Why do the measured values on my electricity bill differ from the measured values in EnergyCloud?

Answer:

Ferroamp measures imported and exported energy using shareable current transformers. This measurement method provides high-resolution readings needed, for example, to perform phase balancing. However, it does not offer the same level of measurement accuracy as a fixed-mounted electricity meter.

Another factor that can contribute to increasingly significant discrepancies with the utility company's meter is the different methods used to measure imported and exported three-phase energy during simultaneous phase balancing. Ferroamp utilizes a different measurement method than most grid companies in Sweden, which is why EnergyHub may report higher values for both imported and exported energy compared to what the utility company measures when phase balancing occurs in combination with export.

A simplified example:

• You have a consumption of 1000 W on phase 1, 1500 W on phase 2, and 2000 W on phase 3.
• You have solar production generating 1500 W on phase 1, 1500 W on phase 2, and 1500 W on phase 3.
• EnergyHub will register 500 W export on phase 1, 0 W import/export on phase 2, and 500 W import on phase 3.
• The utility company will register 0 W import/export since the export on phase 1 is offset by the import on phase 3.

This means that EnergyHub calculates import as 500 W per hour (0.5 kWh) and export as 500 W per hour (0.5 kWh), while the utility company does not count any energy, either imported or exported.

The difference is most significant during winter with less solar radiation, and the system can balance around 0 W in net power over a longer period while simultaneously importing on one phase and exporting on another.

In future software versions, EnergyHub will also measure using the method used by Swedish utility companies.

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If you need to get in contact with Ferroamp's Technical Support or if you have any questions about the system, you can do so by creating a ticket here.