A summation meter is a device that collects data from multiple measurement points – that means your household's electrical installations, the inverter for your solar panels, and your XOLTA battery. It includes both electricity production and consumption across the home's three phases in its calculation.
Why is it important?
The summation meter provides the grid operator with an accurate picture of your electricity usage, ensuring that you only pay for the electricity you consume from the grid.
Without a summation meter, your electricity production would not be offset against your electricity consumption.
Example
In this example, the solar panels produce 4 kW on one phase, while the house consumes 3 kW on another phase. A standard meter does not recognize this correlation – it only sees the consumption, meaning you would be charged for 3 kW.
The summation meter sees the full picture, showing a surplus of 1 kW, which you can sell back to the grid.