FlexBase, a Swiss energy company, is building one of the world's largest batteries near the historic town of Laufenburg, Switzerland, using redox flow technology to store excess renewable energy and stabilize the grid. The project, set for completion in 2024, will have a 2.1 gigawatt-hour capacity and be housed in an 88-foot-deep pit the size of two soccer pitches, according to the report. it will be part of a larger complex including a data center at the historic 'Star of Laufenburg' electricity transmission hub.

An 88-foot-deep pit the size of two soccer pitches

The scale of the project is immediately striking.. The battery will be installed in an excavated pit nearly 27 meters deep, covering an area equivalent to two soccer fields , as FlexBase descriebd. This underground approach not only accommodates the massive liquid electrolyte tanks required for redox flow technology but also integrates with the site's history as a key electricity transmission node.

2.1 GWh: enough power for 200 homes for a year—delivered fast

At 2.1 gigawatt-hours, the battery can supply 200 average U.S. homes for a year, but its real value lies in rapid discharge capabilities. the report notes that the battery can swiftly deliver energy to balance supply and demand fluctuations, a critical function as Switzerland and Europe increase reliance on intermittent wind and solar power. this fast response distinguishes it from many pumped-hydro storage systems.

A chemistry concept from 1879 finally scales up

Redox flow batteries are not new—the underlying chemistry dates to 1879—but they have rarely been built at this scale. Unlike lithium-ion batteries, which store energy in solid electrodes, redox flow uses liquid electrolytes stored in external tanks, allowing easier scalability and improved safety. according to the report, FlexBase's project is a test of whether this older technology can compete with lithium-ion for stationary storage, especially as AI-driven data centers drive demand for reliable , large-scale backup power.

What's still unknown: cost, timeline, and the data center connection

The report does not disclose the project's total cost or the expected return on investment, leaving open questions about economic viability. Additionally, while completion is slated for 2024, no specific commissioning date has been provided. The integration with a data center suggests a synergy between grid storage and digital infrastructure,but the source does not detail who will operate the data center or how the storage capacity will be shared between grid services and direct data center use. These details will be crucial for assessing whether this model can be replicated elsewhere.