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If people wish to control the greenhouse gases that harm the environment they must reduce the amount of carbon they release when producing energy. Biofuel does just that. As plants grow, they collect energy from the sun. Sugars from these plants can then be converted into heat energy. Burning this energy as fuel releases carbon dioxide into the atmosphere, but the gas is soaked up by plants at the beginning of the growing cycle. This give-and-take cancels out harmful carbon emissions, which is why biofuel is often referred to as a "carbon neutral" form of energy.
Right now, the most widely used biofuel is ethanol produced from corn—a process that involves breaking down sugars in the plant's grain and fermenting them into ethanol. Nearly all five or six billion gallons of the fuel made in 2006 were made this way. Perhaps unknown to the East Coast urbanites paying $3 a gallon for petroleum, some 150 corn-to-ethanol factories are already in operation in the United States, mostly in the Midwest.
Still, experts almost unanimously see corn-based ethanol as the beta version of biofuel—an early phase of alternative fuel use that, while necessary, must be improved before realizing success. For starters, making biofuel from corn isn't entirely eco-friendly. Because corn is an annual crop—meaning its life cycle is a single season—farming it can release nitrous oxide, a greenhouse gas more potent than carbon dioxide, Dale's research has shown.
Done correctly, though, corn can be grown in a way that won't release a damaging amount of nitrous oxide. The bigger problem with corn has to do with meeting the presidential benchmarks: it takes a lot of energy to produce fuel from the grain of corn. A prohibitive amount, some feel. "We can't make enough ethanol from corn to change our liquid fuel dependence," says Dale. If you were to add up all the energy it takes to create a bushel of corn—from making the farm machinery to tilling the land—you get only about 1.3 times more energy out of the resulting biofuel, says Somerville. A good energy return would be around 10 times that figure.
However flawed, corn-based biofuel's initial promise—it has resurrected the country's agricultural industry—might have paved the way for a more efficient alternative to enter the market. Experts call this next-generation fuel "cellulosic ethanol." The term is intimidating, but the idea is relatively simple: biofuel producers can convert more sugar into energy if they use the whole plant instead of simply the grain.
In addition to diminishing reliance on petroleum, cellulosic ethanol will neutralize more greenhouse gases than corn. "There's a limit on corn-based biofuel," says energy and environmental scholar David Sandalow of the Brookings Institution in Washington. "But if we can break through technical barriers on cellulosic forces, then the potential is much, much higher."
Overcoming these technical barriers won't require a miracle, just a few research advances and lots of money. In the meantime, scientists and producers continue searching for plants that naturally yield more energy than crops like corn and soybeans do. Most of this focus has been on perennial crops such as switchgrass. Because perennials last several seasons, they don't allow nitrous oxide to escape from the soil into the atmosphere; they are both carbon and nitrous neutral. More importantly, the energy return on these crops is some 15 to 20 times what's used to produce them. The star of this group is Miscanthus giganteus, a wild plant native to tropical regions in Africa and Asia. In addition to its high energy output, Miscanthus requires less water than typical crops and stores more carbon in the soil, says Somerville. The trick for biofuel developers will be domesticating this species and sustaining it over long periods of time.
"I think the industry's going to happen more quickly than most people realize," says Dale. "Once we recognize that we can make ethanol from grass grown to purpose, for something in the neighborhood of $1.50 or $1.20 a gallon, then it's going to explode." This recognition might happen more quickly than even Dale would have imagined. Just five days after his meeting with Bush, the Department of Energy announced that over the next several years it will invest nearly $400 million in six cellulosic ethanol plants across the country.


Comments
I believe this article is truely interesting. I never even knew half of the things, both pros and cons about oil, and our future if what is happenning to it keeps going on. It was fun to learn somthing new. Thank you, Smithsonian!
Posted by yamilette on March 18,2008 | 09:14AM