There are more opinions than facts when it comes to issues around sustainability. As a scientist, engineer, and educator I cannot believe the selective referencing and hysterical pseudo-science I sometimes read in newspapers.

Take for example the opinion “articles” that appear in our newspapers from industry “experts”. A good example was the January 28, 2008 “article” in The Atlanta Journal & Constitution’s @ Issue titled “Controversial ethanol being forced on us” by Tex Pitfield where statements are made like “To make 1 gallon of ethanol, you need in excess of a gallon of fossil fuel by some estimates”. Whose estimates? What type of ethanol? Corn? Cellulosic? Sugar cane? Beet? There are lots of sources for ethanol and lots of studies. Go to Argonne National Laboratory’s publications on this at www.transportation.anl.gov/software/GREET/publications.html. It is dry reading, but you can read for yourself the very thorough reports on this matter. In a nutshell, their peer reviewed (meaning, serious science persons reviewed it and checked the numbers) Greenhouse gases, Regulated Emissions and Energy use in Transportation (GREET) model shows that cornstarch ethanol outpaces petroleum-based fuels, and that cellulose-based ethanol would do even better. But don’t take the government’s word for it. A good overview titled “Ethanol’s Energy Return on Investment: A Survey of the Literature 1990-Present” written by Roel Hammerschlag was published in the respected journal Environmental Science & Technology, Volume 40, No 6. (page 1744-1750) in 2006. The findings of six research teams were compared and except for one (Pimentel and Patzek), all studies found that ethanol produced more energy than you had to put in.

The one classical study that many ethanol nay-sayers refer to is the one from Dr. Pimentel of Cornell who in 2005 concluded that it takes more energy to make ethanol from corn than comes out. The reason for the difference is that he assumes that industrial process energy is generated by fossil fuel combustion and electricity, rather than by burning the biowaste like is commonly done in pulp and paper industry and ethanol production facilities.

Experts agree that corn is probably one of the least efficient ways to make ethanol (politicians should listen more to true experts), but the conventional wisdom/rule of thumb is that for every unit of corn based ethanol you have to put about 0.7-0.8 units into it, and sometimes a bit higher, but not more than you get out. A lot depends on how much fertilizer is used (if any) and how that is produced. And smart processes burn the waste biomass to produce heat and electricity needed for the ethanol production – using more of the plants for energy.

The Brazilians are experts in creating ethanol from sugarcane. When I visited a Brazilian sugarcane-to-ethanol factory last year, they claimed that for every unit of energy they put into producing ethanol, they got about three units of energy in the form of ethanol back. Did you know that Brazil is almost completely energy independent as a nation?

At Georgia Tech, we educate our students to research the facts and read the original sources before writing their papers. I hope readers will check the facts for themselves before believing everything that is printed. As even a fifth grader knows, opinions are not facts.