What is ethanol?
Ethanol, also known as grain alcohol or ethyl alcohol, is a valuable alternative to petroleum-based fuel. It is made by fermenting and distilling simple sugars from biological sources. In Minnesota, most ethanol is produced from corn, but it can also be made from other sugary or starchy crops like sugar cane, wheat, sorghum, and potatoes.
How is ethanol made?
Fuel ethanol can be made through the DRY MILL or WET MILL process. Nineteen of Minnesota’s 20 ethanol plants use a dry mill process, which includes these steps:
- Milling: The entire grain kernel is ground into “meal.”
- Cooking & Liquefaction: The meal is slurried with water to form a “mash.” Enzymes are added to convert the starch to sugar. The mash is cooked, then cooled and transferred to fermenters.
- Fermentation: Yeast is added and the conversion of sugar to ethanol and carbon dioxide begins. CO2 is often captured here for commercial uses, like carbonating beverages. Resulting “beer” is separated from the remaining mash, or “stillage.”
- Distillation & Dehydration: Alcohol is concentrated and water is removed from the hydrous alcohol to form “anhydrous ethanol.”
- Denaturing: The anhydrous ethanol is blended with 2% “denaturant,” which renders it undrinkable and exempt from beverage alcohol tax. It is then ready for shipment and blending with gasoline.
- Co-products: The leftover “stillage” is separated into solids and liquids. The solids become “distillers grains,” an animal feed that can be dried or sold in wet form. The soluble liquids, or “syrup,” can be mixed into the distillers grains or sold as a separate feed product. Most plants also extract corn distillers oil, a feed ingredient or biodiesel feedstock, from the stillage.
How much ethanol does Minnesota produce?
In 2017, Minnesota’s 20 ethanol plants produced 1,204 million gallons of ethanol fuel. The state of Minnesota ranks 4th in total U.S. ethanol production.
What else does an ethanol plant produce, besides renewable fuel?
One bushel of corn (56 lbs.) makes 2.87 gallons of ethanol, 16.4 lbs. of livestock feed, and 0.75 lb. of corn distillers oil.
Ethanol production utilizes only the starch in the grain. The remaining protein, fat & fiber from the grain are returned to the food chain as distillers grains, corn distillers oil, corn gluten feed, or gluten meal. These animal feed co-products are consumed by beef & dairy cattle, swine, poultry, and fish. The ethanol industry produced roughly 41 million metric tons (mmt) of animal feed in 2017.
How does ethanol benefit our air quality?
Because the ethanol molecule contains 35% oxygen, blending ethanol into gasoline results in more complete fuel combustion, reducing carbon monoxide emissions which contribute to smog formation.
Ethanol is also a high-octane fuel that displaces toxic octane boosters, such as benzene (a carcinogen), used in petroleum-based fuel. Learn more about the clean air benefits of higher blends of ethanol from the American Lung Association at CleanAirChoice.org.
Is E15 safe for my car?
88 Octane, also known as E15, is approved for use in all model year 2001 and newer vehicles.
88 Octane is the most tested fuel in history without any fuel performance issues. Before 88 octane began being sold at retail locations, it was tested for more than 6 million miles using 86 vehicles from various manufacturers, makes, models and years.
Can I use ethanol fuel in my small engine?
Regular 87 octane, or E10, is approved for use in all boat, motorcycle, ATV and small engines. E10 is available at all Minnesota fuel stations.
88 Octane, also known as E15, is not approved for use in off-road vehicles, including boats and snowmobiles, and should not be used in small equipment such as lawnmowers, snow blowers, and chainsaws.
Does ethanol have a positive energy balance?
Yes. According to the U.S. Department of Agriculture, even though the process of producing ethanol requires fossil fuels (for example, fuel used by tractors to plan the crop), it takes only 1 unit of fossil fuel to produce 2.1 units of ethanol energy.
To produce gasoline, however, it takes 1 unit of fossil fuel inputs (drilling, delivery, refining, etc.) to produce .87 units of gasoline.