Control method evaluation for battery energy storage system utilized in renewable smoothing

Intermittent renewable energy sources have drawn much attention in the last 15 years. The European network infrastructure is changing towards more renewables, increasing the usage of co-generation while decreasing the capacity for conventional power plants (20-20-20 Energy Policy). However, these renewable sources have outputs which are characterized by poor controllability and unpredictability, thus making grid integration difficult. Battery energy storage is proposed to assist the regulating power plants in following the power output of renewables. In this paper, different control methods for Battery Energy Storage Systems (BESS) for renewable smoothing applications are discussed. The novelty of this paper relies on the fact that each control algorithm is evaluated according to its effectiveness in smoothing and battery stress. A benchmark was performed where the power outputs are compared. The battery stress and lifetime were estimated using a rainflow cycle counting algorithm. The results reveal that although a control method can perform satisfactorily in terms of renewable smoothing it might affect severely the battery lifetime, making this benchmark essential before selecting the control approach in order to maximize the revenue of the investment.