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Rising coal price and increasingly stringent emission policy highlight the importance of balancing economic benefit and sustainable development of coal-fired power plants. In order to make the power plant operate economically and safely, and reduce the emission of pollutants as much as possible, this paper proposed a coal blending optimization framework for coal-fired power plants. This framework constructs a set of mathematical model based on the minimization objective function, including the economy, safety and environmental protection of coal. And a multi-strategy fusion multi-objective particle swarm optimization (MSF-MOPSO) method is proposed to optimize the coal blending model. The feasibility, effectiveness and superiority of the method are theoretically verified by convergence analysis and several sets of simulation experiments. And the practical application of this framework shows that under the coal blending strategy based on different weight combinations, the algorithm proposed in this paper can produce high-quality Pareto spatial distribution. Comparing with other state-of-the-art coal blending algorithms, this method can reduce the coal purchase cost by 4.42% and ${\rm{S}}{{\rm{O}}_{\rm{2}}}$ S O 2 emission by 5.11% at least under the same condition. It has significant environmental protection and economic benefit. [ABSTRACT FROM AUTHOR]

The accumulation of snow is one of the essential reasons for the significant decrease in the power generation efficiency of PV stations in winter. For this reason, this paper firstly provides a detailed review of the current research into the physical processes and shedding reasons for the natural melting of snow on PV module surfaces. Then, several common techniques to promote snow and ice melting on PV surfaces are discussed, and the feasibility and shortcoming of ultrasonic technology in removing high‐density snow and ice are analyzed in detail. Finally, this paper proposes two snow sensing technologies for PV modules, namely, image processing method and interdigital capacitance method. Among them, the image method based on fixed camera and UAV detection is more suitable for wide area PV power stations, while the interdigital capacitance method is helpful in obtaining snow characteristic parameters, such as icing type and LWC. The relevant research has certain reference significance for PV power stations to formulate a more reasonable snow removal plan and power generation forecast. © 2024 Institute of Electrical Engineers of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

A Virtual Power Plant (VPP) is a centralized energy system that manages, and coordinates distributed energy resources, integrating them into a unified entity. While the physical assets may be dispersed across various locations, the VPP integrates them into a virtual unified entity capable of responding to grid demands and market signals. This paper presents a tri-level hierarchical coordinated operational framework of VPP. Firstly, an Improved Pelican Optimization Algorithm (IPOA) is introduced to optimally schedule Distributed Energy Resources (DERs) within the VPP, resulting in a significant reduction in generation costs. Comparative analysis against conventional algorithms such as Genetic Algorithm (GA) and Particle Swarm Optimization (PSO) demonstrates IPOA's superior performance, achieving an average reduction of 8.5% in generation costs across various case studies. The second stage focuses on securing the optimized generation data from rising cyber threats, employing the capabilities of machine learning, preferably, a convolutional autoencoder to learn the normal patterns of the optimized data to detect deviations from the optimized generation data to prevent suboptimal decisions. The model exhibits exceptional performance in detecting manipulated data, with a False Positive Rate (FPR) of 1.92% and a Detection Accuracy (DA) of 98.06%, outperforming traditional detection techniques. Lastly, the paper delves into the dynamic nature of the day ahead market that the VPP participates in. In responding to the grid by selling its optimized generated power via the day-ahead market, the VPP employs the Prophet model, another machine learning technique to forecast the spot market price for the day-ahead to mitigate the adverse effects of price volatility. By utilizing Prophet forecasts, the VPP achieves an average revenue increase of 15.3% compared to scenarios without price prediction, emphasizing the critical role of predictive analytics in optimizing economic gains. This tri-level coordinated approach adopted addresses key challenges in the energy sector, facilitating progress towards achieving universal access to clean and affordable energy. [ABSTRACT FROM AUTHOR]

The integration of renewable generation presents a promising venue for displacing fossil fuels, yet integration remains a challenge. This paper investigates Demand Response (DR) as a means of economically integrating Renewable Energy Resources (RERs). We propose Incentive-Based DR (IBDR) programs, particularly suitable for small customers. The uncertainties in the electricity market price pose a challenge to IBDR programs, which is addressed in this paper through a novel and robust IBDR approach that considers both the electricity market price uncertainties and customer responses to incentives. In this paper, scenarios are simulated premised on the Western Electricity Coordinating Council (WECC) 240-bus system in which coal-fired power plants become inactivated, while the RER contribution increases in the span of one year. The simulation results indicate that the proposed IBDR program mitigates the issues associated with renewable expansion, such as utility benefit loss and market price volatility. In addition, the proposed IBDR effectively manages up to 30% of errors in day-ahead wind forecasts that significantly reduce financial risks linked to IBDR programs. [ABSTRACT FROM AUTHOR]

A new cable-damper stopper equipped for Coal-Fired Thermal Power Plants (CFTPPs) was proposed in our previous paper, where a series of shaking table tests were carried out to investigate its seismic performance, so this paper aims to reveal the working mechanism of the stopper from the theoretical and numerical simulation aspects. The stopper is composed of three main components, i.e. a steel cable, a steel block and a viscous damper. First, the nonlinear restraint stiffness of the steel cable to the boiler was derived; second, the critical damping of the stopper, which makes the vibration of the boiler decay exponentially with no oscillation, was derived; third, an iterative method was proposed to globally tune the CFTPP structure, which makes it possible to obtain the optimal parameters of the cable-damper stopper, including the diameter of the steel cable and damping coefficient of the damper. Finally, finite element models were built and time history analyses were conducted to verify the proposed optimization approach. Firstly, the finite element models were proved valid through the comparison between the results of the simulations and the experiments. Then, based on the results of the simulations, the theoretical procedure was validated. The results revealed that the proposed cable-damper stopper reduced the seismic responses of displacements of the top floor and the boiler significantly, about 30.18% and 60.01% respectively compared with their counterparts of CFTPPs without stoppers. [ABSTRACT FROM AUTHOR]

Oxy-fuel combustion technology replaces air with a mixture of pure O2 and recycled flue gas for coal combustion, which leads to difficulties in the waste heat recovery of flue gas in the boiler tail of coal-fired power plants. This paper proposes a new integration scheme for waste heat recovery of flue gas in coal-fired power plants with oxy-fuel combustion CO2 capture. By introducing an oxygen preheater, a recycled flue gas preheater, and a low-pressure economizer, the waste heat of flue gas is fully recovered to preheat oxygen, recycled flue gas, and feed water, respectively. The proposed scheme simultaneously ensures the safe operation of the recycled fan and improves the thermal performance of the coal-fired power plants. Compared to the air combustion configuration, the boiler's efficiency and gross power efficiency in the oxy-fuel combustion configuration are increased by 0.42% and 1.29%, respectively. Due to power consumption for the added equipment, the net power efficiency is reduced by 10.41%. A techno-economic analysis shows that the cost of electricity for oxy-fuel combustion in coal-fired power plants has increased from USD 46.45/MWh to USD 80.18/MWh, and the cost of the CO2 avoided reaches USD 43.24/t CO2. [ABSTRACT FROM AUTHOR]

