Pat Tate drove into the Citgo Quik Mart in Annapolis and stopped in front of an odd-looking fuel pump. It featured pictures of corn stalks waving in a blue sky and advertised a price per gallon - $2.95 - 9 cents cheaper than the gas at the next pump.
Tate filled up his car with "E85," a mixture of 85 percent ethanol and 15 percent gasoline. The gas station, one of three in Maryland to sell the fuel, has seen a sharp increase in customers filling up on E85 over the past year - a trend across the nation as soaring gas prices and the Iraq war have attracted drivers more to a home-grown alternative to gasoline.
"Anything you can do to reduce your use of oil, and lessen your emissions into the environment, the better," said Tate, 64, who is director of architecture and engineering at the University of Maryland, Baltimore. "We are only borrowing the Earth, and we owe it to our grandchildren to leave it as pristine as we can."
He was driving a state-owned Dodge Stratus with a "flex fuel" engine designed to run on either gasoline or ethanol. Car makers have been building and marketing an increasing number of these flex fuel vehicles, with 5 million on the road today, about 2.5 percent of the nation's cars. Many are owned by government or university fleets.
Five years ago, the U.S. consumed about a billion gallons of ethanol annually. Since then, consumption has multiplied to almost 6 billion gallons a year, according to the U.S. Department of Energy.
"There has been a 50 percent increase in ethanol use over the last year alone, and there are now a lot more cars available that can run on E85," said Craig Stevens, a spokesman for the Energy Department.
General Motors launched a "Live Green, Go Yellow" ad campaign in January, promoting Avalanches, Suburbans, Impalas and other vehicles that can run on the fuel brewed from corn.
"E85 is one way we can help encourage our nation's energy independence," said Dave Barthmuss, a GM spokesman. "I can't remember the last time I saw a Marine division guarding a corn field in Iowa."
Now that more gas stations are selling E85 across the country -150 opened in the past year - GM is actively encouraging its customers to use them. Tom Collina, director of 20/20 Vision, an environmental group, said the environment should benefit. Ethanol produces less air pollution and global warming gasses than petroleum.
One of the first uses of ethanol as a fuel was in 1908, when Henry Ford built Model T's to run on corn alcohol, said Joanna Schroeder, spokeswoman for the nonprofit Ethanol Promotion and Information Council.
Ethanol was used as fuel until 1919, when it was banned during Prohibition because it's a form of alcohol more potent than vodka. Use of ethanol dropped off after World War II because distilling it was more expensive than drilling for oil.
Ethanol came back into style in the 1970s, during the oil crisis, when it was added to gasoline at a 10 percent ratio in such Midwestern states as Iowa and Minnesota that also wanted to boost the price of corn.
Cars with standard engines can run on gasoline mixed with up to 10 percent ethanol. But modern engines must be slightly modified to become flex fuel - a process that costs about $200 - to run on either gasoline or almost pure ethanol.
The rise in the use of ethanol over the past five years has come in part because the federal government encouraged fuel companies to add it to gas at a roughly 10 percent ratio to replace MTBE, methyl tertiary butyl ether, an additive that makes gasoline burn cleaner, said Randy Roy, president of Atlantic Ethanol, a manufacturer. Adding ethanol does the same thing and, unlike MTBE, it has not been implicated in ground water pollution.
But a huge gap remains between the growing number of cars than can run on ethanol and the availability of the fuel.
Tate, who lives in Annapolis, said he's able to use ethanol instead of gasoline almost all the time for his commute to Baltimore because he lives near an E85 station. Most other motorists aren't that fortunate.
Three gas stations in Maryland sell E85 - at 2042 West St. in Annapolis, 3240 Fort Meade Road in Laurel and 16640 Crabbs Branch Way in Gaithersburg. Almost 700 U.S. stations sell the fuel, but that's less than 1 percent of the roughly 100,000 gas stations nationally.
"There are a lot of problems with ethanol, including the fact that there just isn't enough of it," said Frank Maisano, lobbyist for the National Petrochemical and Refiners Association, which represents the gasoline industry.
Federal and state policies aim to help close this gap by offering tax subsidies to service stations that install E85 pumps and encouraging private investors to build new ethanol plants.
The Maryland Grain Producers Association, a farm trade organization, is one of three groups looking to build ethanol plants in Baltimore, said Lynne Hoot, executive director of the group.
"Farms are often not very profitable businesses, and this is a good way to increase the profitability of farming," said Hoot. "Ethanol could help save Maryland farms from being developed."
Robert L. McCormick, principal engineer at the National Renewable Energy Lab, said studies have disproved a myth that making ethanol consumes more energy than the fuel it produces.
But one drawback of ethanol is that a gallon of E85 generates only about 75 percent as much power as a gallon of gasoline. That means that ethanol would have to be roughly 25 percent cheaper per gallon to be a bargain for consumers, which it is not today, McCormick said.
That equation could change as the price of oil rises, he said. Brazil has become energy-independent by making vast amounts of ethanol from sugar cane. This proves that it would be possible for America to give up its addiction to foreign petroleum, too, he said:
"Ethanol could displace all of the oil that we import today."