Disadvantages of corn-based ethanol

Ethanol fuel seems like an environmental panacea during a time of rising concerns about green-house gases and the harmful affects of oil and gasoline on our world. However, there is much discussion going on about the true environmental, not to mention economic, benefits of using ethanol to replace gasoline. Even though there are definitely less harmful gas emissions when using ethanol fuel, this does not encompass every energy-related aspect of the alternative fuel.

A major problem that has been repeatedly argued is the energy cost of producing corn ethanol. In order to understand the full scope of using the fuel, we must take into account all aspects of corn ethanol, which includes every step in the production process. Fossil fuels are used in the production of the fertilizers and pesticides required for crop-growing, the tractors and other machinery to grow and maintain the corn crop run on diesel, and coal and natural gas are used in the final distillation processes. According to some scientists, the energy used just in the production of corn ethanol is about 75% of the energy yield from the fuel. Besides just the production vs. yield energy problem, environmentally, some argue that green-house gas emissions are decreased by only 13% (compared to gasoline fuel) after taking into account all the fuel burned in production. David Pimental of Cornell University says differently however. He found that the production energy of ethanol is actually greater than what is obtained from it: about 70% more input energy is required for ethanol.

Besides the energy cost of ethanol, the practicality of the resource is under question. The physical ability of growing corn is a central issue; whether or not there is enough physical room to sustain a fuel economy based on corn ethanol. According to Pimental, you would need 11 acres of land (for corn) to sustain 1 American car for 1 year. Another scientist, Professor Tad Patzek of UC Berkeley puts this another way, “in Brazil alone you [would] annually damage a jungle the size of Greece.” (quote)

Another disadvantage highlighted by opponents is the economic aspect of using the fuel. According to Pimental, the effective cost of ethanol fuel is $1.74 whereas the cost of gasoline is only $0.95. In 2006, the cost of E85 (an 85%: 15% mix of ethanol: gasoline) car fuel was $2.19 compared to the E10 cost of $2.06. This doesn’t translate well for consumers since a car requires about 1.4 times as much E85 as regular gasoline.

Ethanol as a fuel

Recently, the issue of alternative fuel sources has come to a forefront. This is especially true when considering fueling our cars, particularly in the face of fluctuating gas prices (in some places it neared $4/gallon!). The potential use of ethanol-based fuel instead of the conventional gasoline fuel for cars is increasingly becoming a popular option among Americans.

The interest in ethanol comes from the growing awareness that we, as consumers, are too heavily dependent on foreign oil reserves. That coupled with a growing concern for the environment has brought ethanol fuel to everyone’s attention. Ethanol is an attractive solution because it decreases greenhouse gas emissions, allows fuel to burn more completely thereby decreasing harmful residual gasoline waste, and is an abundant and renewable source.

Ethanol can be derived from high starch-concentrated foods, such as corn kernels. By fermenting the simple sugars obtained from the kernels, ethanol can be acquired. Cellulosic ethanol is derived from biomass such as waste, wood and paper pulp. The end product of cellulosic and corn-based ethanol is identical (EtOH), but the processes differ greatly. Cellulosic ethanol is obtained from the breakdown of complex carbohydrates which are then fermented into ethanol. The difference between the two concerns the energy input: output ratio of production process: corn ethanol yields only 26% more energy whereas cellulosic ethanol yields almost 80% more.

These are some sites to give you more information on the use of ethanol:

http://grist.org/news/maindish/2006/12/04/biofuels/

http://www.ucsusa.org/clean_vehicles/fuel_economy/ethanol-frequently-asked-questions.html

http://www.gate2biotech.com/green-ethanol-provides-environmental/