Ethanol Blog

LINCOLN, Neb. (DTN) -- Poet LLC announced the commissioning of a thermal energy storage system at its ethanol plant in Big Stone City, South Dakota, with expectations that the 5-gigawatt-hour, multi-day system would be fully operational later in 2026, according to a news release from Poet.

The vast majority of more than 200 corn ethanol plants in the U.S. still rely on natural gas boilers for their thermal energy needs. Based on DTN's research, thermal energy storage is very uncommon in the industry and is mostly limited to pilot or demonstration-scale projects.

Poet said in a news release on Tuesday that it has partnered with energy storage company Antora Energy to improve efficiency and lower costs at the plant in South Dakota.

"The significant investment in Poet's facility has created and supported over 300 manufacturing and construction jobs in rural South Dakota and at Antora's recently expanded San Jose, California, gigafactory, where all of the company's thermal batteries are made," Poet said on Tuesday.

"Antora's system provides Poet with competitively priced, around-the-clock energy under a long-term heat offtake agreement, enabling the plant to increase bioethanol production and create tens of millions of dollars annually in new market opportunities for South Dakota farmers."

According to the news release, Poet has an offtake agreement with Antora that allows the South Dakota plant to increase ethanol production and to "create tens of millions of dollars annually" for South Dakota farmers.

Poet and Antora have partnered with the South Dakota Board of Economic Development and the U.S. Department of Energy during the first Trump administration.

"Antora worked closely with Otter Tail Power -- a utility that provides power at some of the lowest costs in the nation to customers across South Dakota, North Dakota and Minnesota -- to develop an innovative electric rate that enables the system to deliver 24/7 thermal energy without increasing costs for other consumers," Poet said on Tuesday.

"Approved by the South Dakota Public Utilities Commission last year, the rate allows the system to selectively and rapidly charge during periods of surplus local energy production, making better use of existing grid infrastructure. The structure offers a model for utilities across the country to responsibly integrate thermal energy storage while benefitting everyone on the grid."

Considering that thermal energy accounts for about 90% of an ethanol plant's energy consumption, the use of thermal energy storage may be among the next wave in technology adopted by ethanol producers as the technology advances.

In addition, the move away from fossil fuels to renewable energy for heat and incentives from the 45Z Clean Fuels Production credit makes thermal energy storage more attractive financially.

Since natural gas combustion is the largest source of Scope 1 emissions at a dry-mill facility like an ethanol plant, replacing it with thermal energy storage can help companies reduce carbon-intensity scores, produce higher per-gallon 45Z credit values and improve eligibility for premium fuel programs and markets.

Todd Neeley can be reached at todd.neeley@dtn.com

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