When a grid connected photovoltaic (PV) or any other embedded generation system is installed on a house or building, our regulation requires that a bi-directional meter must be installed. This bi-directional meter measures and records the net amount of electricity that is consumed or generated.
The net amount of electricity is further explained; when your electricity consumption is higher than your electricity generation then the meter will record the difference between the two, this is the net consumption. When your electricity generation is higher than your electricity consumption then the meter will record the difference, this is the net generation. Over the billing period, two totals (accumulated registers) are stored - one total is the net consumption and the other is the net generation. These consumption and generation totals are net totals over all phases connected at the meter. These are the values which are read periodically and are used for billing.