Simplified guide to Eichrecht conformity I German calibration law for electric vehicle charging

Being used to gas stations with transparent and comprehensible display of: the quantity of fuel pumped, price per litre, and total amount of consumption in every fueling session, it is natural that a common EV driver would expect the same level of transparency while charging electric vehicles too.

However, the existing charging station hardware, software systems and regulations around were not prepared for such a detailed transparent billing per every charging session. Thanks to Germany, who took the lead in bringing up the transparency via Eichrecht measurement & calibration Act, as an amendment to Measuring and Verification Act (Mess und Eichgesetz / MessEG) and the Measuring and Verification Ordinance (Mess- und Eichverordnung / MessEV).

Eichrecht – at a glance:

➤ Eichrecht finds only KWh consumption based billing as fair: Consequently, pure time based tariffs (per-minute billing) and flat-rate session fees per charging process (per-session billing) will not be permitted.

➤ Fully regulated calibration & end-to-end data security of charging data : This means that the charging stations will have the fully calibrated KWh measuring meters and should assure the user a reliable, trustworthy transaction, in line with the requirements set by German law.

In short, the German Eichrecht wants charging pole/ stations to operate like their counterparts – gas stations, where you pay only for what you consume (per litre of fuel) and where you can see in real time what you’ve consumed per fuelling session.

How does Eichrecht - Mess und Eichgesetz work?

The Eichrecht calibration law mandates that the KWh measurement meter used for billing, must be periodically calibrated and be visible to the customer (EV driver).

The customer should be able to verify the KWh reading on the station itself (via a display or position the meter itself visible to customer). In addition, the charging station will also have a unique public key (may be a QR code), through which the customer can verify the "start metervalue", using an independent web/app/IT interface (for example: Transparenz software by S.A.F.E Initiative) that is in accordance with the Eichrecht legislation. This ensures that the EV driver can reliably check how much electricity he/she consumed at what time and price.

Without going deep into details, below diagram shall give a simplified view on what Eichrecht means to a common EV driver and how the transparency of EV charge data is secured.


Once the charging session is complete, the station generates charging data for the particular customer signed and encrypted to the charge point operator(CPO)’s IT back end. Based on this secured signed data, the e-Mobility provider (EMP) creates invoice for the customer.

What does Eichrecht mean for home charging

Home charging can be one of the below scenarios:

1. Personal car - charging at personal charging station - connected to single home meter cabinet:

If you charge your own EV using your personal wall box, which is connected to your own household meter, you do not need Eichrecht conformed charging station. The station does not need to have even a MID (Measuring Instruments Directive) certified meter too. In this case, the EV charging station will be considered just as another home electrical appliance (like cooking plate, oven, heater…etc).

2. Company car – charging at personal charging station - connected to single home meter cabinet:

If you charge your company leased EV at your home wall box, it is sufficient to buy a charging station that has a MID-certified meter – to reimburse the allowances with your employer.

However, if there are more than one electric car charging at your wall box (even occasionally), for example , - if you & your partner work at two different companies and reimburse separately, or  - if your relatives or acquaintances also charge at this charging station when they visit, it is not legally correct to use MID meter equipped station for reimbursements.

The exact requirements for this particular use case is still a bit confusing, as there is no clear guideline published by the Working Group for Metrology and Verification - AGME (Arbeitsgemeinschaft Mess- und Eichwesen) yet. Until there is a clear official statement given, it may all depend on what evidence the employer might ask to prove the EV charging consumption. So always check with your employer’s conditions for reimbursing.

What does Eichrecht mean to company / workplace charging

Company / workplace charging can be one of the below scenarios:

1. Employee charging at company location

If an employer provides charging infrastructure for their employee at free of cost, the charging stations at office does not have to be Eichrecht compliant. This is different if the employee has to pay for charging his/ her electric vehicle at office parking space. Then, the employer must install charging stations that must meet the requirements of Eichrecht calibration law. 

2. Visitors Charging at company location

If an external customer or visitor charges at the office location for a fee, then these charging stations must be Eichrecht compliant. In that case, these stations will be considered as a “public” station, which means it is also necessary to fulfil all the requirements of a public station, like the price information regulations must also be observed!.

3. Pool vehicles charge at the company location

Charging of pool vehicles are mostly free since they are not linked to any user and is difficult to bill/process reimbursements. But in case, a user is assigned and has to be billed, then the regulations are fully internal, up to the company’s tax filing system to decide what kind of evidence they may want to produce to the tax authorities.

What does Eichrecht mean to public / semi-public charging

Public EV charging infrastructures (example: municipality street charging) and semi-public charging stations (example: installed at supermarkets, shopping malls and similar locations) where the charging is billed, must fulfil all the requirements of Eichrecht - Mess und Eichgesetz.

Underlying design principles of Eichrecht conformity

Below are the design principles of Mess und Eichgesetz, which were developed to add price transparency and customer protection.

