Charging infrastructure from A to Z.

The key terms around charging infrastructure, roaming and billing, explained briefly and without jargon.

Last updated: 3 July 2026

CPMS (Charge Point Management System): A CPMS is the software operators use to centrally monitor, control, authorise and bill their charging points. The POWR CPMS connects charging hardware vendor-agnostically via OCPP and bundles operations, load management, roaming connectivity and billing in one backend.
eMSP (e-Mobility Service Provider): An eMSP issues charge cards and lets drivers charge across third-party networks via roaming. As an eMSP, POWR bundles access to the connected partner network with the POWR card and bills charging sessions in your POWR account.
CPO (Charge Point Operator): The CPO operates the charging infrastructure: it builds and runs charging points, keeps them available and sets the tariffs. Many companies are a CPO for their own locations and at the same time a customer of an eMSP for charging on the go.
OCPP (Open Charge Point Protocol): OCPP is the open standard protocol between a charging station and the backend. It keeps operators independent of the hardware manufacturer: OCPP-capable stations from different brands can be operated, monitored and billed in the same system.
OCPI (Open Charge Point Interface): OCPI is the open protocol between the backends of different providers, for example between a CPO and an eMSP. It carries location data, tariffs and charging sessions and is the technical foundation for roaming between charging networks.
Roaming: Roaming means charging at charging points run by other operators with one card or app, billed through your own provider. With the POWR card you charge in the connected partner network and see the price per location upfront.
HPC (High Power Charging): HPC is fast DC charging at high power, typically along long-distance routes and in charging parks. HPC chargers charge compatible vehicles considerably faster than AC charging points and place higher demands on the grid connection and load management.
Charging point and charging station: A charging station is the physical unit or wallbox; a charging point is the individual connector on it where exactly one vehicle charges. One station can have several charging points. Billing and authorisation always refer to the charging point.
Load management: Load management distributes the available electrical power across active charging sessions so the grid connection is never overloaded. Dynamic load management adjusts the distribution continuously and allows more charging points on the same connection.