Capacity optimization of hybrid energy storage systems for offshore wind power volatility smoothing

Abstract

Energy storage devices are frequently included to stabilize the fluctuation of offshore wind power’s output power in order to lessen the effect of intermittency and fluctuation on the electrical grid but doing so will raise operators’ investment costs. To obtain the best economic benefits, this paper presents a hybrid energy storage system based on batteries and super-capacitors and its capacity configuration optimization method. First, the wind power output is divided using the wavelet packet decomposition method, and then power is distributed between the batteries and the super-capacitors. Then, the mathematical model of energy storage system optimization is established to optimize the capacity configuration of hybrid energy storage with the objective of minimizing the daily input cost of energy storage, and the configuration schemes of single energy storage and hybrid energy storage are compared. Finally, using the measured data of a domestic offshore wind farm for simulation, several energy storage schemes are compared to verify the feasibility and effectiveness of the proposed method, at the same time, using the hybrid energy storage devices to participate in the grid-connected stabilization task of offshore wind power is more advantageous than the single energy storage, the results show that the daily input cost of the hybrid energy storage scheme is 2.79% and 3.84% lower than that of the single energy storage scheme using only battery or super-capacitor.

Keywords

• Stabilize fluctuations
• Wavelet packet decomposition
• Hybrid energy storage
• Capacity optimization