U.S. consumers purchased close to 1.8 million alternative fuel automobiles in 2007, according to the automotive research firm R.L. Polk. That's nearly a quarter of a million more than were sold in 2006, Consumer Affairs reports.

Sales of E-85 capable/flexible fuel vehicles and hybrid electric vehicles were up significantly while clean diesel vehicle sales fell slightly.

"Gas prices, consumer incentives, and the increasing number of alternative-fuel models available to consumers continue to play a role in the rising popularity of these vehicles," said Dave McCurdy, president and CEO of the Alliance of Automobile Manufacturers. But McCurdy said the news is not entirely good.

"And while we're pleased these vehicles continue to grow in popularity, refueling infrastructure challenges may prevent the promise of these vehicles from being fully realized. For example, out of more than 170,000 refueling stations in the U.S. less than 1,500 offer ethanol," he said.

There may be another problem for cars using ethanol.

As commodity prices have soared, food processors are mounting a growing backlash against the government's ethanol mandate, accusing it of making good grains harder to come by, and therefore, more expensive. The criticism escalated last week when corn prices rose to a record $6 a bushel.

According to Consumer Affairs, the ethanol industry rejects claims that its biofuels that are driving food prices higher. Industry spokesmen say food prices are going up, long with everything else, because of skyrocketing fuel costs.