Essentially net metering means the utility will trade electricity with you, giving you credit for any excess power your renewable energy system produces for the grid against the electricity you consume.
Net metering allows for the flow of electricity both to and from the customer (you)and typically through a single, bi-directional meter. When your grid-tied system is producing more than you use, the excess power automatically flows back to the grid. This adds credits to your account and offsets electricity consumed by you at a time when your system is not generating electricity.
In effect, you use excess electricity generation to compensate for electricity that you would have had to purchase at the utility’s full retail rate. In net metering you are billed for the net electricity purchased from the utility over the entire billing period whether that period is a month, a quarter, or a year. Aperiod longer than a month is probably to your advantage.
Net metering allows you to get more value from the energy you generate. It also simplifies both the metering process–by eliminating the need for a second meter–and the accounting process–by eliminating the need for monthly payments form your utility.
Oncor Service Area
That said, Oncor (formerly part of TU Electric) is the largest electric service provider in Texas. It does not net meter since deregulation of electricity in Texas (Jan 1, 2002). This means net metering will come from your electricity retailer if you are in the Oncor service area Keep an eye on the Texas Legislature in 2009. There may be some changes.
Electric Co-ops and Municipalities Some do have a net metering policy. Ask your service provider or ask a professional in the field..