As Spotlight Shines on Innovations and Finance, Assessment Busts Old Notion that Energy Input Exceeds Energy Output
NEW YORK (February 9, 2006) -- Production of ethanol 'biofuels' using farm crops and agricultural leftovers yields significant net energy savings, according to a new report that reaffirms the vast potential these fuels have to save oil and reduce the heat-trapping emissions responsible for global warming. The paper is being published today in the journal Environmental Science and Technology and was commissioned by the Natural Resources Defense Council (NRDC) and the Washington-based Climate Solutions.
"There is no longer any question that biofuels can deliver major net savings in energy and emissions," said NRDC senior policy analyst Nathanael Greene. "The corn-based ethanol in wide use in many parts of the country is delivering good results already. We think that new technologies emerging rapidly today that use other kinds of plant material could easily quadruple those savings."
Using a standardized methodology to compare apples to apples, the new analysis reexamines the most important published papers calculating the biofuels' energy balance -- nonrenewable energy in versus total energy out -- from farm field to gas tank, and everything in between.
The two organizations released a condensed version of the report, available on NRDC's website (click here to view). The published paper, written by Roel Hammerschlag of the Institute for Lifecycle Environmental Assessment, can be found on the Environmental Science and Technology website.
The authors first examined the corn-based process used to make 95 percent of the ethanol produced in the United States today. In 2004 American farmers produced more than 3.4 billion gallons of the stuff, accounting for 11 percent of the country's corn harvest. The researchers found a positive energy balance ranging from 1.29 to 1.65 (with 1.00 representing the energy break-even point, and numbers less than that a net loss).
Next they looked at new "cellulosic" ethanol production processes that can utilize many different crops, and much more of the plants themselves. The key to this technology is enzymes or microorganisms that can break down and ferment cellulose, instead of just the sugar found in crops like corn or sugar cane. The solid materials left over are burned to fuel the conversion process. The results were striking: a positive energy balance ranging from 4.40 to 6.61.
The energy return on gasoline is just 0.76, meaning it takes more energy to make than we get back.
"We know that biofuels are going to be a key component of a safer, more secure transportation future," said Rhys Roth, co-director at Climate Solutions. "This report busts a major myth about ethanol. We now know conclusively that the energy balance in current ethanol technologies significantly exceeds even that of conventional gasoline, and that the advantage for cellulosic technologies could be much bigger."
Cellulosic ethanol has never been manufactured on an industrial scale. The first generation of cellulosic ethanol plants is expected to come on line in the next two to four years, likely fed with leftover agricultural or forestry material. Ground up feedstock will be put through as many as four vats containing different enzymes, a process that has not yet been proved at commercial volumes. Developers are striving to achieve a simpler one-vat process.
President Bush spotlighted new ethanol fuels in his State of the Union address last week, promising $150 million in research money. Recent technological advances and an explosion of venture capital investment being drawn to the field were been featured in Fortune magazine (February 6) and the Wall Street Journal (February 2).
"The promise is obvious, but the challenges are very real. What's needed most now is larger-scale production experience to drive down costs and iron out production hurdles," Greene said.