United States
Environmental Protection
Agency
Transportation and Air Quality
Transportation and Regional
Programs Division
EPA420-F-00-032
March 2002
www.epa.gov
SUCCESS STOfty
The Deer Valley School
District in Phoenix, Arizona,
began using biodiesel in 1999
following a state mandate that
school districts use alternative
fuel vehicles to curb air pollu-
tion. In a total fleet of 250 vehi-
cles, 140 school buses and 5
maintenance trucks run on
biodiesel. These vehicles will
travel 2.5 million miles annually
in Deer Valley.
The buses use a B20 blend
of biodiesel mixed on site by
school district staff; the other
vehicles run on B100. Vehicles
run on both reused oil and vir-
gin biodiesel, depending on
suppliers and availability, with
no apparent differences in per-
formance. While the school dis-
trict spends more money on
fuel, its alternative fuels pro-
gram receives state grant money.
The district also encourages sur-
rounding school districts to use
biodiesel so they can order bulk
quantities at a reduced price.
A blind pilot study in Deer
Valley revealed that school bus
drivers noticed performance
increases with biodiesel. They
were baffled, however, by what
they perceived as the smell of
hot dogs throughout the day—
apparently from biodiesel made
from used cooking grease.
For more information, call
Bill Kohn at (602) 467-5072.
Clean
Fuels:
Biodiesel
One in a series of fact sheets
In 1895, Dr. Rudolf Diesel developed the "diesel" engine with the inten-
tion of running it on a variety of fuels, including vegetable oil. In fact,
when Diesel demonstrated his engine at the World Exhibition in Paris in
1900, he used peanut oil as fuel. Since that time, however, the diesel engine
has been modified to run on petroleum-derived fuel (petrodiesel) because his-
torically it was the least expensive fuel available.
Today, the diesel engine is still capable of
running on "biodiesel" fuel, which can be
produced from a variety of renewable
sources, including soybean oil, canola oil,
sunflower oil, cottonseed oil, and animal
fats. These sources can be obtained from
agricultural feedstocks or by recycling
used oil such as cooking grease. Most
biodiesel produced in the United States is
made from soybean oil due to this feed-
stock's abundance.
Biodiesel is usable in its pure form,
known as "neat biodiesel" or B100. In
addition, it is available in various blends
with petrodiesel, the most common of
which is known as B20 (20 percent
biodiesel and 80 percent petrodiesel). It is
also used in smaller percentages as a lubri-
cating fuel additive.
AVAILABILITY
The biodiesel industry is continually
expanding. In 1996, only 2 companies
were registered as biodiesel suppliers; in
1999, that figure had climbed to 13.
Together, these companies have invested
millions of dollars in developing biodiesel
manufacturing plants. In addition, two
major U.S. vehicle manufacturers have
begun biodiesel research initiatives.
Biodiesel is one of the only alternative
fuels usable in any conventional diesel
engine with little or no modification to the
engine or fuel system. More than 40 federal
and state fleets are already using biodiesel
blends in their existing diesel engines.
EMISSIONS
CHARACTERISTI
Actual emissions will vary with
engine design; these numbers reflect
the potential reductions offered by a
biodiesel blend (B20) and pure biodiesel
(B100), relative to conventional diesel.
• Reductions in carbon monoxide emis-
sions of 10 percent (B20) and 50 per-
cent (B100).
• Reductions in particulate emissions of
15 percent (B20) and 70 percent
(B100).
Reductions in total hydrocarbon emis-
sions of 10 percent (B20) and 40 per-
cent (B100).
Reductions in sulfate emissions of 20
percent (B20) and 100 percent (B100).
• Increases in nitrogen oxide emissions of
2 percent (B20) and 9 percent (B100).
• No change in methane emissions using
either B20 or B100.
* Estimates based on biodiesel's inherently
"cleaner" chemical properties with an engine
that takes full advantage of these fuel properties.
