Biofuels
are, in short, fuels made from anything that can be grown.
As long as we can grow more plants and harvest them to make
fuel, biofuels come from renewable resources. With America's
agricultural capacity, and the ease with which the current
energy and transportation systems in the United States could
be converted, biofuels seem like a promising solution to the
oil problem. However, resources once devoted to producing
food are now being diverted to producing fuel, leading to concern
that the rise of biofuels is contributing to the global rise
in food prices.
The
environmental theory behind the use of biofuels is that they
exist on a short-term carbon cycle. Plants take in CO2 from the
atmosphere to grow, then their carbon structures are burned to
release energy. By burning the organic matter, carbon is released
back into the atmosphere. This carbon is then absorbed by other
plants, closing the loop. Petroleum based fuels pull carbon out
of the ground and release it into the atmosphere, making more
of a line.
The future of biofuels depends largely on new technology. Research
in how to produce cellulosic ethanol (ethanol from waste biomass,
i.e.: cornstalks) shows promise to separate the food and fuel
markets. Another development in the production of biodiesel is
extracting oil from algae. Algae produces a high amount of energy
in the form of oil per energy input so if large-scale algae farms
can be created without covering too many lakes and wetlands,
it is a promising source of fuel.
Ethanol
Ethanol, or ethyl alcohol, is made by fermenting
plant sugars and distilling the alcohol. Normally, ethanol intended
for use as fuel is produced from corn, wheat and barley. Ethanol
is frequently blended with petroleum-based gasoline to lower
emissions and increase engine performance. Vehicles manufactured
since 1970 should have no problem with a 10% ethanol blend (E10).
Recently, car manufacturers have been producing “flexfuel” vehicles,
which they market as guaranteed to handle up to 85% ethanol fuel
blends (E85). The increased use of ethanol is thought to have
contributed to a worldwide increase in food prices. An alternative
to food-based ethanol is cellulosic ethanol, a process still
in development that would extract sugars from organic matter
(i.e.: corn stalks, wood processing waste, switchgrasss). Cellulosic
ethanol has been produced in labs, but nobody has yet figured
out how to mass-produce it in a cost effective manner.
Biodiesel is derived not from the sugars in
plants, but from the oils. In fact, diesel engines were
first invented to run on peanut and other plant oils that were
abundant before the discovery of petroleum. Biodiesel is produced
by reacting vegetable oil with an alcohol (usually methanol)
and a catalyst. This process lowers the viscosity of pure vegetable
oil to that of petro-diesel. A similar reaction can make biodiesel
from the animal fats leftover from meat processing. Especially
in Europe, biodiesel is now being used as an additive to regular
diesel in order to meet environmental standards. Like ethanol,
the amount of biodiesel in a fuel blend is noted by the letter
B then the percent of the fuel that is in the mix, so pure biodiesel
is B100 and a 10% mix is B10.
Waste Vegetable Oil is what runs our bus. Pure
vegetable oil is purchased by restaurants to fry things like
french fries in. After they use it, it usually goes in a dumpster
behind the restaurant where, with permission from the owner,
it may be collected for free. Using waste vegetable oil as fuel
is one way to recycle the grease (other uses for waste vegetable
oil include dog food and cosmetics). In order to use WVO as a
fuel, the bits of food must be filtered out, then the oil is
heated (usually by the coolant in the engine) in order to be
less viscous. WVO conversion kits are available to convert the
fuel systems of diesel engines to run WVO.
As the use of biodiesel and WVO conversions on diesel cars,
trucks and busses become more popular, restaurants have started
selling their waste vegetable oil; what was once a waste product
is now a commodity. In some parts of the country, cities, companies
or cooperatives have contracts with local businesses to collect
their waste grease and use it to produce fuel. Filtered vegetable
oil can be used as the feedstock for biodiesel as well as a fuel
on its own.
The last form of biofuel is biomass. Biomass
is any type of plant matter that is used to make electricity,
heat or to power a machine. Putting a log on a fire is a form
of using biomass as fuel. This can be done on a larger scale
by burning farm waste to make electricity. Biomass is not a likely
solution for transportation, as the energy-per-unit-volume of
most plants is too low to be practical.
