Giant batteries could be coming to a French roadside near you

Big batteries housed in green containers are being installed across France by one of the country’s ‘unicorns’ – start-up companies that achieve valuations of more than €1billion.

Known as JBoxes, the container-sized batteries can be installed in parking spaces or on cleared areas beside roads, using a relatively simple planning process, although other regulatory and grid-connection procedures are also required.

By storing electricity and releasing it when needed, they help balance the power grid, which is having to adapt to the intermittent supply of electricity from wind and solar power.

Each battery can store 2MWh of electricity. The company, part of NW Group, says it already has 1.2GWh of battery storage in operation in France.

It receives revenue for providing balancing services to the electricity network, helping to smooth peaks and troughs in supply and demand.

It can also generate revenue by storing electricity when prices are low because of weaker demand and selling it when prices rise as a result of higher demand.

There are several projects for large ‘battery farms’ in France, but these can face lengthier planning, environmental and grid-connection procedures.

By contrast, the relatively small size of a JBox allows it to use a simplified planning process, which can include a déclaration préalable de travaux submitted to the local mairie.

Other products developed by NW Group include high-power electric vehicle chargers connected to nearby JBoxes, reducing the impact of high-power charging on the electricity network.

The company also plans to launch a home battery system, called an OhmBox, in the first half of 2027.

These are designed to store electricity for household use and provide power for charging electric vehicles.

Another system, called TIEBox, uses battery storage for small businesses such as hotels, allowing them to better manage their electricity costs.

Founded and majority-owned by entrepreneur Jean-Christophe Kerdelhué, NW Group began developing its JBox battery storage system in 2018.

In 2022, French investment fund RGreen Invest invested in NW Storm, the group's battery storage subsidiary, in a €300million funding round that valued the business at €1.5billion, making it France’s first energy-transition ‘unicorn’.

The investment was intended to accelerate development of the JBox network in France and internationally.

NW has since expanded outside France, including into Finland and other Nordic and Baltic countries, and is also developing its business in Germany, where it has announced plans to deploy 500 JBoxes by 2029.

The company is continuing to consider options for the future development of its capital structure, while Mr Kerdelhué remains its controlling majority shareholder.