For electric customers who generate their own electricity, net metering allows for the flow of electricity both to and from the customer ? typically through a single, bi-directional meter. With net metering, during times when a customer?s generation exceeds the customer?s use, electricity from the customer flows back to the grid, offsetting electricity consumed by the customer at a different time. In effect, the customer uses excess generation to offset electricity that the customer otherwise would have to purchase at the utility?s full retail rate. Net metering is required by law in most U.S. states, but these policies vary drastically.