Analysis of variations in PV production, focussing on storage and dispatchability decisions

Photovoltaic energy has been consolidated as one of the largest sources of renewable energy. Moreover, there is continuous worldwide growth in installed capacity. However, the inherent variability and uncertainty of these power systems are its main inconveniences. It causes undesirable effects on the distribution power grids and prevents it from participating in the electricity market as a manageable or dispatchable energy source. Energy storage could ensure stabilization of decentralized grids and help to enable the penetration of photovoltaic (PV) energy. However, incorporating batteries in PV installations will require increased investment and the concomitant decrease in their profitability. An optimal design of these storage systems, in order to minimize investment costs, could be achieved by means of accurate knowledge of the PV production variations. In this paper these fluctuations are analyzed in two grid-connected photovoltaic plants located in Andalusia, Spain, over a two-year period. Information about the batteries´ capacity and life-cycle may be extracted. A smoothing effect has been found if the forecast of photovoltaic production is performed at 60-min. intervals.