Joint 13-state lawsuit aims to reverse US DOE ruling on EV fuel efficiency calculations

A new rule aiming to incentivize electric vehicle manufacturing "overstates" the fuel efficiency of EVs, according to a new joint lawsuit from 13 states.

The April 10 lawsuit led by Iowa Attorney General Breanna Bird targets a recently-published rule changing how EVs are calculated for fuel efficiency.

"In Biden's most recent attack in the war on gas vehicles, he is creating a rule that overstates the efficiency of electric cars by more than six-times," a statement from Bird's office reads.

The statement describes the rule as "handouts to electric vehicles." Iowa, Arkansas, Florida, Idaho, Kansas, Mississippi, Missouri, Montana, Nebraska, Ohio, Oklahoma, Texas, Utah and the American Free Enterprise Chamber of Commerce signed onto the lawsuit.

"The States make the case that the electric vehicle handout violates the Administrative Procedure Act and exceeds the Department of Energy's authority," the statement reads.

The Petroleum-Equivalent Fuel (PEF) Economy Calculation rule, published in March, revised the Department of Energy's regulations "regarding procedures for calculating a value for the petroleum-equivalent fuel economy of electric vehicles," according to the text of the rule.

The PEF exists to convert EV energy usage into a miles-per-gallon (mpg) equivalent. This latest update to the PEF will update this conversion, reducing the mpg rating for EVs and incentivizing light-duty vehicle manufacturers to increase EV production.

The calculation is used by the Environmental Protection Agency to determine light-duty vehicle manufacturer's compliance with fuel economy standards. The Department of Transportation sets an average fuel economy target that companies must meet.

The DOE rule argues EV's current higher mpg rating allows companies to meet average fuel economy targets more easily with fewer EVs in production. Reduced mpg ratings for EVs would mean companies must expand their EV portfolios to meet targets. The new rule will affect model years beginning in 2027.

"This overvaluing of EVs can allow a few EV models to provide overall compliance with CAFE standards, which in turn permits manufacturers to maintain less efficient [internal combustion engine] vehicles and disincentivizes production of additional EVs," the rule states.