Plug & Charge billing is the process of charging the customer for an EV charging session that is automatically authorized via Plug & Charge (PnC), without the driver presenting an RFID card, logging in to an app, or making a manual payment at the charger. Billing is tied to a contract associated with the vehicle and enabled by ISO 15118 using digital certificates.
Why Plug & Charge Billing Matters
PnC removes the visible payment step at the charger, so the billing system must be reliable, auditable, and interoperable. It helps operators and mobility providers:
– Deliver a “plug-in, and it works” experience with consistent settlement
– Reduce failed payments and customer support issues from manual flows
– Enable fleet and corporate charging with vehicle-based identity
– Support roaming and interoperability models based on contracts
– Maintain strong security because identity and billing rely on certificate trust
How Plug & Charge Billing Works
A typical Plug & Charge billing flow includes:
– The driver activates PnC with an eMSP, OEM service, or fleet provider (contract setup)
– A contract certificate is provisioned to the vehicle
– When plugged in, the EV and charger perform an ISO 15118 handshake and authenticate
– The charger/CPMS sends an authorization request tied to the contract identity
– The backend validates the contract (often via an eMSP/roaming platform)
– The charging session is recorded with metering data (kWh, timestamps)
– Billing is generated to the contract owner (invoice, card-on-file, fleet account), and settlement occurs between parties
Key Actors in Plug & Charge Billing
PnC billing often involves multiple entities:
– EV driver/contract holder (customer)
– eMSP or OEM mobility provider (holds the customer contract and billing relationship)
– CPO (operates the chargers and delivers the energy service)
– CPMS (handles session control, metering, and records)
– Roaming / interoperability platform (optional; routes authorization and settlement)
– PKI / certificate authority ecosystem (enables trust and identity)
Metering, Receipts, and Auditability
Plug & Charge billing still requires accurate and defensible session records:
– Session start/stop timestamps and unique identifiers
– Meter start/end values and energy delivered (per-kWh billing where used)
– Tariff applied (time-of-use, idle fees, parking-linked rules)
– Customer-facing receipts via the eMSP/OEM app or portal
In many markets, compliant metering (e.g., MID metering) is important for kWh-based billing and dispute handling.
Common Billing Models with Plug & Charge
– Post-paid invoice: common for fleets and corporate accounts
– Card-on-file: customer payment method stored by the eMSP/OEM, billed per session
– Subscription + usage: membership covers access and discounts, with usage billed separately
– Roaming settlement: eMSP pays the CPO via roaming agreements, then bills the driver
Typical Challenges
PnC billing can be impacted by:
– Contract certificate provisioning issues (missing/expired certificates)
– Trust-chain mismatches between ecosystems (who is trusted as CA)
– Backend connectivity problems during authorization
– Session record mismatches (IDs, meter values, tariff application)
– Refund/dispute handling when the driver never “paid at the charger”
– Requirement to support parallel payment methods (e.g., payment terminals) for ad-hoc access
Key Benefits
– Seamless user experience with fewer failed starts
– Strong identity-based billing for fleets and repeat users
– Reduced operational friction compared to manual authentication methods
– Supports advanced interoperability where contracts are accepted cross-network
Related Glossary Terms
Plug & Charge
ISO 15118
OCPP 2.0.1
PKI Infrastructure
Digital Certificates
Interoperability Billing
Roaming
eMSP
Per-kWh Billing
MID Metering
Payment Terminals