Britain's Invinity Energy Systems has taken another concrete step toward what would be the world's largest vanadium redox flow battery, signing an engineering, procurement and construction (EPC) contract with Equans Switzerland for the gigawatt-hour-scale project on the Swiss-German border.
An Initial 1.5 GWh, Expandable To 2.1 GWh
The system will be built at Laufenberg Technology Center (TZL), an AI-oriented data-centre campus being developed by Swiss energy and digital-infrastructure company FlexBase. Invinity's modular vanadium redox flow batteries (VRFBs) will provide an initial 1.5 GWh of storage, expandable to 2.1 GWh in later phases. FlexBase received construction approval from local authorities in 2025 after unveiling its plan for a 500 MW / 1.6 GWh flow battery on the site the year before.
Why Vanadium Instead Of Lithium
FlexBase has said it selected vanadium flow chemistry because it is non-flammable, offers long cycle life and delivers lower levelised cost of storage (LCOS) at scale. Unlike lithium-ion batteries, VRFBs decouple power and energy — energy capacity can be extended by increasing tank size and electrolyte volume, rather than adding whole battery cabinets. "Lithium batteries cannot do the job that is needed in Laufenburg," Invinity president Matt Harper told ESN Premium in June.
Equans As The Build Partner
Equans, part of France's Bouygues Group, will handle mechanical, electrical and plumbing (MEP) and other technical services on the site — reprising a partnership with Invinity from an earlier Belgian project. Invinity CEO Jonathan Marren said Equans cleared "a demanding evaluation process," while Equans Switzerland CEO Claudio Picech called the installation a "landmark project."
A Global Milestone For Flow Batteries
Invinity said in early August that its deployed systems have cumulatively dispatched over 10 GWh globally, with dispatch up 85 percent year-on-year since 2025. The Laufenburg deal follows a wave of long-duration energy-storage momentum in Europe — from Form Energy's iron-air scale-up to Ore Energy's 1 GWh Dutch iron-air deal and the 1.25 GW BESS Energy Vault signed for a Texas AI data centre. Engineering revenue for Invinity will run through 2026 and into 2027, with a phased manufacturing purchase order expected upon successful hand-off.
Reporting based on coverage from Energy-Storage.News, Invinity Energy Systems and FlexBase.