Battery storage at EV charging stations: what CPOs need to know in Europe

Adding battery storage to a charging site is first a grid-connection and energy-management decision, and only then a software one. A battery pays off only if the system that controls the chargers can also control the battery, within the limits of the site connection. European regulation makes this easier, but it does not require it.

What a battery does on a charging site

A stationary battery can cover part of the site demand during peaks, so the site draws less power from the grid at those moments. In practice this can lower the connection capacity you ask the network operator for, and reduce peak-related charges where your tariff includes them. It can also store local solar production for later use, and, depending on the market, be offered as flexibility.

How much you gain depends on your connection offer, your tariff and your charging profile. We do not publish a general figure: model each site with your own data.

What the regulation says, and what it does not

AFIR does not require batteries. It requires that public charging points built after 13 April 2024, or renovated after 14 October 2024, are capable of smart recharging, meaning the charging current is adjusted in real time from information received electronically. Since 14 October 2024, public points must also be digitally connected, which includes remote monitoring and control (AFIR).

The regulation links smart charging to the grid. Its recitals explain that smart charging helps integrate charging into the electricity system through aggregation and demand response.

RED III opens markets to small flexible assets. The national framework must let small or mobile systems, home batteries and electric vehicles take part in congestion management, flexibility and balancing, including through aggregation. It does not make vehicle-to-grid mandatory (RED III). The transposition deadline was 21 May 2025; the national status is not covered here, so check your country.

Grid connection. The electricity market directive asks Member States to facilitate the connection of charging points and requires distribution operators to cooperate without discrimination (Directive 2019/944).

Protocols: do not mix up three different links

A site with storage involves three separate communication links.

1. Charger to CSMS. This is OCPP. OCPP 1.6 and 2.0.1 are not compatible with each other. OCPP 2.1 extends 2.0.1 and adds functional blocks for distributed energy resources and bidirectional flows, which 2.0.1 does not have (Open Charge Alliance).

2. Vehicle to charger. This is ISO 15118. ISO 15118-2 does not cover advanced smart charging or bidirectional charging; ISO 15118-20 does. Under the delegated regulation, public points installed or renovated from 1 January 2027 must support at least ISO 15118-20 (Delegated Regulation 2025/656).

3. Battery system to site controller. This link does not belong to OCPP or ISO 15118. Battery and inverter vendors expose their own interfaces, so ask which interface is available and who runs the control loop.

AFIR does not name OCPP. Using it remains a practical way to keep several brands of chargers under one supervision tool.

Checks before you commit

Ask the network operator for the connection offer with and without storage, and compare the timelines.

Read your tariff to see which charges a battery can actually reduce.

Check that your CSMS can apply a power limit to the whole site in real time, not only per charger.

Obtain the battery control interface in writing, before choosing the hardware.

Find out whether an aggregator in your country can market the flexibility, and under which rules.

Keep the ability to change supervision tool without replacing the battery.

What to do this week

List your sites where the connection capacity limits the number of chargers. For two of them, request a connection offer and a tariff statement, and ask your equipment suppliers for the control interface of their storage product. GFO Omni is a CSMS that supervises charging points over OCPP 1.6, 2.0.1 and 2.1.