Offshore photovoltaic power stations (OPVPS) greatly help solve energy problems and land resource scarcity. A crucial phase of the OPVPS project lifecycle is site selection. To select the optimal location of OPVPS with many difficulties such as the uncertainty of the environment, the compensating relationships among criteria, and the different attributes of the alternatives, this paper proposed a fuzzy multi-criteria decision-making framework based on Pythagorean fuzzy Elimination et Choix Traduisant la Realité-III (ELECTRE-III) method. First, the comprehensive criteria system for siting OPVPS was constructed, which included veto and evaluation criteria. Second, the Pythagorean fuzzy set was used to express the uncertain evaluation of experts. Third, considering the actual situation that experts had different experiences and abilities, this paper proposed a novel expert weighting method. Fourth, entropy weighting method, best–worst method, and combination weighting of game theory were introduced to calculate the criteria weights. Fifth, considering the compensation between criteria, ELECTRE-III was used for ranking. Finally, to verify the applicability and robustness of the proposed framework, a China case study was conducted; the results showed that Haizhou Bay is the best alternative. [ABSTRACT FROM AUTHOR]

One of the most frequent causes of coal fired power plant shutdown is boiler tube leak. Superheaters are crucial components of boilers operating under high temperatures and pressures. Understanding the superheater potential damages is essential to define the rectification action needed to keep and elevate overall power plant productivity. This paper highlights the analysis of platen superheater tube failure in a 2x150 MW coal-fired power plant in South Sumatera. Various test including chemical composition, hardness, tensile, metallography, SEM fracture surface examination, and XRD compound analysis were conducted for investigation purposed. The failure was initiated by the plugging of the tube elbow due to deposits and ashes adhering to the tube's interior. This obstruction prevented saturated steam flow inside the tube, leading to overheating and a subsequent drop in mechanical strength. Overheating was confirmed by the presence of spheroid particles in the ferrite matrix. Prolonged overheating resulted in the formation of microvoids, leading to creep failure and crack formation in the tube. The improvements made by adding refractory material give positive results. The platen superheater tubes which previously exceeded temperature limits, currently operate within normal range temperatures, reduced spray water consumption 6-10 tons/day, and significantly increased boiler efficiency from 83.19% to 83.54%. [ABSTRACT FROM AUTHOR]

The conversion of coal-fired power plants to nuclear power stations is a potential method for decarbonizing coal power and offers a pathway for low-carbon development in China's power industry. This paper focuses on retrofitting China's coastal coal-fired power stations and compares the potential nuclear reactor technologies for the retrofit: China's mainstream pressurized water reactor and the commercially operated fourth-generation high-temperature gas-cooled reactor (HTGR). The analysis compares the degree of matching between the two technologies and coal-fired power stations in terms of unit capacity, thermal system parameters, unit speed, structural dimensions, and weight, which significantly impact the retrofit scheme. The results indicate that HTGR is more compatible with coal-fired power plants and is recommended as the type of nuclear reactor technology to be retrofitted. The study selected the 210 MWe High-Temperature Gas-Cooled Reactor Pebble-Bed Module (HTR-PM) as the reactor technology for retrofitting a typical 300 MW class subcritical coal-fired unit. Based on the concept of subcritical parameters upgrading, the potential analysis and strategy study of retrofit is carried out in terms of the turbine, the main heat exchange equipment, the main pumps, and the main thermal system pipelines in the conventional island. The results indicate that the conventional island of the HTR-PM nuclear power plant has significant potential for retrofitting, which can be a crucial research direction for nuclear retrofitting of coal-fired power plants. [ABSTRACT FROM AUTHOR]

With a significant share of renewable power generation integrated into the power supply, it is crucial to timely adjust the regulating peak load for coal-fired power plants equipped with CO2 capture to ensure the stable operation of the multi-energy supply system. In this paper, the effects of varying boiler loads on the techno-economic performance of the retrofitted power plant were studied. Furthermore, the potential for reducing the cost of CO2 capture was investigated, and early opportunities for demonstration were discussed. Results showed that when the boiler load decreased from 100% turbine heat acceptance condition to 50% turbine heat acceptance condition, the cost of CO2 capture increased from 37.0 $/t CO2 to 57.0 $/t CO2, cost contribution of energy penalty and extra capital investment also increased from 20.6 $/t-CO2 to 25.7 $/t-CO2, and from 16.4 $/t-CO2 to 31.3 $/t-CO2, respectively. Furthermore, by improving separation efficiency from 0.15 to 0.5, a 25% to 30% reduction in CO2 capture cost can be achieved. The cost of CO2 capture could decrease by 42.2–50.5% when the cumulative capacity reaches 250 GW under the high investment learning rate scenario. According to the distribution of coal prices and renewable energy sources in China, the early demonstration projects of multi-energy supply systems should prioritize the northern region. The results of this work can provide informative references for making roadmaps and policies for CO2 emission reduction toward carbon neutrality. [ABSTRACT FROM AUTHOR]

In the case of new investment in RES technology, there are two issues related to efficiency assessment. The first one is how to join technical, financial and economic efficiency assessments in one. An investment feasibility study is usually conducted through a financial analysis to obtain the internal rate of return and the net present value. However, a new RES investment is typically financially unprofitable unless the environmental and social aspects are included. The second one is a lack of required financial data. The new RES investment is often innovative and neither the owner nor other entities have financial data on the operating costs and expenditure for the last periods. Therefore, in this paper, we proposed two methods of efficiency assessment. The first one is based on the avoided costs theory. Furthermore, the second one belongs to heuristic methods and is based on the experts' assessment of different kinds of parameters. The purpose of this study is to assess the efficiency of the pilot project of VPPs using two recommended methods. This paper emphasizes the advantages and disadvantages of each method. The actual technical and financial data for the period of six months from the pilot study were calculated. [ABSTRACT FROM AUTHOR]

Alternative solvents based on aqueous solutions of amino acids have been recently developed as possible substitutes for Mono Ethanol Amine (MEA) for CO2 removal from flue gas streams. The potassium taurate solvent has the advantages of degradation resistance, low toxicity and low energy requirements for its regeneration. With any type of solvent, CO2 removal applied to a power production plant decreases the revenues obtained from selling electricity because of the energy requirements. Operating the CO2 removal section in flexible mode avoids significant effects on the profits of the power plant, while accomplishing environmental regulations. This work is the first journal paper focusing on the application in flexible mode of the potassium taurate system for treating a flue gas stream from a 500 MW coal-fired power plant. Techno-economic evaluations are performed to determine the best operating conditions considering the variation in the electricity demand and its price, and different values of carbon tax. In the summer period, with high electricity prices and demands, carbon tax values between 45 EUR/tCO2 and 60 EUR/tCO2 favor CO2 absorption in the flexible mode, without periods of full CO2 emissions during the day. [ABSTRACT FROM AUTHOR]

