Analysis On Peak Regulating Of The Grid-connected Photovoltaic Power Generation With Energy Storage

In recent years, the Chinese electricity demand keeps sustainable growth, while the peak-valley difference of load is large which lasts for a long time. Thermal power generation takes a very large proportion in our power structure. Regulating the peak load by thermal power generation costs a lot since large thermal power units have to decrease the output at valley hours and small units have to stop in the night according to the needs.In the21st century, people face the severe suitation with shortage of traditional energy sources and environmental pollution. Since the burning of fossil fuels is the major factor of environmental deterioration, solar and other clean renewable energy become an inevitable choice and develop quickly. With the increasing capacity of the grid-connected photovoltaic(PV) power generation, once the photovoltaic installed reached a certain proportion in total capacity installed, it will generate under the same dispatch policy with other conventional units. However, it is difficult to utilize the photovoltaic due to its intermittent nature.Under this background, a grid-connected photovoltaic generation with energy storage for regulating peak load was proposed.Firstly, this paper analyzes the feasibility of the grid-connected photovoltaic generation with energy storage for regulating peak load. There is a certain similarity between the photovoltaic output and the load fluctuation. With the help of the energy storage system, on the one hand, energy storage system can reduce the intermittent of the PV generation, improve its controllability and reduce its negative impact on the grid, on the other hand, the PV generation which is used for peak load shifting can smooth the load curve, reduce the peak-valley difference of load, improve the efficiency of other generation units and power equipment, delay units and transmission capacity expansion, significantly improve the comprehensive benefit of the PV system.Secondly, based on the traditional balanced generation scheduling model, the paper analyzes the peaking capability of the thermal power plants and the grid-connected photovoltaic generation with energy storage. Through analyzing the impact on system regulating capacity, the peak-valley difference of load, the adjustment of the load curve and the output of other generation units, the peaking capability of the thermal and the grid-connected photovoltaic generation with energy storage can be compared. Analysis by example of the IEEE30system and the large intermittent load peaking regulation, the peaking capability of the grid-connected photovoltaic generation with energy storage is proved to be superior to that of the thermal power plants.