Energy Storage Capacity Optimization in Smoothing Renewable Energy Power Fluctuations Based on Empirical Mode Decomposition

With the improvement of renewable energy grid permeability, renewable energy grid power fluctuations have many adverse effects on power grid. Energy storage system(ESS) can effectively overcome the power fluctuation problem of renewable energy generation systems. In order to smooth power fluctuations in renewable energy and determine energy storage capacity, EMD method was used to decompose renewable energy power output samples, and a series of intrinsic mode function(IMF) was obtained. Based on the decomposition results and considering the ESS charge-discharge efficiency, state of charge(SOC) and renewable energy system power output volatility constraints, the minimum required capacity of ESS was determined. In wind power actual data in a given area, for example, the results show that the method can effectively ease wind power fluctuations, and the energy storage capacity is small, and can guarantee the stability of system operation.