Biodiesel
Fuel
See
also:
other
readings with assessment in Alternative Energy -- Wind
Energy -- Geothermal Energy -- Hydropower -- Nuclear Energy
--
see
Alternative Energy Basics
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BIODIESEL MADE FROM VEGETABLE OILS AND ANIMAL FATS
Biodiesel is
a renewable fuel that can be used instead of diesel fuel made from
petroleum. Biodioesel 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 percent
(B2), 5 percent (B5), or 20 percent (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.
Fueling engines
with biodiesel has just started to catch on, but this isn't a new
idea. Before petroleum diesel fuel became popular, Rudolf Diesel,
the designer of the diesel engine, experimented with using vegetable
oil (biodiesel) as fuel.
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.
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 owner fueling
stations. As the number of public fueling stations that offer biodiesel
grows, it may become more popular with individual consumers.
B100 and biodiesel
blends are sensitive to cold weather and may require special 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.
BIODIESEL
AND THE ENVIRONMENT
Biodiesel is
renewable, nontoxic, and biodegradable. Compared to diesel, biodiesel,
is significantly cleaner burning. It produces fewer air pollutants,
like particulates, carbon monoxide, hydrocarbons, and air toxics.
It does slightly increase emissions of nitrogen oxides, though.
Biodiesel produces less black smoke, and smells better, too. Sometimes
biodiesel smells like french fries!
Regular diesel
fuel contains sulfur. Sulfur can cause damage to the environment
when it is burned in fuels. New environmental laws will require
the amount of sulfur in diesel fuel to be dramatically reduced over
the next few years. 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
more smoothly.
Last
reviewed: October 2007
Sources: The National Energy Education Development Project, Alternative
Fuels: What Car Will You Drive?, 2004.
U.S. Department of Energy, Energy Efficiency and Renewable Energy,
Alternative Fuels Data Center, October 2004.
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