Is ethanol just a process to recycle existing energy?

Posted on 06/16/2009 at 12:00 AM by Christa Hartsook

Blog entry written by Don Hofstrand, Co-director, Agricultural Marketing Resource Center, Iowa State University Extension, dhof@iastate.edu 

I was in West Virginia last week, working on a business project, and a colleague asked, “Is it true that it takes more energy to make ethanol than is contained in the ethanol?”  In Dallas, Texas, a couple of months earlier, I got the same question. The question pops up enough that you get the impression that the general public believes it is true. 

Let’s look at some of the issues surrounding this topic. 

First of all, let’s define what we talking about.  Yes, it is true, that it takes more energy to make ethanol than is contained in the ethanol.  This is a law of nature.  We can no more create new energy where it did not exist previously than we can create a new car out of thin air. However, in the case of ethanol, sunlight is the major energy source that is converted to making corn through photosynthesis. The relevant question is, “Does it take more fossil fuel energy to make ethanol than the energy contained in ethanol?" 

Various studies have been conducted on the topic with a range of answers, as you would expect.  A midpoint of this range is that ethanol produces about 30 percent more energy than the fossil fuel energy used in making ethanol.  However, we have additional research that sheds light on this question.  It is explored in the article titled, Efficiency and Environmental Improvements of Corn Ethanol Production, in the upcoming July issue of the AgMRC Renewable Energy Newsletter.

How does this compare to other types of energy we use in our daily lives.  Gasoline takes about 20 percent more fossil fuel energy to make gasoline than is contained in the gasoline. To start with, gasoline is made from a fossil fuel (crude oil.)  Then it must be pumped, transported and refined, all of which rely on fossil fuel energy.  Another example is electricity, which takes more than twice as much fossil fuel energy to make electricity than is contained in the electricity. This is easy to understand when we realize that the major source for making electricity is by burning coal.  Natural gas is another major energy source for making electricity. The advantage of this system is that electricity is a convenient way of utilizing energy in our homes (it’s hard to find a coal-fired toaster.) However, when we consider electricity as a substitute for gasoline and ethanol, then the energy balance issue becomes a relevant question (use of plug-in hybrids.)

Ethanol production is an emerging industry.  As the industry matures, new technologies will be enlisted to improve the efficiency of the industry.  Also, because ethanol is essentially a manufacturing industry, utilizing alternative feedstocks (including cellulosic) will result in improved efficiencies.  Potential technological advancements for the corn-ethanol industry are explored in the article titled, Efficiency and Environmental Improvements of Corn Ethanol Production, in the upcoming July issue of the AgMRC Renewable Energy Newsletter.

As ethanol production efficiencies are improving, we can expect the net energy balance of energy sources associated with crude oil to deteriorate. Petroleum is essentially a mining industry. As sources of crude oil become more difficult to recover and lower petroleum quality requires more refining, the amount of fossil fuel energy required to make gasoline will increase. So, the difference in net energy balanced between ethanol and gasoline is expected to widen significantly because the two are going in different directions.

The fossil fuels used in producing ethanol include more than just diesel fuel and gasoline. A large portion of the fossil fuel is in the form of natural gas used to power the ethanol plant and to make nitrogen fertilizer. Electricity for drying the corn and running the ethanol plant is another significant energy source. As we indicated above, most of the electricity is made from either coal or natural gas.  Actually, relatively little gasoline and diesel fuel are used in the ethanol process, or in producing its feedstock corn. 

So, if our goal is to reduce our dependence on foreign crude oil sources, ethanol is a very good alternative because ethanol yields about ten times more energy than is contained in the gasoline and diesel fuel used to make the ethanol (ethanol to petroleum ratio).  Once again, current research is outlined in the article titled, Efficiency and Environmental Improvements of Corn Ethanol Production, in the upcoming July issue of the AgMRC Renewable Energy Newsletter.

So, does ethanol deserve the bad wrap it has been receiving in the media?  Has the general public been getting half-truths and mis-truths about ethanol’s net energy balance?  Let me know what you think.  I welcome you to discuss other perspectives that should see the “light of day” on this issue.

Categories: Renewable Energy