U.S. government incentives to spur a market for battery-powered autos aren't a cost-effective way to cut oil use and tailpipe emissions, compared with boosting sales of hybrids and plug-in cars that go short distances on electricity, according to a new study.

Battery breakthroughs, more-expensive oil and a more-efficient electric power grid will be needed to justify the expense, weight and assembly-related costs of "large battery pack" cars, according to the review by Carnegie Mellon University, Arizona State University and Rand Corp. that was published this week in Proceedings of the National Academy of Sciences.

Hybrids similar to Toyota Motor Corp.'s Prius and plug-in hybrids that go about 16 km on battery power offer fuel-use and carbon-exhaust savings similar to more advanced rechargeable models such as Nissan Motor Co.'s electric Leaf and General Motors Co.'s Volt, and at lower cost, the study found.