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.
Most ethanol in our region is made using a dry milling process: grinding corn kernels into a powder, mixing with water to form a mash, and then cooking with enzymes that turn the starch to glucose. The mash is fermented and then distilled to separate the ethanol from the solids and water. The solids are a high protein livestock feed called distillers grains. Many Minnesota ethanol plants also produce carbon dioxide, which is used for refrigeration or as an industrial chemical.
There is also a wet milling process: corn is steeped in water and sulfur dioxide before grinding, then the germ, fiber, gluten and starch components are separated. The starch can be sold for use in food processing, paper milling and other uses, or it can be further processed into corn syrup, ethanol, amino-acids or a wide variety of other products. The germ, fiber and gluten can be made into corn oil, livestock feed and many other products. An advantage to the wet mill process is the wider variety of valuable co-products that can be produced.
What is cellulosic ethanol?
Cellulosic ethanol is not yet widely commercialized, but many states, including Minnesota are researching this manufacturing process that makes ethanol from cellulosic feedstocks. Cellulose is the main component of the cell walls of plants. Cellulosic materials that can be made into ethanol include corn stover (leaves, stalks, cobs), wood products, trees, grasses, and – most recently – the fiber from the corn kernels used in traditional ethanol production.
In order to qualify for the federal Renewable Fuel Standard program, cellulosic ethanol and other biofuels must demonstrate a 60% improvement in greenhouse gas emissions compared to straight gasoline. Because of this, other forms of renewable energy may be needed to support the production facility.
What economic benefits does ethanol have for Minnesota?
The Minnesota Department of Agriculture conducted an economic impact study in 2012 and concluded that Minnesota’s ethanol industry generated a total economic impact of $5 billion and supported 12,686 jobs. (See the MDA’s Ethanol Economic Impact Report (PDF)).
How does ethanol benefit the environment and public health?
Ethanol reduces harmful vehicle emissions. Because it contains 35 percent oxygen, blending ethanol into gasoline results in more complete fuel combustion, reducing carbon monoxide emissions, which contribute to smog formation. Ethanol is a high-octane fuel that displaces toxic octane boosters, such as benzene (a carcinogen), used in petroleum-based fuel. Toxics and particulate matter are the most dangerous air pollutants to humans.
Will there be enough ethanol to meet consumer demand?
In 2017, Minnesota produced approximately 1.3 billion gallons of ethanol—more than enough to meet current annual consumption of approximately 270 million gallons.
Does ethanol have a positive energy balance?
Yes. It takes energy to make energy. According to the U.S. Department of Agriculture, even though the process of producing ethanol requires fossil fuels (in fertilizers, fuel used by tractors and to plant, harvest, and dry the crop, and sometimes to run the ethanol plant), 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.