Antora Energy and POET have commissioned a 5GW-hour (GWh) thermal energy storage system at the latter’s Big Stone City bioprocessing facility in South Dakota, US.
The project began initial construction less than a year ago and has already started delivering energy. Full operations are expected later in the year.
After completion, the project will rank among the largest energy storage installations globally, designed to accommodate increasing energy demand.
The thermal battery system, manufactured at Antora’s facility in San Jose, California, provides continuous energy through a long-term heat offtake agreement with POET.
The agreement enables POET to maintain competitive bioethanol production at the Big Stone plant and helps South Dakota farmers access new market opportunities.
The project deployed more than 200 of Antora’s thermal batteries, which store inexpensive electricity as heat in insulated solid‑carbon blocks. That heat can be supplied continuously for industrial processes or converted back into electricity.
POET founder and CEO Jeff Broin said: “POET is dedicated to supplying the world with affordable, American-made biofuels and bioproducts. By investing in next-generation technologies, we are leading the way to a biofuture powered by American energy.”
The project’s installation and manufacturing phase has supported more than 300 jobs, split between South Dakota and California.
South Dakota Governor Larry Rhoden said: “I am proud that the State of South Dakota helped make this project a reality. Antora’s partnership with POET creates new jobs and strengthens our economy for years to come.”
Grok Ventures is the sole external investor, providing the project-level financing necessary for the facility to reach financial close.
The South Dakota Board of Economic Development and other local partners have supported the initiative.
The US Department of Energy supplied key early research and development funding to Antora, contributing to private investment growth in the company.
Otter Tail Power worked with Antora to implement a new electric rate approved by the South Dakota Public Utilities Commission.
The structure permits the system to charge during periods of excess local energy production, allowing consistent, 24-hour thermal energy delivery without raising costs for other grid customers. This approach aims to maximise existing grid infrastructure.
Antora co-founder and CEO Andrew Ponec said: “With this project, Antora is delivering affordable energy to POET – fast. We are proud of what this deployment means for the workers who designed, built and installed these batteries, and more broadly, for American manufacturing.”
