ethanol fuels

Clearly the most successful renewable biofuel to date has been ethanol. Ethanol is basically grain alcohol, the same type of alcohol that is used in corn whiskey. Ethanol can be made from corn, sugar cane, and several other types of plants.  One bushel of corn can be used to produce 2.5 gallons of ethanol and 10 bushels of corn are roughly equivalent to a barrel of crude oil.  Ethanol is becoming increasingly used as a fuel additive and in many parts of the mid-west is supported by state legislation mandating its use as a fuel additive. There has been a significant rise in the number of refineries that manufacture ethanol with over 100 refineries now in operation.

Ethanol is added to many gasolines at low percentages.  About 46% of all gasolines contain some percentage of ethanol. The most common blend is 90% gasoline to 10% ethanol (E-10).  This mixture can be used in about any type of vehicle sold in the U.S. that is designed to run on gasoline.  It is possible to create a mixture that is 85% ethanol and only 15% gasoline.  This type of  blend is referred to as E-85.  However, most cars require significant modification before they can use this type of fuel. Currently the ethanol industry is putting considerable pressure on automotive manufacturers to produce cars (referred to as flexible-fuel vehicles) that can run E-85 but so far there has been relatively little attempt so far by the automobile industry to adapt to it. 

One of the major advantages of ethanol is that it is a somewhat cleaner fuel than gasoline when it comes to hydrocarbon emissions. According to the EPA ethanol blends have the potential to reduce carbon monoxide emissions in vehicles by between 10% - 30%, depending upon the combustion technology without reducing performance. It also has lower greenhouse emissions.  One reason that ethanol tends to burn cleaner is that it has a higher level of oxygen in it than gasoline (about 35%). 

Ethanol also has a fair share of critics because ethanol has very low net energy.  For many years it actually took more energy to distill ethanol than the fuel produced.  In recent years new manufacturing techniques have led to greater efficiency to the point that ethanol production is net positive but the overall efficiency is still very low, about 1.34 units of energy for every unit used in its manufacture.

Another controversy that has sprung up surrounding ethanol has been the food versus fuel controversy.  As the number of ethanol manufacturing plants has increased the demand in the U.S. for corn has increased leading to corn prices that are at all time highs.  This has led to concerns that using corn for fuel instead of food may lead to food shortages in some parts of world where corn and corn meal are often shipped to address hunger in 3rd world countries. 

There is considerable research going on right now to see if ethanol production can be made more efficient.  Some of this research is sponsored by state governments in crop producing states and some is supported by the federal government.  Ethanol has been one of the areas of focus of the current administration.  The U.S. Department of Energy laboratory called the National Renewable Energy Laboratory (NREL) is one of the leaders of research on ethanol.  One of the areas they are researching is whether or not crop byproducts rather than crops themselves can be used to create ethanol.  For example, they are researching whether or not organic materials such as corn stalks or corn cobs can be used for fuel instead of the corn itself.  It is too early to say if this research will pan out but if it does this could allow ethanol to bypass the current food vs. fuel debate because the source material is a waste product not a food product.

The economics of ethanol are still in flux.  Ethanol production costs about twice as much as gasoline.  The price differential between ethanol and gasoline has improved somewhat with the rising price of crude oil and therefore gasoline.  At the same time corn prices have also  increased so it is hard to say if ethanol will become more price competitive. 

In other parts of the world the economics of ethanol are much stronger than they are in the U.S.  Brazil has made huge progress in using ethanol as a byproduct of its sugar cane industry. In Brazil flex-fuel cars are extremely common and almost 50%  are able to use 100% ethanol as fuel. One reason ethanol is so popular in Brazil is that sugar cane has a much higher concentration of sucrose than core (about 30% more) and it is much easier to extract.  As a result the production process for creating ethanol is simpler and cheaper.  Brazil also uses ethanol for electricity production, not just automobile fuel.