Hi Riya Pulickathara ,

The sizing of the battery depends on the specific application and it has two different ratings called power and energy ratings. The power rating is determined based on the instantaneous change in power, whereas the energy rating is determined using the autonomy (hours of operation).

For instance, if the battery is to be designed to mitigate the intermittency, then the battery should be designed to meet the worst-case scenario, with the probable deviation in the power output of PV or Wind turbines.

Firstly, the PV and wind turbines should be simulated with real-time solar irradiation and wind speed data to find the worst-cases. Secondly, the power deviation has to be calculated from the simulated results. The net power deviation gives your power rating of the battery. Meanwhile, the energy capacity is obtained from the question; how long should the battery support?

Please note that this procedure is to find a rough estimate of your battery size if your work focusses on the control aspects of solar PV and wind turbines.

However, if your work focusses on sizing in particular, then you may have to go in for advanced algorithms like heuristics and metaheuristics to find the capacity of the battery.

Hope it answers your question.