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This study addresses the intermittent renewable energy supply and the large footprint of battery storage on an island reef in China by proposing an integrated energy system that incorporates hydrogen production, storage, and utilisation. Mathematical models for wind and photovoltaic power generation, energy storage, hydrogen production and utilisation, diesel generators, and energy management systems are established. Additionally, an integrated energy system is constructed using Simulink software to simulate and analyse its operational characteristics in various seasonal scenarios. The simulation results indicate that the surplus from wind power and photovoltaic systems, after supplying the load for over 70 % of the day, constitutes more than 40 % of the load demand. The energy storage system can maintain a maximum charging rate for more than 50 % of the day and a maximum discharge rate for less than 16.7 % of the day. The electrolysis tank produces hydrogen for more than 71 % of the day and simultaneously consumes up to 750 % of the load. The fuel cell consumes hydrogen for less than 12.5 % of the day and simultaneously provides up to 27 % of the load. Analysis revealed that the hydrogen system improves the energy utilisation, the control strategy realises stable supply and demand within the system. [ABSTRACT FROM AUTHOR]

With the development of new-power generation sources, the difference between maximum and minimum power requirements from a power grid is growing. However, the peaking power installed capacity, such as pumped-hydro energy storage and gas-fired power, is too small to meet the peaking regulation requirements. Chinese coal-based energy resources structure determines coal-fired power plants to be the main source of power. This means that coal-fired power units will need to undertake more peak shaving tasks for a long period of time. In this paper, we provide an overall review of China׳s coal-fired power units׳ peak regulation with a detailed presentation of the installed capacity, peak shaving operation modes and support policies. High energy-consumption problems, environmental pollutants and safety barriers when coal-fired power units run in low-load operation are noted from the power generation perspective. Some policy recommendations are given to solve the peak shaving problem to some extent and to ensure the sustainable development of the power energy system. [ABSTRACT FROM AUTHOR]

• Operation modes were considered in energy consumption of a CHP plant. • The heat rate was obtained considering two units operating in parallel. • Optimization model based on the energy consumption was established. • 304.44 kJ·kWh−1 can be saved for the reference CHP plant. Optimizing thermal–electric load distribution toward combined heat and power (CHP) units can improve the efficiency of thermal power plants. Here, a thermal–electric load distribution method is proposed based on the energy consumption characteristics of CHP plants. The influence of operation modes on the energy consumption characteristics has been considered. Based on the energy consumption characteristics, the influence of load distribution on the heat rate is expounded considering two units operating in parallel. Firstly, a 600 MW unit model is developed using the EBSILON software, and the associated energy consumption model is established by passing the simulation results to a MATLAB routine. Then, three distribution methods are used to study the influence of the thermal–electric load distribution on the heat rate. Finally, the energy consumption model is embedded into a momentum particle swarm optimization (MPSO) algorithm, and the thermal–electric load distribution is optimized using the load data from a characteristic day with the operation feasible region taken as the boundary. The results show that the thermal load plays a major role in the energy efficiency of the unit, and the electric load determines the exergy efficiency distribution. The operation mode of the unit has little influence on the energy utilization rate, but has a significant influence on the exergy efficiency. When two CHP units are running in parallel, their heat rate can be reduced by optimizing the thermal–electric load distribution. A more uneven distribution of thermal–electric load between units results in a lower heat rate. The optimized heat rate given by the MPSO algorithm for a characteristic day is 6887.93 kJ·kWh−1, which is 304.44 kJ·kWh−1 less than under the average thermal–electric load distribution. These findings may be helpful to get insight into the energy consumption characteristics of CHP plants and guide for its economic operation. [ABSTRACT FROM AUTHOR]

Two of the most critical issues encountered in the day-ahead scheduling of regional integrated energy systems are the uncertainty of renewable energy resources and complexity of load demand. Furthermore, varying operating conditions also pose challenges for economical day-ahead scheduling. This paper proposes a scenario-based day-ahead scheduling approach for regional integrated energy systems to minimize operating costs by mining historical data. A hybrid dynamic energy hub model with variable efficiency that integrates an extreme gradient boosting (XGBoost) algorithm and analytical formulation is proposed. We developed a scenario-based scheduling optimization model in which climate data and load data are predicted using XGBoost and the probability distributions of their predicted errors are estimated using a Gaussian mixture model. Monte Carlo simulation and K-means clustering were used to generate and reduce scenarios and a success-history-based adaptive differential evolution algorithm was adopted to search for optimal solutions for day-ahead scheduling. Furthermore, a weighted average electricity purchasing strategy was adopted to address uncertainty and further improve operating economy by adjusting the output of gas turbines and electricity purchasing for actual scheduling. Case studies were conducted to verify that the proposed approach can reduce daily operating costs and enhance the operating economy of regional integrated energy systems. • A hybrid DEH model integrating operating data and an analytical formulation characterizes flexible performance accurately. • Considering the uncertainty by scenario-based stochastic optimization method increases the operating cost. • A weighted average electricity purchasing strategy can address the uncertainty and further improve operating economy. [ABSTRACT FROM AUTHOR]

