Sherco iron-air battery

Form Energy · Sherburne County Generating Station, Becker, MN · Minnesota DEVELOPER HEALTHWATCH

100-hour iron-air battery at the retiring Sherco coal plant. Form said it could come online as early as 2025; no newer status found.

Long-duration storage · Multi-day, thermal and mechanical storage SEE CONNECTIONS →

ANNOUNCED
DEVELOPMENT
PERMITTED
FINANCED
CONSTRUCTION
OPERATING

Power

10 MW

Long-duration storage · First commercial

Storage

1 GWh

100-hour duration

Online

Q2 2028

approximate target

Capital committed

—

closed or awarded

Capital pending

—

conditional or under review

ONLINE DATE HISTORY · 1 CHANGE

Nov 9, 2026: none → Q2 2028 · source

How it works

Iron-air

Discharging lets iron pellets rust in air, which releases electricity; charging turns the rust back into iron. Cheap, plentiful materials make 100-hour storage affordable.

OPEN IN 3D →

Capital stack

1 SOURCES

Grant · US DOE Office of Clean Energy DemonstrationsPhases 1–2 for Sherco and Comanche together (up to $70M in later phases); DOE said in Oct 2025 the project won't proceed past the current budget period. Xcel appealedCANCELLED · 2024-06-05 · energy.gov$4.3M

Milestones

Grid, permits and build

Permits: Minnesota PUC approval (July 6, 2023), with a cost cap
Who's building it: Form Energy iron-air batteries (10 MW / 1,000 MWh)

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Sherco iron-air battery

Iron-air

Capital stack

Milestones

Grid, permits and build

Sherco iron-air battery

Iron-air

Capital stack

Milestones

Grid, permits and build

Who buys and who finances

Dependencies

Related

More from Form Energy

Sources