A US startup has delivered the first commercial sodium-ion home batteries in Europe, marking a significant milestone in the quest for a lithium-free alternative to residential energy storage.
UNIGRID, a spin-off from the University of California San Diego, announced that the first units of its Na+Casa sodium-ion battery have been installed in European homes. The system stores 9.25 kilowatt-hours of energy and carries a rated lifespan of 25 years, matching the typical lifespan of rooftop solar panel arrays, with an operating temperature range of -40°C to 60°C (-40°F to 140°F).
Unlike lithium-ion batteries, the Na+Casa uses a proprietary NCO sodium-ion chemistry that contains no lithium, cobalt, or nickel, all materials with volatile supply chains and significant environmental and geopolitical extraction costs. The sodium-ion chemistry also eliminates thermal propagation, the chain-reaction overheating that has caused fires in lithium-ion home battery installations.
“As residential energy bills rise, especially during extreme weather events such as the record heatwave we are seeing around the world, homeowners need storage that is safe, reliable, and financially sound,” said Darren H. S. Tan, UNIGRID’s CEO and co-founder. “With Na+Casa, UNIGRID is moving NCO sodium-ion from just a promising technology to a tangible residential storage product.”
The European debut was chosen partly because of favorable regulatory conditions and consumer readiness for alternative battery technologies. UNIGRID plans to launch in the United States by the end of 2026, pending additional compliance certifications. The company is currently producing at 200 megawatt-hours per year of cell capacity and expects to scale to 2 gigawatt-hours per year by 2027, with manufacturing partners in China, South Korea, and Japan.
The battery is compatible with most existing hybrid inverters, and UNIGRID says its pricing is competitive with current lithium-ion home batteries, a critical factor for mass adoption. Analysts have long argued that sodium-ion technology’s main advantage is raw material abundance: sodium is extracted from seawater and common salt deposits, whereas lithium and cobalt require mining operations concentrated in a handful of countries.
Sources: Beyond lithium? Sodium-ion home battery debuts in Europe (Interesting Engineering, Jul 2026)