Are Plug-In Electric Cars Dirtier Than Regular Hybrids?

A common argument against electric vehicles goes something like this: The majority of our power still comes from coal, so plugging in EVs to a coal-powered grid isn’t any better than using gasoline-powered vehicles. A new report from MIT supports that argument–sort of.

ChargePoint EV charging station


There’s a common argument against electric vehicles that goes something like this: the majority of our power still comes from coal, so plugging in EVs to a coal-powered grid isn’t any better, and may even be worse, than using gasoline-powered vehicles. A new report from MIT, The Electrification of the Transportation System: Issues and Opportunities, supports that argument–sort of.

According to MIT, plug-in hybrids fueled by coal-fired power plants have lower emissions than gas-powered cars, but higher CO2 emissions than conventional hybrids. Plug-ins that are juiced up by carbon-free electricity (i.e. nuclear, biomass, solar), cut CO2 emissions by 66% compared to gas-powered vehicles, while traditional hybrids containing both an internal combustion engine and an electric motor only cut emissions by 33%. What can be done to make sure that plug-ins reach their maximum CO2-saving potential?

MIT suggests that state and federal bodies establish carbon emissions policies that sway the electricity generation mix to cleaner alternatives. The university offers a number of suggestions:

Government could provide funding derived from carbon-indexed fuel taxes, where a higher tax would be imposed on fuels higher in carbon (on a life-cycle basis). Carbon-indexed fuel taxes would have a relatively modest effect at first in transforming fuels or reducing fuel use, but they could be a source of revenue initially to support new fuel infrastructure. With future vehicles likely outfitted with transponder devices that could be coded with the vehicles’ certified greenhouse gas attributes, it would be possible for vehicles to communicate with the fuel pump (or electricity charger) to determine the correct tax. Incentives to develop low-carbon fuel infrastructure could also come from the auctioning of emission credits under a carbon cap-and-trade program.

MIT’s study clearly can’t be used as fodder for those who would rather not see electric vehicles succeed. But it does show how an electric vehicle revolution can’t be led by automakers alone; it’s a process that will involve utilities, governments, and communities.

Ariel Schwartz can be reached on Twitter or by email.


About the author

Ariel Schwartz is a Senior Editor at Co.Exist. She has contributed to SF Weekly, Popular Science, Inhabitat, Greenbiz, NBC Bay Area, GOOD Magazine and more.