primary frequency regulation in the operation of the peak shaving unit. The comparison results show that the opening point of the overload valve of the peak regulation unit needs to be calculated according to the annual load situation and then considered as a whole. The primary frequency regulation capacity of the overload valve is increased by 53% more than that of the throttling regulation. The design technology studied in this paper can be used to reference the subsequent design of units with overload valves. The opening point optimization technology of the overload valve can be promoted in the ultra-supercritical units involved in deep peak regulation to improve the operating efficiency of units during wide load peak regulation.

Biomass syngas can be considered as a supplementary fuel to partially substitute coal, which is beneficial to CO2 emission reduction. For the case study, the influences of co-firing typical biomass syngas (gasification from palm, straw, and wood) with coal on the thermodynamic parameters of a 300 MW tangentially fired boiler are evaluated through a thermal calculation based on the principles of mass conservation, heat conservation, and heat transfer. The effects of boiler loads, biomass syngas species, and consumption rates are discussed. The results show that the introduction of biomass syngas weakens the radiative characteristics of the flame and reduces the furnace exit flue-gas temperature. As 3 × 104 m3 h−1 of wood syngas is introduced, the decrement of thermal efficiency reaches 0.4%, while that of the coal consumption rate is 5.1%. The retrofitting of the boiler was not necessary and the corrosion of the low-temperature heating surface did not appear. The CO2 annual emission reduction could achieve 0.001 to 0.095 million tons for palm syngas, 0.005 to 0.069 million tons for straw syngas, and 0.013 to 0.107 million tons for wood syngas with increasing biomass syngas consumption rates under the full load. Moreover, the main thermodynamic parameters changed more significantly under the low loads.

The optimal configuration of the rated capacity, rated power and daily output power is an important prerequisite for energy storage systems to participate in peak regulation on the grid side. Economic benefits are the main reason driving investment in energy storage systems. In this paper, the relationship between the economic indicators of an energy storage system and its configuration is first analyzed, and the optimization objective function is formulated. Then, according to the objective limitations of the energy storage system configuration and operation, the constraints are formulated. A set of typical parameters is selected, and the CPLEX (IBM ILOG CPLEX Optimization Studio) solver is used in MATLAB to solve the optimal configuration results. Several sets of optimization results are obtained by taking different subjective coefficient β values, and the economic and social benefits of the optimization results are analyzed. When the economic benefits of the energy storage system are more important, the value of β needs to be smaller, such as a value of 1000. Conversely, when the peak-regulation effect is more important, the value of β should be larger. Finally, configuration results of the control groups are given, and the effect of optimizing the calculation for improving economic benefits is verified.

To achieve the national carbon-peak and carbon-neutral strategic development goals, it is necessary to build power systems dominated by renewable and sustainable energy. The future power system with a high proportion of renewable and sustainable energy is required to have large-scale, low-cost, flexible, and adjustable resources. To this end, this article aggregates user-side distributed energy storage and electric vehicles into a virtual power plant, considering the uncertainty of wind power fluctuations and the uncertainty of electric vehicle charging and discharging to establish a day-ahead and intra-day peak regulation model for combined peak regulation of virtual and thermal power plants. The bounding algorithm seeks the optimal strategy for the two-stage model of joint peak regulation and obtains the day-ahead and intra-day two-stage optimal peak regulation strategy. The simulation example shows that the virtual power plant and its day-ahead and intra-day optimal peak regulation strategy can reduce the peak regulation cost of the power system, as compared with the deep peak regulation of thermal power plants with a special supporting energy storage power station. This work provides a global perspective for virtual power plants to participate in the formulation of power system peak regulation rules.

An hourglass cup-shape pattern of regulation at the molecular level was detected during the development of the primate brain. Specifically, a peak of temporally differentially expressed genes around the time of birth has been observed in the human brain. However, to what extend this peak of regulation exists among species has not been investigated in great detail. Here, by integrating multiple large-scale transcriptome data from rhesus macaques, we confirmed that a similar differential expression peak exists during the development of the macaque brain. We also found that a similar peak exists during the development of other organs, such as liver, testis, kidney and heart. Furthermore, we found that distinct pathways are regulated in the peak period of those organs. Our results highlight the importance of co-evolution of diverse organs during critical periods of perinatal development in primates.

An hourglass cup-shape pattern of regulation at the molecular level was detected during the development of the primate brain. Specifically, a peak of temporally differentially expressed genes around the time of birth has been observed in the human brain. However, to what extend this peak of regulation exists among species has not been investigated in great detail. Here, by integrating multiple large-scale transcriptome data from rhesus macaques, we confirmed that a similar differential expression peak exists during the development of the macaque brain. We also found that a similar peak exists during the development of other organs, such as liver, testis, kidney and heart. Furthermore, we found that distinct pathways are regulated in the peak period of those organs. Our results highlight the importance of co-evolution of diverse organs during critical periods of perinatal development in primates. [ABSTRACT FROM AUTHOR]

The increasing penetration rate of wind power and photovoltaic challenges the stable operation of the grid. Energy storage technology can effectively control the fluctuation of renewable energy generation, enhance the controllability of renewable energy power generation and improve the accessing capability of renewable energy sources connected to the grid. Therefore, the related research and technology of energy storage systems in the grid are getting more and more attention. In this paper, taking energy storage systems to access the grid as a starting point, the application value of energy storage systems in four scenarios such as frequency regulation, peak regulation, backup capacity, delay transmission and distribution expansion were studied and summarized. The development prospects of the commercial modes related to energy storage systems and the key scientific issues to be studied in the future were discussed.

