U.S. consumers are willing to consider buying vehicles capable of running on alternative fuels or equipped with hybrid powertrains, but the real indicator to the popularity of such products lies in the details of the specific technology, a new study shows.

Thirty-seven percent of U.S. car buyers say they would consider buying a flex-fuel vehicle that can run on gasoline or a mix of 15% gasoline and 85% ethanol the next time they are shopping for a new car.

However, more than a third of the same consumers shun the technology once they learn E85 provides considerably poorer fuel economy than gasoline.

The findings come from a new, semi-annual survey of 1,240 vehicle buyers in the U.S. conducted by Synovate Motoresearch, the global market-research arm of Aegis Group plc.

“It certainly appears as if consumers have bought into the appeal of a flex- fuel vehicle that can run on either gasoline or E85,” Synovate Motoresearch CEO Scott Miller says.

“However, consumers also are largely unaware that they will experience a 25% loss in fuel economy when the vehicle is running on ethanol,” he says, adding E85 will have to retain a substantially lower price-per-gallon over gasoline to have any impact on reducing U.S. consumption of petroleum.

Similarly, awareness of plug-in hybrid-electric vehicles (PHEV) currently under consideration by some major auto makers, is low, yet 49% of those surveyed indicate they would consider purchasing a PHEV after hearing an explanation of the benefits of the technology.

PHEVs have a significantly longer range in electric-only mode than regular hybrids due to larger batteries and the ability to be recharged via a wall outlet.

Plugging the vehicle in at home means fewer trips to the gas station and lower operating costs,” says Tim Englehart, Synovate Motoresearch manager-alternative fuels studies, “The unknown with this technology is the additional purchase cost.”

Consideration of conventional HEVs also is quite high, the study shows, with about 50% of respondents open to purchasing a hybrid as their next vehicle.

Clean-diesel vehicles also were part of the survey, with consumer consideration standing at approximately half that of HEVs.

“The story around diesels is not the percent of U.S. consumers who will consider it, just those who are very interested,” Miller says.

“If (auto makers) can meet the emissions requirements of the new-diesel legislation, some are going to surprise the market with the products they introduce and the buyers to whom those vehicles appeal.”