Every once in a while, I catch wind of a curious defense of the TransAlta coal-fired power plant in Centralia, WA:  that without a big coal plant smack between Seattle and Portland, the Northwest’s electricity grid could somehow become “unstable.”

To be clear, this is NOT a claim that the region will run out of power if the Centralia plant shuts down.  That’s an entirely separate (and arguably false) claim.  Instead, this is a deeply technical argument about electricity infrastructure: namely, that the region’s power grid was constructed and tested by engineers who assumed that the massive coal-fired power plant at Centralia would always be there.  Shutter that plant, and the complex transmission system might go subtly out of whack, raising the chances of a region-wide power outage.

To me, this sounds…well…awfully convenient for TransAlta, which is trying to extend the life of its carbon-belching, tax-subsidized monstrosity.  But at the same time, power grids are just wacky enough that it could be true.  After all, the Northeast blackout of 2003 was caused by a cascade of minor glitches, none of which seemed catastrophic on its own, but which ultimately left 55 million people without power.  So maybe, just maybe, shutting down Centralia could amp up the risk that small power-supply glitches could escalate into a catastrophic meltdown of the Northwest’s grid.

I’m not a power engineer, so I can’t really debate the merits here.  But I did play around with the numbers a bit.  Take a look at the chart below, which shows hourly power output from Centralia’s coal-fired generators from 2006 through 2009.  (Click the chart to see a bigger version.)

TransAlta is sometimes off

The bottom line is this:  Centralia already shuts down for months at a time.  Both boilers were shut down for 84 consecutive days in 2006, and for 75 consecutive days last year.  Each of the last three shutdowns occurred in late spring and early summer, when hydropower was peaking—meaning that the grid was well supplied with power.  But none of that power was actually coming from Centralia’s coal-fired burners.

So periodically, TransAlta withholds the magic grid-stabilization juju that its Centralia coal plant allegedly provides.  I haven’t noticed any mysterious power outages, have you?

  • Snark aside, there are some serious implications here.

    First, if Centralia’s coal-fired power plant is really so important for keeping the grid stable, then the chart above suggests that we need to fix the grid so that it’s no longer reliant on Centralia.  It’s not that we’ve got to keep the Centralia plant around, but rather that we need to move as quickly as possible to make Centralia irrelevant to grid stability.  Otherwise, the entire region’s power system is being held hostage to a Canadian multinational that from time to time decides to turn off a key stabilizing component. I mean, if a multinational corporation decided to disable the emergency brakes on my car every so often, then I’d sure as heck try to install new brakes!

    Second, it’s really not clear how important Centralia is for grid stability at all!  I’ll leave aside the obvious point that in the very recent past, the grid functioned just fine when Centralia was turned off. Perhaps we were just lucky, or perhaps hydropower—which tends to be running hot when coal is turned off—stabilizes the grid in a way that the abundant gas-fired power in the Seattle-to-Portland corridor simply can’t.  But if Centralia really were critical to grid stability, then you’d think that power engineers would be sounding the alarm every time both boilers were shut down, and that grid operators would be arguing for infrastructure upgrades to deal with the “the Centralia problem”.  Instead, the “grid stability” argument only seems to rear its head when someone points out the Centralia plant’s massive and probably unnecessary carbon footprint, or questions the various tax subsidies that TransAlta’s lobbyists have inexplicably been able to protect, even in a time of massive state budget woes.

    If I were in charge of the asylum, I’d try to figure this grid stability thing out as quickly as possible.  And if I found that stability were really a problem, I’d put people to work trying to upgrade the power grid—the sooner the better.  For the politicians who are trying to figure out Centralia’s future, that might make a nifty dance step, since the jobs created in building and maintaining a smarter, more resilient electricity grid would likely make up for jobs lost in shutting down a coal plant.  (Hint, hint.)