For Dan Norte, deciding where to fuel up his Ford F150 pickup is not always as simple as scanning pump prices. When he heads to Iowa to see family, the synthetic-oil dealer from Owatonna, Minn., burns an 87-octane Minnesota-mandated gasoline blend that is 10 percent corn-based ethanol. It costs about the same as comparable-grade gasoline.
For the trip back he has a 15-percent option, an Iowa blend rated at 89 octane that can be up to a nickel a gallon cheaper. But Mr. Norte has figured out that his savings would probably be erased by lost m.p.g. from the faster-burning fuel.
With energy independence increasingly cast as a matter of national security, and the doubling of biofuel output by 2012 mandated by last summer's energy bill, plenty of other Americans are finding more cause for making complex calculations that involve alternative fuels.
Some 90 percent of 1,000 voters surveyed last month by the nonpartisan Energy Future Coalition in Washington supported the notion of having one-quarter of US energy demand met by renewables by 2025.
"We have a new reality," says Ron Cogan, editor of the Green Car Journal in San Luis Obispo, Calif. "And I think that's changing the way people look at the vehicles they want to buy and operate on a daily basis."
"Two years ago, it looked like the alternative-fuels business was going to atrophy," says Fred Mayes, who tracks renewable-fuel data for the Energy Information Administration, a quasi-independent arm of the Department of Energy. "There was no interest, no direction, no incentives, no major breakthroughs. It was stuck in low gear."
Barriers still exist, including not enough filling stations and a projected shortfall of ethanol production that will contribute to higher gas prices this summer, many experts say.
Still, energy remains in an evolutionary mode. Mr. Mayes says government analysts trying to make projections can barely keep up with all the emerging options. As gas-electric hybrids fill a gap, and hydrogen fuel cells remain a holy grail, old-school combustion engines show signs of hanging on - and leaving fewer smudges - because of what they can burn.
That has alternative-fuel vehicles merging out of the slow lane for the near term - and consumers facing more signposts than they can easily read.
"There are so many balls up in the air," says Mayes. Consider: Biodiesel made from soy or other forms of biomass; cellulosic ethanol, derived from corn husks and other organic waste rather than corn; E85 ethanol that's only 15 percent gasoline; even "petro" diesel that burns cleaner than the diesel used in the smoke- belching cars many Americans recall - and that is made cleaner still by exhaust-treatment technologies like DaimlerChrysler's BlueTec, announced last month.
Mayes has just returned from a conference at which he heard of a new "biomass gasification" technology that "can produce ethanol cheaply in huge quantities from trash, coal, wood, switchgrass - anything you name that has carbon in it," he says.
Don't expect a federal decree favoring sales of one fuel, like the legislation of unleaded in the 1970s, experts say. If anything, Washington might step back and let automakers go nose-to-tailpipe with states. A federally sponsored panel (the National Academies' National Research Council) this month strongly urged that states should have the power to follow California's lead in adopting emissions standards tougher than the federal ones.
Many automakers have several horses in the alt-fuels race. Perennial innovator Honda - a leader, with Toyota, in hybrids - also has its hydrogen FCX and its natural-gas-powered Civic GX, "the cleanest internal-combustion ever," Mr. Cogan says.
GM, which has pushed ahead with hybrids, has also ramped up marketing for flexible-fuel vehicles that can run on either straight gasoline or E85. It …