Switzerland’s Giant Battery to Store Renewable Energy and Ease Europe’s Grid from 2029

Power produced at the wrong moment becomes a tangible challenge. In Laufenburg, FlexBase is building a technology center where a redox-flow battery will store solar and wind surpluses and then release them when Swiss and European grids draw more.

Laufenburg Prepares a Giant Battery at the Heart of an Energy Campus

In Laufenburg, in the canton of Aargau, FlexBase is digging a 27-meter pit for its Technology Center. The site spans more than 40,000 square meters, according to the project lead, and will host offices, laboratories, an AI data center and electricity storage.

The heart of the site remains the redox-flow battery, touted as the largest of its kind. FlexBase reports a capacity exceeding 2.1 GWh, enough to power about 210,000 homes for 24 hours, if this performance holds.

The Redox Principle Turns Two Liquids into an Electricity Reserve

Redox technology means reduction-oxidation, an exchange of electrons between two liquids. An electrolyte is the liquid that carries these charges. In this system, energy does not sleep in a solid block, but in large, separate reservoirs.

The idea is like two tanks connected to a motor. When the grid has excess electricity, the liquids charge. When demand rises, they pass through cells that transform this chemical energy into usable current.

This architecture explains the appeal compared to lithium-ion. FlexBase highlights an electrolyte made of roughly 75% water, non-flammable and non-explosive. Capacity depends more on the volume of the reservoirs than on compact cells alone.

Why This Battery Is of Interest to Swissgrid and European Grids

The project targets moments when renewable production exceeds demand. Sun power delivers a lot at noon, wind varies with the weather, while households, industry and data centers require electricity at other times.

Marcel Aumer, co-founder of FlexBase, mentioned a potential capacity of up to 1.2 GW of injection or absorption. Power measures the instantaneous flow, like a faucet opened wide, while GWh measures the amount stored.

This Swiss Project Is Part of a European Storage Race

Laufenburg carries a particular energy significance. The town has served as a node in the European interconnection, and Swissgrid, Switzerland’s high-voltage network operator, plans a direct interconnection of the facility, presented as a national first for this pilot project.

At the European level, storage becomes a strategic undertaking. The European Commission’s Joint Research Centre lists 2,356 projects, with 70 GW operational and 97.26 GW expected by 2030, across all statuses in its public database.

The International Energy Agency notes that grid batteries primarily balance hours and days. FlexBase targets completion between 2025 and 2028, followed by commissioning in 2029, with around 300 jobs around the Laufenburg site in the canton of Aargau.