In accordance with German calibration law (Mess-und Eichrecht), charge point operators in Germany may be required to provide signed meter data to EMSPs and drivers, so they can verify these values against the information displayed on the invoice for that charge session.

GreenFlux has developed a solution to retrieve this data from charge stations and share it via roaming networks – a technical description is available here below.

This approach works for all manufacturers but may require some integration work, depending on the OCPP implementation. Please contact Technical Integrations ( chargepoints@greenflux.com) for further assistance.   Hardware models with a built-in display for drivers to check meter values do not need to exchange signed data via roaming networks

This resource is for e-mobility service providers (EMSPs) and EV drivers who wish to see how much

electricity was supplied in a particular charge session.

In accordance with the German calibration law (Mess-und Eichrecht), charge point operators may be required to provide signed meter data to EMSPs and drivers, so they can verify these values against the information displayed on the invoice for that charge session.

GreenFlux offer software for  Charge Point Operators (CPO) to manage a network of charge stations. In this capacity, we facilitate the exchange of Signed Meter Values through networks and provide instructions to support users in understanding and processing the information provided by CPOs.

A charge station with a calibrated meter will produce digitally signed (encrypted) meter values. These encrypted meter values cannot be manipulated by a third party. With the help of ‘ Transparency software’ , users can decrypt the meter values and compare them against the values that have been charged to them.

To verify that the right amount of electricity has been charged, users need to know:

GreenFlux provides the data in the correct format to be opened directly in the transparency software. Since most ChargeStation models have slightly different implementations of Eichrecht these bespoke files will be generated for supported models as found below.

If we do not support the Charger specific implementation GreenFlux provides this data in a JSON format via a URL that is included in the CDR data set. Below is an example of the default Signed Data file for a charging session.

GreenFlux detects automatically based on the Manufacturer attribute of the charge station's boot notification data which Encoding Method should be used. For instance, if GreenFlux detects the Manufacturer 'Alfen', the 'Alfen' Encoding Method will be applied. If no Manufacturer specific Encoding applies, GreenFlux uses the default Encoding Method (i.e. the SAFE Transparenzsoftware Encoding method).

Open the file in the Transparency software if charging on a supported charger. Otherwise manually fill the signed data from the JSON file in the transparency software and use the public key that is displayed on the charger.

I n most cases, the “public_key” is not provided through the Signed Data file. The public key then can be retrieved either:

Manufacturers may have their own transparency software or use a software implemented by multiple companies.

Below is a list of relevant Encoding Methods known to GreenFlux.

Please note that GreenFlux is not responsible for the availability and usability of these transparency software suppliers. For questions, please contact the manufacturer or Charge Point Operator directly.