1. Confidentiality: The value of the measurand (KWh) must be correctly measured by a (periodically) calibrated measuring device according to the regulation. This is something comparable to every petrol station that are regularly inspected by the state calibration authority.

2. Integrity: The contents of a remotely transmitted message (charge consumption data) with measured values cannot be falsified undetected. This means that the end-to-end communication from the charging station to E-Mobility provider (EMP) billing fully secured.

3. Authenticity: A message with measured values can be assigned to a specific data source without doubt after the remote transmission. This means, that the every message (charging data) has to contain unique identification of the corresponding charge point or meter.

4. Imputability: A message with measured values after remote transmission can be assigned without doubt to the person which has caused an invoice debt in connection with the measurement. Meaning, the message has to contain customer’s identification as well to cross check, in case of doubts.

5. Availability: A message with measured values must be available to the contractors of the transaction until the process, including the mutual settlement of the invoice debt, is finally completed. Meaning, the customer must be able to access the data at any time until the end of the objection period.

How is Eichrecht conformity regulated?

Measuring and Verification Ordinance (Mess- und Eichverordnung / MessEV) lays down guidelines and requirements for the Eichrecht conformity and empowers the National Metrology Institute of Germany (PTB) to take care of the type testing and pattern approval process. Accordingly, the PTB assigns 16 local control measurement offices in each of the federal states for market surveillance with local inspection bodies.


When did Eichrecht come in to effect?

The Eichrecht calibration law is not new; the amendment to the Measurement and Verification Law (Mess- und Eichrechtsgesetz) came into effect on 1st Jan 2015. However, till the start of last year (2019), there were only three charge station hardware manufacturers were approved for Eichrecht conformity. 

Now since we have many charge station hardware have got Eichtrecht approval from PTB/VDE; and many CPO platforms have implemented the necessary IT architecture, this year 2020 is going to be a year when Eichrecht stations will be installed & operated through out Germany.

Why there was so much delay ? Is Eichrecht implementation complex?

Yes, though the technologies involved (such as KWh meter calibration, Public-Key-Infrastructure (PKI) are already in use in telecom, banking and other industries, the Eichrecht implementation for electric vehicle charging was not an easy one, took nearly 4 years to roll-out in large scale.

In order to ensure the measurement accuracy and traceability of data, the entire chain of measurement and data value transmission had to be redesigned; which required a huge change in the entire eMobility ecosystem, start from using charge point hardware to eMobility provider back office communication and billing. In addition, there were also so many unclarities on the legislation and approval processes.

Why is Eichrecht not ready for DC & Wireless (Inductive) charging?

Compleo expects to launch Eichrecht conformed DC stations in Feb/Mar-2020, but as of today, there is no Eichrecht compliant DC fast charging stations and inductive charging. Though both are totally different technologies, the underlying reason that blocks Eichrecht implementation is the same - the energy loss during charging.

Both DC and inductive charging processes involves a rectification of the alternating current into direct current (AC-to-DC) with losses. These losses can be minimal with higher efficiency AC-DC conversion modules, yet loss is loss; should the customer has to pay for it or not, is the open question!.

Second, most impactful is the loss in the charging medium. Cable losses can be significant with high power DC chargers (which is also hard to estimate since DC charging never happens at the same charging speed throughout the charging session). This medium loss will be even more with inductive charging (especially if the vehicle is not optimally positioned above the primary coil).


💡 In this context, it is also necessary to clarify where the measurement for billing should take place. This is relevant because it has a direct impact on the questions of which energy quantity can be invoiced to the customer and who has to bear the losses.

The Eichrecht calibration law makes clear indication that the DC powered delivered to the EV should be billed; so consequently may forbid the DC stations which still use AC measurement meters. Previously, the use of an AC meter was permitted if a discount of 20 percent was deducted from the measured value. But I think this provision is also ended (or will be ending soon).

eRoaming challenges to Eichrecht implementation

Implementation of Eichrecht (any technology for that matter) becomes full success only when it rolls-out in large scale and thus, it is important that all the CPOs and EMPs should work together to enable e-roaming. (also read: What is eRoaming and why it is critical for the growth of eMobility interoperability).

However as of today, it is still not clear on how to roam between two Eichrecht conformed stations / EMPs. Though the Eichrecht architecture supports exchange of data via roaming protocols (for example Open Charge Point Interface protocol (OCPI) or via  Open Inter Charge Protocol (OICP) with Hubject platform), the current PTB examination process does not give/test the requirements related to connecting to external roaming systems.

Hope is that the eRomaing implementations will come anytime soon and the Eichrecht solution will be suitable for all CPO to MSP combinations, and be compatible with a great number of charging infrastructure (AC & DC) of different manufacturers.

Disclaimer: All the above info are based on multiple talks, webinars, and interviews of leading lawyers and subject experts involved in the Eichrecht roll-out, combined with my hands-on experience in implementing it. However, in case of doubts, I strongly advise to consult with the legal authorities, before making a decision. This article is posted solely with an intention of knowledge sharing and shall have no liability for the accuracy of the information; thus cannot be held liable for any claims or losses.


