LOS ANGELES -- California regulators today approved a plan that would require 15.4 percent of new vehicles sold in the state be electric, fuel-cell or plug-in hybrid vehicles by 2025.
The rule -- aimed at improving air quality -- is part of a broader package of regulations called the Advanced Clean Car program that includes measures to cut vehicle greenhouse gas and smog-forming emissions.
The sweeping new auto emission standards include the mandate to have 1.4 million electric and hybrid vehicles on California roads by 2025.
It would also support development of an infrastructure for hydrogen fueling stations across California, the nation's largest car and light truck market.
"That's actually a relatively modest goal, but that's all that we're mandating," Mary Nichols, chair of the Air Resources Board, said in a conference call with reporters following the vote. "We expect to go beyond that with other incentives we are hoping to be able to offer in terms of direct incentives to people who buy these cars (like) rebates and credits."
The California Air Resources Board voted unanimously to approve the program during a 2-day meeting that ended today.
General Motors, Ford Motor Co., Chrysler Group, Nissan Motor Co. and other automakers -- usually at odds with California regulators -- submitted testimony this week in support of the new standards.
Nichols applauded the auto industry's cooperation as these new rules were being developed.
"Probably the most heartening aspect of this whole rulemaking was the level of cooperation that we received from the industry," Nichols said during the call. "Overall, the degree of support for the package was just extraordinary."
But the California New Car Dealers Association and other industry groups representing businesses that sell cars said the board overestimated consumer demand for electric vehicles and other so-called "zero-emission vehicles."
Some groups estimate that $3,200 would be added to the average price of a car or light truck because of the technological changes, and that consumers have been slow to adopt them.
Jonathan Morrison, of the state car dealers' association, said dealers are supportive of new technologies that are accepted by customers but the acceptance of electric and other vehicles has been slow, the Associated Press reported.
The plan, which would reduce smog-forming emissions 75 percent by 2025, and carbon dioxide emissions from passenger vehicles 34 percent between 2015 and 2025, align with federal emissions regulations proposed by President Obama.
The revised mandate that electric, fuel-cell or plug-in hybrid vehicles account for 15.4 percent of new vehicles sold in California by 2025, or roughly 1.4 million units, represents a toughening of state's zero-emission vehicle mandate that has been on the books since 1990.
Under the update, starting in 2018, automakers accounting for about 97 percent of new light-vehicle sales in California will be required to sell plug-in hybrid, electric and fuel-cell vehicles in greater volumes every year to reach the 15.4 percent target by 2025.
BMW, Daimler, Hyundai, Kia, Mazda and Volkswagen are scheduled join Chrysler, Ford, General Motors, Honda, Toyota and Nissan and be subject to comply with the new ZEV mandate starting in 2018.
California has pushed automakers since the 1970s to sell cleaner vehicles to reduce the state's air pollution.
Earlier state rules led to catalytic converters and exhaust treatment systems becoming standard on U.S. vehicles. State officials have said they want to repeat that by pushing automakers to offer a range of models that also emit less of the carbon dioxide created from petroleum-based fuels.
Ten other states plan to adopt California's advanced vehicle requirements if they are implemented, including New York and New Jersey, said Roland Hwang, transportation program director for the Natural Resources Defense Council, an environmental group.
That would at least double the impact of California's program to more than 3 million advanced vehicles being sold nationwide, Hwang said.
"We believe that's a very reasonable total by 2025," Hwang said. U.S. sales of such low-carbon autos would be only about 3 percent of total volume, he said.
According to CARB estimates, plug-in hybrids, fuel-cell and battery-powered vehicles would account for one of every seven new vehicles sold in California by 2025.
Gloria Bergquist, a spokeswoman for the Alliance of Automobile Manufacturers, said the industry trade group has concerns about the California rule, and in general, opposes mandates on specific technologies.
"We think it's a disconnect with the marketplace," Bergquist said.
"Automakers have invested literally billions of dollars in these technologies, so we have a real stake in trying to sell as many as possible," she said. "But no one knows what that number is going to be. And it doesn't help anyone if those cars sit on lots unsold."
California's long-term goal is for hydrogen fuel-cell or battery electric vehicles to account for 87 percent of new vehicle sales in the state by 2050. CARB says the latest targets would put the state on pace to meet that goal.
The proposal is unique to California and isn't part of new fuel economy standards being proposed by the Obama administration for the 2017-25 model years.
Car companies can generate credits to apply to the California standard if they exceed greenhouse emission requirements on the federal level.
Bloomberg and Christina Rogers contributed to this report