Negative Aspects of Using Ethanol
Though there is an agreement in how
much energy is produced by corn ethanol, what the disagreement seems to be
about is how much energy it takes to actually make the fuel.
The views vary.
According to USDA, there is a large energy gain from ethanol, however according to Tad
Patzek there is actually a 21% loss of energy. The energy it requires to spray the corn with pesticides,
fertilize it, run farm machinery, irrigation, grinding, transporting,
fermenting, and distilling is an enormous amount compared to how much energy
is produced.
Furthermore, the U.S. does not have enough fields to grow corn required for effective ethanol production; if all the corn in the US was converted into ethanol it would still only replace 6% of the petroleum fuel used now. Adding ethanol to fuel also decreases fuel efficiency by 20%-30%.
Requirements for Production v. Energy Yield
corn requires 29 percent more fossil energy than the fuel produced
switch grass requires 45 percent more fossil energy than the fuel produced
wood biomass requires 57 percent more fossil energy than the fuel produced.
Positive Aspects of Using Ethanol
New developments and innovations in ethanol production make ethanol still a viable source of energy. Switch grass, species of grass which grows in almost any type of soil, provides an excellent alternative to corn based ethanol. Switch grass based ethanol is about 20 times as efficient as corn-based ethanol, considering how much energy is spent on the production of corn ethanol.15 tons of switchgrass can be grown per acre planted from which about 1,500 gallons of ethanol can be obtained, compared to corn which produces about 400 gallons per acre or sugarcane which produces about 650 gallons per acre. Another benefit of switch grass is that many farmers use it to feed livestock or prevent erosion, thus the potential source of energy already exists.