All generation is provided by the solar electric array.
Load autonomy during inclement periods is provided by energy stored in the battery and the solar array is sized to meet the load requirement for the month with the least sunshine. Stand-alone PV systems are designed to provide excess energy for the rest of the year, and may still be more cost effective than other generator technologies. TEGs continuously consume fuel and require frequent maintenance. For applications where the daily load is large or in areas where winter sunlight is scant, the PV and batteries required to maintain a site's entire electrical design load may render a stand-alone PV system too costly. In such cases a solar-hybrid system can help reduce the initial system cost while maintaining low operating costs and required liability.