The surest way to spur the widespread development of plug-in electric vehicles in the U.S. is to offer the consumer tax credits that have been proposed in Congress, makers of plug-in cars told a Senate committee Tuesday.

The proposed tax incentives would lead to a spike in demand, allowing manufacturers to invest profits for further development of plug-in technology, industry officials told the Senate Energy and Natural Resources Committee.

"I think the best way to get people to be early adopters and broaden the deployment of these vehicles is to bring the cost down," said Thad Balkman of California-based Phoenix Motorcars, which plans to roll out its line of plug-in battery electric trucks next year. The trucks will sell for $47,500.

Pending Senate legislation that would extend a wide range of expiring tax cuts would provide a tax credit of $3,000 for the purchase of qualified plug-in vehicles. While tax credits have long been available for the purchase of hybrid cars that use a combination of gasoline engines and electric batteries, the new tax credit is designed to spur the market entry of electric-only cars.

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