What types of photovoltaic systems are there?
There are 2 main types: 1) a utility inter-tie system which connects you to the grid, but will disconnect from it when the grid goes down in a black out our seismic event; and 2) the stand-alone system that is completely independent from the electrical grid and includes all the components from 1) plus a bank of batteries that allows you to store energy either when the power goes down, or when the sun goes down. These are generally found in rural areas where power is either not reliable, or where utility power is unavailable. The inter-tie system consists of the photovoltaic panels (~$350 per 110-watt panel); an inverter to change DC (direct current) power from the panel to AC (alternating current) power that is on the grid and in your home; an inter-tie switching system and shut-down capability; and optional batteries to back up and store excess power on sunny days for use at night and in emergencies. Note that windmill systems have similar requirements. However, there are new developm
