When it comes to having a solar electric system with pv modules and generating your own electricity, you will fall into one of two main groups.
On-grid systems are linked to an electric utility, such as PG&E, and are usually the best option for individuals who utilize that infrastructure. If you currently pay an electricity bill, then you are already tied to the grid which means offsetting your current monthly bill is possible and the logistics of maintaining the system will be relatively smooth. Roof mounts are popular for those with smaller yards and when space is at a premium, whereas ground and pole mounts are a more inexpensive solution if you have the ground space to spare. Components include a power inverter, a collection of modules, and mounting equipment.
Off-grid systems are one of the only options for homes that are not receiving electricity from a electric utility, typically in more rural locations. While off grid photovoltaic systems are more of an initial investment, you are but freed from being grid tied and may end up saving money when compared to having the electric company extending their power lines to your location. The components typically include everything an on-grid system contains, in addition to a set of deep cycle batteries inside a battery enclosure, and perhaps a diesel or propane-powered generator backup, if desired.