A new front is opening in the emerging market for electric vehicles — not for selling cars, but for credits required to meet clean-air rules.
Starting this year, California is requiring the biggest automakers to sell increasing numbers of "zero-emission vehicles," or ZEVs, such as pure-electric, plug-in hybrid and hydrogen-powered autos. Companies that fail to meet their quotas have the option of buying ZEV credits from rivals that exceed their targets.
Nissan Motor Co. says it may sell credits earned in the past two years from its battery-powered Leaf, the best-selling all-electric car in the U.S.