Switzerland Revives 1879 Battery Technology for Europe's Largest Underground Energy Storage System
Zurich, Wednesday, 6 May 2026.
Switzerland is constructing the world’s most powerful redox flow battery in Laufenburg, reviving technology first conceived in 1879. The 2.1 GWh underground system could power 210,000 homes for 24 hours and will be stored 27 meters deep. Expected to cost up to $6.2 billion and create 300 jobs by 2029, this project addresses Europe’s critical renewable energy storage challenge, providing grid stability when solar and wind power fluctuate.
FlexBase Leads Ambitious Swiss Energy Revolution
Swiss energy firm FlexBase is spearheading this groundbreaking project in Laufenberg, canton Aargau, Switzerland, constructing what will become the world’s largest redox flow battery [1][2]. The company is developing this massive underground storage facility at the Laufenburg Technology Center, a 20,000 square meter site near the German border [1][2]. Marcel Aumer, FlexBase co-founder, emphasized the system’s unprecedented capability: “We will be able to inject or absorb up to 1.2 gigawatt-hours (GWh) of electricity in a few milliseconds, equivalent to the power of the Leibstadt nuclear power plant” [2]. This project represents a privately funded initiative with an investment ranging between $1.2 billion and $6.2 billion [2].
Reviving Victorian-Era Innovation for Modern Challenges
The redox flow battery concept traces its origins back to 1879, making this cutting-edge project a remarkable revival of Victorian-era innovation [1][2]. The technology was later refined through research in the space sector, including development by NASA in the second half of the 20th century [1][2]. Unlike conventional lithium-ion batteries, redox flow systems store energy in liquid electrolytes that are circulated through a cell where ions are exchanged via a membrane [1]. The electrolyte composition is 75% water, making it non-flammable, non-toxic, and recyclable [2]. This water-based approach offers significant advantages over traditional battery technologies, as the materials degrade minimally over time, promising extended operational lifespans without significant capacity loss [1].
Massive Scale and Strategic Timeline
The Laufenburg installation will exceed 2.1 GWh in storage capacity, positioning it to surpass China’s current record-holder, the 700-MWh Xinhua Ushi plant [2]. To put this capacity into perspective, the system could support one million households for five hours or provide power to 210,000 households for an entire 24-hour period [2]. Construction is taking place in a 27-meter-deep excavation pit, emphasizing the project’s underground nature [1][2]. FlexBase has scheduled the battery for completion in 2029 and expects the project to create approximately 300 new jobs [2]. The massive scale of this undertaking reflects the growing urgency to address Europe’s renewable energy storage challenges as countries rapidly expand their wind and solar capacity.
Addressing Europe’s Grid Stability Crisis
The installation in Laufenburg is specifically designed to accommodate the inherent variations in renewable energy supply and demand, providing crucial stabilization for both the electricity grid and AI data centers [1][2]. As Europe continues expanding wind and solar energy infrastructure, the continent faces increasing supply fluctuations that challenge grid stability, while the electricity grid benefits from maintaining constant load conditions [1]. The growth of data centers, particularly those supporting artificial intelligence operations, is simultaneously increasing demand for continuous power supply, further amplifying the need for large-scale storage capacity [1]. This dual pressure from variable renewable supply and growing digital infrastructure demand makes projects like FlexBase’s Laufenburg facility essential for Europe’s energy transition. The technology’s scalability makes it particularly suitable for large-scale grid-level applications, addressing the limitations of lithium-ion batteries in stationary storage scenarios [1]. If proven reliable at this unprecedented scale, the Laufenburg project could serve as a blueprint for other European energy systems, providing a reference point for future infrastructure development across the continent [1].