Fuel pumps are checked by the weights and measures office. For charge points, accurate metering alone is not enough — the data path has to be tamper-proof too.
Anyone filling up with petrol or diesel can be confident of receiving — and paying at the till for — the quantity of fuel shown on the pump, because fuel pumps are checked regularly by the weights and measures office.
What does metrology compliance mean?
Unlike a petrol or diesel pump, simply capturing the reading via a metrology-compliant meter is not sufficient for electric-vehicle charging infrastructure. Further arrangements are required for transmitting and storing the data, such as the amount of energy charged.
In order to offer a transparent and verifiable market for EV charging stations, German weights and measures law (Mess- und Eichrecht) establishes the basis for values measured during the sale of energy in the form of electricity to be displayed and billed correctly.
After charging, EV drivers should be able to check
- how much electrical energy was drawn,
- how long the charging session lasted, and
- how the price is calculated from the measured kWh or time value.
The transfer of these measurements to the backend should also be tamper-proof, so that they can be verified after the fact.
Implications for shared residential buildings
If only one resident uses each charger, then chargers with MID-certified meters are sufficient to attribute electricity costs accurately. The property manager includes those figures in the annual service-charge statement.
Where a company car is charged at an employee's home and the total charging electricity cannot be unambiguously attributed to the company vehicle, an MID meter is often no longer sufficient for billing the employer, and it comes down to the evidence the employer requires. The employer may insist on metrology compliance.
We consider metrology-compliant chargers the safest way to protect your investment in charging infrastructure. They not only cover every scenario, they also leave no room for arguments or misunderstandings with unhappy owners.
To bill and manage your charging infrastructure we use aCharge Cloud, the portal we developed for exactly this purpose here in Aachen. Details are available at ladesmart.de.
Questions about your charging infrastructure?
We're happy to advise you on load management, incentives, and the right aCharge product.
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