In recent years, the high percentage of wind power accessibility in Northwest China has worsened the dilemma of peak regulation and spinning reserve in the power system, frequently resulting in wind abandonment. Therefore, a concentrated solar power (CSP) plant equipped with an electric heater (EH) is implemented to join the peak regulation, and the joint peak regulation strategy between thermal power units (TPUs) and a CSP plant is proposed. Firstly, the peak regulation principle of a CSP plant with EH is analyzed in detail. The CSP plant is divided into load mode and power source mode of peak regulation, and mathematical models of the two modes are established. Secondly, the effectiveness of joint peak regulation of TPUs and CSP plants with EH is analyzed, and the principle of low-carbon power supply during peak and off-peak periods is analyzed in the proposed strategy. On this basis, the ladder carbon trading mechanism is introduced to quantify the low-carbon level of the system, and an economic scheduling model considering the operation cost of the system is established to determine the optimal schedule. The results suggest that the proposed scheme can improve the operational efficiency of the system and create more consumptive space for wind power by utilizing the flexible operating potential of a CSP plant. [ABSTRACT FROM AUTHOR]

In China, the increasing amount of electricity imported from high voltage direct current (HVDC) transmission systems in some provinces has led to the retirement of local units. Lack of local generating capacity is adverse to the stability of system frequency and the adequacy of ancillary services. This study proposes a practical method to determine the minimum requirement of generating capacity (which is called the reliable generating capacity, RGC) in the sink side of a power grid. The relation between the minimum system frequency and the generating capacity is theoretically analysed. Based on simulation results, a function that determines RGC under a certain frequency drop constraint can be specified by data fitting. Meanwhile, the requirement of ancillary services (such as peak regulation, automatic generation control, and reserves) on typical days also imposes a floor constraint on the generating capacity. So the relation between generating capacities and ancillary services is also explored. Finally, the overall RGC value is the maximum of the above two aspects. A case study in East China Power Grid proves the effectiveness of the proposed method. The result can be used as a reference for power system planning and operation. [ABSTRACT FROM AUTHOR]

Wind curtailment is currently one of the major challenges in China’s renewable energy development. Technical solutions to wind curtailment could include more flexible power sources, storage and grid facilities. These, however, are long-term solutions due to physical, economic and institutional constraints. We argue that an effective short-term solution could be the full utilization of the technical potential of the existing power system, particularly by using China’s dominant coal-fired power capacity to provide peak regulation services for the priority dispatch of wind power. This paper assesses the economic and environmental effects of this approach. To this end, four scenarios are developed: Scenario I—full wind curtailment and average dispatch of coal-fired power, Scenario II—no wind curtailment and average dispatch of coal-fired power, Scenario III— no wind curtailment and optimal dispatch of coal-fired power, and Scenario IV —partial wind curtailment and optimal dispatch of coal-fired power. The economic and environmental effects under the four scenarios are then computed using the GAMS program based on the load curve on a typical spring day for a coal-fired power plant and a wind farm in China’s northeastern Harbin City. The results of our research show that whilst Scenario IV has the best economic effects, Scenarios III and IV have the best environmental effects. Scenario IV is considered the optimal solution as more economic benefits could be realized at the expense of smaller wind curtailment. Drawing on these results, it is recommended to amend the Renewable Energy Law to allow a small proportion of renewable energy curtailment; to enhance the flexibility of the existing coal-fired power units; to advance energy efficient power dispatch approach; and to incentivise coal-fired power to provide peak regulation services for renewable energy. [ABSTRACT FROM AUTHOR]

The reserves and exploitable capacity of the wind power resource in China are both ranked first in the world and could be developed to strengthen China’s energy security and mitigate global warming. Carbon footprint accounting of wind farms is vital for large-scale wind energy exploitation. This paper establishes a systematic accounting framework with life cycle assessment (LCA) and input–output analysis (IOA) for the overall carbon footprint of the life cycle of a typical wind farm. Carbon emissions from the construction, operation, and dismantling phases are considered in the LCA of the wind farm. Then, each expense of the wind farm is treated as a change in exogenous demand for the output of the corresponding economic sectors according to the IOA. In addition, the virtual carbon footprint from peak regulation triggered by the on-grid fluctuation of wind power is incorporated. The results show the total carbon footprint of the studied wind farm is 1.45 × 10 4 tCO 2 over the 21-year lifetime. The construction phase accounts for the largest fraction (76.74%), followed by the operation phase (15.32%) and dismantling phase (7.94%). According to the IOA, the indirect carbon footprint of the wind farm is greater than the direct footprint. The “Smelting and Pressing of Metals” sector that produces the steel and copper used to manufacture the wind turbines dominates the carbon footprint. The virtual carbon footprint of coal-fired power for wind power peak regulation is estimated to be 2.08 × 10 3 tCO 2 , which is close to that of the operation phase. [ABSTRACT FROM AUTHOR]