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Biofuels Basics
Grade: A. Reason: ready
(From http://www.eia.doe.gov/kids/energyexplained/renewable/biomass.html)
"Biofuels" are transportation fuels like ethanol and biodiesel that are made from biomass materials. These fuels are usually blended with the petroleum fuels — gasoline and diesel fuel, but they can also be used on their own. Using ethanol or biodiesel means we don't burn quite as much fossil fuel. Ethanol and biodiesel are usually more expensive than the fossil fuels that they replace, but they are also cleaner-burning fuels, producing fewer air pollutants.
What Is Ethanol?
Ethanol is an alcohol fuel made from the sugars found in grains, such as:
USDA research geneticists study switchgrass as a source of ethanol.
Other sources of sugars to produce ethanol include:
- Potato skins
- Rice
- Sugar cane
- Sugar beets
- Yard clippings
- Bark
- Switchgrass
Most of the ethanol used in the United States today is distilled from corn. Scientists are working on cheaper ways to make ethanol by using all parts of plants and trees rather than just the grain. Farmers are experimenting with "woody crops," mostly small poplar trees and switchgrass, to see if they can be grown cheaply and abundantly.
Ethanol Is Blended With Gasoline
A Biodiesel and Standard Gasoline Pump
About 99% of the ethanol produced in the United States is used to make "E10" or "gasohol," a mixture of 10% ethanol and 90% gasoline. Any gasoline powered engine can use E10, but only specially made vehicles can run on E85, a fuel that is 85% ethanol and 15% gasoline.
What Is Biodiesel?
Biodiesel is a fuel made from vegetable oils, fats, or greases — such as recycled restaurant grease. Biodiesel fuel can be used in diesel engines without changing them. It is the fastest growing alternative fuel in the United States.
Biodiesel, a renewable fuel, is safe, biodegradable, and produces lower levels of most air pollutants than petroleum-based products.
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Ethanol
Grade: A. Reason: ready
Ethanol Made from Corn and Other Crops
Ethanol is a clear, colorless alcohol fuel made from the sugars found in grains, such as corn, sorghum, and barley, as well as potato skins, rice, sugar cane, sugar beets, and yard clippings. Ethanol is a renewable fuel because it is made from plants. There are several ways to make ethanol from these sources.
USDA Researchers Adding Yeast To Begin Ethanol Fermentation
The most common processes today use yeast to ferment the sugars and starch in corn. Corn is the main ingredient for ethanol in the United States due to its abundance and low price. Most ethanol is produced in the corn-growing States in the Midwest. The starch in the corn is fermented into sugar, which is then fermented into alcohol.
Sugar cane and sugar beets are the most common ingredients used to make ethanol in other parts of the world. Since alcohol is created by fermenting sugar, sugar crops are the easiest ingredients to convert into alcohol. Brazil, the country with the world's largest ethanol production, makes most of its ethanol from sugar cane. Today, many cars in Brazil run on ethanol.
Cellulosic Ethanol
Ethanol can also be produced by breaking down cellulose in woody fibers. Cellulosic ethanol is considered an “advanced” biofuel and involves a more complicated production process than conventional ethanol made from starches or sugars. However, with this process we can make ethanol from trees, grasses, and crop wastes, reducing concerns that increasing ethanol production will reduce food supply.
Trees and grasses are potential feedstocks for cellulosic ethanol production. They require less energy, fertilizers, and water than grains and can also be grown on lands that are not suitable for growing food. Scientists have developed fast-growing trees that grow to size in 10 years. Many grasses can produce two harvests a year for many years without a need for annual replanting.
Someday, you may find yourself driving by huge farms that are not producing food or animal feed, but feedstock for ethanol. Feedstock is the raw material used to make a product like ethanol.
History of Ethanol
Model T Vehicle
Ethanol is not a new fuel. In the 1850s, ethanol was a major lighting fuel. During the Civil War, a liquor tax was placed on ethanol to raise money for the war. The tax increased the price of ethanol so much that it could no longer compete with other fuels such as kerosene in lighting devices. Ethanol production declined sharply because of this tax, and production levels did not begin to recover until the tax was repealed in 1906.
The Model T Ran on Ethanol
In 1908, Henry Ford designed his Model T, a very early automobile, to run on a mixture of gasoline and alcohol. Ford called this mixture the fuel of the future. In 1919, when Prohibition began, ethanol was banned because it was considered a liquor. It could only be sold when it was mixed with petroleum. With the end of Prohibition in 1933, ethanol was used as a fuel again.
Ethanol Is Here to Stay
Ethanol use increased temporarily during World War II when oil and other resources were scarce. In the 1970s, interest in ethanol as a transportation fuel was revived as oil embargoes, rising oil prices, and growing dependence on imported oil increased interest in alternative fuels. Since that time, ethanol use has been encouraged by tax benefits for producing ethanol and for blending ethanol into gasoline and by environmental requirements for cleaner-burning fuels.
In 2005, a renewable fuel standard was enacted that set minimum requirements for the use of renewable fuels, including ethanol. In 2007, the RFS targets were substantially raised and now rise steadily to a level of 36 billion gallons by 2022. Learn more about the history of ethanol in a timeline.
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Uses of Ethanol
Grade: A. Reason: ready
Ethanol as a Transportation Fuel
E10
An E-85 Car Being Fueled
Did You Know?
Henry Ford’s original automobile, the Model T, had an engine capable of running on either gasoline or ethanol.
As a transportation fuel, ethanol can be used as a total or partial replacement for gasoline. Gasoline containing 10% ethanol — E10 — is used in most areas.