  1. Good article, only if you reference the protocol please the correct ones. Hubject uses OICP (Open InterCharge Protocol) and the open roaming protocol voor peer2peer is OCPI (Open Charge Point Interface). Same 4 characters, but totally different protocols and approaches. And both supporting Eichrecht, OCPI better than OICP.

    1. @Kor Meelker, Yes, it was a typo and I have corrected it now. Thanks for the feedback, much appreciated!.

  2. The statement "Pure time tariffs (per-minute billing) and flat-rate session fees per charging process (per-session billing) are no longer permitted" is -excuse my language- rubbish. Session billing is totally fine by the current laws (Preisangabenverordnung). The ministry wants to change that but right now it's totally ok (see the article by one of the most famous German energy lawyers
    And billing by the minute is fine as well as long as the time is measured Eichrecht compliant.
    eRomaing is quite simple - the EMP has to delivery the data to verify the charging session with the Transparenzsoftware. Hubject just doesnt support that yet. Consequenlty EMPs facing some trouble very soon.

    1. Hi Stefan, thanks for your feedback. As exactly you mentioned, the current law does not bother about “per minute / - session” billing, but Eichrecht recommends only KWh billing as fair. Request you to read the MessEV & MessEG documents.

      Yes, you are correct about the time measurement, but unfortunately there are not even a MID certified “time measurement meters” yet; and fixing such meter inside the station is also not practical, as none of the charge station hardware has a fully calibrated real-time-clock nor battery back-up to keep it alive. All the stations sync-up their timing via connection to CPO back office, which is not calibrated anyway.

      Even if we assume that all these challenges are resolved, invoicing different EVs, with different battery charging capacity, different state-of-charging, different temperature….etc – based on time is totally unfair. Do you think a VE eGolf and Tesla Model-X consume the same amount of electricity in a given time. If you invoice them both on time, you’re punishing the smaller car – just because it has a smaller on-board charger. In another post, I have mentioned What's wrong with per minute billing?. Please check it out :

      Apart from this, I fully agree with your comment on eRoaming, thanks for sharing your views.

  3. Excellent summary, you have captured most of the topics related to Eichrecht. Thanks!

  4. Brilliant article!. As a fellow product developer on Eichrecht and a person with business law background, truly appreciate your efforts. I can point out a few ‘wording mistakes’, but it doesn’t matter as the overall message is clearly explained in every section. Continue your good job mate!

    1. Thank you Jonel. Please feel free to comment/email me the ‘wording mistakes’, I shall update them.

  5. I have some remarks on the Eichrecht roll-out on DC fast charging stations. By now, everyone should have adapted to DC metering, which didn’t happen., so then the session fee kicked in.

    There are now DC meters Eichrecht conform but indeed ensuring the right losses are measured/taken into account (so when to take which 'loss' profile based on heat of the cable, voltage and current) is difficult but then being able to PROOF that, that is really difficult. what might happen that you will see very short cables so that the bandwith up and down in the losses will stay acceptable (because otherwise you dont only measure for example the heat but you also have to keep a correct logging which is eichrecht comform of the cable heat to 'prove' the resistance)

    On the AC charging stations: : issue why you don’t have this issue with AC is not only because of the lower losses in the cable but even more important: the cable is from the customer, so the 'delivery point' is the socket of the station; not the end of the cable ;)

  6. Dear Pon, Thank you very much for this interesting article. You mention that EV charging at home is not impacted by Eichrecht regulation as long it is considered as an electrical appliance. But what would be your view when you consider VEtoHome services meaning my EV battery supplies my home. I do not see any reason why this case should be compliant with Eichrecht.
    If I go deeper in the details :
    -case of a simple house with no solar installation
    As a end-user, I charge at work and come back at home and use my EV battery to discharge for suppling in Real Time my home appliances.
    This case enables me to make some savings, but as the solution provider, I can not garanty any fixed savings, because the sourcing of Kwh is not predictable.
    -Case of an installation with solar energy and full energy management solution (meter, controler, charging station etc)
    The energy in Kwh is predictable (with an error margin)
    The sourcing at work or in navigation is still unpredictable.
    But imagine as a solution provider, I provide to the end-user a contract offering a garanty on 10% savings on his electricity bill and if they are not met, I would have to pay for the savings not reached compensating for the Kwh paid to his energy supplier.
    For that I would need the annual index of consumption from the energy supplier and the amount in € invoiced VAT included.
    The First scenario is simple. The second is complex and may be achievable only by an energy supplier.
    But in both cases, do you think there is an impact from Eichrecht regulation.
    I would be glad to hear from your views guys.
    Thank you
    Best regards,

  7. Is there any consulting firm in Germany who helps to obtain eichrecht certification for DC EV charger?


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