Fueling vehicles with ethanol is not a new concept by any means. In fact, before gasoline became readily available, early auto makers suspected that ethanol would be the fuel that would power their vehicles.
We all know that didn't turn out to be the case. But that vision of ethanol-fueled transportation still has some life in it. Many researchers agree that converting to ethanol could substantially offset the use of petroleum fuels – and the harms that can come from those fuels.
What Is Ethanol?
Ethanol (CH3CH2OH), is created by breaking down the sugars and starches in plant matter and having it undergo a fermentation process. The resulting product is a clear and odorless liquid alcohol. It happens to be the very same alcohol found in alcoholic beverages, but it also functions as an excellent renewable fuel when it is derived from plant biomass.
Ethanol is widespread in the United States, which produces approximately 15 billion gallons of fuel ethanol each year (primarily from corn). According to the United States Department of Energy, approximately 95% of U.S. gasoline contains a low-level blend of ethanol known as gasohol.
The Ethanol Fuel Market
Ethanol as an alternative motor vehicle fuel is available in two forms:
- E100 (nearly 100% ethanol)
- E85 (a mixture of 85% ethanol and 15% gasoline)
To promote and encourage the use of ethanol as an alternative fuel, the United States government has subsidized ethanol use by partly exempting gasohol from gasoline taxes.
Advantages of Ethanol as an Alternative Fuel
- It is in liquid form, making it more suitable to replace other liquid fuels
- E85 reduces carbon dioxide emissions
- E100 reduces the reactivity of organic emissions
- Lower emissions of pollutants
- Organic emissions, such as ozone precursors, have a lower reactivity than gasoline
- It can be produced from domestic sources, requiring fewer imports, reduced transportation, and minimal pipeline infrastructure
- Allows the engine to run effectively lean since the air-fuel mixture would contain more oxygen atoms
- The availability of oxygen facilitates the combustion of carbon monoxide into carbon dioxide
(Learn more about Carbon Monoxide: The Silent Killer)
Disadvantages of Switching to Ethanol Fuel
- It is currently costlier than gasoline
- If produced strictly from corn, supply would be limited
- It is less fuel efficient than gasoline
- It increases emissions of nitrogen oxides
- E100 is associated engine cold start problems, which can increase carbon monoxide emissions
- E85 has a higher volatility than gasoline, resulting in a net increase in VOC emission, which then negatively impacts upon ozone levels
The Economics of Ethanol Compared to Gasoline
Ethanol Facts: Environment
- Ethanol is a highly effective tool in the fight to reduce motor vehicle air pollution
- Ethanol contains 35% oxygen, resulting in a more complete combustion and a reduction in tailpipe emissions
- Ethanol displaces the use of carcinogenic BTEX toxins found in gasoline
- Ethanol is non-toxic, water soluble, and quickly biodegradable
- Ethanol is a renewable fuel produced from plants, meaning its supply is essentially unlimited
Ethanol Facts: Health and Safety
- Ethanol mixed with gasoline releases other potentially harmful components into the air, such as peroxyacetyl nitrate, formaldehyde, and acetaldehyde
- Ethanol mixtures have been found to irritate the eyes, nose, skin, and respiratory system
- Exposure to vapors released during the mixing process can cause dizziness, nausea, loss of consciousness, or death
The Verdict?
While there have been various social, economic, environmental, and technical concerns surrounding the production and use of fuel ethanol, no one can dispute the fact that ethanol fuel is overall better for health and safety than traditional petroleum fuels.
Still not convinced? Well, consider this. Using ethanol in place of gasoline helps to reduce carbon dioxide emissions by an average of 34 percent. 13.3 billion gallons of ethanol produced reduced greenhouse gas emissions from on-road vehicles by 38 million metric tons in 2013, which is equivalent to removing 8 million cars from the road!
New technologies are increasing ethanol yields. Therefore, efficiencies are also being improved, allowing ethanol biorefineries to make better use of natural resources.