Flow batteries

Regulatory mandates for long-duration storage will force the market to flow batteries

California SB 1373, the EU Net Zero Industry Act, and China's 15th Five-Year Plan (2026-2030) all include targets for storage and a new-type power system that lithium-ion alone cannot meet. As grids approach 80%+ renewable penetration, the need for multi-day storage during extended low-wind, low-solar periods becomes unavoidable. Flow batteries, with their 20+ year life and unlimited cycling, are among the few electrochemical technologies that can economically provide this buffer. The policy push is converting from aspirational targets to funded procurement mandates.

State of the art (2026)

Flow batteries are scaling in China and stalling in the West. In January 2026 China connected the world's largest vanadium flow project at Jimusaer (200 MW / 1,000 MWh, Rongke Power), alongside the 175 MW / 700 MWh Xinhua system, anchoring a market worth roughly 1.5 billion dollars in 2026. Vanadium redox still dominates, and Rongke, Sumitomo and VRB hold the installed base. In the West the picture is harder: Invinity has put its next-generation ENDURIUM (4-18h, made in Scotland) into general sale, but ESS Tech (NYSE: GWH) drew a delisting warning in June 2026 and had pivoted toward sodium-ion in April while keeping iron-flow alive. Western deployment remains pilot-scale; China owns the frontier.

Vanadium supply concentration is the Achilles heel — and the opportunity for alternatives

A large share of global vanadium production comes from China and Russia, creating a geopolitical vulnerability that has kept Western utilities cautious about large-scale VRFB deployment. Vanadium pentoxide prices are volatile (roughly $5-35/lb over the past decade), making VRFB project economics unpredictable. This supply concentration has catalysed a wave of alternative flow battery chemistries: all-iron (ESS Tech), zinc-bromine (Eos), organic (Quino Energy, CMBlu), plus iron-air hybrids, all using earth-abundant materials. If any alternative chemistry achieves VRFB-like performance with diversified supply chains, it could unlock an order-of-magnitude expansion in flow battery deployment.

Flow batteries own the long-duration storage market that lithium-ion cannot serve

Lithium-ion batteries are economically optimal for 2-4 hour storage applications but degrade significantly with deep cycling and become prohibitively expensive beyond 6 hours of duration. Flow batteries, particularly vanadium redox flow batteries (VRFBs), decouple power (determined by stack size) from energy (determined by electrolyte volume), enabling cost-effective scaling to 8, 12, or even 24+ hours of storage by simply adding more electrolyte tanks. This architectural advantage is structural, not incremental — no amount of lithium-ion cost reduction can overcome the fundamental limitation that longer duration requires more cells that degrade with use. Flow batteries don't degrade with cycling because the energy is stored in liquid electrolyte, not in solid electrodes.