A law signed by Governor Chris Gregoire on Friday phases out coal-fired power production in Washington State with the closure of two coal boilers at TransAlta’s Centralia power plant.

The law, SB 5769, requires that the plant’s two coal boilers meet the state’s emissions performance standard for new and modified power plants, which will require the boilers to shut down. The standard will apply to one boiler on Dec. 31, 2020, and to the other boiler on Dec. 31, 2025—essentially ending coal-fired power in Washington State in the next 14 years.

In 2013, TransAlta plans to install additional air pollution control technology to further reduce emissions of nitrogen oxides at the plant. It will also be allowed in the interim to sell coal power under long-term contracts within Washington. This measure will give the company the financial stability needed to transition to a cleaner source of energy, the governor’s office said.

“The TransAlta plant is the state’s largest single industrial source of nitrogen oxide emissions,” the governor’s office claimed, though Gov. Gregoire hailed the Centralia plant as “a critical part of the regional economy.” TransAlta President and CEO Steve Snyder said his was a progressive company that would strive to produce more electricity with less environmental impact.

In 2009, Gregoire signed an executive order directing the Department of Ecology to work with TransAlta on an agreement that would apply the greenhouse gas emissions performance standards by no later than December 31, 2025. The law established on Friday culminates two years of negotiations that produced an agreement between the company, the environmental community, and the state, the governor’s office said.

Sources: POWERnews, Gov. Chris Gregoire