Net metering is a billing mechanism that credits solar energy system owners for the electricity they add to the grid. For example, if a residential customer has a PV system on the home’s rooftop, it may generate more electricity than the home uses during daylight hours.
Net metering (or net energy metering, NEM) allows consumers who generate some or all of their own electricity to use that electricity anytime, instead of when it is generated. This is particularly important with wind and solar, which are non-dispatchable. Monthly net metering allows consumers to use solar power generated during the day at night. Annual net metering rolls over a net kilowatt credit to the following month, allowing solar power that was generated in July to be used in December.