Comparison of AC and DC Bus Interconnections of Energy Storage Systems in PV Power Plants with Oversized PV Generator

Oversizing the photovoltaic (PV) generator improves the profitability of PV power plants, but a downside is energy losses due to power clipping. If an energy storage system (ESS) is needed, connecting it to the DC side enables the utilization of the clipped energy. We compared the AC and DC bus interconnections of ESS in a typical building block of megawatt-scale PV power plants. The DC bus interconnection increases the energy yield, but also the utilization of the ESS. The operation of the ESS is affected by the production profile of the PV generator, ESS energy capacity and DC-to-AC power ratio.