Permits threaten timeline for Laufenburg battery project

Flexbase says its giant battery project in Laufenburg, Aargau, can begin operating in 2028 or 2029, but unresolved permits and a complex power substation raise doubts about the schedule, SRF reported.

The company is building what it describes as the world’s largest storage battery at the Technology Centre Laufenburg. The planned liquid battery will store electricity in 1,600 tanks with a combined capacity of 75 million litres.

The system is designed to draw electricity from the grid when demand is low and feed it back when consumption rises, helping to stabilise the network. The technology centre is also expected to house an artificial intelligence data centre.

Construction has been under way for about 18 months, with around 150 million francs already invested. Flexbase says work is progressing well and that its timetable remains achievable. The project is currently Switzerland’s largest private construction site.

However, the canton of Aargau has so far approved only the building’s outer shell, not the battery itself. It is examining whether the battery is environmentally compatible. Such a review generally takes considerable time, and approval is not guaranteed.

Installing the tanks will also be technically complex. The project additionally requires a substation connected to Switzerland’s electricity grid so that the battery can draw in and feed back electricity.

The substation is considered the biggest obstacle. Before Flexbase can even submit a building application, agricultural land in the municipality of Kaisten, Aargau, must be rezoned. Swissgrid, the national grid operator responsible for the reliable operation of the high-voltage network, says building a substation is complex and time-consuming.

Swissgrid generally allows up to 10 years for a substation to enter operation. The transformers alone have a delivery time of about five years. The land required for the facility is also owned by Axpo, not Flexbase.

The project’s estimated total cost ranges from two billion to 10 billion francs, although Flexbase has not disclosed its own figure. The company says 51 percent of its funding comes from Swiss investors. A delay would affect whether the investment begins generating returns in 2029 or much later.

Diego Ochsner, Flexbase’s head of public affairs, said the timetable remained realistic. The company was working with a rolling plan and moving quickly, he told SRF. Waiting for all approvals before starting construction would have left the site as open land, he said.