A saved kilowatt-hour and an exported kilowatt-hour can have different values. Keep the two revenue lines separate.
Draw the two flows
Electricity used at home as it is generated reduces some grid purchases. Surplus sent to the grid is a different flow and needs the appropriate arrangements. The national energy mediator’s guide explains self-consumption and the options to examine.
Read the export terms
Ask who buys the surplus, which contract applies, how payment is measured and which conditions determine the rate. Do not copy a tariff from a neighbour’s older installation into your own estimate. Keep connection, commissioning and payment conditions visible in the project documents.
Treat virtual storage as a contract
An offer described as virtual storage does not put the electricity in a physical battery at home. Read the credit rules, charges and exit terms carefully, and check compatibility with support arrangements. Compare the complete annual cost with a straightforward surplus-sale scenario.