Photovoltaic systems supported by energy storage are commonly applied solutions for supplying power in off-grid locations. Properly designed systems can ensure reliability at a level comparable to conventional diesel generators. In addition, renewables-based systems not only have lower cost of maintenance (its operation is not fuel supply dependent) but also a significantly smaller environmental footprint. In this paper, a PV-battery system is designed to supply four different loads in a remote location. The cost of reliability as well as related emissions are estimated and compared with a diesel generator. In contrast to the previous approach, PV-battery system reliability of is determined in a long-term horizon. The performance of the PV-battery is influenced not only by the variability of irradiation and temperature but also the degradation of PV system efficiency and a drop in battery capacity. In the available literature these three aspects are frequently neglected but even if considered, then never simultaneously. Based on the conducted analysis the following conclusions are drawn: PV-battery system has a significantly lower environmental impact than a diesel generator but it is not close to zero as the system tends to be oversized and the utilization of PV generation is relatively low; the solar energy system supplies variable loads at a cost comparable to a diesel generator (0.68 (sic)/kWh) but for constant loads it is more expensive by over 0.3 (Sic).