EV Charging Glossary —
OCPP, OCPI, CPO, EMSP & More
EV charging comes with a lot of acronyms. This glossary explains the terms you'll meet across the industry — the open protocols, the roles in the ecosystem, the charging technologies and the metrics that matter — in clear, accurate language, so you can plan and operate charging infrastructure with confidence.
Key Terms, Explained
Standards, roles, technologies and metrics — the vocabulary of EV charging, defined.
OCPP (Open Charge Point Protocol)
The open communication standard between a charging station and its central management system. Widely deployed versions are OCPP 1.6 and the newer OCPP 2.1.
OCPI (Open Charge Point Interface)
An open protocol for exchanging data and enabling roaming between charging networks, connecting a CPO with an EMSP.
CPO (Charge Point Operator)
The company that operates, maintains and manages the physical charging stations.
EMSP / eMSP (e-Mobility Service Provider)
Provides drivers with access to charging across many networks, handling accounts, billing and roaming.
V2G (Vehicle-to-Grid)
Bidirectional charging in which an EV feeds stored energy back to the electricity grid.
Plug & Charge (ISO 15118)
A standard that lets the car authenticate and pay automatically the moment it is plugged in — no app or card needed.
AC vs DC Charging
AC charging is slower and uses the car's onboard converter; DC fast charging uses an external converter to deliver high power directly.
kW vs kWh
kW is power — the rate of charging; kWh is energy — the amount actually delivered.
RFID
A card or tag used to authenticate a driver and start a charging session.
Load Balancing / Smart Charging
Dynamically distributing the available electrical power across multiple chargers.
SLA (Service Level Agreement)
A contractual commitment to guaranteed service levels and uptime.
Roaming
Using one provider's account to charge on another operator's network.
Still Have Questions?
Whatever the acronym, we speak it fluently. Tell us about your project and we'll map the path from planning to a live, revenue-earning charging network.