Power systems vary in design depending on what energy sources are used and what purpose they must fulfill. There are essentially three types of solar power systems: Grid-Tie Systems Also called grid-interactive, grid-intertie, utility-interconnected and other such terms, grid-tie solar systems built onto your building and property that connect directly into the electric utility feed. This is possible in areas that allow net-metering, whereby a solar or wind powered system turns your electric meter backwards when it is producing more power than you are using. This type of system provides no backup power when the utility fails. Grid-Tie Systems with Battery Back-up a grid-tie system with battery backup feeds excess solar electricity to the grid and provides backup power when the utility grid is down. With this type of system you sacrifice some power generation efficiency in exchange for having power when there is a utility power failure. The amount of backup power you have depends on the size of the battery and electrical loads that draw on them. Off-Grid Systems This type of power system is independent of the utility grid. It can use solar modules, a wind generator, a micro-hydroelectric generator, or a combination of any or all of them to produce your electric power. Owners of this type of system often use a gas or diesel generator for backup when the power system does not meet all of the needs. sitemap