A Swiss company called FlexBase is building what is considered one of the most powerful batteries in the world near the picturesque medieval town of Laufenburg, Switzerland. The battery, based on a technology called redox flow that joins other emerging battery technologies that could change the world, will live in an 88-foot-deep pit, in a sprawling excavation that is “the length of two football fields,” according to a report in the New Atlas (or more than 200 meters for our American readers).
The goal of the project is to store excess energy when sources are abundant, then release it to stabilize the grid in times of shortage. It aims to help solve problems linked to the intermittent nature of renewable energy sources such as wind and solar, which are increasingly becoming an important part of the European energy network. Beyond the headline-grabbing scale of the project, it is also interesting in that it highlights a relatively old chemical concept and places it at the center of a major energy infrastructure project.
The Swiss project
According to FlexBase, a Swiss energy group, the project will combine energy storage with data infrastructure, creating a huge interconnected complex including the battery installation, a data center and associated technical space. It is being built on the evocatively named historic “Star of Laufenburg,” a complex of power transmission centers and substations that was the site of the first high-voltage synchronization of the power grids of Germany, France and Switzerland.
The battery has a claimed capacity of 2.1 gigawatt hours (GWh). That means it can store enough energy to run 200 average American homes for a year. Importantly, it is also capable of delivering this energy quickly, meaning it can respond quickly to grid fluctuations and balance supply and demand deficits. If it works as promised, it could become a model for how large-scale storage supports renewable energy networks, while also serving digital infrastructure (an area of growing concern as we enter the era of AI data centers and their voracious appetite for energy).
How Redox Flow Batteries Work
Redox flow batteries operate somewhat differently from lithium-ion packs (including new lithium-metal technology launched in China) that have become so ubiquitous in consumer electronics and electric vehicles. Rather than storing energy in solid electrodes like Li-ions, they conserve energy in reservoirs of liquid electrolyte. They then move this liquid through a stack of cells, triggering chemical reactions.
In a vanadium redox flow battery, for example, electrolytes flow on opposite sides of a membrane that allows the exchange of ions (charged particles) while keeping the liquids separated. When the battery charges, the electricity changes the oxidation state (the effective charge) of the fluids and chemically stores the energy; when it discharges, the process reverses and electricity is returned.
This is a technology originally pioneered in 1879, and it offers flow batteries several advantages for use on the grid (although it may not survive a civilization like this nuclear battery). They can be scaled by increasing tank size, they tolerate frequent cycling well, and they are considered safer than many conventional battery chemicals because the electrolyte is nonflammable. The trade-off is that, as the Swiss project proves, they are very large and complex, which is why they make more sense for stationary storage than for things like your smartphone or your car.
