Originally published on CleanTechnica.
A new study from researchers at Carnegie Mellon University has found that the federal laws incentivizing the sale of alternative-fuel vehicles (Corporate Average Fuel Economy/CAFE standards) could lead to a short-term increase in the total fuel consumption and emissions associated with new vehicles from major auto manufacturers.
“Recent updates of federal policy for model years 2012 through 2025 include incentives that allow automakers to meet less stringent fleet efficiency targets when they sell AFVs (alternative-fuel vehicles) — so the more alternative fuel vehicles an automaker sells, the dirtier its overall vehicle fleet is permitted to be,” stated Jeremy Michalek, a professor of engineering and public policy and professor of mechanical engineering.
An associate professor of engineering and public policy, Inês Azevedo, commented as well: “With the binding federal policy in place, other federal and state policies that encourage or mandate alternative fuel vehicle sales as well as individuals who purchase AFVs in an effort to reduce petroleum use and gasoline consumption may be creating exactly the opposite effect — at least in the near term.”
The press release for the study explains:
The study finds that each time an alternative fuel vehicle, such as an electric vehicle, is sold, US fleet-wide emissions increase by 0 to 60 tons of carbon dioxide and gasoline consumption increases by 0 to 7,000 gallons, depending on the vehicle and year of sale.
“This effect peaks for electric vehicles in 2017, when the policy has its largest incentives,” stated Azevedo. “When one consumer buys an electric vehicle, it enables other consumers to buy higher-emitting vehicles than they would have been able to otherwise. In total, we estimate about 30 to 70 million metric tons of extra carbon dioxide emitted.”
That said, the researchers caution that these findings shouldn’t be used to disparage alternative-fuel vehicles (all-electrics, plug-in hybrids, etc) themselves — but, rather, current policy.
“A transition of the vehicle fleet away from petroleum and toward low-emission energy alternatives could produce an enormous amount of good in the long run,” continued Michalek. “So, depending on what you believe about how AFV adoption today will influence adoption patterns beyond 2025, it’s possible that encouraging adoption now might be worthwhile in the long run despite the short term disadvantages.”
Details on the new research findings can be found in a paper published in the March 2016 edition of Environmental Science & Technology.