In the context of a low‐carbon economy, considering the output uncertainties of the renewable energy sources and the fluctuation of electrical price, the cost–benefit analysis is proposed for multi‐investor virtual power plant (VPP) under different risk preferences, and multi‐investor VPP capacity sizing problem is researched. First, the structural organization and flexible regulation characteristics of multi‐investor VPPs are analyzed. Second, integrated model and cost–benefit analysis indexes of VPP are built. Third, an optimal capacity sizing model of multi‐investor VPP is established, aiming at income maximization. Game theory is used to configure the distributed generators in the VPP under various cooperative modes and noncooperative modes of multiple investors. Fourth, according to the installed proportion of each distributed generator and the risk preference coefficient of each investor, the income allocation correction model based on the improved Shapley value method is proposed to stabilize the optimal VPP alliance. Finally, the demonstration project in the animation industry park of Sino‐Singapore Tianjin Eco‐City is employed as representative scenarios, which is used to validate the effectiveness of the proposed model. The results prove that the method proposed in this paper can guide knowledge for the investors with different risk preferences when planning the optimal capacity of multiple distributed generators in the VPP. [ABSTRACT FROM AUTHOR]

This paper studies when and under what conditions the actions undertaken by the power plants involved in China's emission trading scheme (ETS) pilot became cost effective. Based on unique plant-level panel data and the difference-in-differences strategy, we identify that an insignificant initial reduction in cost efficiency occurred at the announcement stage for power plants in the pilot provinces; however, the cost efficiency of the pilot plants increased significantly following formal policy implementation. Additionally, the by-stage treatment effects differed across the pilot provinces due to localized market and non-market variations. Localized conditions of higher marketization, stricter policy enforcement, and lower carbon dependence enhanced this positive effect. The synthetic control results confirmed this variation in the policy effects. The carbon trading pilots resulted in improved efficiency in power plants in Shanghai, Guangdong, and Tianjin during the period 2013--2017, with an associated total cost saving of approximately 29.75 million RMB. To enhance the efficacy of the ETS policy, our findings suggest that the design of the policy should consider localized external factors. [ABSTRACT FROM AUTHOR]

The low-low-temperature electrostatic precipitator (LLT-ESP) is considered one of the mainstream technological approaches for achieving ultra-low ash emissions and has already been applied in many coal-fired power plants. Particulate matter and SO3 can both be removed by LLT-ESP. However, the removal performance of SO3 is relatively lower than that of particulate matter, which is caused by the condensation characteristics of SO3. In this paper, the condensation characteristics of SO3 were investigated on a simulated experimental system, and several measurement and characteristic methods were used to investigate mechanisms. After reducing the flue gas temperature with a heat exchanger, the size distribution of particulate matter, the mass concentration of SO3 on different sizes of particulate matter, as well as the microscopic morphology and elemental composition of particulate matter, were all experimentally studied. The results indicate that gaseous SO3 transformed into a liquid phase by heterogeneous or homogeneous condensation and then adhered to the surface of particulate matter through nucleation–condensation, collision–coalescence, and adsorption reactions. Furthermore, the removal efficiency of SO3 in LLT-ESP was also investigated under various conditions, such as ash concentration and flue gas temperature drop, suggesting that a higher ash concentration and a more significant temperature drop were beneficial for improving SO3 removal efficiency. Nevertheless, it is worth noting that the impact was limited by a further increase in ash concentration and a drop in flue gas temperature. [ABSTRACT FROM AUTHOR]

This paper presents the development process and key findings of the first-ever health impact assessment (HIA) conducted on the proposed Alpu coal-fired power plant (ACPP) in Eskisehir, Turkiye. The study followed a systematic HIA methodology, commencing with an extensive literature search on coal-fired power plants and the region's specific characteristics during the screening step. In the subsequent scoping phase, in-depth discussions were conducted with a diverse range of experts and stakeholders to be used as inputs. The study findings highlight that the ACPP's impact on human health will be multifaceted. In addition to the estimated additional 10,000 premature deaths attributed to air pollution during the 35-year, the ACPP is expected to have implications for occupational health, including increased occupational diseases and injuries. Furthermore, it may also affect income, employment, food access, and nutritional quality. The health implications of the ACPP will extend beyond Eskisehir, potentially affecting a region with a current population of approximately 11 million residents throughout its lifetime. [ABSTRACT FROM AUTHOR]

The paper discusses the threat of decommissioning to the thermal power plant (TPP) heat exchanger tubes because of erosion and develops a computer-integrated control system (CICS) for the process of distribution of steam coal flows with different indicators of abrasive materials content, which is based on fuzzy logic. The problem of rapid decommissioning of TPP heat exchangers, particularly abrasive damage to furnace screen tubes, economizer, superheater, etc. This may indicate a discrepancy between the expected fuel ash content and the actual one, as well as a high content of abrasive impurities in steam coal. The work aims to develop a CICS of the wear resistance of the heat exchange surface of a steam boiler of a coal-fired power plant by measuring and fuzzy control of the content of abrasive impurities in steam coal. The problems of damage to the equipment of the TPP boiler are investigated, and a system for controlling the wear resistance of the surface by automatic fuzzy control of the quality of coal is developed. The results were investigated during coal preparation and combustion in the furnace of a thermal power plant to investigate the effectiveness of the proposed fuzzy controller. The model results confirm the feasibility of the fuzzy control method for the system with different coal quality parameters. [ABSTRACT FROM AUTHOR]

Large amounts of cooling water are required for the cooling process in coal-fired or nuclear power plants. Because the primary use of water in a power plant is to condense steam and remove waste heat as part of a Rankine cycle, seawater temperature (SWT) is of critical importance for electrical output in power plant applications installed at the seaside. Moreover, the analysis of SWT is an important criterion for researching sea life and global climate, and it also serves as an important indicator of climate change. In this paper, multilayer perceptron, which is in the class of a feed-forward artificial neural network, deep learning approach based on long short-term memory and bidirectional long short-term memory neural networks and data-driven methods, such as adaptive neuro-fuzzy inference system (ANFIS) accompanied by fuzzy c-means, ANFIS with grid partition and ANFIS with subtractive clustering methods were applied to make 1-day ahead SWT predictions. Analyses were conducted using 5-year daily mean SWTs measured by the Turkish State Meteorological Service for Antalya province between 2014 and 2018. The models were evaluated using mean absolute error (MAE), root-mean-square error (RMSE), and correlation coefficient (R). According to the daily SWT prediction, the best MAE, RMSE, and R values were obtained with the ANFIS-SC model, which were 0.1877 °C, 0.2683 °C, and 0.99814, respectively. [ABSTRACT FROM AUTHOR]

This paper presents a systematic approach to study the dominant electromechanical oscillatory modes in a large-scale coal-fired thermal power plant. The proposed methodology first involves analysing the fault recorder data. Next a detailed linearized model is developed, and the oscillatory modes are identified via the eigenvalue analysis. Computations of the participation factors and mode shapes are useful in identifying the contributing sources on the oscillatory modes and their types. The importance of verifying the accuracy of the dynamic data used in the simulation environment for practical power systems and validation of the linear model with nonlinear simulation are highlighted in the paper. The proposed methodology is applied to a 900 MW coal-fired real power plant in Sri Lanka power system. A dominant oscillatory mode of frequency 1.2 Hz where the coal power plant oscillates against the network is identified using the proposed methodology. This systematic approach can be applied to any real power system including renewable energy sources using correct dynamic models. [ABSTRACT FROM AUTHOR]

