How dirty is the TransAlta coal plant in Centralia, Washington? Eliminating TransAlta’s carbon emissions would be like taking every car and truck off the road in King County, plus every car and truck in Yakima County, Lincoln County, Columbia County, and Garfield County.

centralia comparison

Or put another way, phasing out the TransAlta plant hasthe same climate significance as magically making every car and truck zero emissions in Washington’s most populous county, plus a decent swath of Eastern Washington to boot.

You could slice the data in different ways, of course. TransAlta’s emissions are also equivalent to:

  • All the driving in King County and Kitsap County.
  • All the driving in Eastern Washington plus all of southwest Washington (or all of Eastern Washington plus all of northwest Washington).

You get the idea. Replacing the Centralia power with clean alternatives—like renewable energy or conservation—would be just as effective climate-wise as taking 1 out of every 3 cars and trucks off the road statewide. So it’s a very big deal.

And when you think about how much we’re spending on driving alternatives, the TransAlta question looms even larger. Consider, for example, that voters recently approved an $18 billion package of light rail expansion in the greater Seattle area. And while support for transit has to do with a lot more than greenhouse gas emissions, it would be a shame if all that money—and all that public goodwill—were, in the end, swamped by the carbon emissions from the state’s single biggest polluter.

Notes: The emissions data I used for these calculations come from Washington’s official greenhouse gas inventory. I used 10.1 MMtCO2e for the TransAlta plant based on the second figure on page A-3. For statewide driving-related emissions, I combined the 2005 figures for on-road gasoline and on-road diesel emissions for a total of 31.1 MMtCO2e. To derive county-level driving emissions, I assumed that each county’s share of total state on-road emissions are exactly proportional to its share of the state’s total population. (This assumption verylikely overstates theactual emissions from urban counties, like King County, where per capita driving is lower than in rural counties.) Population shares were calculated from Washington’s official population counts published by the Office of Financial Management. All comparisons in this post are annual. The original map image is from the public domain available at the WikiMedia Commons; modified by Christine Winckler.