Energy and Economic Yield of Photovoltaic Systems: Reactive- Power Impact

Abstract. The reactive-power service will be or is already obligatory for new grid-connected photovoltaic systems. The paper investigates the impact of the reactive-power service on the energy yield of a photovoltaic system and its effect on the inverter sizing and economic yield. Based on simulations and analysis of an operating photovoltaic system we show that energy losses due to the reactive-power service are low but become notable at high irradiance levels. Also, the optimal inverter sizing is affected by the reactive-power service more at low irradiance levels than at the high ones. Nonetheless, economically there is no reason to oversize the inverter due to reactive power needs. A photovoltaic system with a balanced or slightly larger inverter can provide the reactive-power service and achieve a little lower but still optimal internal rate of return