• A high-efficient pressure matcher was proposed, validated and analyzed in Ebsilon. • Low-stent-placed steam supply pipeline module was furtherly investigated and used to transport steam within 4 km. • A steam-driven screw turbine was introduced to satisfy an eco-industrial park's electric and heat need. • Solar thermal utilization part was used to pre-heat domestic water with taking Beijing and Huzhou's DNI into consideration. • Energy, exergy and entransy analysis was simultaneously considered to analyze main equipment in regional system. Regional integrated energy system has been a suitable scheme in China to satisfy eco-industrial park's both electric and heat needs. Combined heat and power (CHP) is an efficient technology for coal-fired plants during heating seasons. Currently, wires transport electric from CHP to destination while urban pipes network transport heat from CHP to destination, respectively. However, this might not be the case in future, when eco-industrial parks are close to plants or pipes network can't carry enough heat. This paper presents a feasible regional integrated energy system which meets both electric and heat's needs with steam from CHP while maintaining photothermal resources' high percent utilization. This system includes a coal-fired CHP plant, pressure matcher, steam supply pipeline, screw turbine and solar thermal utilization part. This paper set up a model of 600 MW electric power CHP with pressure matcher and screw turbine in Ebsilon software. Then the steam supply pipeline and solar thermal utilization part were developed and analyzed based on the basic thermodynamic theories with Beijing and Huzhou's meteorological statistics taken into consideration. Besides, the operational issues of the regional system were also listed. Meanwhile, the regional integrated energy system was obtained and a lot of characteristics were analyzed. Main devices were further investigated with energy, exergy and entransy analysis. Three extreme working situations were also carried out and discussed in the end. Several useful conclusions were drawn. It's necessary for China to masterly integrate regional energy system with multi-energy. Moreover, pressure matcher is high-efficient in general under other parameters' influences. This extracting steam's technology might be considered in future. Besides, low-stent placed pipeline which can transport high-parameter steam 4 km at most was introduced. A proper mass flow value or lower inlet temperature will both reduce loss of pipeline. Furthermore, heat user side can offer electric power about 9.22 MW, heating acreage about 0.79 km2 to the eco-industrial park. More solar heat's import, lower upper temperature difference and less sunlight will favor solar thermal utilization part. Higher heat load or lower CHP's working condition will benefit screw turbine. Peak heat exchanger doesn't need to work when supply domestic water temperature's demand is less than 65 °C. The simulation in this paper might give technological statistics to the regional integrated energy system which has CHP and photothermal. This will help to put this energy system into actual use in future. [ABSTRACT FROM AUTHOR]

Abstract: The hydro turboset is the key equipment of the electric power system. Thus, it is very important and necessary to monitor and diagnose the running conditions and the faults of the hydro turboset for the safe and normal running of the electric power system. Fault diagnosis of the hydro turbine is a complicated process and requires a high level of expertise. In order to significantly reduce the cost consumed in the fault diagnosis, to increase the consistency of diagnosing decision-making, and to better utilize the turbine’s management information resource, in this paper, an integrated Web-based expert system of the fault diagnosis has been developed for the hydro turbine of a power station. Moreover, it can be regarded as an advisory tool to those who have much technical experience and as a training tool for the less-experienced personnel who seek guidance and advice. This paper describes a research project aiming to develop a Web-based intelligent diagnosis system for the hydro turbine and discusses the process of the fault diagnosis and the difficulties involved in developing the system. The paper also includes several practical issues related to the architectures of the intelligent Web-based applications. The system is built on a three-tier architecture, including the following components: knowledge base, inference engine, knowledge administration interface, user interface, knowledge administration unit and integrated database. The expert system employs heuristic rules to diagnose the hydro turbine fault. Some issues on developing Web-based expert systems are also discussed. [Copyright &y& Elsevier]