Last week, Bloomberg reported that the U.S. Environmental Protection Agency (EPA) and the National Highway Traffic Safety Administration (NHTSA) will move to rescind California's authority to set its own emission standards for automobiles, including its mandate for electric vehicles (EVs).

In specific, the proposed rule will seek to freeze federal vehicle efficiency standards at 35 miles per gallon, rather than the 50 mpg target (for 2025) that was set during the Obama administration.

It will also seek to revoke the waiver that California received in 2009 from the EPA (as part of the passage of the Clean Air Act) to issue its own auto pollution rules, set its own vehicle emission standards and require zero-emission vehicles.

Currently, California accounts for approximately one-half of all EV sales in the U.S., partly as a result of its mandate to put 1.5 million zero-emission vehicles on the road by 2025. (This is being accomplished by the state requiring auto manufacturers to sell a certain number of EVs each year in California.) Subsequently, in January 2018, Governor Jerry Brown announced more ambitious plans to set a new goal of 5 million zero-emission vehicles by 2030.

The proposed EPA and NHTSA rule, if passed, besides slowing EV growth in California, also has the potential to slow EV growth nationwide, since a number of other states have subsequently followed California's lead on emission standards.

The EPA and NHTSA call their regulatory notice the "Safer and Affordable Fuel Efficient Vehicle Rule" (SAFER), suggesting that by not requiring more stringent emission standards, vehicle prices can remain lower, thus encouraging more consumers to replace aging, dangerous vehicles with newer, safer models.

 If the new ruling is implemented, industry observers have said court battles are virtually guaranteed, many of them being led by electric utilities that stand to reap the benefits of more revenue as a result of the growing EV market.

And, in response to hearing about the proposed rule, California Attorney General Xavier Becerra said in a statement that his department is "ready to use every legal tool at our disposal to protect the current vehicle emission standards."