New studies published this week cast heavy doubt on ethanol’s value as a potential solution to global warming. Writing in Science, Timothy Searchinger and colleagues find that in their worldwide agricultural model, corn-based ethanol, “instead of producing a 20% savings, nearly doubles greenhouse emissions over 30 years and increases greenhouse gases for 167 years.” While ethanol combustion is cleaner than gasoline, carbon savings are more than washed out by the corn farming done on the front end to produce the biofuel.
Applied to the full range of alternative energy sources, this net assessment approach yields further insight. The figure below, published in the November 2007 issue of the British journal The Ecologist charts the net energy return for each source, taking into account the front-end energy inputs needed for power generation.
Ethanol fares poorly here, too, returning just 2.2 units of energy for each unit of energy invested in production of the biofuel, a ratio better only than tar sands. On the other end of the spectrum, tidal ranges (87.4), sewage and landfill gas (40) and offshore wind (35.1) produced the most favorable ratios of energy return on energy invested. The full data tables can be accessed here.
Searchinger’s research is causing turbulence on Capitol Hill, where Congress just passed an energy bill that mandated a more-than-fourfold increase in production of biofuels annually by 2022.
6 Comments | 
47. February 13th, 2008 Anon wrote:
Ethanol has often been referred to as a solution to global warming. I have never believed it to be as promising as people predict. In addition to net energy results for ethanol, I would like to hear more about the possibility of harmful side products of ethanol production. Also, from what I understand, engines that utilize ethanol as a primary source of fuel require twenty five percent more fuel per mile than conventional engines. There appear to be multiple drawbacks to the ethanol solution.
63. February 16th, 2008 Dina wrote:
Using corn as a key precursor to fuel is, as we are coming to see, is a fruitless endeavor. For one, it generally requires somewhere around 50 gallons of oil to make one bushel of industrial corn, a process which negates the positive outcomes that could possibly be yielded by using ethanol. Perhaps more perplexingly, there are currently billions of bushels of unused corn in America right now as a result of Earl Butz doing away with New Deal loan payments to farmers, replacing them with direct payments and lowering the standard cost of a bushel of corn. As a result, farmers must produce more and more corn to earn enough to support themselves and their families. Why can’t all of this excess corn be used as fuel? It would certainly lower the emissions that result from growing the corn crops, not to mention lessen the dependence of the food industry on corn, who are currently using the crop to create everything from beef to cereal.
On a related note, Dot Earth is making references to a new technology that could essentially create fuel out of air . However, this method is heavily reliant on the use of nuclear power, which would be a costly endeavor to pursue, nevermind the hesitance a good many people have when it comes to using nuclear power in general.
68. February 21st, 2008 Anon wrote:
The Dot Earth technology of making fuel out of air is something I had have before. According to Kenneth Change a writer for Science Times, the idea is to supply fuel by recycling the CO2 already found in the atmosphere. The same process can be done with solar panels as well, but because this won’t monetarily benefit anybody, is unlikely, as nucelar power is the frontrunner. I think that the realization of biofuels and innovative ways to create fuel should be void of economic worries. The implications of these ideas should surpass that of the pocketbook.
69. February 21st, 2008 Anon wrote:
Does anybody have any opinions on other opposing viewpoints on energy use? I’ve recently heard that recycling causes more energy to enact than it saves. The overall process of recycling, especially the curbside collection of recyclables, uses more energy because of things like the extra trucks used to transport the material. Also, according to analyst James V. DeLong, the manufacturing of recyclables uses more energy than it saves. Except for aluminum, this uses more to make from scratch. Recycling this, such as cans, saves about 95% of the energy needed to create it from scratch.
114. April 19th, 2008 Anonymous wrote:
There may be certain factors in recycling where the energy savings do not outweigh the spent energy needed for their reprocessing. I am interested to see if someone can come up with specific stats - I am still looking.
The Pennsylvania DEP website provides visitors with the cookie cutter version of how recycling leads to energy savings. However, they do provide one point that I think is very valid when it comes to taking action in recycling…buying products with less packaging.
In my opinion, if a person wants to guarantee doing their small part purchasing less waste to begin with is the way to go.
The Pennsylvania DEP site:
http://www.dep.state.pa.us/dep/deputate/airwaste/wm/RECYCLE/FACTS/benefits3.htm
115. April 19th, 2008 Anonymous wrote:
There is one interesting study that was reported in 2006 in an issue of “Science News.” The study, conducted by Ecologist David Tilman of the University of Minnesota in St. Paul and and his colleagues determined the resources required for and energy gained from biofuels made from perennial grassland plants.
The scientists determined first that the native grassland species do not require regular “herbicide treatments, irrigation, or fertilization and could be grown on agriculturally abandoned land. Grassland plants aren’t yet used in biofuels.”
The experiment began in 1994 when the scientists planted 152 degraded plots of land with about 16 different grassland perennials. They included species such as legumes, herbs, and grasses. The sample plots were monitored from 1996 to 2005
“Researchers found that the most diverse plots-those with 16 different species-were also the most productive, with the potential to generate more than three times as much energy as plots that bore only one species.The prairie-grass mixtures would give a net energy return that’s more than 17 times that of corn-grain ethanol.”
This piece of information may have more bearing if I could figure the alternate chemical process, but here it is anyways: The team calculated that with the use of an alternative chemical process (which was just beginning to be investigated for biofuel production)fuel from grassland plants could yield 51 percent more net energy per hectare than corn-grain ethanol.
Some interesting information. Does anyone have any information regarding native prairie grasses incorporation into biofuel or any similar research?