Grid-tie

Grid-tie (or tied) is a term used to describe an energy producing system whose output is connected to the utility grid. In these systems, the electrical output must be syncronised with the utility's power and must not continue to feed the grid when the grid has failed. Those tasks are usually taken care of by an inverter, although induction generators can be equipped to do the same.

The purpose of a gridtie AE/RE system is to reduce one's electric bill through a net metering plan or even to sell excess energy to a utility company. Most DIY alternative energy systems will not generate enough energy to pay for their own cost in a reasonable time period and may not even be able justify the added cost of the grid-tie feature.