Ethanol / E85
Ethanol is ethyl alcohol, and
is often referred to as grain alcohol. E85 is a blend of 85
percent ethanol and 15 percent gasoline. Ethanol is usually
made from grain, just as moonshine is, though research into
making commercial quantities of ethanol
from plants (cellulosic);
a complex process that uses plant matter such as switch grass
as a base feedstock. A gallon of E85 has an energy content
of about 80,000 BTU, compared to gasoline's 124,800 BTU, so
you would need approximately 1.56 gallons of E85 to travel
the same distance as you could on 1 gallon of gasoline.
PROS: Ethanol is an excellent, clean-burning fuel, potentially providing more horsepower than gasoline with a higher octane rating (over 100) and a cooler burn temperature than gasoline. A lesser blend of ethanol (E10 / E15) is added to about 30 percent of the gasoline sold in the States to meet EPA requirements for oxygenated fuels in metropolitan areas with the country's worst ozone air pollution. Compressed Natural gas powered vehicles are able to start on most any temperature condition and don’t require any warm up time before driving.
According to the National Ethanol Vehicle Coalition (NEVC), E85 currently is available in 36 states. The Environmental Protection Agency (EPA) lists 34 models of flex-fuel
vehicles (FFV)--cars and trucks that can burn pure gasoline, E85, or any blend of gas/ethanol in between--available in the 2006 model year. The NEVC estimates that 6 million FFVs have been sold in the States to date. Almost any car is capable or burning E10 or E15 ethanol blended gasoline without
The performance of E85 vehicles has the potential to be higher
than that of gasoline powered vehicles due to E85's higher octane
rating. This allows a much higher compression ratio, which translates
into higher thermodynamic efficiency. However, FFVs that retain
the capacity to run on gasoline alone can't really take advantage
of this octane boost since they also have to be able to run on
pure, pump-grade gasoline.
Growing corn is an intensive process that requires pesticides, fertilizer, heavy equipment and transport. When considering the viability of ethanol, the total impact of all that activity needs to be taken into account. Cynics claim that it takes more energy to grow
corn and distill it into alcohol than you can get out of the alcohol. However, according to the DOE, the growing, fermenting and distillation chain actually results in a surplus of energy that ranges from 34 to 66 percent. Moreover, the carbon dioxide (CO2) that an engine produces started out as atmospheric CO2 that the cornstalk captured during growth; this contributes to making ethanol greenhouse gas neutral. Recent DOE studies note that using ethanol in blends substantially lowers carbon monoxide (CO) and CO2 emissions. In 2005, burning such blends had the same effect on greenhouse gas emissions as removing 1 million petroleum fuel burning cars from American roads.
CONS: Alcohol is a corrosive solvent; anything exposed to ethanol must be made of corrosion-resistant materials. These materials can be expensive stainless steel or cheaper plastics, and include fuel-injection components to tanks, pumps and hoses that dispense E85, as well as the tankers that deliver it. Another issue is that alcohol based fuel isn't volatile enough to get a cool engine started on cold days, so a gasoline blend of 85 percent ethanol was born.
Outlook: According to the Renewable Fuels Association, 95 ethanol refineries produced more than 4.3 billion gallons of ethanol in 2005. An additional 40 new or expanded refineries slated to come on line in 2007 will increase that to 6.3 billion gallons While that may sound like a lot, it represents a mere 3 percent of our annual consumption of more than 200 billion gallons of gasoline and diesel.
A single acre of corn has the potential to produce 300 gallons of ethanol per growing season. So, in order to replace a small percentage of petroleum product usage, American farmers would need to dedicate more than 675 million acres, (over 70 percent) of the nation's 938 million acres of farmland, to growing feedstock. Clearly, we will need additional, renewable resources in order to displace our fossil fuel dependence.