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Photovoltaic power generation relies on power electronics and therefore does not have natural inertia and damping characteristics. In order to make the capacitance of the medium time scale participate in the grid frequency response without adding additional equipment, this paper takes the grid-connected photovoltaic power generation system based on DC voltage droop control as the research object, and establishes the static synchronous generator (SSG) model of the system. The model is used to analyze the main parameters affecting the inertia, damping and synchronization characteristics of the system and their influence laws. The research results show that the energy storage effect of the capacitor on the medium time scale can also make the system exhibit certain inertia characteristics. From the point of view of control parameters, as the droop coefficient $D_{\mathrm {p}}$ decreases, the inertia characteristic exhibited by the system is stronger. The larger the DC voltage outer loop proportional coefficient $K_{\mathrm {p}}$ is, the stronger the damping effect of the system is. The larger the DC voltage outer loop integral coefficient $K_{\mathrm {i}}$ , the stronger the synchronization capability of the system. In addition, the MATLAB/Simulink simulation platform is used to verify the correctness of the theoretical analysis results.

As the renewable energy fluctuating in the power grid, the traditional coal-fired power plant needs to operate on the extremely low load, so as to increase the share of renewable energy. This paper deals with thermodynamic simulation and exergy analysis of the coal-fired power plant integrated with the molten-salt energy storage system to explore the potential of reducing the minimum operation load. A steady-state simulation was performed to obtain the thermodynamic properties of process streams in a subcritical 600 MW unit. The results indicated that with simple main steam and re-heat steam energy storage plan, the storage efficiencies are 39.4-42.9% and 51.3-51.4%, the minimum operation load would decrease by 27.2 MW, 10.6 MW, respectively. Exergy analysis shows that the exergy loss mainly comes from the throttling process and temperature difference in the phase-changer heat transfer process. With optimized Molten-salt energy storage plans, the storage efficiencies increase to 72.6% and 78% via lead the exhaust drains or steam into higher pressure points; the minimum operation load decreases by 35.1 MW and 3 MW, respectively. Moreover, with the coupled plan including both optimized main steam and re-heat steam energy storage system, the minimum operation load would decrease by 80.7 MW, and storage efficiency is 75.1%.

Compared to the step tariff, the real-time pricing (RTP) could be more stimulated for household consumers to change their electricity consumption behaviors. It can reduce the reserve capacity, peak load, and of course the electricity bill, which could achieve the purpose of saving energy. This paper proposes a coordinated optimization algorithm and data-driven RTP strategy in electricity market. First, the electricity price is divided into two parts, basic electricity price and fluctuating price. When the electricity consumption is equal to the average daily electricity consumption, the price is defined as the basic electricity price, which is the clearing electricity price. The consumer electricity data are analyzed. A random forest algorithm is adopted to predict the load data. Optimal adjustment parameters are obtained and the load fluctuation and the fluctuation of the electricity price are further quantified. Secondly, the appliances are modeled. The operation priority is established based on the preferences of customers and the Monte Carlo method is used to form the power load curve. Then, the smart energy planning unit is proposed to optimize the appliances on/off time and running time of residential electrical appliances. An incentive mechanism is used to further standardize the temporary electricity consumption. An improved multiobjective particle swarm optimization (IMOPSO) algorithm is adopted, which adopts the linear weighted evaluation function method to maximize the consumer’s social welfare while minimizing the electricity bill. The simulation proves that the stability of the power grid is improved while obtaining the best power strategy.

Storage of thermal energy is a key technology for energy conservation and application of renewable energy sources. In this paper, the thermal performance of inorganic composite phase-change materials (PCMs; NaNO3/SiO2/C) is studied under extreme thermal conditions and the effect of raw particle size is examined. We designed a thermal shock test platform with a diffusive combustion system and in-situ infrared thermal imaging. The influences of the heat flux magnitude and exposure time on the performance of the PCMs were examined under vertical thermal shock conditions. Leakage of molten salt in the composite PCMs was observed as the heat flux reached a threshold point. The morphology and thermal properties were characterized by ex-situ SEM, XRD, DSC, and BET. Raw particles with sizes in the range of 105–500 μm were used to synthesize the composite material and examine its role in thermal shock behavior. Our experiments showed that deterioration of the thermal storage density was slowed as the particle size was increased. This work provides useful guidance for improving the anti-thermal shock ability of future material designs.

Aiming at the problem of urban waste reduction in the "no waste city" plan, the multi-energy microgrid operation problem raised by full renewable energy supply, this paper proposes a coordinated energy storage based on multiple energy sources and is highly compatible Multi-energy microgrid optimized operation model for waste treatment facilities. First, the energy conversion process of waste pyrolysis and gasification is studied, and the power, heat, and gas energy output characteristics model of the waste treatment facility and the power balance characteristic model of the multi-energy microgrid connected to it are established, based on this, the garbage treatment is proposed multi-source integrated coordinated energy storage system (WDM-CCS); Then, study the economic model of garbage disposal and multi-energy microgrid operation, With the goal of minimizing the overall operating cost and maximizing the amount of waste disposal, the multi-energy microgrid optimization operation model of WDM-CCS is established. Finally, based on the operational data of multi-energy microgrid and garbage disposal facilities in a certain area in Northeast China, a multi-energy microgrid simulation model based on WDM-CCS is established. The simulation results show that compared with the traditional multi-energy micro-grid, the multi-energy micro-grid using WDM-CCS not only has better regulation ability and higher regenerative energy consumption, and can effectively improve waste disposal capacity.

With the rapid increase in power loads, power supply capacity plays a significant role in power distribution network. However, attributing to the tremendous differences in regional economic development and diversified characteristics of power distribution network, power supply capacity should be evaluated based on regional differences to better promote the efficiency of distribution network. In this paper, the evaluated indexes including supply capacity reserve, supply capacity margin and supply capacity balance are defined, and the evaluated models for single and inter-layer equipment are established. Furthermore, a case study with ten different regions is employed to validate the proposed models. Results illustrate that considering the effects of “N-x” criterion, network structures and overload features, the proposed comprehensive models could quantitatively evaluate the supply capacity and offer better supports for planning and operation of large-scale power distribution network.

With the continuous expansion of wind power installed capacity in China, the scale of wind power integration in the North Region is also growing. During the winter heating period, the operation mode of pricing electricity based on heat amount and cogeneration units is forced to output electricity, it’s one of the most important factors for the abandonment of wind power in the northern region. The configuration of heat storage and electric boilers is an effective mean to enhance their regulation capabilities and increase the amount of wind power accommodation. In this paper, a comprehensive control strategy is proposed for combined operation of wind power and thermoelectric storage boiler, based on thermal power, cogeneration unit operating cost and abandoned wind cost. The simulation models were built to study the control strategy of heat storage device and introduces environmental penalty cost, and to analyze the strength of wind power accommodation and the total revenue of the system under three different modes of operation. At the same time, the environmental penalty cost is introduced in the specific operation mode, and the impact on the operation cost and the abandonment of the wind is analyzed, verifying the validity of the proposed model.