Fluence Energy has completed one of the energy storage sector’s most extensive fire safety evaluations, validating the safety of its high-density Gridstack Pro 5000 system.
Conducted in partnership with CSA Group, the tests confirmed the system exceeds current and emerging safety standards, including UL 9540A and the upcoming NFPA 855 (2026).
The 5.6MWh system underwent five days of explosion testing – covering gas dispersion and deflagration – followed by full-scale fire trials using live batteries. The tests demonstrated that Gridstack Pro 5000’s active ventilation and deflagration panels performed as designed, preventing gas buildup and safely venting pressure.
In the fire scenario, four enclosures were placed with minimal spacing. A fire was ignited in the center unit and allowed to burn without suppression. The system successfully prevented fire spread to adjacent enclosures.
“We designed Gridstack Pro 5000 to push the boundaries of what is possible in energy storage density, and with that comes a responsibility to prove it can be done safely,” said Peter Williams, Fluence SVP and chief product and supply chain officer. “This testing goes far beyond what the industry currently requires and is not only a validation of our design, but a real-world demonstration of how next-generation systems must perform under worst-case scenarios.”
Fluence also collected gas data to support emergency response planning and invited independent observers to ensure transparency. The results reinforce Gridstack Pro 5000’s position as a next-generation benchmark for energy storage safety.
Image: Fluence’s Gridstack Pro 5000 has passed fire safety tests
