Minimising output power fluctuation of large photovoltaic plant using vanadium redox battery storage

The large-scale photovoltaic (PV) installations have experienced an unprecedented growth in the past decade, mainly due to renewable deployment targets, government incentives and advancement of the PV technologies. This growth brings new technical challenges to the electricity grid. For instance, the inherent intermittency of PV power has given rise to a number of approaches to compensate for the variability of its output. A possible solution could be the integration of battery energy storage with the PV plant. The Vanadium Redox Battery (VRB) is one of the batteries having the potential to increase the supply reliability of large-scale PV plants. This paper proposes the grid integration of a 1MW PV system using a 250kW/250kWh VRB energy storage. The VRB was designed to smooth the fluctuating PV power, thus being able to deliver constant power to the electricity grid within a five minutes time frame. An equivalent electrical model of the PV system is developed in MATLAB/Simulink/PLECS environment to analyse the operational performance of the proposed system and to discuss the elements affecting the VRB efficiency.