Roaming is the ability for an EV driver to use one charging account, app, or RFID charging card to start sessions across multiple charging networks—without needing to register separately with each charge point operator (CPO). Roaming is enabled through commercial agreements and technical integrations that allow networks to exchange authorization, pricing, and session records.
In practice, roaming connects eMSPs (e-mobility service providers that serve drivers) with CPOs (charging infrastructure operators).
Why Roaming Matters
Roaming improves accessibility and charging network usability:
– Reduces “app overload” by letting drivers charge across networks with one contract
– Expands customer reach for CPOs by attracting roaming users to their locations
– Supports cross-border charging where drivers frequently encounter different operators
– Improves utilization rate and revenue opportunity for public charging sites
– Enables fleet and corporate mobility programs to manage charging access across regions
How Roaming Works
A typical roaming flow includes:
– Driver authenticates using an app, QR, or RFID authentication method from their home provider (eMSP)
– The CPO network validates the token via the roaming connection and authorizes the session
– The charging session runs and is logged by the CPO (timestamps, EVSE ID, kWh, costs)
– A charge detail record (CDR) is generated and sent to the eMSP
– The eMSP bills the driver (or fleet), then settlement occurs between eMSP and CPO based on the agreed rules
Roaming requires reliable identity mapping (tokens), charger identification (EVSE IDs), and consistent session reporting.
Technical Standards Used for Roaming
Roaming integrations often rely on:
– OCPI for exchanging locations, tariffs, tokens, sessions, and CDRs
– Intermediary roaming hubs that simplify multi-party connectivity
– Clear data models for EVSE IDs, connector IDs, and tariff structures
Roaming can coexist with direct CPO customer access—many networks support both.
Roaming Pricing and Commercial Models
Roaming pricing can be structured in different ways:
– eMSP adds a markup on the CPO price and bills the end user
– CPO charges the eMSP a wholesale rate; eMSP sets retail pricing
– Fixed fees per session or per kWh added to cover roaming and support costs
– Different tariffs for roaming vs direct users (where allowed and transparently communicated)
Clear definitions of gross vs net revenue are important for revenue reporting.
Operational Challenges and Risks
Common roaming issues that impact user experience and revenue:
– Token authorization failures due to mismatched formats or outdated token lists
– Tariff and price display inconsistencies between platforms
– Missing or rejected CDRs leading to settlement gaps and revenue leakage
– Delayed settlement and dispute management overhead
– Session start/stop edge cases (timeouts, offline chargers, partial records)
– Customer support complexity when the driver’s contract is with the eMSP, not the CPO
Roaming Best Practices for CPOs and eMSPs
– Maintain high uptime and stable connectivity to reduce failed roaming sessions
– Implement strong reconciliation between sessions and CDRs to detect leakage early
– Use consistent EVSE ID schemes and connector mapping across systems
– Monitor roaming KPIs: authorization success rate, CDR acceptance rate, settlement cycle time
– Define clear support responsibilities and escalation paths in roaming agreements
Related Glossary Terms
OCPI
OCPP
Charge detail records (CDRs)
RFID authentication
RFID charging cards
RFID billing
Revenue reporting
Revenue leakage detection
Public charging networks
Interoperability networks