A promising way to electrify regions lacked to reliable access to electricity is the employment of standalone photovoltaic power systems (SPPSs). Recently, the cost of electricity from such systems has fallen, and it is expected that this tendency will continue in the future. Within this paper, a new design methodology of highly reliable and sustainable SPPSs is presented. The approach consists of the following processes: prediction of the load demand, characterization of the PV performance on site, sizing the SPPS considering different storage technologies, and forming the most effective design. On the other hand, a new dimensionless number will be introduced to characterize the PV performance at a particular location. In order to demonstrate the methodology, an intention to electrify 93 households in a rural community is given as an example. The results show that a SPPS configuration including compressed air energy storage and supercapacitor may be the most effective SPPS design. (C) 2017 Elsevier Ltd. All rights reserved.