Underground, More Powerful Than a Power Plant: What They Are Building in Switzerland

In Switzerland, what is described as the most powerful energy storage system based on redox-flow technology is under construction. The project is led by the FlexBase group and will be located in Laufenburg, in the canton of Aargau. The goal is to store large amounts of renewable energy and contribute to the stability of Swiss and European power grids.

To host the facility, excavation of an underground structure approximately 27 meters deep and over two soccer fields long is underway. According to co-founder Marcel Aumer, the system will be able to absorb or inject up to 1.2 gigawatt-hours of electricity in just a few milliseconds, a capacity comparable to that of the Leibstadt Nuclear Power Plant.

The infrastructure will be part of a larger technological center that will include a data center dedicated to artificial intelligence, as well as offices and laboratories, covering a total area of about 20,000 square meters. The facility is expected to be operational by 2029 and is estimated to generate around 300 jobs. The investment, which is entirely private, ranges between 1 and 5 billion Swiss francs.

Technical Details of Redox-Flow Batteries

Unlike lithium-ion batteries, redox-flow systems use liquid electrolytes contained in large tanks. Energy is stored in chemical form and then converted into electricity through dedicated cells. This type of technology allows for the storage of energy produced from renewable sources, such as solar and wind, to be returned to the grid during peak demand.

The national electricity grid operator, Swissgrid, plans to connect the facility, marking an important step for the Swiss energy system. According to representatives of the organization, these batteries will play a crucial role in balancing the variable production of renewables and ensuring a stable supply. In addition to enhancing energy security, such systems can help meet the growing electricity demand, particularly that related to data centers for artificial intelligence. Although this technology is still under development in Europe, it is already more advanced in countries like Japan, China, and South Korea, with an estimated several years' advantage over the European continent.