Gradual Configuration Research on Energy Storage System for a Photovoltaic Plant

A gradual configuration research on energy storage system (ESS) is proposed and applied for photovoltaic (PV) plant in this paper. First, the ESS is used to absorb the unbalanced energy between the solar power generation and load demand. It is found that ESS capacity will be extremely large to meet all the balancing requirements. A simple solution for this problem is to allow excess power generation. Then, the ESS is installed at a PV plant to achieve generation schedule based on power forecast. A modified probabilistic approach is adopted to study the impact on the needs for storage because of the forecast errors. Results show that the required ESS capacity can be significantly reduced when a small amount of residual PV output uncertainty has been permitted. Lastly, to be more practical and economical, utilising the ESS for power fluctuations smoothing is also included in this study. It is shown that the ESS capacity is strongly influenced by the smoothness of the output wanted, but much smaller than the two situations mentioned above.