Net metering is the arrangement that makes on-grid solar pay. Your meter counts in both directions: solar you consume directly reduces your draw, and surplus you export spins the count the other way as a credit.
At billing time you pay for the net - imports minus exports - plus fixed charges. Generate more than you use in a month and the credit typically rolls forward. This is why most homes skip batteries entirely: the grid is your battery.
Each DISCOM has its own capacity caps and settlement rules, and they do change. Your installer files the net-metering application as part of the job - make sure that's in the quote.