Is EV energy efficiency over-rated? What happens to the US CAFE regulations?
It has become a popular justification these days that “EVs are good for the environment because they have no driving emissions and are highly energy efficient.” However, the reality is often unclear.
Even in the USA, which is considered relatively indifferent to the environment and energy efficiency, the Environmental Protection Agency (EPA) recently announced a shocking proposed regulation to reduce greenhouse gas (GHG) emissions from light-duty vehicles by a third by 2032 MY The EPA’s GHG regulation leads to the ‘EVs have no driving emissions’ part. The ‘energy efficiency’ part of the regulation is a key component of the GHG regulation.
The ‘energy efficiency’ part is the domain of the Department of Transportation’s National Highway Traffic Safety Administration’s (NHTSA) Corporate Average Fuel Economy (CAFE) regulations, which set the fuel economy conversion factor for EVs. On 11 April 2023, the DOE proposed to review the fuel efficiency conversion factor for electricity costs for the first time in 20 years.
This review will reduce the energy efficiency (MPGe) of EVs by approximately 70% compared to the current standard, and the gap in energy efficiency between EVs and equivalent petrol vehicles will shrink from nearly 10 times the current level to two to three times. However, it may lead to the argument that the energy efficiency of EVs is being overestimated.