• A dynamic model for a 300 MW subcritical power plant boiler is developed. • A novel dynamic exergy analysis and assessment model is proposed. • The influence of drum level control on dynamic exergy behavior is evaluate. • The asynchronous responses are discussed in flow and heat transfer processes. • The dynamic exergy analysis reveals exergy destruction rates of heating surfaces. In the era of high penetration of renewable energy sources (RESs), traditional coal-fired power plants are facing increasing requirements of operational flexibility which is limited by the inherent slow dynamics of boiler. To this end, this paper presents a comprehensive dynamic model of the heating surfaces for a 300 MW power plant boiler and analyzes the exergy performance from the perspective of transient responses. Based on the object-oriented modelling language Modelica, the multi-domain first-principal model is developed by unifying the equations of thermal, mechanical, liquid and control components and interfaces. The model accuracy is validated by the field measurements. The model takes into account the multi-scale time constants in terms of the flow and heat transfer processes and drum level control. As an extension to the conventional steady-state thermodynamic analysis, a methodology of dynamic exergy analysis and evaluation is proposed. Dynamic simulation results well describe the initial reverse response of the drum level, i.e., false water level indicator, as a result of which the mass flow rate of feedwater exhibits the oscillatory performance. It is revealed that the step disturbances of flue gas mass flow and feedwater temperature, respectively, renders the temperature responses in different positions being of multi-scale setting-time and magnitudes. The exergy evaluation reveals that the water-wall suffers from the largest dynamic exergy destruction, approximately 8.2 and 8.5 times higher than the superheater and economizer, respectively. Economizer is the most sensitive component to the drum level control performance, whose dynamic exergy performance oscillates significantly. The proposed dynamic modelling and analysis method in this paper lays a solid foundation for the development of dynamic optimal control in power plants. [ABSTRACT FROM AUTHOR]

Growing demand for electricity due to economic development contributes to increased greenhouse gas production, especially CO 2. However, emissions can be limited by enhancing the efficiency of primary energy conversion, such as integrating geothermal energy into coal-fired power plants. Therefore, this paper proposes replacing conventional feed-water heaters with geothermal preheaters to create a hybridized system. This study was based on a numerical model validated at a selected Polish power unit. The model was subsequently calibrated for off-design conditions to facilitate partial load analysis. The obtained characteristics outperformed those of the non-hybrid unit, generating over 18 MW of electric power output. Such an improvement could potentially boost the unit's net efficiency by more than 2.6 %. This enhancement is significant as power units typically operate under part load for approximately 90 % of the time, hence the need to evaluate the performance characteristics of hybridized units in those states. Furthermore, the research outlines the potential decrease in the plant's CO 2 emission factor, with reductions reaching up to 6.5 % under off-design conditions. Based on a gap analysis of the existing literature, this paper's comprehensive partial load evaluation serves as a new addition to research on hybridized systems. • An in-depth analysis of feed-water heaters operation is performed. • Turbine performance calculations for both design and off-design states is validated. • The comprehensive study of hybridized systems integrates three major factors. • Hybrid geothermal-fossil power cycle is vital for specific CO 2 emissions reduction. [ABSTRACT FROM AUTHOR]

With the high proportion of renewable energy connected to the grid, the problem of insufficient flexibility in the power system has emerged. Renewable energy and controllable distributed resources can be aggregated and managed through virtual power plants, reducing the need for flexibility to a certain extent. Although building new energy storage systems can compensate for the lack of flexibility, it requires high initial investment costs. To address this, this paper proposes a lease mechanism for coal-fired units based on the combination of carbon credits and prices, providing the right to use coal-fired units for virtual power plants. Subsequently, different demand response strategies are utilized to control the controllable loads of various users, thereby providing certain controllable resources for the virtual power plant. Additionally, to ensure the optimal decision-making of the virtual power plant operator, a cost model accurately describing the capacity degradation state of the energy storage system is adopted. Moreover, a multi-time scale scheduling strategy of virtual power plant is implemented to fully utilize controllable resources of different time scales, effectively dealing with the power imbalance caused by multiple uncertainties. The results show that utilizing the leasing mechanism of coal-fired units and employing demand response strategies from different users can provide flexibility to the virtual power plant. The accuracy of the capacity degradation model used by the operator significantly impacts the optimality of the scheduling plan. • The scheduling model of VPP consider capacity degradation of ESSs, carbon trading, and DR strategies. • A lease mechanism for coal-fired units based on the combination of carbon credits and prices is proposed. • This paper proposes ISBDR strategies for reduceable loads. • The ESSs capacity degradation model adopted takes into account DOD and SOC. • A multi-time scale scheduling strategy of VPP is adopted to deal with multiple uncertainties. [ABSTRACT FROM AUTHOR]

This research constructs an assessment model for carbon capture and storage (CCS) retrofit of coal-fired power plants (CFPP) by adopting the real option theory. Due to the prohibitive costs associated with retrofitting and insufficient residual lifespan of CFPP, CCS projects may fail to recoup their investment before units are decommissioned. The key contribution of this paper is that it investigates the impact of the residual lifespan of the units on the failure rate of the retrofit investment in addition to the optimal timing of the unit's CCS retrofit. Considering different installed capacities, utilization hours, clean energy subsidy and carbon trading mechanism, this study sets up seven scenarios to assess the impact of different investment environments on the value of project investment. In terms of sensitivity analysis, the residual lifespan of the unit, its interaction with carbon price, carbon price volatility, technological advancement rate, and subsidy level are examined for their impacts on the project investment risk. The findings suggest that the critical period for determining the long-term success of most coal-fired unit retrofits may be present, and more supportive policies need to be examined to facilitate the green transformation and upgrading of coal-fired units. • The impact of coal-fired units' residual lifespan on CCS retrofits is examined. • An assessment model for CCS retrofit is proposed based on real option theory. • Insufficient residual lifespan may lead to failure risk for CCS retrofits. • The current period may be critical for the long-term success of most CCS retrofits. • More policy mixes should be introduced in time to promote the deployment of CCS. [ABSTRACT FROM AUTHOR]

[Display omitted] • A Carnot battery based on calcium looping thermochemical energy storage is proposed. • Excess renewable energy and coal-fired power plant are integrated. • Coal saving in the coal-fired power plant and carbon capture are achieved. • The boiler of the plant and the energy efficiencies of the system are optimized. • The influences of the calcium oxide conversion on system performance are discussed. Long-term energy storage and carbon capture technologies are pivotal in managing renewable energy surpluses and achieving carbon neutrality. This paper proposes a Carnot battery system integrating calcium-looping thermochemical energy storage with a coal-fired power plant. The system utilizes excess electricity from the grid for energy input, facilitating long-term energy storage, achieving carbon capture, and reducing coal consumption in the power plant. An optimization framework is developed, incorporating component thermodynamic models and optimization algorithms, to maximize the coal savings in plants and energy efficiencies of the Carnot battery system. During the energy release process, the carbonator partially replaces the reheat load of the boiler, necessitating retrofitting of the boiler's heating surface to ensure normal operation. The base system demonstrates a CO 2 capture capacity of 3.23 MJ/kg and a reduction in coal consumption by 7.07 %. The round-trip efficiency and comprehensive efficiency of the base system are 36.93 % and 37.91 %, respectively. The relatively low energy efficiency is primarily due to the deactivation of circulating adsorbents and the limited efficiency of the subcritical coal-fired power plant. By incorporating an additional recarbonation step to mitigate adsorbent deactivation, the system's comprehensive efficiency is improved to 42.20 %. Further improvements in system efficiency can be achieved by using modified adsorbents with high cycling stability instead of natural limestone and by coupling the system with more efficient ultra-supercritical units instead of the investigated subcritical units. This study offers valuable insights into the development of long-term energy storage solutions and multifunctional Carnot battery technology. [ABSTRACT FROM AUTHOR]

