Abstract: Output power of a photovoltaic (PV) generator depends mainly on incident solar irradiance on the PV modules. Due to moving clouds in the sky, the incident solar irradiance on the PV modules fluctuate frequently. As a result, output power from PV generator also fluctuates. Rapid changes in PV generated power can cause serious problems for relatively small electricity networks with high penetrations of PV generation. Energy storage systems can be used to balance the fluctuations in PV generated output power, thus ensuring a smooth supply of power to the grid. The grid-connected solar PV research power plant equipped with climatic and electric measurement systems in Tampere University of Technology is used to analyse fluctuations in PV generator output power. Different aspects of energy storage utilization have been considered to control the ramp-rate of PV generated output power.

Keywords: Energy storage, irradiance transition, power fluctuation, PV system.