Sustainable Energy

Plug-In Hybrids: Tailpipes vs. Smokestacks

Plug-ins will lead to lower overall emissions, even if the electricity that powers them comes from coal.

Plug-in hybrids may one day constitute a majority of the cars on U.S. roads. Like today’s hybrids, they have both a gasoline engine and an electric-drive motor whose batteries can be recharged by the engine. But they can also be recharged at a standard wall socket. Given that they’ll raise electricity demand and increase power-plant emissions, will they really reduce overall ­greenhouse-gas production? It turns out that plug-ins always result in lower emissions than conventional cars do, and they beat regular hybrids handily–except when the electricity comes from coal (the source of 43 percent of U.S. electricity), according to a study. But as gasoline comes from dirtier oil sources, such as tar sands, plug-ins may win even when powered indirectly by coal, one study author says.

GM’s Chevy Volt concept car
This story is part of our March/April 2008 Issue
See the rest of the issue
Subscribe

Infographic by Tommy McCall

1. Incomplete data. 2. Partial-year sales figures. *Median projection
Sources: Comparisons and projections: Electric Power Research Institute
and Natural Resources Defense Council (www.epri-reports.org) ;
Hybrid sales figures: Electric Drive Transportation Association

Become an MIT Technology Review Insider for in-depth analysis and unparalleled perspective.
Subscribe today

Uh oh–you've read all five of your free articles for this month.

Insider Premium

$179.95/yr US PRICE

More from Sustainable Energy

Can we sustainably provide food, water, and energy to a growing population during a climate crisis?

Want more award-winning journalism? Subscribe and become an Insider.

  • Insider Premium {! insider.prices.premium !}*

    {! insider.display.menuOptionsLabel !}

    Our award winning magazine, unlimited access to our story archive, special discounts to MIT Technology Review Events, and exclusive content.

    See details+

    What's Included

    Bimonthly home delivery and unlimited 24/7 access to MIT Technology Review’s website.

    The Download. Our daily newsletter of what's important in technology and innovation.

    Access to the Magazine archive. Over 24,000 articles going back to 1899 at your fingertips.

    Special Discounts to select partner offerings

    Discount to MIT Technology Review events

    Ad-free web experience

    First Look. Exclusive early access to stories.

    Insider Conversations. Join in and ask questions as our editors talk to innovators from around the world.

  • Insider Plus {! insider.prices.plus !}* Best Value

    {! insider.display.menuOptionsLabel !}

    Everything included in Insider Basic, plus ad-free web experience, select discounts to partner offerings and MIT Technology Review events

    See details+

    What's Included

    Bimonthly home delivery and unlimited 24/7 access to MIT Technology Review’s website.

    The Download. Our daily newsletter of what's important in technology and innovation.

    Access to the Magazine archive. Over 24,000 articles going back to 1899 at your fingertips.

    Special Discounts to select partner offerings

    Discount to MIT Technology Review events

    Ad-free web experience

  • Insider Basic {! insider.prices.basic !}*

    {! insider.display.menuOptionsLabel !}

    Six issues of our award winning magazine and daily delivery of The Download, our newsletter of what’s important in technology and innovation.

    See details+

    What's Included

    Bimonthly home delivery and unlimited 24/7 access to MIT Technology Review’s website.

    The Download. Our daily newsletter of what's important in technology and innovation.

You've read of free articles this month.