• A novel rapid flame annealing for materials synthesis with prototyping typical structures has been developed. • Hollow tubular MnO x (MnCot) has been prepared by flame annealing using cotton fiber as a sacrificial template. • The Hg0 removal efficiency on MnCot is as high as 90% in flue gas from 120°C to 240°C. The mass discharge of mercury from coal-fired power plant has caused great harm, abating mercury emissions is of preoccupation for protecting public environmental safety and human health. Metal oxides are often used for Hg0 removal in the flue gas. In this paper, a hollow tubular MnO x (MnCot) was successfully prepared by rapid flame annealing using cotton fiber as a sacrificial template. The MnCot were then well characterized and tested for its capability for Hg0 removal in flue gas. The results indicate that the flame assisted synthesis method for rapidly prototyping metal oxides with typical structures is achievable. The hollow tubular structure of the cotton fiber is well reprinted with good crystallization of Mn 3 O 4. The inner diameter of the hollow tubular MnCot is about 10 μm, and the thickness of the tube is about 1 μm. The Hg0 removal efficiency on MnCot can be maintained as high as 90 % under simulated flue gas atmosphere below 240°C. O 2 and NO have a positive effect on the Hg0 removal, which can act as the fresh active sits thus enhancing its capability for Hg0 removal. However, the presence of SO 2 will result in the surface sulfation on MnCot, thus deteriorating its capability for Hg0 removal. Further, the competitive adsorption between SO 2 and Hg0 on the material will also weaken its capability for Hg0 removal. The hollow tubular MnO x rapidly prepared by one-step flame annealing has a good industrial application potential for Hg0 removal in coal-fired flue gas. [ABSTRACT FROM AUTHOR]

Solar aided coal-fired power generation (SAPG) technology has been proven to be an effective way of renewable energy utilization. However, the efficiency of coal-fired units declines at partial loads, and solar inputs may further force the system to deviate from its design condition. In particular, part-load operation solutions for coal-fired units (PLOS) are conventionally applied to the SAPG system, a practice whose appropriateness has not yet been thoroughly evaluated. This paper, therefore, selects a 330 MW SAPG plant as a case study to conduct an exhaustive exergy analysis under off-design conditions. The findings indicate that the governing stage of the steam turbine and the slip-pressure operation are the main contributors to the efficiency degradation at partial loads. In addition, solar input resulted in significant changes in key operating parameters, such as exhaust flow rate and the pressure of each turbine stage. Merely adopting the PLOS for SAPG systems results in a marked increase in standard coal consumption by 0.99, 2.82, and 3.63 g/kWh at 50 %, 40 %, and 30 % load, respectively. However, the introduction of solar energy presents the potential to operate the unit more efficiently, particularly when valve point conditions are optimally adjusted. For instance, upon input of 28 MW solar thermal power, the #3 valve point condition shifted from a load of 321 MW–330 MW, achieving a reduction in standard coal consumption by 0.96 g/kWh, compared to the design condition of the original coal-fired unit. This study underscores the irrationality of directly applying PLOS from coal-fired units to SAPG system without tailored adjustments for solar integration. • Identifies the causes of efficiency decline in coal-fired units at partial loads. • Analyzes the impacts of solar inputs on exergy loss across processes in SAPG systems. • Highlights irrationality in using coal unit part-load solutions to SAPG systems. • Demonstrates potential efficiency improvements through strategic valve point changes. [ABSTRACT FROM AUTHOR]

Accurate measurement of flue gas velocity is of great significance for the safe production, energy saving, and emission reduction of coal-fired power plants. In this paper, a method of flue gas velocimetry based on a hyperbolic chirp-modulating acoustic source was proposed, and its superiority was verified by numerical simulations and field experiments. For an acoustic velocimeter, it is crucial to ensure the accuracy of the acoustic Time-of-Flight (TOF), which directly affects the flue gas velocity measurements. The improvement of the accuracy of estimation of the TOF directly determines the accuracy of the flue gas velocity measurement. Simulation on the different types of acoustic sources at different signal-to-noise ratios (SNRs) was conducted, and the results proved that the hyperbolic chirp signal is more accurate in the measurement of TOF. In the strong noise range of − 10 dB to − 20 dB, the average relative root mean square error (RRMSE) obtained using this hyperbolic chirp modulating acoustic source is 0.60 dB and 0.36 dB lower than obtained using the linear and logarithmic modulating modes, respectively. The average relative error (RE) is approximately 0.87 times that of the linear chirp. Power plant flue field experiments show that the measurement error using this hyperbolic modulating mode is about 0.52 times and 0.74 times that of using linear and logarithmic modulating modes, respectively. In harsh measurement environments with strong noise, the proposed acoustic source modulation scheme can significantly improve the measurement SNR and effectively enhance the accuracy and robustness of flue gas velocimetry. [Display omitted] • The proposed method is a flue gas velocimetry method based on a hyperbolic chirp modulating acoustic source. • This method can be applied to the non-contact measurement of velocity of gaseous media in coal-fired power plants. • The proposed method is able to iomprove the estimation accuracy of acoustic TOF. • The proposed method offers better noise resistance, and reduced attenuation. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel coal-fired power plant coupling with waste incineration scheme is proposed. • The PCDD/Fs emission could be suppressed by a three stages controlling method. • The flue gas circulation can also suppress the emission of PCDD/Fs effectively. The production of organic solid waste is increasing as the development of society. However, the investment of waste incineration power plant is very high and the thermal efficiency is very low. At the same time, the load of coal-fired power plant is suppressed due to the carbon neutralization policy. Therefore, using the existed coal-fired power plant to co-process the organic solid waste is a feasible method. In this paper, a coal-fired power plant indirect coupling with waste incineration technology based on flue gas circulation was proposed and studied on a 100 kW pilot-test bench. In this technology, the polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs) was reduced by a three stages controlling method, which adopts the blending of multi-source organic wastes, high-temperature decomposition and selective catalytic reduction (SCR) catalyst decomposition, simultaneously. The effects of waste incineration coupling, replacement ratio of coal, and flue gas circulation on the combustion and pollutant emission characteristics of the system were studied. The experimental results indicate that the waste incineration coupling has minor influence on the temperature distribution and the toxicity of fly ash of the coal-fired furnace. The NO, HCl, and PCDD/Fs concentrations of flue gas of coal-fired furnace generally decrease as the replacement ratio of coal increases, while the SO 2 concentration increases. With the help of three stages controlling method or the flue gas circulation, the PCDDFs concentration of the flue gas of coal-fired furnace can be much lower than 0.1 TEQ ng/Nm3. [ABSTRACT FROM AUTHOR]

