How do tariffs travel?
The session ends after 34 minutes and 41 kWh. The car then stays for another 12 minutes while the driver finishes a coffee.
The operator's tariff has a price per kWh and a fee per minute after charging.
The questionHow does a tariff describe that, and how does the provider learn it?
| Priced in | Step size counted in | |
|---|---|---|
| ENERGYthe energy delivered | kWh | Wh |
| TIMEtime while charging | hours | seconds |
| PARKING_TIMEtime not charging | hours | seconds |
| FLATa fixed fee per session | fee |
Tariff dimension types of OCPI 2.3.0; a tariff combines one or more of them, and each can set a step size, for example 300 seconds to bill time in blocks of five minutes.
41 kWh at 0.59 EUR
12 minutes at 0.10 EUR after charging
not priced in this tariff
what the CDR states
A composed tariff. The amounts are what the operator charges; what the driver pays is set by the provider's own contract with the driver.
Two prices, one session
With a contract, the driver usually pays the provider's price, not the operator's tariff. The operator's tariff is what the provider pays to the operator. The two can differ, which is why drivers at the same charger can pay different prices, see EV charging fundamentals, stop 05.
At public chargers of 50 kW and more deployed since April 2024, the price must be shown before the session starts, per kWh, and any per minute. The tariffs exchanged in let apps show the same information.
Check your understanding
3 questions. Answer all of them to complete this stop. Each answer explains itself.
Which OCPI tariff dimension prices the minutes while the car is charging?
TIME prices time while charging; PARKING_TIME prices time connected but not charging.
41 kWh at 0.59 EUR per kWh. What is the energy component?
41 × 0.59 = 24.19 EUR.
A driver with a contract charges at a roaming partner's charger. Whose price does the driver pay?
The provider bills the driver under its own contract; the operator's tariff applies between the two companies.
- OCPI Open Charge Point Interface: an open protocol for roaming between operators and e-mobility service providers. EV charging fundamentals, stop 03 Glossary
- Ad hoc Charging without a contract, paid directly at the charger, for example by card or QR code. EV charging fundamentals, stop 05 Glossary
- Occupancy fee A price per minute that AFIR allows at fast chargers to discourage cars from blocking a charge point after charging. Charging infrastructure, stop 07 Glossary
- EVRoaming Foundation: OCPI 2.3.0, Tariffs module: tariff dimension types. https://github.com/ocpi/ocpi/blob/2.3.0/release/core/mod_tariffs.asciidoc. Checked 09 Oct 2026.
- EUR-Lex: Regulation (EU) 2023/1804 (AFIR), Article 5. https://eur-lex.europa.eu/eli/reg/2023/1804/oj. Checked 09 Oct 2026. © European Union, reused under Commission Decision 2011/833/EU.