Carbon-capture projects have been slow to take root in the U.S., but that may be changing as a number of companies are now advancing plans to capture the carbon dioxide that results from ethanol production in the Midwest. Ethanol plants are an obvious choice, given that the CO2 resulting from ethanol fermentation is highly concentrated, which makes capturing it more efficient (and less expensive) compared to many other industrial processes. But while the relative ease and economy of capturing those emissions might seem like a no-brainer, convincing the public to go along with those plans has been more difficult. In today’s RBN blog, we look at what’s being planned.
We’ve written a lot about carbon capture in the RBN blogosphere recently, starting with the basics of carbon capture and sequestration (CCS); followed by a look at the extensive CO2 value chain; the federal 45Q tax credit and why variable costs can make some projects uneconomic; legislation that could expand the size and reach of those credits; and some underlying economic and technological reasons why project successes have been limited. Most recently, we discussed the Houston CCS Innovation Zone, the biggest project currently taking shape. (Carbon capture was also the subject of a recent Drill Down Report.)
Today, we turn our attention to ethanol production, a significant contributor to CO2 emissions but one with a lot of potential for carbon-capture opportunities. Most ethanol plants in the U.S. are dry mills. To start the ethanol-production process, they take finely ground corn and add water along with enzymes to prepare the starch for fermentation. The mixture, also known as mash, is cooked to further break down the starch. The mash is allowed to cool before a second enzyme is added, turning the liquid starch into sugars. The yeast is added and fermentation begins, yielding ethanol and CO2.
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