Some States require use of E10. Minnesota, for example, requires almost all gasoline sold in the State to contain 10% ethanol.
All vehicles that run on gasoline can use E10 without changes to their engines. Over 99% of the ethanol produced in the United States is mixed with gasoline to make E10.
E85
E85 is an alternative fuel that contains up to 85% ethanol. It is used mainly in the Midwest and South. Vehicles that use E85 are specially named as flexible fuel vehicles (FFV).
Flexible Fuel Vehicles (FFVs)
FFVs can use any mixture of ethanol and gasoline up to E85. In 2007, there were about 364,000 cars and trucks using E85. Most of these were fleet vehicles. Millions of other FFVs are on the road, but are fueled with gasoline or E10 rather than fuels containing higher amounts of ethanol.
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Ethanol & the Environment
Grade: B. Content is thin.
Ethanol Is Nontoxic and Biodegradable
Using ethanol means that we use less oil (a nonrenewable fuel) to make gasoline. Unlike gasoline, ethanol is nontoxic (safe to handle) and biodegradable; it quickly breaks down into harmless substances if spilled.
Ethanol Can Reduce Pollution
When small amounts of ethanol are added to gasoline, usually less than 10%, there are many advantages. Ethanol reduces carbon monoxide and other toxic pollution from the tailpipes of vehicles, making less air pollution. It also keeps engines running smoothly without the need for lead or other chemical additives.
Ethanol is made from crops that absorb carbon dioxide and give off oxygen. So growing crops for ethanol may have the potential to reduce carbon dioxide emissions to the atmosphere.
The impact of greater ethanol use on net carbon dioxide emissions depends on how ethanol is made and on whether or not indirect impacts on land use are included in the calculations.
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Biodiesel
Grade: A. Reason: ready
Biodiesel Is Made from Vegetable Oils and Animal Fats
Vegetable Oil in a Bottle
Biodiesel is a renewable fuel that can be used instead of diesel fuel,
which is made from petroleum. Biodiesel can be made from vegetable oils, animal fats, or greases. Most biodiesel today is made from soybean oil. About half of biodiesel producers are able to make biodiesel from used oils or fats, including recycled restaurant grease.
Biodiesel is most often blended with petroleum diesel in ratios of 2% (B2), 5% (B5), or 20% (B20). It can also be used as pure biodiesel (B100). Biodiesel fuels can be used in regular diesel vehicles without making any changes to the engines. It can also be stored and transported using diesel tanks and equipment.
History of Biodiesel
Fueling engines with biodiesel has just started to catch on, but it isn't a new idea. Before petroleum diesel fuel became popular, Rudolf Diesel, the inventor of the diesel engine in 1897, experimented with using vegetable oil (biodiesel) as fuel.
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Uses of Biodiesel
Grade: A. Reason: ready
Biodiesel as a Transportation Fuel
Most trucks, buses, and tractors in the United States use diesel fuel. Diesel is a nonrenewable fuel made from petroleum. Using biodiesel means that we use a little bit less petroleum. Biodiesel results in less pollution than petroleum diesel. Any vehicle that operates on diesel fuel can switch to biodiesel without changes to its engine.
Biodiesel has chemical characteristics much like petroleum-based diesel, so it can be used as a direct substitute for diesel fuel. Biodiesel can also be blended with petroleum diesel in any percentage without suffering any significant loss of fuel economy.
A Bus Powered by Soybean Oil
The Fastest Growing Fuel for Fleet Vehicles
Because it is so clean-burning and easy to use, biodiesel is the fastest growing and most cost efficient fuel for fleet vehicles. Many school districts are switching to biodiesel blends for their school buses. Biodiesel is also being used for fleets of snowplows, garbage trucks, mail trucks, and military vehicles.
So far, the use of biodiesel has been limited to fleets of vehicles that have their own fueling stations. As the number of public fueling stations that offer biodiesel grows, it may become more popular with individual consumers.
Biodiesel Blends
A blend of 20% biodiesel with 80% petroleum diesel is known as B20. Low-level biodiesel blends like B2 through B5 are popular fuels in the trucking industry because biodiesel has excellent lubricating properties, and therefore usage of the blends can be beneficial for engine performance.
Pure biodiesel (often called B100) and biodiesel blends are sensitive to cold weather and may require a special type of anti-freeze, just like petroleum-based diesel fuel does. Biodiesel acts like a detergent additive, loosening and dissolving sediments in storage tanks. Because biodiesel is a solvent, B100 may cause rubber and other components to fail in older vehicles. This problem does not occur with biodiesel blends.
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Biodiesel & the Environment
Grade: A. Reason: ready
Biodiesel Burns Significantly Cleaner than Diesel
Biodiesel is renewable, nontoxic, and biodegradable. Compared to diesel, biodiesel burns significantly cleaner. It produces fewer air pollutants like particulates, carbon monoxide, hydrocarbons, and air toxics. However, it does slightly increase emissions of nitrogen oxides.
A Fuel That Smells Like French Fries
Biodiesel produces less black smoke than regular diesel, and it smells better, too. Sometimes biodiesel exhaust smells like french fries!
A Fuel With No Sulfur
Regular diesel fuel contains sulfur. Sulfur can cause damage to the environment when it is burned in fuels. The amount of sulfur in diesel fuel is regulated by the Federal government.
When sulfur is removed from regular diesel fuel, the fuel doesn't work as well. Adding a small amount of biodiesel can fix the problem. Biodiesel has no sulfur, so it can reduce sulfur levels in the Nation's diesel fuel supply while making engines run smoother.
