You're at this Wisconsin gas station. You're scanning the pumps -- octane 87, octane 93. One pump offers an ethanol blend, E-10, which is gas with 10 percent ethanol. The other pumps contain just gasoline. Wisconsin is one of the many states that offers consumers a choice.
Typically, the gas with ethanol is cheaper because it's subsidized. So which do you pick? Has anyone ever asked you which you wanted?
Ethanol use across the country has increased because governors and legislators want something to reduce air emissions and petroleum dependence. They're using ethanol to accomplish that.
Consumer interest is beside the point here. No study has been done on consumer preference. In some states, officials say annecdotally some consumers see ethanol as a great new fuel, while others say it's bad for your engine and reduces mileage.
Studies have shown that producing ethanol bolsters local economies.
Minnesota has led the nation in ethanol use. All of the state's gasoline is E-10, and Gov. Tim Pawlenty wants the state's gas to contain 20 percent corn-based ethanol by 2013.
Greg Dierkers of the National Governors Association says each state takes its own approach to alternative fuels. In Indiana, state fleet vehicles must use ethanol-based gasoline. In Missouri, Dierkers says all gas will have to be E-10 by January 2008.
Most ethanol is made from heavily fertilized, heavily tilled corn. Producing ethanol that way has an environmental cost that barely outweighs the benefits of using it in your gas tank.David Green, U.S. Department of Energy
"In a lot of cases these are mandates. These are examples where governors are showing leadership by setting an executive order," Dierkers says.
But Wisconsin doesn't have an ethanol mandate.
Gena Cooper in Wisconsin's Office of Energy Independence says Wisconsin has instead focused on making its state fleet vehicles compatible with E-85 or biodeisel.
She says the state does encourage the use of E-10 by consumers, and 50 percent of the state's gas stations sell E-10. She says Wisconsin's Legislature voted against making it a requirement.
"We have a very strong history of people being aware, and rightfully so, of consumer rights and a consumer's right to choose," says Cooper. "And I think maybe that's what we're seeing a little bit of here in Wisconsin."
Some scientists say choosing to buy ethanol-blended gasoline doesn't mean you've chosen to greatly reduce car emissions.
David Green, a senior researcher at the Department of Energy's Oak Ridge National Laboratory, says most ethanol today is boiled and fermented from heavily fertilized, heavily tilled corn.
Green says producing ethanol that way has an environmental cost that barely outweighs the benefits of using ethanol in your gas tank, especially with federal subsidies.
"There's a small greenhouse gas benefit. Subsidizing the fuel at 50 cents a gallon is a quite expensive way to reduce greenhouse gases," Green says.
It also cuts into the state's federal highway dollars, and some states offer tax cuts for new ethanol plants.
If ethanol isn't cleaning up the air as well as some had hoped, and consumers don't beg for it, why are more ethanol plants and pumps popping up?
Perhaps policy is dictating science. President Bush has voiced support for ethanol, and he wants to reduce the country's gas consumption by 20 percent over the next decade.
To do that, researcher David Green says, almost every driver in the nation would have to fill up their tanks with E-20, a 20 percent blend of ethanol.
Car manufacturers aren't certain that's safe for vehicles. The EPA has concerns about the volatility of the fuel. Plus, Green says consuming that much ethanol from corn would hurt the food supply. He says ethanol producers would have to use plant material instead of corn.
"That begs the whole question of whether that's really the best solution. If you have that much biomass to make into liquid fuels, is the very best thing you can do with it is make it into ethanol? My suggestion would be probably not," Green says.
Green says biomass can be turned into synthetic fuels like gasoline as easily as ethanol. That would likely be easier on car manufacturers and consumers.
To his knowledge, no one has studied what might be the best plan for the nation to get the fuel we need and clean up the environment.