The two coal plants located in Washington and Oregon appear to be living on borrowed time. Portland General Electric has moved to close the Boardman coal plant by the end of the decade, and Washington’s governor is negotiating with the owners of the Centralia plant to phase out the coal it burns. That would reduce a sizeable chunk of each state’s greenhouse gas emissions. But does that mean that the states will be coal-free?

Not exactly.

In broad swaths of the Northwest, there’s a decent chance that some of the power consumers are buying comes from the Colstrip coal-fired power plant in eastern Montana. And depending on how far away you live, chances are also good that you’ve never heard of it, even though it’s a giant power producer that in 2008 generated nearly twice as much power as Centralia and more than four times more than Boardman. Accordingly, Colstrip is also a pretty giant polluter, as the charts below show:


Colstrip smog pollution chart

So where does Colstrip’s dirty electricity go? The utility with the largest ownership stake is Puget Sound Energy, which supplies power to more than a million homes and businesses, mostly in Western Washington. Its delivery area includes King, Kittitas, Kitsap, Island, Jefferson, Pierce, Skagit, Thurston and Whatcom counties. Even though the Colstrip plant is hundreds of miles away from PSE’s closest customer, its coal-fired power accounts for nearly a quarter of the power that the utility generates.

colstrip flickr ambimbThe other owners of the Colstrip coal plant include utilities that electrify toasters in Spokane, hair dryers in Astoria, washing machines in Walla Walla, light bulbs in Bend, laptops in Hood River, clocks in Coeur D’Alene and blenders in Butte and Bozeman. In short, Colstrip’s coal-fired power is all over the place, contradicting common perceptions that the Northwest’s power grid is super green.

Here’s a closer look at the utilities with an ownership stake in Colstrip —  the second largest coal plant west of the Mississippi—and to what degree they rely on it:


    Why bother to elaborate on this? Because as Washington’s and Oregon’s leaders start to talk about going coal-free, it’s important to remember that energy generation — and air pollution—doesn’t stop at state borders. In calculating a state’s greenhouse gas emissions, for instance, it’s not quite enough to look at how much coal is burned within its borders. To get a fair picture, you should probably consider how much electricity consumed in-state comes from coal — even if the coal is actually burned somewhere else.

    So if Washington Gov. Christine Gregoire is successful in weaning Centralia off coal and reducing its emissions, that would be a great accomplishment; just as PGE’s phaseout of Boardman is welcome news. But let’s not forget that there may still be millions of customers in Oregon and Washington getting their power from the even bigger coal plant next door.

    Notes on sources: CO2, MWh, NOx and SO2 data come fromthe EPA’s Clean Air Markets Data and Maps.

    Colstrip photo courtesy of flickr user ambimb under a Creative Commons license.