Net metering is an agreement that allows the solar PV system owner to sell excess solar energy to the utility company or buy deficit energy from the utility company using a meter to track this energy exchange.
Under Net metering arrangement, The Distribution Licensee i.e. your utility (MSEDCL, Reliance, Tata etc) and Eligible Consumer enters into a Net metering connection agreement after providing approval for connectivity of Rooftop Solar system with the distribution network under these Regulations but before starting the actual generation from the Solar Roof top system installed by the Eligible Consumer.
For each billing period, the Distribution Licensee shows separately;
a) the units of electricity exported by Eligible Consumer,
b) the units of electricity imported by Eligible Consumer,
c) the Net units of electricity billed for payment to the Eligible Consumer and
d) the Net units of electricity carried over to the next billing period
In the event, the units of the electricity exported exceeds the units of electricity imported during the billing period, such excess units of electricity exported is carried forward to the next billing period as credited units of electricity.
Thus Net metering arrangement providers a customer benefit of exporting the units which otherwise without a battery would get wasted.