Roaming tariffs are the pricing rules applied when an EV driver charges on a network via roaming—meaning the driver uses an account, app, or RFID charging card from their home e-mobility service provider (eMSP) to access a third-party charge point operator (CPO) network. Roaming tariffs determine what the driver pays and how the session is priced for settlement between companies.
Roaming tariffs can differ from “direct” CPO tariffs because they include additional commercial layers such as eMSP markups, hub fees, and different billing rules.
Why Roaming Tariffs Matter
Roaming tariffs influence:
– The final price the driver sees (and whether they choose to charge at that site)
– Utilization rate at roaming-heavy locations
– CPO profitability, because wholesale settlement may be lower than retail pricing
– Customer trust, because roaming price surprises lead to refunds and complaints
– Risk of revenue leakage if tariff data is inconsistent across systems
For EV charging networks, roaming tariffs are both a commercial strategy and an interoperability requirement.
How Roaming Tariffs Are Structured
Roaming tariffs can include one or more price components:
– Per-kWh billing (most common where legally supported)
– Per-minute billing (often used to reflect occupancy or where kWh billing is constrained)
– Session start fee (fixed fee per session)
– Idle fees (fees after charging stops to encourage bay turnover)
– Minimum charge (ensures small sessions still cover transaction costs)
– Time-of-day or peak pricing components (where supported and communicated)
The roaming tariff must be communicated consistently to enable correct billing and settlement.
Who Defines the Roaming Tariff
Roaming tariffs depend on the commercial setup:
– eMSP-defined retail tariff
– eMSP sets the price the driver pays (may include markup)
– CPO receives a wholesale rate based on agreement
– CPO tariff pass-through + eMSP fee
– eMSP passes through the CPO price and adds a service fee
– Hub-influenced tariff
– A roaming hub may standardize or mediate tariff exchange and apply its own fees
This is why two drivers can pay different prices at the same charger depending on their roaming provider.
How Roaming Tariffs Are Exchanged Technically
Roaming tariffs and their validity periods are commonly exchanged via OCPI, alongside:
– Locations and EVSE details
– Tokens (RFID/app identifiers)
– Sessions and charge detail records (CDRs)
Accurate tariff versioning is important—old tariff data can cause mismatches between displayed and billed price.
Common Issues With Roaming Tariffs
– Price display mismatch: app shows one price, invoice shows another
– Old tariff versions cached in one system
– Complex tariffs not represented consistently (rounding, VAT inclusion, minimum fees)
– Different legal billing rules between countries (kWh vs time-based constraints)
– Idle fee policies misunderstood or poorly communicated
– Settlement disputes when retail and wholesale tariff components are not clearly separated
Best Practices for Managing Roaming Tariffs
– Keep tariffs simple and transparent where possible
– Version tariffs and define validity windows clearly
– Align how VAT/taxes are shown and billed (included vs excluded)
– Monitor roaming complaints, refunds, and chargebacks as “tariff trust” indicators
– Reconcile billed amounts against tariffs and CDRs to detect systematic errors
– Segment performance and margins for roaming vs direct customers in revenue analytics
Related Glossary Terms
Roaming
Roaming fees
Roaming agreements
Roaming payments
OCPI
Charge detail records (CDRs)
kWh-based billing
Per-minute billing
Idle fees
Revenue reporting
Revenue leakage detection