What are biofuels and how much do we use?
Targets for Renewable Fuels Usage as Established by the Energy
Independence and Security Act of 2007
Year |
Total Renewable
Fuels Standard
(billion credit gallons) |
2008 |
9.00 |
2009 |
11.10 |
2010 |
12.95 |
2011 |
13.95 |
2012 |
15.20 |
2013 |
16.55 |
2014 |
18.15 |
2015 |
20.50 |
2016 |
22.25 |
2017 |
24.00 |
2018 |
26.00 |
2019 |
28.00 |
2020 |
30.00 |
2021 |
33.00 |
2022 |
36.00 |
|
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Henry Ford’s original automobile, the Model T, had an engine
capable of running on either gasoline or ethanol.
|
Biofuels are liquid fuels produced from biomass materials and
are used primarily for transportation 1.
The term biofuels most commonly refers to ethanol and biodiesel.
In 2007, the United States consumed 6.8 billion gallons of
ethanol and 491 million gallons of biodiesel. By comparison,
2007 consumption of motor gasoline and diesel (not inclusive of
biofuels) was 139 billion gallons and 39 billion gallons,
respectively.
Biofuels are made by converting various
forms of biomass such as corn or animal fat into liquid fuels and
can be used as replacements or additives for gasoline or diesel.
Biofuels generally have lower life-cycle carbon dioxide emissions
than do their fossil fuel counterparts. In recent years, several
new Federal laws designed to increase the production and
consumption of domestic biofuels have been enacted. The Energy
Policy Act of 2005 established the Renewable Fuel Standard, which
mandated that transportation fuels sold in the United States
contain a minimum volume of renewable fuels2,
the level of which increases yearly until 2022. In December 2007,
the Energy Independence and Security Act of 2007 increased the
mandatory levels of renewable fuel blending credits to a total of
36 billion gallons by 2022, including 16 million gallons of
cellulosic biofuels3.
What Is Ethanol?
Ethanol is a clear, colorless alcohol—the
same as is found in alcoholic beverages. In fact, ethanol is
produced when yeast ferments sugar in a process similar to that used
to produce beer. Ethanol can be made from the starches or sugars
found in various agricultural crops, such as corn, barley, and sugar
cane, or from cellulosic residues from woody biomass, such as bark
or switchgrass. Cellulosic ethanol is considered an “advanced”
biofuel and involves a more complicated production process than
conventional ethanol made from starches or sugars; however, its
commercial viability has yet to be demonstrated4.
How Is Ethanol Used?
Prior to the passage of the Energy Policy
Act of 2005, gasoline sold in certain geographic areas was required
to contain oxygen, which helps the fuel mixture combust more
completely. Originally, a chemical called methyl tertiary butyl
ether (MTBE) was the preferred oxygenate, but it was phased out due
to concerns about seepage into groundwater and ethanol was mandated
as a replacement. The usage of ethanol also gained market share due
to the Renewable Fuel Standard requirements of the Energy Policy Act
of 2005. Today, a little more than half of the gasoline in the
United States has some amount of ethanol blended into it, and these
blends are named by their ethanol content: for example, a blend of
90% gasoline and 10% ethanol (by volume) is known as E10. However,
because ethanol contains approximately 67% the energy content of
gasoline per gallon, usage of ethanol blends results in decreased
gas mileage. Despite this reduced gas mileage, high crude oil prices
and government incentives have resulted in the consumption of
increasing amounts of ethanol. |
While almost any regular gasoline car can run on
blends of ethanol up to E10, special cars known as “flex-fuel” vehicles are
required for use of blends above E10. Flex-fueled vehicles are currently
available from every major American automobile manufacturer and are almost
identical to regular gasoline vehicles, except for a few modifications to
the fuel system and minor engine components. On a mass production basis, it
costs less than $200 extra per car to make a flex-fuel automobile compared
with a conventional gasoline vehicle. As of August 2008, more than 1,400 of
a total of 170,000 gas stations in the United States are offering E85 to the
public5.
Ethanol is expected to play a major role in helping to reach the annual
minimum renewable fuel consumption required by the Renewable Fuel Standard.
What Is Biodiesel?
