At the end of January 2026, Slovenian AC charging station manufacturer Etrel hosted their Re-Charging Days event in Ljubljana. One of the highlights was an expert panel discussion on ISO 15118 — the standard that defines how electric vehicles communicate with charging stations, enabling features like Plug & Charge, smart charging, and Vehicle-to-Grid (V2G).
Learn more about Plug & Charge in my five-part articles series. It covers everything from market actors to cryptographic foundations and the complete workflow to create, install and use the all-important digital contract certificate that enables and secure seamless EV charging. All you need to know to master Plug & Charge.
The panel brought together perspectives from across the EV charging ecosystem: a standards expert (myself), two leading European charge point operators (CPOs), and a charger manufacturer’s R&D lead. Here’s what they had to say.
Meet the panellists
Marc Mültin (myself): Director of Technology Strategy & Innovation at Believ in the UK. I’m a globally recognised expert and co-author of ISO 15118 and OCPP 2.0.1. With a PhD in Computer Science and over 15 years in e-mobility, I have trained 80+ companies worldwide on EV communication standards and run this popular Current Affairs newsletter educating the industry on what’s really happening behind the scenes.
Daniel Porubcsánszki: Charging Solutions Engineer at Allego in The Netherlands. Daniel works at one of Europe’s top CPOs, which operates over 34,000 public charging points across 16 countries. He brought the real-world deployment perspective — having personally driven the rollout of OCPP 2.0.1 and Plug & Charge across Allego’s high-power DC charging network.
Kasper Dahl: Responsible for Product Strategy and Portfolio at Clever in Denmark. Clever is the leading CPO in Denmark, operating both AC and DC chargers across public and semi-public locations. Kasper joined remotely and brought the market and user experience lens, particularly from a market where 90% of new car sales are already fully electric.
Matej Anzin: Head of R&D at Etrel in Slovenia. With over seven years at Etrel, first as R&D Manager and now heading the department, Matej brought the charger manufacturer’s perspective on implementing ISO 15118 and the practical challenges of making it work in hardware.
The panel was moderated by Erazem Štancar, Regional Sales Manager at Etrel.
Key insights from the discussion
You can listen to the full panel discussion in the audio recording linked above. Unfortunately, the video recording was corrupted — but look on the bright side: for once you get to hear my voice instead of just reading another one of my lengthy articles.
Below are the 11 highlights summarised.
1. Regulation is driving adoption faster than expected
One of the biggest drivers of ISO 15118 adoption is regulation and compliance. Since January 2026, all newly installed charging stations in the EU must support ISO 15118-2. As Daniel from Allego noted, Plug & Charge interest and usage “is picking up and it’s more popular than we expected.” What was once a nice-to-have is now becoming a must-have, and the industry is responding.
2. “Following the standard” isn’t enough for interoperability
In theory, everyone implementing the same standard should guarantee interoperability. In practice, different interpretations of ISO 15118 — plus gaps in implementation — still cause systems that should work together to fail. I illustrated this with a concrete example: one message in ISO 15118 called PowerDeliveryReq (request message the EV sends to the charger) contains a parameter for the ChargingProfile that communicates how the EV intends to charge, and it’s marked as “optional.” But it’s only optional because the same message is used both to start and stop a session. When starting, the parameter is actually required. Some less diligent implementers skip it because it says “optional” — and interoperability goes down the drain.
3. Compliance testing is only 50% of the effort
Getting certified against the conformance test specifications (ISO 15118-4 and -5) is important, but it’s only half the battle. The other half is real-world interoperability testing, because you can be fully compliant with the standard and still run into issues. The interoperability testing events, also known as “Testivals”, have been running since around 2016 and hosted by CharIN since 2019 — since then also known as CharIN Testivals. These events remain the best venue for discovering edge cases, until a comprehensive “golden test device” exists that covers all possible scenarios.
4. Collaboration is the real bottleneck
Plug & Charge isn’t built by one player. It requires tight coordination between vehicle and charger manufacturers (aka OEMs), Charge Point Operators (CPOs), Mobility Service Providers (MSPs), and public key infrastructure (PKI) providers like Hubject or Irdeto. Daniel shared how it took significant cross-company effort to get Plug & Charge working across Allego’s network with even just one charger vendor. The message: start working together as early as possible. Don’t wait until you think your implementation is “ready” — get it into testing with real partners immediately.
