Form Energy closed a $750 million Series G financing round in August 2026, bringing cumulative equity financing to more than $2 billion, according to reporting from 36Kr and GreentechLead. The company said the funds will be used to expand iron-air battery manufacturing and commercial deployment.

An 80 GWh backlog, not 80 GWh online

Form Energy is developing iron-air batteries capable of about 100 hours of storage and has reported an approximately 80 GWh project backlog under agreement. That figure covers contracted and planned projects rather than commissioned capacity — a distinction that matters when comparing LDES pipelines with operating fleets. The backlog includes the planned 300 MW/30 GWh system with Xcel Energy and Google in Minnesota.

About 80 GWh of Form Energy projects are under agreement, while global cumulative novel LDES deployment stood at 5 GW/25 GWh at end-2025.

Cost benchmarks still have a gap where iron-air sits

BloombergNEF's 2026 LCOS benchmarks show vanadium flow batteries at $214/MWh, solid-state thermal storage at $225/MWh, molten-salt thermal storage at $250/MWh and lithium-ion batteries at $122/MWh. A commercial LCOS for iron-air batteries is not yet established — a reflection of how few iron-air systems operate at scale, not necessarily of the technology's eventual economics.

The modelling uses 2024 cost assumptions, 365 annual cycles and limits counted discharge to 12 hours for longer-duration systems. That last assumption is important: it compresses the advantage of technologies designed to run far longer than 12 hours, and means headline LCOS comparisons can understate value in applications requiring multi-day firming.

What the equity buys

More than $2 billion of cumulative equity is unusual for a hardware company in this sector and signals investor patience with a manufacturing-heavy path. The spending priorities are manufacturing capacity and commercial deployment, which is where iron-air costs will be determined: electrode area, stack assembly and the balance of plant around a very large, low-power battery.

Globally, about 2 GW and 9 GWh of novel long-duration storage was installed in 2025, bringing cumulative deployment to 5 GW and 25 GWh. Announced project pipelines substantially exceed commissioned capacity. The LDES Council, working with McKinsey in 2021, estimated global LDES deployment potential of 85–140 TWh by 2040 under power-system decarbonization scenarios.

The gap between announcements and steel in the ground is the central question for the sector — and for converting Form Energy's backlog into operating assets.

This article was assisted by AI analysis. Please refer to the original source for official information.