Photovoltaic solar systems have a number of merits and unique advantages over conventional power-generating technologies. PV solar systems can be designed for a variety of applications and operational requirements, and can be used for either centralized or distributed power generation. PV systems have no moving parts, are modular, easily to install and upgrade. Energy independence and environmental compatibility are two attractive features of PV solar systems. The fuel (sunlight) is free, no noise or pollution is created from operating solar systems. In general, alternative energy systems that are well designed and properly installed require minimal maintenance.
At present, the high upfront cost of PV solar modules and equipment (as compared to conventional energy sources) is the primary limiting factor for the technology. Consequently, the economic value of PV systems is realized over many years. In some cases, the surface area requirements for PV arrays may be a limiting factor as well. Due to the diffuse nature of sunlight and the electrical energy conversion efficiency of solar panels, surface area requirements for PV array installations are on the order of 6 to 8 m² (64 to 86 ft²) per kilowatt of installed peak capacity.
However battery storage must be used. This type of system is extremely popular for homeowners and small businesses where a critical backup power supply is required for critical loads such as refrigeration, water pumps, lighting and other necessities. Under normal circumstances, the system operates in grid-connected mode, serving the on-site loads or sending excess power back onto the grid while keeping the battery fully charged. In the event that grid becomes unavailable, control circuitry in the solar inverter opens the changeover switch with the utility and operates the inverter from the battery to supply power to the dedicated loads only. In this configuration, the critical loads must be supplied from a dedicated distribution panel.