Energy losses in photovoltaic systems

Abstract The maximum power generated by photovoltaic (PV) arrays is not fully used. There are many reasons leading to energy loss. A main reason of energy loss during the summer is the system design which necessitates PV array oversizing to supply the load during the winter season when solar energy is limited. Other reasons that cause energy loss are mismatch between the array and the load or battery, energy loss in batteries and loss due to PV array disconnect. The array disconnect loss takes place during the summer season when the storage battery is fully charged. To avoid the disconnect loss, a novel Battery Voltage Regulator (BVR) that allows supplying the load directly from the array is used, when the battery is fully charged. In this work, energy losses have been analysed and divided into fundamental (unavoidable) and non-fundamental losses. Both conventional (using conventional BVR) and novel (using novel BVR) PV systems are studied. A load consuming a constant power 24 h a day through the year is considered. The climatic condition of Cairo is regarded.