Sizing of Energy Storage Systems for Different Levels of PV and Wind Power in Combined PV-Wind Power Plants

Energy storage systems (ESS) can be used to mitigate rapidly fluctuating photovoltaic (PV) and wind power productions. In this paper, sizing of ESSs for different levels of PV and wind power in combined PV–wind power plants is studied. The study is based on PV powers simulated based on operating condition measurements and on measured wind turbine powers. It was found that as the amount of nominal PV power increased in the combined PV–wind power plants, the relative energy, charging power and discharging power capacity requirements for the ESSs of the combined PV–wind power plants decreased gradually. The daily maximum and median shares of energy cycled through the ESSs decreased gradually as well when the amount of nominal PV power increased. It was found that the occasional wind power (WP) regulation periods significantly affected the ESS sizing considering the charging and discharging powers of the ESSs. Moreover, it was found that within these power plant sizes, the measured WP fluctuations were faster than the simulated PV power fluctuations.