How Roaming Impacts EV Charging Tariffs and Revenue

Roaming is one of the fastest ways for a charging network to increase utilization. It also introduces a new layer between the CPO and the driver, where pricing decisions are no longer fully owned by the operator. 

Once roaming is active, the price a driver sees and pays often differs from the CPO’s base tariff. Fees, markups, and settlement rules change how revenue is calculated and how margins are formed. This affects tariff control, pricing consistency, and profitability in ways that are easy to underestimate. 

This article examines how EV charging roaming tariffs work in practice, how roaming fees and OCPI pricing affect CPO revenue, and where pricing visibility is lost once roaming partners are involved. 

In our previous article on EV charging tariffs and operational control, we looked at how tariffs function as a control layer across a charging network. Roaming is one of the clearest examples of where that control is tested. 

This article looks at how EV charging roaming tariffs work in practice, how roaming fees affect margins and revenue, and where CPOs lose visibility once OCPI-based roaming is introduced. 

How EV charging roaming tariffs work in practice 

In a direct charging relationship, the CPO defines the tariff, presents the price, and charges the driver according to that logic. With roaming, that flow changes. 

The CPO still defines a tariff, but that tariff is exposed to roaming partners through OCPI pricing structures. These prices are not always shown to the driver as-is. The roaming partner may add markups, apply its own pricing logic, or present the price in a different format. 

From the driver’s perspective, the roaming price is the price. From the CPO’s perspective, it is only a starting point. What the driver pays and what the CPO earns are no longer the same number. 

This distinction is critical. EV charging roaming tariffs define the commercial terms between the CPO and the roaming partner, not the final customer price. Once roaming is active, tariffs stop being customer-facing pricing and become an input into a multi-party pricing chain. 

How roaming fees affect EV charging margins 

Roaming fees are often treated as a simple commission. In reality, they affect margins in several ways at once. 

First, roaming partners typically take a fee per session or per kilowatt-hour. This reduces the effective revenue the CPO receives, even when the base tariff looks healthy. 

Second, settlement delays mean that revenue arrives later than in direct payment flows. This complicates cash flow and makes margin tracking less immediate. 

Third, roaming volume often grows faster than expected. What starts as a small share of sessions can quickly become a significant part of network usage. If roaming fees were not fully accounted for in tariff design, margins erode quietly as roaming traffic increases. 

Because roaming fees EV charging are deducted downstream, they are easy to underestimate. Utilization metrics improve and revenue grows, while profitability weakens beneath the surface. 

OCPI pricing and control over EV charging price presentation 

OCPI pricing is designed to standardize how tariffs are exchanged between parties. It does not guarantee how prices are presented to drivers. 

OCPI supports complex tariff structures, including energy-based pricing, time components, and fixed fees. In practice, not all roaming partners present all components equally clearly. Some simplify pricing for usability. Others aggregate components into a single number. Some add markups that are invisible to the CPO. 

This creates a gap between tariff logic and customer experience. The CPO may carefully design a tariff to manage utilization or protect margins, only to see a different price logic presented to the driver through a roaming app. 

At that point, pricing control shifts. The CPO controls the wholesale input. The roaming partner controls the retail output. Any assumption that the driver sees the CPO’s tariff directly is incorrect once roaming is involved. 

CPO roaming revenue visibility and reporting challenges 

CPO roaming revenue is harder to analyze than direct revenue. The data arrives later, in aggregated form, and often with less detail. 

Session-level transparency can be limited. Fees are deducted before revenue is reported. Differences between expected and actual revenue may only become visible during reconciliation, not at the time of charging. 

This makes it harder to answer basic questions. Which sites perform well under roaming. Which tariffs hold up after fees. Which roaming partners contribute volume without contributing margin. 

Without structured visibility, roaming revenue looks positive in aggregate but opaque in detail. Decisions are then made based on utilization and gross revenue, rather than contribution margin. 

Why roaming complicates EV charging tariff strategy at scale 

At small scale, roaming can be managed manually, with tariffs reviewed occasionally and fees absorbed or explained away without much scrutiny. 

At scale, this breaks down. More roaming partners mean more pricing paths. More sites mean more tariff variants. More volume means that small discrepancies have material impact. 

Tariff strategy becomes harder because tariffs now serve multiple roles at once. They must support direct customers, roaming partners, and internal margin targets, all under different pricing mechanics. 

This is where many CPOs lose pricing discipline. Tariffs are designed for direct charging, then copied into roaming contexts without adjustment. Over time, roaming traffic grows and the tariff logic no longer reflects the commercial reality of those sessions. 

How EV charging tariffs are managed in roaming networks 

eMabler’s Tariff Engine is built to support tariff management in environments where pricing complexity is unavoidable. This includes networks with multiple roaming partners, site types, and customer groups. 

The Tariff Engine provides a centralized way to define tariff logic and deploy it consistently across contexts. Energy pricing, time components, session fees, and conditional rules can be combined without custom development. Tariffs can be tailored for roaming use cases where different commercial assumptions apply. 

Because tariffs are managed centrally, updates can be rolled out quickly across large networks. This reduces the lag between cost changes, roaming fee adjustments, and live pricing logic. APIs allow tariff changes to be integrated into broader operational workflows rather than handled manually. 

The value here is control. Not control over what roaming partners charge drivers, but control over the tariff inputs that determine CPO roaming revenue and margin exposure. As roaming volume grows, that control becomes a must. 

Conclusion 

Roaming expands access and utilization, but it changes how pricing works at a fundamental level. EV charging roaming tariffs define the commercial relationship between CPOs and roaming partners, with fees, markups, and settlement rules shaping how revenue is ultimately distributed. 

Roaming fees EV charging reduce effective revenue, OCPI pricing limits control over price presentation, and settlement structures reduce visibility into margins. As roaming volume grows, these effects compound and quietly reshape profitability. 

For CPOs, roaming affects pricing control, margin formation, and utilization, and needs to be evaluated on all three dimensions. Tariffs need to be designed and managed with roaming dynamics in mind, not copied across contexts without adjustment. 

eMabler helps CPOs manage this complexity by providing a centralized Tariff Engine that supports consistent tariff logic across direct and roaming use cases. This gives operators the tools to maintain pricing discipline and visibility as networks scale. 

If roaming tariffs need to be defined and deployed consistently across your charging network, get in touch with us!