Question

Discuss ethanol as a transportation fuel.

Identify at least three advantages and three disadvantages of its use.

Assess the government’s policy regarding ethanol and make a recommendation as to whether you feel use of ethanol is a feasible approach to decreasing the amount of oil used to power vehicles.

Answer 1

Pros
Greenhouse Gas Reduction - Corn-based ethanol reduces GHG emissions by 18% to 29% per vehicle mile traveled compared to petroleum-based fuels.

Positive Net Energy Balance - Corn-based ethanol has a positive net energy balance of 1.06btu per gallon for 1.00btu of energy used without ethanol by-product credits. With these credits, for things such as DDGS, corn-based ethanol has a positive net energy balance of 1.67btu per gallon for 1.00btu of energy used.

Biodegradable - As ethanol is made with organic materials it is highly biodegradable making spills far less worrysome than petroleum spills. When spilled, 74% of ethanol is broken down within 5 days.

Cons
Food vs. Fuel - 2.4 to 2.8 gallons of ethanol can be produced per bushel of corn. As a result, there has been massive media coverage over the use of food as fuel. While there are mountains of findings showing how the use of corn has increased food costs and equal amounts showing it does not, in the end food crops are being used as fuel, making corn-based ethanol inferior to cellulosic ethanol in this regard.

Fuel Transportation - Ethanol absorbs water and is corrosive, which make it difficult to ship through existing pipelines from the Midwest of the U.S., where most production occurs. Remedies include shipping or building dedicated ethanol pipelines, however the most likely scenario seems to involve rail or road transport. The best scenario would be local ethanol plants, with the easiest way to accomplish this through continued development of cellulosic ethanol, where feedstocks are abundant everywhere as opposed to corn or sugar.

Water Absorbtion - Ethanol absorbs water, which can contaminate it as a fuel and makes it more difficult to ship through pipelines. As a result, ethanol has a shorter shelf and tank life than gasoline.