This past summer Marilyn Brown attended a meeting of the National Resources Defense Council, at which discussion topics included Hubbert's calculations.

"I think people have some faith in Hubbert's analysis, but there is disagreement about where we are," says Brown, a professor in the School of Public Policy who teaches a course on energy technology and public policy. She came to Tech in August from Oak Ridge National Laboratory, where she was director of its Energy Efficiency and Renewable Energy Program.

"There are those who say we will keep finding oil as long as we're looking for it, and through advances in technology and the use of what they call 'unconventional petroleum,' we will continue to grow our reserves. And then there's the rest of us, who think we're reaching the peak," she says.

M. King Hubbert was a Shell Oil geophysicist who in 1956 applied to oil a well-known technique for describing consumption of other natural resources. In basic terms he plotted global oil production volume over time and used that upward slope as a guide to configure a bell-shaped area representing the world's total known oil reserves. By extrapolating the historical production data to the top of the bell, Hubbert could predict the approximate time when oil production would peak, followed by a steady decline.

The ambiguity in Hubbert's formula, Brown says, rests with the estimate of oil reserves. Hubbert was talking about light sweet crude — the purest, easiest kind of oil to pump and the grade refineries are designed to process. But as the price of oil increases, it becomes economical for companies to extract "unconventional" supplies that are harder to reach or of lesser quality.

Thus the supply increases, pushing Hubbert's peak further into the future. The per-barrel cost of oil spikes too and with it, the cost of everything that uses petroleum in one form or another — which is to say, just about everything.

There are few major oil fields left to discover on the planet, "but there are the oil shale and tar sands options," Brown points out. "That's what people are turning to now, thinking that they represent the next Saudi Arabia of oil. Shell and other oil companies are putting a lot of money into projects out in Alberta, Canada, and in the American West."

Art Ragauskas, an expert in wood chemistry and a professor in the School of Chemistry and Biochemistry, is the Georgia Tech team leader in a collaborative effort with the Imperial College of London and Oak Ridge National Laboratory in Knoxville, Tenn., to develop practical, commercial processes for converting biomaterials into biofuels.

The Tech group is focused on "finding an area where we'd have a significant impact," says Ragauskas. "In the spectrum of biofuels, bioethanol seems to be the most promising growth area."

The choice of wood and forest waste as ethanol sources was logical because both are plentiful in Georgia and they "utilize our existing expertise in wood chemistry and process engineering," adds Ragauskas. "In reality, it's basically a chemical-processing procedure."

Ragauskas contends that deriving ethanol from the constituents of wood — cellulose and hemicellulose, hence the distinction "cellulosic ethanol" — is at least four times more energy efficient than distilling corn. In addition, bioengineering certain fast-growing species such as pine, willow and poplar to produce denser biomass could promote efficiency and production volume further.

Ragauskas envisions biorefineries that function similar to oil refineries and produce a variety of cellulosic fuels and organic chemical products from wood, crop wastes and other cellulosic biomass. The facilities would operate with innovative biomass conversion processes that form the mainstay of the Georgia Tech research effort: that is the process of liberating cellulose from wood and converting it into fermentable sugars.

Ethanol could dramatically decrease U.S. oil consumption when paired with another innovation: hybrid cars. Georgia Tech students designed and equipped a stock vehicle with a hybrid power train for a FutureTruck competition held during 2000-04. Their last entry, a 2002 Ford Explorer, was retired to an off-campus garage two years ago.

But if Jerome "Jerry" Meisel gets his wish, further hybrid development and experimentation at Tech will pick up where they left off.

A professor of electrical and computer engineering and faculty adviser to the Tech FutureTruck team, Meisel is trying to obtain funding to engineer the Explorer into what he considers the next step in hybrid evolution: the plug-in hybrid.

Plug-in hybrids enable drivers to recharge the car's batteries by connecting them to a standard 110- or 220-volt electrical outlet, in effect allowing drivers to maximize the amount of time spent driving in a predominantly electric mode. This option could be especially useful for drivers whose round-trip daily commutes fall within the typical plug-in hybrid's electric-power range of about 40 miles. If battery power gets too low, the gasoline engine would still kick in like a regular hybrid.

"The plug-in hybrid will not operate on one source or the other," Meisel says. "The engine torque and electric motor torque must be blended in an optimal way to minimize gasoline consumption and yet provide the expected drivability. It's a tricky open problem that will only be solved by adjusting control algorithms on an actual research vehicle. That is why I want to continue with work on a plug-in design with our Explorer.

"With a normal hybrid you can get about 20 percent or a 25 percent improvement in fuel economy with normal driving, not the EPA test," Meisel says. "If you could plug it in every night, with our Explorer I believe we could get about 60 miles out of every gallon of gasoline by substituting grid-supplied electric energy for gasoline. Even considering the present cost of electricity, this trade-off of energy supply is equivalent to buying gasoline at about 66 cents a gallon."

Substitute a gasoline-ethanol mix for regular unleaded in the tank and the potential miles per gallon skyrockets by a factor of six — to 360 miles per gallon of gasoline, Meisel says. "There's no infrastructure for ethanol distribution on a national basis," he adds, "but if one comes along, we can have plug-ins running on ethanol — and we'd have no imported oil problem at all."

©2006 Georgia Tech Alumni Association