Currently, tail flues of coal-fired power plants are treated using wet desulfurization process to remove pollutants. But, the treated flue gas has a significant moisture loss and this process also contributes to environmental pollution. Acoustic agglomeration is a non-contact treatment process that can effectively solve the problem of moisture loss in flue gas; however, there are few theoretical and experimental studies on acoustic droplet agglomeration applied to coal-fired power generation. In this paper, an experimental platform for acoustic droplet agglomeration is demonstrated to recover moisture. Further, the effects of important factors such as acoustic frequency, sound pressure level and droplet flow rate on the agglomeration efficiency are investigated. The experimental results show that there are two optimal frequencies exist, namely 500 Hz and 1200 Hz, for the droplets used in this experiment with acoustic droplet agglomeration. A highest efficiency of 58% is achieved at 500 Hz. The acoustic action differs between the 500 Hz and 1200 Hz cases. The analysis suggests that the primary force driving droplet agglomeration at 500 Hz is likely the acoustic flow effect. On the other hand, the main mechanism behind acoustic agglomeration at 1200 Hz could be related to the acoustic wake effect. Sound pressure level is the primary factor affecting droplet agglomeration, and the agglomeration efficiency increases with sound pressure, reaching 96.7% at 150 dB. Furthermore, the agglomeration effect shows a positive correlation with droplet flow rate, while the agglomerated particle size also increases simultaneously. This research provides a new idea for moisture recovery, which could offer valuable insights for implementing acoustic droplet agglomeration and moisture recovery in power plants. [ABSTRACT FROM AUTHOR]

• Stacked target enhanced autoencoder used to extract the useful features. • Attention mechanism-based long short-term memory used to predict the target output. • Data cleaning strategy used to filter the redundant data. • A three-layer-based attention network is designed to allocate different weights. Accurate and robust measurement of the oxygen content in the flue gas of power plant is significant to optimal the coal combustion process. Conventional hard measurement algorithms have low accuracy, short lifetime and high cost. Therefore, it is urgent to establish a precise and reliable soft measurement model. However, how to extract effective feature representations from complex process data is still the difficult and hot spot in the soft measurement field. The paper develops a novel soft measurement model, which integrates stacked target-enhanced autoencoder (STAE) with attention mechanism-based long short-term memory (ALSTM) in view of the above issues. The data cleaning strategy is firstly designed to filter the redundant data from the original data. Then STAE is developed to extract the useful features, which introduces target output into each autoencoder to ensure the feature representation is output-related and stacks several autoencoder units to learn high-level information. The extracted hierarchical features can not only represent the input data, but also have high correlation with the target output. A three-layer-based attention network is designed to allocate different weights on the different levels' features. Finally, due to the dynamic characteristic of the problem, a LSTM-based prediction network is dexterously designed to learn the potential relation from extracted features to target output, i.e., oxygen content. Numerous real-word data is collected from a 300 MW power plant and extensive experiments are conducted. The maximum prediction errors of A and B are 0.42 and 0.41. The 95.1 % prediction errors of A side are within [−0.2, 0.2], and the 96.2 % prediction errors of B side are within [−0.2, 0.2]. [ABSTRACT FROM AUTHOR]

CO 2 capture, utilization, and storage (CCUS) are critical technical measures to effectively mitigate the global climate change problem. However, most of the existing research has focused on the capture end and lacks in-depth analysis of subsequent processes such as compression, leading to limitations in the improvement of system economics. Therefore, a novel CCS system for a 300 MW coal-fired power plant was proposed in this paper with two strategies: (1) a CCS system integrating CO 2 refrigeration cycle (CFPP-CCS-CRC); and (2) a CCS co-generation plant integrating CO 2 refrigeration cycle (CHP-CCS-CRC). The proposed systems' performance was comparatively evaluated by applying energy, exergy, and economic (3E) analyses. The results demonstrated that at different CO 2 capture percentages (13.1 %∼72.9 %), the CHP-CCS-CRC system has improved energy utilization efficiency by 1.2 %∼5.6 % and exergy efficiency by 7.7 %∼25.8 %, compared to the conventional CCUS system (CFPP-CCS). In particular, at a percentage of 13.1 %, the combined energy consumption of the CHP-CCS-CRC system was 0.39 GJ/tCO 2 , a 79 % reduction compared to 1.87 GJ/tCO 2 of the CFPP-CCS system, which resulted in a static payback period of less than 2 years. In general, the newly proposed system features more adequate energy utilization, lower operating costs, and higher economic efficiency. [Display omitted] • A novel CCUS system coupled with CO 2 refrigeration were proposed. • The performance of the proposed systems is comparatively evaluated by 3E analysis. • The energy consumption of the proposed CCUS systems is reduced by 29.24 %–79 %. • The exergy efficiency of the proposed CCUS systems is reduced by 7.7 %–25.8 %. • The static payback period for the proposed systems is reduced to less than 2 years. [ABSTRACT FROM AUTHOR]

Conventional assessment methods of albedo measurement, like satellite imagery and on-site single-point measurements, lack the precision to address surface textural variances that can lead to power mismatches in a string of bifacial photovoltaic modules (BF-PV). To overcome this, we propose an innovative solution — an autonomous rover equipped with back-to-back pyranometers on its arm to measure the upward (plane-of-array) and downward (albedo) irradiance of a given surface. Employing an efficient path-planning algorithm, the rover ensures comprehensive spatial albedo data collection, overcoming the limitations of existing methods. The paper details the verification of the proposed methodology, its efficacy, and its importance over traditional approaches. This system enables holistic spatial albedo mapping of large areas, capturing textural/topographical non-uniformity, which is crucial for BF-PV installations. Simulations are conducted at the MBR Solar Park in Dubai, UAE, using albedo values measured and collected by the rover. The simulations involved calculating power output for a string of 20 modules across three cases of spatial albedo variations (0.32–0.38, 0.329–0.330, and 0.12–0.36). In the worst-case scenario (case 3), a power mismatch of 18.7% across the module string and a 4.2 °C temperature mismatch are observed. Cases 1 and 2 showed 4.6% and 0.2% power mismatch losses, respectively. These results underscore the critical role of precise spatial albedo measurements in optimizing installation conditions, emphasizing the need for spatial mapping to enhance energy yield estimates. • Developed a new methodology for spatial albedo mapping using a rover. • Highlighted importance of non-uniform spatial albedo on bifacial PV. • A novel albedo-map of an area of 1 sq. km to visualize topographical variation. • Power mismatch of 18.7% for a string of 20 modules when albedo variation is within 0.12–0.36. • Precise estimate for bifacial PV plant installation. [ABSTRACT FROM AUTHOR]

