This paper discusses the integration of solar photovoltaic (PV) and battery energy storage (BES) units for reducing energy loss and enhancing voltage stability. Here, each nondispatchable PV unit is converted into a dispatchable source with a combination of PV and BES units. New multiobjective index (IMO)-based analytical expressions are proposed to capture the size and power factor of the combination of PV and BES units. A self-correction algorithm (SCA) is also developed for sizing multiple PV and BES units while considering the time-varying demand and probabilistic generation. The power factors of PV and BES units are optimally dispatched at each load level. Results obtained on a 33-bus commercial distribution system show the validity of the proposed approach and algorithm for calculating the optimal size and power factor of multiple PV and BES units. The results show that operation of PV and BES units with optimal power factors can substantially reduce energy loss and better enhance voltage stability when compared to that with unity power factor. As a result of the tangible technical benefits, it may be appropriate for utilities to set up frameworks and standards for PV units operation at optimal power factor as the current IEEE 1547 standard only allows PV generation at unity power factor. (C) 2013 Elsevier Ltd. All rights reserved.