US presidential Republican candidate John McCain has proposed a $300 million (£152 million) government prize to develop a car battery that outstrips current technology.
Mr McCain said the development of more efficient technologies would make the US less dependent on foreign oil.
The Arizona senator said the $300 million Clean Car Challenge was "a small price to pay for helping to break the back of our oil dependency".
"The unwise policies of our government have left America's energy future in the control of others,'' he said.
Speaking at Fresno State College in California, he also proposed tougher fines for car makers who failed to honour fuel-efficiency standards.
In addition, he pledged incentives to boost the use of fuels such as ethanol.
And he is also proposing a $5000 (£2,500) tax credit for every zero-carbon emissions car US car makers develop and sell.
Gasoline currently costs $4 a gallon in the US.
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