Two pieces of the European bidirectional-charging puzzle were supposed to click together this year. One landed in July. The other was written before it and points at the wrong version — and in German, at the wrong vehicles.
The analysis comes from Andreas Varesi, an electrical engineer who has worked on vehicle-to-grid interfaces since 2011, writing for electrive.
What Amendment 1 adds
ISO 15118-20:2022/Amd 1:2026 was published on 13 July 2026, titled AC DER service, MCS service, and improved security concept.
The AC DER — distributed energy resource — service is the part that matters for cars. Until now an AC charging station could only send a vehicle a target value: draw this much, feed back that much. It could not send the regulatory parameters and characteristic curves a grid-connected inverter needs to behave correctly on its own — reactive power Q(U) response, active power against frequency, voltage and frequency thresholds, protection behaviour.
Amendment 1 specifies that handover. With it, the car's onboard charger can respond to the grid autonomously and legally. Without it, AC vehicle-to-grid had a communication standard but no way to be grid-compliant.
The EU rule points at the version before that
Delegated Regulation (EU) 2025/656, which supplements AFIR and was published in the Official Journal on 18 June 2025, sets the mandate:
| Date | Requirement | Scope |
|---|---|---|
| 8 January 2026 | EN ISO 15118-2:2016 | New publicly accessible charging points |
| 1 January 2027 | EN ISO 15118-20:2022 | New and renovated Mode 3 points, public and private |
Read the second row carefully. It names the 2022 base standard, because the regulation was finalised in 2025 — a year before Amendment 1 existed. A wallbox installed on 1 January 2027 can therefore be fully AFIR-compliant and still lack the AC DER service that makes AC V2G work. Whether an existing unit can reach Amendment 1 by firmware alone depends on the hardware already inside it.
The translation error
The German text of Regulation 2025/656 renders the English "light-duty and heavy-duty electric vehicles" as "leichte und schwere Nutzfahrzeuge mit Elektroantrieb" — light and heavy commercial vehicles.
That is not a nuance. It reads as though the obligation covers only infrastructure for commercial fleets, when the English original covers all vehicles, private cars and residential wallboxes included. In Europe's largest EV market, an installer reading the national-language version of a binding EU rule can reasonably conclude it does not apply. Non-compliance and deferred investment both follow.
Why AC is the hard case in Europe
DC bidirectional charging puts the grid-facing inverter in the stationary charger, certified once, where it stands. AC puts it inside the car — and the car crosses borders.
European grid-connection requirements still differ nationally on reactive power behaviour, frequency-deviation thresholds and protection settings. An AC-V2G-capable vehicle has to satisfy all of them at once. That is the structural reason AC stays behind DC, and no standard removes it alone.
Varesi's timeline is sober: 2026–2027 for pilots and closed ecosystems, 2028–2029 for the first AC DER-capable vehicles, 2030 and beyond for mass deployment.
What it means if you drive a Tesla
Less than the headlines suggest. European Teslas cannot export to the grid at all, so none of this changes what a Model 3 or Model Y does today. Tesla's own bidirectional step this month was V2L on the US Model Y Premium — the car powering a socket, never the grid.
The useful reading is for the hardware you buy around the car. Germany has already redrawn the grid-fee and metering rules that made V2G uneconomic. If you are specifying a wallbox now with V2G in mind, the question for a supplier is not whether it does ISO 15118-20 — from 2027 it must — but whether the hardware can reach Amendment 1.