• The NO emission characteristics of co-combustion of pulverized coal and NH 3 at O 2 /N 2 and O 2 /CO 2 atmospheres were studied. • The effects of temperature, NH 3 blending ratio and combustion atmosphere on NO emission during co-combustion were investigated. • The molecular dynamics simulation was used to study the migration pathways of N in NH 3. The use of ammonia as a co-combustion fuel instead of fossil fuel combustion is an important way to reduce carbon emissions from coal-fired power plants. This paper investigates the NO emission characteristics of coal/NH 3 co-combustion at O 2 /N 2 and O 2 /CO 2 atmospheres through experiments and molecular dynamics studies. The results demonstrate that increasing the combustion temperature enhances the formation of NO with the NH 3 blending ratio is 0–60 %. When coal and NH 3 are burned together, the emission of NO is lower at O 2 /CO 2 atmosphere compared to that at O 2 /N 2 atmosphere. Reactive force field molecular dynamics (ReaxFF MD) simulation results show that the effect of high concentration of CO 2 on nitrogen conversion is mainly related to temperature. When the temperature is low, the physical characteristics of CO 2 with large specific heat capacity inhibits the conversion of NH 3 to NO. However, at high temperature, CO 2 participates in the reaction in large amounts, which increases the number of OH radicals in the combustion process and promotes the conversion of NH 3 to NO. The results show that with the increase of combustion temperature, the conversion of nitrogen-containing intermediates to NO is promoted. Furthermore, the reactive molecular dynamics simulation revealed the transfer pathway of N atoms in NH 3 during co-combustion process at two atmospheres. [ABSTRACT FROM AUTHOR]

• Studied the effects of NH 3 cofiring ratio, injection mode and OFA on NO x emission. • NO x exhibited a variety of trends under different injection modes and OFA rates. • Revealed all the different NO x trends are governed by the same NO mechanism. • Found air-staging is not always effective in the NO x reduction of NH 3 cofiring. Ammonia (NH 3) cofiring is a promising approach to reduce the CO 2 emissions from coal-fired power plants. However, the potential drastic increase of NO x emissions may inhibit the wide implementation of NH 3 cofiring. To explore the potential NO x control strategies, the effects of NH 3 cofiring ratio (R N H 3 ), NH 3 injection mode and overfire air (OFA) rates on the NO x emission characteristics of NH 3 /coal cofiring are studied in a test furnace that allow for flexible control of the injection positions and combustion environment of NH 3. The results show that when NH 3 is injected with coal stream (top mixing mode), the NO x emissions increase and then decrease with the increase of R N H 3 under all OFA rates. However, when NH 3 is fed through the side port of furnace separately (side mixing mode), the NO x emissions exhibit distinct trends under different OFA rates. Under lower OFA rates, the NO x emissions show monotonical decrease with the increase of R N H 3 , while under higher OFA rates the NO x emissions first decrease and then increase with the increase of R N H 3 . Consequently, higher OFA rates could produce higher NO x emissions than lower OFA rates. This indicates that air-staging is not always effective in the NO x reduction of NH 3 cofiring. Thus, although the side mixing mode of NH 3 cofiring exhibits overall better performance in NO x control, caution is needed to accommodate the OFA rate with NH 3 cofiring ratio. Although a variety of trends of NO x emissions were observed in this study, the results demonstrate that all these trends are in fact governed by the same mechanism – the competition between the NO-formation and NO-reduction reactions of NH 3 in the varying O 2 environment in the furnace. By creating appropriate O 2 environment in the furnace, the NO x emissions of NH 3 /coal cofiring could be substantially lower than that of pure coal combustion. The findings of these paper are instrumental in the design and operation of NH 3 cofiring system in full scale coal-fired boilers to achieve effective NO x control. [ABSTRACT FROM AUTHOR]

Improving the peaking capacity of coal-fired units is imperative to ensure the stability of the power grid, thus facilitating the grid integration and popularization of large-scale renewable energy. To address this issue, this paper introduces a new concept that combines molten salt energy storage with coal-fired power plants. The proposed design consists of extracting a portion of steam from the turbine side and adjusting the extracted steam mass flow rate by adjusting the valve opening to improve the dynamic characteristics of a coal-fired power plant in terms of both increasing the peaking depth and peaking speed. A coal-fired boiler with integrated thermal energy storage was dynamically modeled using Dymola and its accuracy was verified. The results show that the highest equivalent round-trip efficiency is achieved by extracting from the main steam and discharging into the feedwater during charging process and from reheater1 and discharging into the feedwater during discharging process; The peaking potential during charging and discharging is 12.83 % P e and 6.86 % P e respectively, with maximum peaking rates of 9.27 % P e /min and 5.11 % P e /min respectively, and the optimal peaking method is also proposed according to the different peaking situations. The total cost of equipment and materials to retrofit the conventional coal-fired units was 19,948,193 USD and the levelized cost of delivery was 151.29 USD/MWh. • Coal-fired power plant systems incorporating molten salt energy storage. • Dynamic characteristics and economic analysis of coal-fired power plants. • A peaking potential of 12.83 % P e during charging process and 6.86 % P e during discharging process. • A theoretical maximum peaking rate of 9.27 % P e /min during charging process and 5.11 % P e /min during discharging process. • LCOD is determined to be 151.29 USD/MWh. [ABSTRACT FROM AUTHOR]

Large-scale distributed renewable energy sources as well as emerging controllable loads such as electric vehicles connected to the distribution grids have posed challenges to the efficient management of these distributed energy resources. Promoting energy-sharing of distributed energy resources through economic incentives is a cost-effective and equitable solution to the challenge. This paper proposes a two-stage transactive energy control mechanism by the virtual power plant (VPP) for energy-sharing of multiple prosumers. Firstly, a VPP internal price mechanism based on the supply-demand ratio of prosumers in the energy-sharing alliance is proposed. Then, a two-stage economic optimization model is developed. Trading prices between VPP and prosumers are established in the first stage, and prosumers make operating plans based on those prices in the second stage. Then, considering that prosumers and VPP are independent stakeholders, a decentralized optimization algorithm based on the analytical target cascading method is developed. The upper-level VPP coordinates the energy-sharing alliance and sets the transaction price following the overall supply and demand ratio. Lower-level prosumers independently make decisions and feedback on the trading power of the VPP. Then, iterative calculations provide a distributed and independent solution. Finally, the case study verifies that the proposed energy-sharing model can reduce the operating cost of prosumers by 14.29 %. Moreover, prosumer privacy protection is achieved by the analytical target cascading-based distributed model at a cost of less than 1.5 % accuracy. [ABSTRACT FROM AUTHOR]

The paper undertakes a novel study that aims to analyze the performance characteristics of ten monocrystalline or polycrystalline silicon modules employing different emerging technologies in waters environment. In this work, monitoring data were collected over a duration of one year using a multi-technology empirical platform within a floating photovoltaic power plant. The energy performance of different module technologies was evaluated using multiple performance metrics such as array yield, performance ratio, capacity factor, efficiency and energy density. By considering environmental variables such as irradiance, ambient temperature, and water temperature, the thermal behavior of photovoltaic modules under water surface deployment conditions is revealed. Furthermore, the multiple variable coupling analysis was conducted to determine the correlation between the performance metrics of various technology type modules and meteorological variables in waters environment. The results indicate that the energy performance and reliability of monocrystalline silicon modules using double-glass double-sided P-type PERC technology is superior to other technologies in waters environment, and the performance ratio and capacity factor reach 88.95 % and 15.04 %, respectively. The heterojunction with intrinsic thin-layer (HIT) technology module exhibits better thermal stability and holds an advantage in the deployment of limited water surface areas due to its higher energy density. Moreover, the performance ratio of floating photovoltaic systems shows a weak correlation with irradiance, and is more significantly affected by the negative correlation of ambient temperature than water temperature. [ABSTRACT FROM AUTHOR]

