POET Big Stone thermal battery

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Antora Energy · Big Stone City, SD · South Dakota DEVELOPER HEALTHHEALTHY

5 GWh thermal battery at a POET biorefinery, built in under 12 months from 200+ factory-made units.

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

ANNOUNCED
DEVELOPMENT
PERMITTED
FINANCED
CONSTRUCTION
OPERATING

Power

50 MW

Long-duration storage · First commercial

Storage

5 GWh

100-hour duration

Online

May 2026

actual

Capital committed

—

closed or awarded

Capital pending

—

conditional or under review

How it works

Thermal

Cheap electricity heats bricks or carbon blocks to well over 1,000°C. The stored heat comes back out as factory heat or steam hours later.

OPEN IN 3D →

Others on this approach

Capital stack

1 SOURCES

Equity · Grok Ventures (with Antora)Project-level equity; amount not disclosedCLOSED · 2026-05-15 · enkiai.comundisclosed

Milestones

May 15, 2026Commissioned

Grid, permits and build

Grid connection: Otter Tail Power special rate (approved by the South Dakota PUC) lets it charge from surplus local power
Who's building it: Antora Energy (more than 200 thermal batteries from its San Jose factory)

Who buys and who finances

POET

Long-term heat and power offtake

POET

LOADING…

POET Big Stone thermal battery

Thermal

Capital stack

Milestones

Grid, permits and build

Who buys and who finances

POET Big Stone thermal battery

Thermal

Capital stack

Milestones

Grid, permits and build

Who buys and who finances

Dependencies

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