Performance of a grid-connected PV system with energy storage

With sponsorship from the Pennsylvania Energy Office and Philadelphia Electric Company (PECO), a one kilowatt amorphous photovoltaic system has been operated in a grid-connected mode with energy storage. The purpose of the system development and performance experiment is to investigate the additional value a grid-connected system garners with dispatchable battery energy storage. These values are then weighed against the added cost of the system and inefficiencies incurred in the charging and discharging of the battery. The basic feasibility of operating such a system was of primary importance to PECO in particular. From the start of the project the first goal of the systems operation was to provide a given rated power supply to the grid during a pre-set dispatch interval every day. As such, the ability to maximize total energy output was compromised in order to meet this goal. Meeting the reliability goal while minimizing energy loss provided the stimulus for much of the simulation analysis performed early in the project. >