[continua]

It's also true that there's a difference between edible sweet corn and the feed corn that's used for ethanol production. But because farmers try to grow the most profitable crop they can, higher prices for feed corn tend to discourage the production of sweet corn. That decreases its supply, driving the price of sweet corn up, too.

In fact, many agricultural economists believe rising demand for feed corn has squeezed the supply — and boosted the price — of not just sweet corn but also wheat, soybeans and several other crops.

America's appetite for corn is enormous. But Americans consume so much gasoline that all the corn in the world couldn't make enough ethanol to slake the nation's lust for transportation fuels. Last year ethanol production used 12 percent of the U.S. corn harvest, but it replaced only 2.8 percent of the nation's gasoline consumption.

"If we were to adopt automobile fuel efficiency standards to increase efficiency by 20 percent, that would contribute as much as converting the entire U.S. grain harvest into ethanol," Brown said.

ISN'T THERE A BETTER RENEWABLE FUEL SUBSTITUTE FOR GASOLINE?

Most experts think it will take an array of renewable energy technologies to replace fossil fuels. Ethanol's main drawbacks come not from the nature of the fuel itself, but from the fact that it is made using a critical component of the world's food supply. Ethanol would be more beneficial both environmentally and economically if scientists could figure out how to make it from a nonfood plant that could be grown without the need for fertilizers, pesticides and other inputs. Researchers are currently working on methods to do just that, making ethanol from the cellulose in a wide variety of plants, including poplar trees, switchgrass and cornstalks.

But plant cellulose is more difficult to break down than the starch in corn kernels. That's why people eat corn instead of grass. Plus it tastes better.

There are also technical hurdles related to separating, digesting and fermenting the cellulose fiber. Though it can be done, making ethanol from cellulose-rich material costs at least twice as much as making it from corn.

HOW LONG WILL IT TAKE BEFORE CELLULOSIC ETHANOL IS COMPETITIVE WITH CORN ETHANOL AND GASOLINE?

Some experts estimate that it will take 10 to 15 years before cellulosic ethanol becomes competitive. But Mitch Mandich, CEO of Range Fuels, thinks it will be a lot sooner than that. The Colorado-based company has started building a cellulosic ethanol plant in Georgia that converts wood chips and other waste left behind by the forest products industry. Another company, Iogen Corp., has been producing cellulosic ethanol from wheat, oat and barley straw for several years at a demonstration plant in Ottawa, Canada.

HOW MUCH MORE EFFICIENT WOULD CELLULOSIC ETHANOL BE COMPARED TO CORN ETHANOL?

Studies suggest that cellulosic ethanol could yield at least four to six times the energy expended to produce it. It would also produce less greenhouse gas emissions than corn-based ethanol because much of the energy needed to refine it could come not from fossil fuels, but from burning other chemical components of the very same plants that contained the cellulose.

HOW MUCH GASOLINE COULD CELLULOSIC ETHANOL REPLACE?

The U.S.
Department of Energy estimates that the United States could produce more than a billion tons of cellulosic material annually for ethanol production, from switchgrass grown on marginal agricultural lands to wood chips and other waste produced by the timber industry. In theory, that material could produce enough ethanol to substitute for about 30 percent of the country's oil consumption.

A University of Tennessee study released in November reached similar conclusions. As much as 100 million acres of land would have to be dedicated to energy crops in order to reach the goal of substituting renewable biofuels for 25 percent of the nation's fuel consumption by 2025, the report estimated. That would be a significant fraction of the nation's 800 million acres of cultivable land, the study's authors said, but not enough to cause disruptions in agricultural markets.

"There really aren't any losers," said University of Tennessee agricultural economist Burton English.

REALLY? NO LOSERS AT ALL?

There might be losers. Simple economics dictates that if farmers find it more profitable to grow switchgrass rather than corn, soy or cotton, the price of those commodities is bound to rise in response to falling supply.

"You can produce a lot of ethanol from cellulose without competing with food," said Wallace Tyner, an agricultural economist at Purdue University. "But if you want to get half your fuel supply from it you will compete with food agriculture."

There may also be ecological impacts. The government currently pays farmers not to farm about 35 million acres of conservation land, mostly in the Midwest. Those fallow tracts provide valuable habitat for wildlife, especially birds. Though switchgrass is a good home for most birds, if it became profitable to grow it or another energy crop on conservation land some species could decline.

WILL ETHANOL SOLVE ALL OF OUR PROBLEMS?

Ethanol is certainly a valuable tool in our efforts to address the economic and environmental problems associated with fossil fuels. But even the most optimistic projections suggest it can only replace a fraction of the 140 billion gallons of gasoline that Americans consume every year. It will take a mix of technologies to achieve energy independence and reduce the country's production of greenhouse gases.

"I think we're in a very interesting era. We are recognizing a problem and we are finding lots of potential solutions," said David Tilman, an ecologist at the University of Minnesota.

But if we're serious about achieving energy independence and mitigating global warming, Tilman and other experts said, one of those solutions must be energy conservation.

That means doubling the fuel economy of our automobiles, expanding mass transit and decreasing the amount of energy it takes to light, heat and cool our buildings. Without such measures, ethanol and other innovations will make little more than a dent in the nation's fossil fuel consumption.


----

ahhh l'america che grande paese

lì se si decide una cosa la si fa subito


mica quei 4 co**oni che abbiamo in italia che stanno sprecando il mandato cazzeggiando sui DICO sì DICO no....

oltretutto questo progetto genererà milioni di posti di lavoro.

in Italia usare l'etanolo è evasione fiscale....