What happens when the sun doesn shine?
The amount to which a period of little or no sunlight will effect a home using solar power varies greatly depending on the physical location of a particular home and the nature of the solar system being used. For instance, if the home uses PV and solar thermal, and is also connected to the standard electricity grid, a period of no sunlight will simply mean relying on grid power. On the other hand, homes that are not connected to grid power must either be able to rely on other energy producers, such as a fuel cell, a wind turbine, a diesel generator, or on a supply of electricity stored in batteries. For some solar technologies, such as passive solar applications that utilize a large thermal mass, stored power in batteries or power from a standard utility cannot serve as a backup.
