Cars Technica —

Could more electric cars mean greater fleet emissions and fuel consumption?

There might be near-term unintended consequences of emissions standards.

Individual tax credits and rebates aren't the only policy levers we use to try and increase the adoption of electric cars and other alternative fuel vehicles. The Environmental Protection Agency and the National Highway Traffic Safety Administration both have quite a lot to say about the matter as well, especially through rules that set fleet-wide standards for both fuel efficiency (the Corporate Average Fuel Efficiency, or CAFE standards) and an associated Greenhouse Gas Emission standard. But a new paper from Jeremy Michalek and colleagues suggests that the incentives built into those standards—meant to encourage the uptake of alternative fuel vehicles—might actually increase fuel consumption and CO2 emissions.





Researcher Jeremy Michalek and his colleagues at Carnegie Mellon calculated the net effects of the alternative fuel incentives from 2010 through 2025 using projection data from the Energy Information Agency. They found that the effects of the EPA and NHTSA weighting may actually increase the amount of CO2 emitted over that timeframe by between 30 and 70 million tons—equivalent to relaxing the GHG standard by between 0.8 and 1.5 percent. That also means using an extra 3-8 billion US gallons (11-30 billion L) of gasoline over the same period.

We've previously looked at the way that EV incentives have unintended consequences, and their effects are not equal. The picture here in the US is complicated by state emissions and economy standards that can concentrate cleaner vehicles in some areas (like California) at the expense of other states that don't care what comes out of a tailpipe.

Ideally, getting a cleaner US passenger car and light truck fleet would be achieved through other policy levers, like an escalating federal gasoline tax or proper carbon pricing that reflects the externalities of fossil fuels. But the level of gridlock in Congress shows no signs of changing any time soon, making these goals politically unrealistic. For now, government agencies tasked by Congress to improve fuel efficiency and decrease climate emissions are restricted to using existing mechanisms already under their control. But as Prof. Michalek told Ars, it's possible that in the near term, those might not work exactly as well as intended.

DOI: 10.1021/acs.est.5b02842 (About DOIs).

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