Energy · Profile from Energy Research Companion
Form Energy
The Somerville, Massachusetts start-up building an iron-air battery that stores electricity for ~100 hours by rusting and un-rusting iron pellets, made in a converted steel town in Weirton, West Virginia. It is the leading US bet on multi-day storage: a product whose cost per kWh of capacity is meant to be a small fraction of lithium-ion's, at the price of low power density and low round-trip efficiency, aimed at the few days a year when wind and solar are scarce. Form has raised more than $2bn of equity (company, 2026) and signed utility deals in Minnesota, Georgia, Colorado, California, Virginia and Washington, but by spring 2026 only its first commercial system — a 1.5 MW / 150 MWh battery for Great River Energy in Cambridge, Minnesota, energised in late 2025 (company, reported) — was known to be operating. In March 2026 it signed a 12 GWh deal with Crusoe for AI data centres (pv magazine USA), and it reported its backlog rising from ~20 GWh to ~80 GWh (Mercom, 2026). It is the clearest case of long-duration storage as a product looking for a market structure that pays for it.
At a glance
- Founded
- 2017, Somerville, Massachusetts (reported)
- Headquarters
- Somerville, Massachusetts; factory (Form Factory 1) in Weirton, West Virginia; R&D in Berkeley, California (verify)
- Ownership / structure
- Private, venture-backed. Investors reported to include Breakthrough Energy Ventures, Prelude Ventures, Eni Next, ArcelorMittal, TPG Rise Climate, T. Rowe Price, NGP and GE Vernova (reported, verify each); total equity >$2bn after a ~$750m Series G (2026, reported)
- Leadership (2026)
- Mateo Jaramillo (CEO, co-founder; formerly led Tesla's stationary-storage business); co-founders Yet-Ming Chiang (MIT; co-founder of A123 Systems and 24M), Billy Woodford, Ted Wiley and Marco Ferrara (reported)
- Technology
- Aqueous iron-air battery: iron anode oxidises to rust on discharge and is reduced back on charge; air cathode; water-based electrolyte; non-flammable (company). Systems sized ~100× power in energy (e.g. 1.5 MW / 150 MWh); round-trip efficiency well below lithium-ion's ~85% (reported ~40–50%, verify); target system cost reported at under ~$20/kWh at scale (2021, company aspiration, not achieved price)
- Factories
- Weirton, West Virginia, on the former Weirton Steel site: ~$760m investment announced Dec 2022 with West Virginia incentives (reported, verify amount); ~1m sq ft and just over 400 staff (Apr 2026, local press); expansion planned to roughly double size (2026, reported)
- Scale
- Operating: ~150 MWh (Cambridge, Minnesota) as of spring 2026 (secondary, verify); announced utility projects ~13.5 GWh for 2026–28 (secondary, verify — named project sizes in the KB sum to only ~4.2 GWh); backlog ~80 GWh including Crusoe's 12 GWh (company via Mercom, 2026, verify basis)
- Signature moves (incl. setbacks)
- Founding and the multi-day thesis (2017); the iron-air reveal and first utility pilots (2021); the Weirton factory decision (2022); utility resource-plan deals (2023); Series F and schedule slips (2024); Cambridge, the first commercial battery (2025); the Crusoe data-centre deal (2026); Series G and factory expansion (2026)
8 strategic moves analysed
Each one gets a full strategy file in the companion: context, the decision, the financing, what happened, and the lesson.
2017
Founding and the Multi Day Thesis
Founding / technology bet
2021
Iron Air Reveal and First Utility Pilots
Technology bet (public disclosure) / offtake (utility pilots) / financing
2022
Weirton Factory Decision
Construction / state support
2023
Utility Resource Plan Deals
Offtake or supply contract / regulatory (resource-plan approvals)
2024
Series F and Schedule Slips
Financing / execution (setback)
2025
Cambridge First Commercial Battery
Construction or commissioning
2026
Crusoe Data Centre Deal
Offtake or supply contract
2026
Series G and Factory Expansion
Financing / construction (expansion)