5. Smart charging is a massive (and underappreciated) value driver
While Plug & Charge gets most of the attention, the panellists highlighted that smart charging — already possible with ISO 15118-2 — is an equally important value driver. I stressed that ISO 15118 is the only way to know how much energy the EV needs and when the driver intends to leave the charging station. Without these data points, real smart charging is impossible. And you don’t need the newer ISO 15118-20 for this — it’s already built into the existing standard.
6. V2G is the biggest long-term business case
For Kasper at Clever, the biggest value proposition of ISO 15118 is the potential for Vehicle-to-Grid services. Bidirectional charging, energy arbitrage (charging during cheap hours), and providing grid stability services represent a “very positive business case.” ISO 15118-20 is the key enabler for V2G, alongside wireless charging and Megawatt Charging. While some grid-side standardisation still needs to mature, the potential is enormous.
7. Cybersecurity matters more than people realise
Daniel emphasised that one of Allego’s primary motivations for moving to ISO 15118 was cybersecurity. The TLS-based security in ISO 15118 is a significant step up from RFID cards, which are trivially cloneable. As Daniel put it: “It’s just not that marketable to say we are doing the move because of cybersecurity” — but it’s becoming increasingly critical as the charging infrastructure scales.
8. The charger screen is crucial for the user experience
When Plug & Charge goes wrong, the CPO often doesn’t know who the user is (since authentication failed), and therefore can’t send them a message via their app. The charger’s display becomes the only communication channel. I stressed that charger manufacturers need to enable CPOs to surface meaningful error information — not just “computer says no” but specific guidance like “your certificate has expired, please check with your mobility service provider.” I also noted the CharIN initiative on unified error codes across ISO 15118 and OCPP, which could be a significant step forward for troubleshooting.
9. The RFID vs. Plug & Charge conflict is real — and tricky
A practical challenge the panellists discussed at length: what happens when a user plugs in their EV and it starts the Plug & Charge process, but they actually want to use their RFID card? Or when someone swipes their card first and then plugs in? This can lead to “interruption errors” and even double-charging customers. One approach is once the cable is plugged in, the RFID reader is blocked for a period to avoid conflicts. But this creates its own UX problems. I suggested that chargers could prompt users on screen: “Your car supports Plug & Charge. Do you want to use it? Yes/No”, giving them a 30-second window before defaulting to Plug & Charge.
10. Multi-contract handling is key for user convenience
Not all charging sessions should go to the same billing account. I highlighted BMW as a good example: they support up to five different MSP contracts for Plug & Charge, so drivers can choose which one to use — similar to selecting a different card in Apple Pay. This is particularly relevant for company car drivers who sometimes charge privately and sometimes on the company account. Some OEMs do a much better job than others at making Plug & Charge activation intuitive in their in-car HMI. Some drivers don’t even know the feature exists in their car.
11. Don’t reinvent the wheel
ISO 15118 and OCPP 2.0.1 are becoming baseline capabilities, not differentiators. I pointed out that there are now a handful of proven software stack providers for charger manufacturers, including the open-source EVerest from Pionix, EcoG OS from EcoG, and vSECClib from Vector. Plus charge controllers you can get from vendors like chargebyte (for both EV and charger). The advice: use what’s proven, integrate it, and differentiate on other things — like user experience, hardware design, and smart services on top.
The Bottom Line
ISO 15118 is transitioning from a niche technical standard to a foundational layer of the EV charging experience. The panellists agreed that we are likely just one to two years away from widespread rollout across Europe and the UK, and possibly also the US. But getting there requires more than technical compliance — it demands cross-industry collaboration, rigorous real-world testing, and an unrelenting focus on making the user experience seamless.
As Kasper from Clever put it: “If we start requiring customers to educate themselves or do things in a particular way, I think we’ve failed as an industry”.
The tech can be complex. The experience can’t be.
Below is also a short presentation from Etrel with some high-level insights from the panel discussion.
