The Ethanol Industry’s Commercial Capture

by Katie Schroeder (Ethanol Producer Magazine) CO2 from corn ethanol plants is a great candidate for capture and sequestration because it is so clean. That also makes it a versatile and critical product for myriad commercial and industrial uses. -- New and improving methods of reducing the carbon intensity (CI) scores of corn ethanol are enabling producers to tap into markets that place a premium on low-carbon biofuel. Carbon dioxide pipelines, which seek to aggregate CO2 from Midwest ethanol plants for permanent geologic sequestration—and cut CI scores in half—is an attractive option for ethanol plants that don’t already capture CO2 for commercial use. For the those that do, the jump to sequestration may be complicated by their already vital role as merchant CO2 suppliers.

Sam Rushing, president of consulting firm Advanced Cyrogenics and frequent contributor to Ethanol Producer Magazine, is an expert on the myriad commercial uses for CO2. He explains that 40 to 45 percent of the CO2 on the U.S. market comes from ethanol production. Rushing’s company helps producers find ways to “monetize what would otherwise be vented to the atmosphere” or, in the near future, sequestered. He says Advanced Cryogenics helps corn ethanol producers find the right use for their CO2, whether that be for captive or merchant use. “It’s all about sustainability as well, trying to come up with programs and sources and destinations that would be sustainable throughout time,” Rushing says.

Ethanol giant POET actively captures and sells ultra-high purity CO2 to the beverage industry for carbonated drinks, the food processing industry for refrigeration, municipalities for water treatment, and more, under the POET Pure brand, according to Doug Berven, POET’s vice president of corporate affairs.

Berven explains that the CO2 produced at POET has 65 to 85 percent less greenhouse gas emissions compared to competitors capturing CO2 from oil wells or ammonia manufacturing.

“We are capturing CO2 off the fermentation process and then we condense it, and can sell it as a liquid,” he says. “What it really amounts to is, we have a skid that takes that CO2, scrubs it and then utilizes it, puts it in a form that is easy to ship either via truck mostly, or rail.”

The other 30 percent of the CO2 merchant market is used for industrial purposes, everything from agriculture to the metal trade. CO2 is used for growth enhancement for high-quality crops like cannabis and tomatoes in an enclosed greenhouse environment. “Plants utilize CO2 for photosynthesis and exhale oxygen, so it’s essentially a very good application that’s very common in some markets,” Rushing says. The increased use of CBD has also brought another use for CO2, as it is used to extract CBD oil from cannabis and may be preferred over some other hydrocarbons like propane or butane since it doesn’t have any extra byproducts. CO2 is also used in metallurgy to stir molten metal, a gas shield for welding, hardening sand cores in the foundry industry along with many other applications. CO2 is also used for high-pressure blasting with small rice-sized dry ice pellets.

CO2 that is sequestered may earn producer tax credits, but CO2 captured for merchant use does not earn tax credits since it generally ends up in the atmosphere after its use as a product, Rushing explains. Although merchant CO2 products generally dissipate into the air after commercial use, Rushing says there are technologies being developed to potentially recycle CO2 for additional uses, in refrigerant systems for example.

Much of the value proposition for sequestering carbon dioxide currently comes from federal tax credits from Section 45Q, which Rushing says yield producers $20 to $50 per sequestered ton of CO2. Plus, Rushing says, credits given to biofuels that, because of future sequestration, attain a low CI score (under California’s Low Carbon Fuel Standard) further amplify the financial allure of sequestration.

Although he sees value in merchant CO2, Rushing sees sequestration as the end goal.

Berven believes that there is potential for growth in the CO2 market. “We can use CO2 for so many things, from drop-in designer fuels, to plastics, organic chemistry … the medical field, fire suppression … I mean there’s a lot of different areas where we can use CO2,” he says. “And I think especially for the bioethanol industry, the market is going to expand.” READ MORE