-------
To encourage its use, most major
diesel engine manufacturers have
affirmed that using B20 in their
equipment will not void their war-
ranties. Although B100 is also usable
in any diesel engine, its use might
void warranties.
According to the National
Biodiesel Board (NBB), biodiesel can
be made available in every state, even
if no fueling stations exist. Suppliers
can deliver fuel anywhere in the
country, either in pure or blended
form. Farmers often order biodiesel
through cooperatives. A list of fuel
marketers can be obtained by con-
tacting NBB.
AFFORDABILITY
B100 can be purchased for $1.95 to
$3 per gallon, depending on the
feedstock and the supplier. In gener-
al, B20 costs 30 to 40 cents more per
gallon than conventional diesel.
Although biodiesel costs more than
petrodiesel, fleet managers can make
the switch to alternative fuels with-
out purchasing new vehicles, acquir-
ing new spare parts inventories,
rebuilding refueling stations, or hir-
ing new mechanics. In addition, buy-
ing biodiesel in bulk quantities
decreases the fuel's cost.
PERFORMANCE
Biodiesel maintains the same payload
capacity and range as conventional
diesel, and provides similar horse-
power, torque, and fuel economy.
Biodiesel has a higher cetane number
than conventional diesel, which
increases the engine's performance. It
also serves as a high-quality lubricant
and can enhance the life of heavy-
duty engines.
Biodiesel vehicles can have cold
start problems relative to petrodiesel,
but this is more of an issue for B100
than B20 fuels. For example, B20
freezes at temperatures 3°F to 5°F
higher than petrodiesel, but it has
been used in upper Wisconsin and
Iowa during -25°F weather with no
reported problems. B100 will begin
to freeze at 25°F, however. Vehicle
owners can solve cold start problems
with biodiesel in the same manner as
with conventionally fueled vehicles
(e.g., using engine block or fuel filter
heaters or storing the vehicles near or
in a building).
SAFETY
Biodiesel is biodegradable, which
means it dissipates quickly after a
spill. Biodiesel has a high flashpoint
and low volatility so it does not ignite
as easily as petrodiesel, which increas-
es the margin of safety in fuel han-
dling. In fact, it degrades four times
faster than petrodiesel and is not par-
ticularly soluble in water. It is nontox-
ic, which makes it safe to handle,
transport, and store. When blended
with petrodiesel, the spill's petrodiesel
portion is still a problem, but less so
than with 100 percent petrodiesel. As
with all vehicles, adequate training is
recommended to operate and main-
tain biodiesel vehicles.
MAINTENANCE
Maintenance requirements for B20
vehicles and petrodiesel vehicles are
the same. B100 does pose a few con-
cerns, however. Biodiesel acts as a sol-
vent to some fuel system components
and concrete-lined tanks. This effect
can release deposits accumulated on
tank walls and pipes from previous
diesel fuel storage, initially causing
fuel filter clogs. As a result, vehicle
owners should change the fuel filter
after the first tank of fuel.
In addition, biodiesel will soften
and degrade certain types of elas-
tomers and natural rubber com-
pounds over time, which can impact
fuel system components such as fuel
hoses and fuel pump seals. This is less
of a concern with biodiesel blends
than with B100. Manufacturers rec-
ommend replacing these parts with
compatible elastomers. Some newer
vehicles have biodiesel-compatible
components, but users should con-
tact their vehicle manufacturers for
specific information.
For More Information
EPA Alternative Fuels Web Site
www.epa.gov/otaq/consumer/
fuels/altfuels/altfuels.htm
National Biodiesel Board
1907 Williams Street, Suite B
P.O. Box 104898
Jefferson City, MO 65110-4898
Phone: 573 635-3893 or
800 841-5849
Fax: 573 635-7913
E-mail: biodiesel@socket.net
Web site: www.biodiesel.org
Alternative Fuels Data Center
Web site: www.afdc.nrel.gov
National Alternative Fuels
Hotline
Phone: 800 423-1 DOE
Printed on paper that contains at least 30 percent postconsumer fiber.
------- |