In grid tie solar photovoltaic system in which the solar inverter output is connected to the AC power grid, there are 2 ways of electrical energy metering scheme: gross metering and net metering. And here we shall discuss the difference in between.
Net Metering Scheme:
Actually nowadays, this metering scheme is used for most of solar photovoltaic systems, and it means the generated electrical energy from the solar system will go to a meter box, then from the meter box to your house. If your house electrical equipment needs such energy at that point of time, the whole solar generated electricity will feed your equipment, and No need to consume any electricity from the power grid, so now this electricity is free of charge. But if the generated electricity is larger than what your equipment need at that point of time, then the extra electricity will be exported to the power grid to be used by other electricity consumers. Your electricity meter exists on the meter box will measure the amount of exported energy, and you will get paid for such exported energy by your power grid retailer and that is called feed in tariff. The price of exported kWh is usually lower than the price of consumed kWh. At night times, you will receive your needs of electricity from the power grid, and of course the electricity meter will measure the consumed energy from the grid during the day.
The feed in tariff differ from one country to another, and from one energy company to another, it even differs from one energy retailer to another, and your guide to the best retailer tariff will be your solar system installer.
Gross Metering Scheme:
Under this scheme, all solar generated electricity will be exported to the grid, and you will get paid for it by away of certain credit according the power company rules/tariff, and that also called feed in tariff, its generous tariff in which you will get paid with a very good electricity rate. In brief, in gross metering scheme, the meter measures the entire generated electricity from the solar system separately from your electricity consumption. Almost, this meter scheme is no longer exist, and most of countries governments follow net metering scheme.