Auto executives maintained their optimism about taking electric vehicles to the mass market after two studies cast doubt on Americans' willingness to pay for the technology.

Jason Forcier, vice president of the automotive solutions group at battery manufacturer A123 Systems, told a conference in Novi the market for electrified vehicles in 2020 will exceed 50% of sales, including stop-start hybrids. Mark Perry, Nissan's North American product planning chief, said pure electric vehicles should reach more than 10% in the U.S. in the next decade.

"Cars in the road are really the only way to get this done," Perry said, arguing the electric vehicle market will take off once buyers start noticing other EVs on streets and in neighbors' garages.

Countering the enthusiasm at the Automotive News Green Car Conference were two reports issued Tuesday, one by the Boston Consulting Group and the second by the Center for Automotive Research in Ann Arbor.

In the U.S., consumers will tend to stick with conventional gasoline engines because automakers here have been able to get substantial fuel economy from those engines at lower-than-expected costs, BCG said.

The Center for Automotive Research took a more pessimistic view. It forecast U.S. consumers will see all car sticker prices jump between $3,700 and $9,000 by 2025 simply to cover manufacturers' increased costs of meeting possible tougher government fuel economy requirements.