Capture, Utilization, and Storage
Carbon capture, utilization, and storage (CCUS) is a process that captures carbon dioxide (CO₂) before it enters the atmosphere, then either stores it underground in deep rock formations (sequestration), or uses it to make products like dry ice, plastics, fuels, or chemicals.
Ethanol plants are considered one of the easiest and cheapest sources of CO₂ to capture because the CO₂ they emit during fermentation is already extremely pure – far purer than CO₂ from power plants or factories. The GAO has identified ethanol as the most promising near‑term source for CCUS because of this purity.
How carbon capture works (step-by-step)
Capture at the source
At an ethanol plant, CO₂ is released during fermentation. This CO₂ is collected from fermentation tanks, compressed into a dense fluid, then dehydrated and purified (though it is already very pure).
Transport by pipeline
The compressed CO₂ is moved through high‑pressure pipelines to a storage site.
This is where Iowa’s controversy comes in. Companies want to build long CO₂ pipelines across private land, often using eminent domain.
Injection underground
At the storage site, CO₂ is injected thousands of feet underground into porous rock formations capped by impermeable rock, where it mineralizes or remains trapped long‑term.
Some projects claim the CO₂ will not be used for enhanced oil recovery, but watchdog groups note there is no guarantee it won’t be diverted for that purpose.
Why ethanol is central to carbon capture in the Midwest
Ethanol plants are the backbone of current CCUS proposals because their CO₂ is cheap to capture, they produce large, steady volumes, and capturing their CO₂ dramatically lowers ethanol’s “carbon intensity score,” which boosts profits under low‑carbon fuel standards
The GAO explicitly states ethanol is the most promising source for CCUS among all major industrial sectors.
Will carbon capture still be viable if ethanol declines?
This is the key question. And the honest answer is maybe, but not in the way pipeline companies claim.
Why viability is uncertain
Most Midwest CCUS projects are financially justified ONLY because of ethanol. Without ethanol, the CO₂ supply disappears.
Ethanol demand may fall as electric vehicles grow and federal fuel standards evolve. If ethanol production drops, the economics of CCUS pipelines collapse.
Other industries produce CO₂, but it is far more expensive to capture. Power plants, cement, and steel emit CO₂ mixed with other gases, requiring costly separation.
Direct air capture is possible but extremely expensive. It is nowhere near cost‑competitive today.
What the industry is trying to do
Pipeline developers argue that they can eventually capture CO₂ from fertilizer plants, steel, cement, or even the air, and they can repurpose pipelines for other industrial uses.
But none of these alternatives are technologically mature, economically viable, or available at the scale needed to justify thousands of miles of pipeline.
Bottom line
Carbon capture in the Midwest is almost entirely dependent on ethanol. If ethanol declines, the pipelines lose their primary purpose.
So, is carbon capture a long-term climate solution?
Not in its current form.
Right now, CCUS tied to ethanol is a short‑term strategy driven by tax credits and low‑carbon fuel markets and dependent on a fuel whose long‑term demand is uncertain.
For CCUS to be viable without ethanol, the U.S. would need massive investment in new capture technologies, industries willing to pay for expensive CO₂ removal, and a regulatory framework that rewards long‑term sequestration
We are not there yet.