Steam system plays a crucial role in industrial energy usage. Steam generation in the industry domain is transferring from coal-fired or gas-fired plant/boiler to green-electricity steamer for net-zero purpose. The increasing coupling of the electricity-steam energy system in the industry domain, called electricity-steam coupled industrial energy system (ES-IES), brings enormous challenges to the system day-ahead operation optimization due to the uncertainties of renewable generation and the nonlinearities of the system mathematical model. Therefore, this paper introduces the steam accumulator (SA) into the steam system to mitigate the renewable fluctuations, proposes an isothermal linearization method of the steam flow model, and optimizes the operation based on an interactive iteration scheme between optimization and simulation for the global optimum and a balance between accuracy and speed. Results show that considering the storage characteristics of SA and the complementary coordination of electricity and steam through coupling equipment can significantly optimize the operation of ES-IES with an increase in the renewable energy consumption rate by 23.81 % and a decrease in the total operating cost by 11.39 %. The static payback period for the investment of EB and SA is 7 years, indicating a favorable application prospect. • Linearization methods of steam flow model are used for global optimum. • Equivalent energy storage model of steam accumulator is proposed for optimization. • An interactive iteration scheme between optimization and simulation is presented. • Economic and efficiency performance of the electricity-steam coupled system is evaluated. [ABSTRACT FROM AUTHOR]

Large-scale distributed renewable energy sources as well as emerging controllable loads such as electric vehicles connected to the distribution grids have posed challenges to the efficient management of these distributed energy resources. Promoting energy-sharing of distributed energy resources through economic incentives is a cost-effective and equitable solution to the challenge. This paper proposes a two-stage transactive energy control mechanism by the virtual power plant (VPP) for energy-sharing of multiple prosumers. Firstly, a VPP internal price mechanism based on the supply-demand ratio of prosumers in the energy-sharing alliance is proposed. Then, a two-stage economic optimization model is developed. Trading prices between VPP and prosumers are established in the first stage, and prosumers make operating plans based on those prices in the second stage. Then, considering that prosumers and VPP are independent stakeholders, a decentralized optimization algorithm based on the analytical target cascading method is developed. The upper-level VPP coordinates the energy-sharing alliance and sets the transaction price following the overall supply and demand ratio. Lower-level prosumers independently make decisions and feedback on the trading power of the VPP. Then, iterative calculations provide a distributed and independent solution. Finally, the case study verifies that the proposed energy-sharing model can reduce the operating cost of prosumers by 14.29 %. Moreover, prosumer privacy protection is achieved by the analytical target cascading-based distributed model at a cost of less than 1.5 % accuracy. [ABSTRACT FROM AUTHOR]

The paper undertakes a novel study that aims to analyze the performance characteristics of ten monocrystalline or polycrystalline silicon modules employing different emerging technologies in waters environment. In this work, monitoring data were collected over a duration of one year using a multi-technology empirical platform within a floating photovoltaic power plant. The energy performance of different module technologies was evaluated using multiple performance metrics such as array yield, performance ratio, capacity factor, efficiency and energy density. By considering environmental variables such as irradiance, ambient temperature, and water temperature, the thermal behavior of photovoltaic modules under water surface deployment conditions is revealed. Furthermore, the multiple variable coupling analysis was conducted to determine the correlation between the performance metrics of various technology type modules and meteorological variables in waters environment. The results indicate that the energy performance and reliability of monocrystalline silicon modules using double-glass double-sided P-type PERC technology is superior to other technologies in waters environment, and the performance ratio and capacity factor reach 88.95 % and 15.04 %, respectively. The heterojunction with intrinsic thin-layer (HIT) technology module exhibits better thermal stability and holds an advantage in the deployment of limited water surface areas due to its higher energy density. Moreover, the performance ratio of floating photovoltaic systems shows a weak correlation with irradiance, and is more significantly affected by the negative correlation of ambient temperature than water temperature. [ABSTRACT FROM AUTHOR]

• Methodology for assessing the operational flexibility of Virtual Power Plants. • Methodology to facilitate the integration of renewable energies into the power system. • Graphical representation of operational flexibility of distributed energy resources. • Assessment of the available flexibility to facilitate decision-making under uncertainty. • Participation of Virtual Power Plants in the ancillary services and power reserve offer. Distributed energy resources (DERs) are elements that actively participate in the supply of renewable energy and contribute to the decarbonization of the power system. However, they lack two factors necessary to take advantage of their operational flexibility: observability and controllability. In this sense, Virtual Power Plants (VPPs) are a feasible alternative to provide the necessary requirements for the optimal management of a set of distributed units. Therefore, knowledge of the technical and energy characteristics of each unit that makes up the VPP is a necessary condition for the effective integration of DERs into the power system. This paper proposes a methodology to graphically represent, quantify and exploit the aggregate operational flexibility of a set of units. The proposed methodology is based on five metrics related to active and reactive power, which serve as a tool to facilitate the VPP Operator's decision-making under uncertainty. Consequently, achieving the coordinated operation of several distributed units makes it possible to achieve common objectives. For instance, frequency and voltage regulation, compliance with a planned power curve, or dealing with the variability of renewable energies. The proposal is applied to a theoretical case study and through real operational tests between a hydroelectric unit and a photovoltaic plant. Finally, it is shown that the results obtained are a useful tool in real-time. [ABSTRACT FROM AUTHOR]

To construct a new energy system during the low-carbon transition, renewable energy sources (RESs) are increasingly being installed on a large scale worldwide which require thermal power units to operate at low loads and respond quickly to compensate for frequency fluctuations of the power grid during deep peak shaving and frequent load changes. While coal-fired thermal power plants operate under the deep-peak shaving process, low-frequency oscillation (LFO) accidents from the generation side have occurred constantly. According to our investigation, the reasons are the overlook of the nonlinearity of control valves is obviously highlighted under low load, and the preset parameters of the original control device can not match the flow characteristics, which may seriously cause a recurrence of LFOs. This paper focuses on generation-side LFO caused by the prime mover and its governor under all operating conditions constructing a novel nonlinear model and designing an oscillation feature observation matrix to identify the LFO modes, and a hierarchy feature-state observation classification method preventing LFO on the generation side is proposed. The results show that the proposed method can suppress the LFOs ahead, and this approach can weaken the oscillation amplitude by 85% and reduce the oscillation duration by 30 s. • Retrofit the small frequency offset compensation and the valve flow module, simulate dynamic characteristics accuracy. • Propose an oscillation ranking method to evaluate the security level of power oscillation and verify its reliability. • Design the hierarchical prevention control strategy for LFO in stages and validate the effectiveness of thecontrol strategy. [ABSTRACT FROM AUTHOR]

The article is an editorial from the journal Impact Assessment & Project Appraisal. It celebrates the beginning of the new year and the 25th anniversary of the journal. The editorial highlights the importance of the Impact Assessment community in promoting sustainability and addressing climate change and biodiversity loss. It also announces a special collection of articles that have received the "Best Paper Award" to commemorate the journal's journey. The editorial provides a brief overview of the research articles and book review included in the current issue, covering topics such as the role of Environmental Impact Assessment (EIA) in protecting landscapes, incorporating climate change consequences in Environmental Assessments, and indigenous-led impact assessment tools. The editorial concludes by expressing the hope that readers will enjoy reading the articles. [Extracted from the article]