"Higher power is not just more current": inside the making of the global megawatt charging standard

The standard has just been published after five years of work. For readers who do not follow standardization closely: why does a document like IEC 61851-23-3 matter for whether electric trucks succeed?

Miguel: Because without it, every manufacturer solves the same problems differently, and a truck from one brand cannot rely on a charger from another. For heavy commercial vehicles that cross borders and depend on public charging along their routes, that is not a minor inconvenience, it decides whether the business case works at all. The standard defines the basic interfaces, common safety, interoperability, and performance requirements so that a vehicle and a charger built by different companies, in different markets, can work together predictably. That predictability is what lets operators invest with confidence.

Megawatt charging is often described simply as faster charging. Is that the right way to think about it?

Stefan: It is the visible part, but it understates the engineering. Delivering several megawatts of power is not a matter of turning up the current or the voltage on what we already have. At these power levels, new technical questions become central. Insulation coordination, thermal management, functional safety, protection against electric shock, the communication between vehicle and charger, and the reliability of the system as a whole are considered. Each of those has to be solved in a way that holds up not in a laboratory, but in daily operation, in heat and cold, over thousands of charging cycles, across vehicles the charger has never encountered before. That is the real work behind the headline number.

Of those challenges, which was the hardest to reach agreement on?

Miguel:  The hardest part was reaching consensus on a more robust technology for digital communication between the vehicle and the charger. But the deeper challenge in a standard like this is not technical alone, it is building consensus among people who arrive with genuinely different priorities. A manufacturer, a utility, a regulator, a testing laboratory and a fleet operator each see the same requirement through a different lens. Getting to a document that all of them can accept, without watering it down to the point where it no longer guides anything, is the actual craft.

More than 75 experts were involved. How do you keep a process like that from either stalling or producing a lowest-common-denominator result?

Miguel: You accept that it will be slow, and that you need to provide a platform to discuss all open questions. The temptation in any large group is to smooth over the hard conflicts to keep things moving. In standardization that is a mistake, because the conflicts usually mark exactly the points that matter most in the field. Our job as the group leading the work was to propose solutions for open topics, and to openly discuss them to reach a decision. The result reflects that. It is a genuine consensus, not an average.

The standard puts weight on robustness and electrical safety. Why?

Stefan: The challenge with MCS was to raise the charging power without lowering the level of safety that people operating a charger can rely on. At these currents and voltages, the protective measures against electric shock or thermal faults do not simply carry over from lower-power charging. They have to be re-established. That meant innovation on both sides, in the charger and in the vehicle, so that the safety requirements already proven in other charging standards are maintained at megawatt power as well. Reaching that power while preserving the same level of protection was the real engineering work.

What does publication change in practice? Is the work now finished?

Miguel: Publication changes a great deal, because manufacturers and operators finally have a stable, globally agreed foundation to build on and to certify against. That removes a large source of uncertainty. But the work is not finished, and it should not be. Charging technology will keep evolving, and a good standard leaves room for that evolution rather than freezing the field in place. What we have built is a foundation that can carry the next generation of development.

You led this effort. Looking back, what stays with you?

Miguel: The willingness of people to build something together that none of them could have built alone. Everyone in that process represented an organization with its own interests, and yet the shared goal held. That is what makes an international standard possible, and it is genuinely rewarding to have helped guide it to completion alongside experts of that calibre.

ABB E-mobility was actively involved in the development of IEC 61851-23-3. For us, an interoperable megawatt charging standard is a precondition for the heavy-duty charging market to scale: it lets operators plan infrastructure that works across vehicle brands and borders, and it lets manufacturers build against a shared, certifiable benchmark. That is the ground the next phase of commercial deployment stands on.

The full standard and its background are available via the website of the International Electrotechnical Commission (IEC): “New standard for the fast charging of heavy dutyvehicles”.