Now, here’s something I didn’t know: since mid-2007, electric utilities have added a total of 1,360 megawatts of new electricity generation capacity in the Seattle-to-Portland corridor.

First the details.  Then I’ll explain why this number is so important.

Why do I mention this?  Well, because the 1,360 megawatts of brand-new, highly efficient generating capacity are nearly equal to the maximum generating capacity of the coal-fired power plant located in Centralia, Washington.  Take a look at the chart below:  the pink represents actual hourly generation from Centralia’s coal-fired power plant from 2006 though 2008, and the green line represents the peak capacity of new gas-fired plants that have been brought online since mid-2007. (Click the chart to embiggen…)

centralia coal vs. new gas

Looking at the numbers, the new gas generating capacity, if fully utilized, could have completely covered Centralia’s power output a little over 75 percent of the time.  And in theory, these new gas plants were just 104 MW shy of covering Centralia’s coal-fired power output over the entire three-year period.

  • Now, here’s the thing. The Centralia coal plant, owned by Canadian energy giant TransAlta, happens to be the single largest greenhouse gas emitter in Washington state.  It’s also a major source of conventional air pollutants, like smog-forming compounds and mercury.  In fact, the National Park Service says that the Centralia plant is the third worst of all power plants in the nation for degrading visibility at wilderness areas and national parks—a testament both to how dirty Centralia is, and how close it is to natural areas.

    So a lot of folks in the Northwest have been calling for an accelerated shutdown for Centralia—asking Washington to follow the lead of Oregon, where aggressive regulation convinced owners of the Boardman to phase it out by 2020.  But Washington hasn’t been nearly as quick on its feet about Centralia as Oregon has been about Boardman—in part because the state is concerned that phasing out Centralia will make it harder to keep the lights on in Seattle and Portland.

    But given all the new gas plants that have been added to the grid, perhaps Centralia is no longer quite so critical to the region’s power picture.  Of course, I’m not saying that turning off Centralia is a no-brainer.  Still, given how much new gas power has come online in the past few years—not to mention about 1,000 megawatts of new wind power in the state since 2007, or the fact that Satsop is asking to add an additional 650 MW of gas power at the Grays Harbor facility—you have to wonder if ramping down Centralia is actually a lot less of a stretch than one the conventional wisdom says.