Huge news from Oregon today: Portland General Electric is planning to shut down the state’s only coal plant by 2020, years earlier than expected. From the Oregonian:

Based on its analysis of carbon and natural gas prices, however, PGE maintains that a 2020 shutdown would be the low-cost, least-risk plan for utility ratepayers and shareholders. Under the existing plan, both face the risk of making the huge investment to control haze causing pollution—which does nothing to control the plant’s carbon emissions—then seeing the plant close anyway if global warming legislation or a carbon tax makes its output prohibitively expensive.

Shutting down PGE’s Boardman coal plant would decrease Oregon’s carbon emissions by 8 percent when calculated on an electricity-generation basis. That plant is the single largest source of emissions in Oregon, so the news today marks a very significant milestone in the Northwest’s movement toward smart climate policy.

Meanwhile, Washington appears to be lagging. As Jennifer Langston documented in her first-rate coverage—Coal Cuts: Oregon vs. Washington—the Evergreen State appears to be taking a more lenient approach to regulating pollution from Washington’s only coal plant, the TransAlta facility in Centralia.

Like Boardman, the long-term financial viability of the Centralia plant depends in large part on how much of its air pollution it is required to clean up. But because Washington’s clean-up targets are less serious than Oregon’s, there’s less pressure on Centralia to switch away from coal—a move that would also result in a huge savings in greenhouse gas emissions.

Two final points:

1.) This doesn’t solve Oregon’s climate emissions problem. In fact, when calculated on an electricity-consumption basis, the state currently relies on coal for 38 percent of its electricity, as opposed to just 17 percent in Washington. (See Jennifer’s post, A Lump of Coal in Your Outlet. for more details.)

2.) The Boardman shut-down is a win for cap and trade. How so? Because the plant’s majority owners, PGE, know that carbon pricing is coming at some point. Responsible to their ratepayers and shareholders, they must manage their risks and take steps to controls costs—and that means moving away from carbon-intensive power.

In other words, PGE’s move is precisely the sort of smart early action that results from policies like the Western Climate Initiative and federal climate policy, even though neither yet has the force of law. What’s more, shutdowns like this one will make it easier and cheaper to meet our emissions targets when we do eventually have a firm carbon cap in place.

The question now is whether Washington policymakers will start getting more aggressive about moving the state’s electricity portfolio away from coal.

Update 12:30: Not everyone thinks today’s announcement goes far enough. Friends of the Columbia Gorge and the Oregon Sierra Club are arguing that PGE’s own analysis shows that a 2014 shut-down would be more cost-effective and climate-friendly.