How does the roaming fee work?

What is a Roaming Fee?

A roaming fee is an additional cost applied when an electric vehicle (EV) driver charges at a public charging station using a pass or app issued by an external eMobility Service Provider (eMSP), rather than the one operating the charging station. This fee covers the technical and financial requirements for interoperability and data exchange between different eMobility platforms, ensuring a seamless charging experience across multiple networks.

Who Pays the Roaming Fee?

The EV driver pays the roaming fee. It is typically included in the total price per kilowatt-hour (kWh) displayed in the eMSP’s application or invoice. The fee guarantees drivers can access a wide network of public charging stations—even those outside their home provider.

How is the Roaming Fee Calculated?

The total price an EV driver pays incorporates several components:

1. Base Tariff: Set by the Charging Point Operator (CPO) for energy (€/kWh), parking (€/min), or session (€/session).
2. Roaming Surcharge: Added by the roaming platform or CPO to cover operational, infrastructure, and data exchange costs.
3. eMSP Margin: A markup added by the eMSP to offset their own transaction costs and profit margin. This is unknown Maxem and varies per eMSP.

Example Calculation

Backend Process Flow

1. The EV driver starts a charging session using their roaming-enabled pass or app.
2. The charging transaction is recorded as a Charge Detail Record (CDR) and sent to the eMSP.
3. The roaming fee is automatically added to the base tariff during processing.
4. The eMSP invoices the driver for the total amount (including their own surcharge).
5. The eMSP pays the total transaction cost to Maxem
6. Maxem settles directly with the location owner for the base amount

Where Can Roaming Fees Be Viewed?

1. Maxem Energy Cloud: Roaming transactions are clearly labeled and can be filtered for reporting.
2. Monthly Transaction Records: Roaming fees are itemized per charging session.