Biodiesel consists of chemicals known as fatty
acid methyl esters (FAME) that can be used as a diesel fuel substitute or
diesel fuel additive. Biodiesel is typically made from oils produced from
agricultural crops such as soybeans or canola but can also be made from
various other feedstocks such as animal fats.
Currently, most biodiesel in the United States is
produced from soybean oil, but recent increases in soybean crop prices have
caused producers to switch to other feedstocks such as waste animal fats
from processing plants or recycled grease from restaurants. Biodiesel can be
made from virtually any feedstock that contains an adequate amount of free
fatty acids, which are the raw materials that are converted to biodiesel
through a chemical process. Research is underway to harvest algae for
biodiesel production because they contain fat pockets that help them float,
and this fat can be collected and processed into biodiesel. Continued
biodiesel production and usage will help the United States meet levels of
biofuels consumption mandated by the Renewable Fuel Standard.
In addition to biodiesel derived from FAME, it is
also possible to make a diesel fuel substitute from cellulosic material.
This fuel, sometimes called renewable diesel, would also count towards
meeting the Renewable Fuel Standard mandate. Like cellulosic ethanol,
however, its commercial viability has yet to be demonstrated.
How Is Biodiesel Used?
Biodiesel has chemical characteristics much like
petroleum-based diesel and, therefore, can be used as a direct substitute
for diesel fuel or blended with petroleum diesel in any percentage without
suffering any significant loss of fuel economy6.
Blends are named in the same manner as ethanol-gasoline blends, for example,
a blend of 20% biodiesel with 80% petroleum diesel is known as B20. Low
level, i.e., B2-B5, biodiesel blends are a popular fuel in the trucking
industry because biodiesel has excellent lubricating properties, and
therefore usage of the blends can be beneficial for engine performance.
Biodiesel also has virtually no sulfur content, making it a popular additive
for low- and ultra-low-sulfur diesel fuels required by the Environmental
Protection Agency7.
How Much Do We Consume?
In 2007, the United States consumed 6.8 billion
gallons of ethanol and 491 million gallons of biodiesel. According to EIA’s
Annual Energy Outlook 2008, ethanol usage is predicted to increase
to nearly 24 billion gallons in 2030, which would represent approximately
16% of total gasoline consumption by volume in 2030. Thirty-one percent of
corn production in 2008 is projected to be used for ethanol, and this
percentage is expected to rise to 36 percent by 20308.
Biodiesel consumption is predicted to increase to 1.2 billion gallons by
2030, or approximately 1.5% of total diesel consumption. Consumption of
renewable diesel, made from cellulosic materials, is expected to
substantially exceed biodiesel consumption by 2030.
1Biomass
is defined as organic nonfossil material of biological origin constituting a
renewable energy source.
2Eligible renewable fuels include ethanol,
biodiesel, renewable diesel, and biomass-to-liquids.
3Note: A gallon of biofuel with greater
energy content per gallon than ethanol would count as more than one ethanol
gallon equivalent. For example, each gallon of biodiesel counts as 1.5
gallons toward the advanced and total biofuels requirements.
4According to the Energy Independence and
Security Act of 2007, an advanced biofuel is a renewable fuel (other than
ethanol from corn starch) that is derived from renewable biomass and
achieves greenhouse gas emissions reductions of 50 percent.
5Department of Energy Office of Energy
Efficiency and Renewable Energy’s Alternative Fuel Data Center,
(accessed August 21,
2008).
6Some alterations may need to be made to
older engines in order to run on blends with high percentages of biodiesel.
Also, higher blends of biodiesel do have temperature-related issues such as
the tendency to coagulate at higher temperatures than petroleum diesel.
7Regulations limiting the sulfur content of
on-road diesel fuel to 15 parts per million became effective in 2006. Diesel
fuel meeting the 15-parts-er-million requirement is known as
“ultra-low-sulfur diesel.” Diesel fuel meeting the previous highway standard
of 500 parts per million is known as “low-sulfur diesel.” The lubricity of
diesel fuel has generally been reduced due to the processes used to reduce
sulfur and aromatic compounds in the fuel ().
8Energy Information Administration,
Annual Energy Outlook 2008 (March 2008).
http://tonto.eia.doe.gov/energy_in_brief/biofuels_use.cfm |