TransAlta's Centralia Coal Plant Plans to Cut Mercury Emissions to 200 Pounds Per Year

A hazy Mount Rainier

Coal, you may be surprised to learn, here in the cradle of hydroelectric power, supplies about eight to ten percent of Washington's electricity. That's thanks to a single coal-fired plant in Centralia, owned since 2000 by Canada's TransAlta, proponents of "the greening of power generation." Not coincidentally, the plant was also responsible for "11 percent of the state’s 99 million metric tons of carbon dioxide equivalents (MMT CO2e) in 2008."

(Speaking of green, Seattle can feel smug about the fact that Seattle City Light gets over twice as much electricity from wind power as from coal.)

This week, after months of negotiation, the Department of Ecology and TransAlta announced an Agreement and Consent Decree that will govern the plant's emission of smog-producing pollutants and mercury vapor. Essentially, Ecology (as the department troublingly synechdochizes itself) argues that it got the best voluntary deal from TransAlta it could, and on a faster implementation timeline, than if it instituted mandatory requirements. Sightline sighs in exasperation at this, along with a host of conservation and environmental groups.

Mercury emissions are to be reduced by half by 2012. (Half of what? The Ecology staffer I spoke with didn't have the precise numbers in front of him, but elsewhere in the agreement documentation there's reference to cutting mercury emissions by 200 pounds--indicating 400 pounds of mercury are released annually. [See UPDATE below.]) To be fair, TransAlta thinks they may achieve 70 percent--they just wanted some regulatory cushion, apparently.

TransAlta's existing controls for haze-causing pollutants will be deemed "good enough." TransAlta says they've invested $300 million in pollution controls since they took over the plant, reducing sulfur dioxide emissions by up to 90 percent. (They've also stopped burning Centralia coal and switched to cleaner-burning stuff from Powder River Basin.)

Controversially, the National Park Service and U.S. Forest Service have gone on record to say the haze the plant currently produces is unacceptable. (Besides obscuring visibility, atmospheric pollution is linked to higher asthma rates.) Yet the agreement not only maintains current pollution levels (12,000 tons of nitrogen oxides), but shelters TransAlta from any new regulatory demands until 2018.

"Ecology has agreed not to request additional NOx reductions from TransAlta in 2018 because that date is only a few years from the current analysis," says Ecology. "Eight" is not considered "a few" in the English language. The real driver would seem to be the memorandum of understanding (pdf) that the state and TransAlta have that the coal-fired plant will be shut down by 2025.

Given that window, Ecology felt that TransAlta's commitment to "the greening of power generation" did not extend to refraining from multimillion-dollar, years-long legal suits in reaction to nitrogen oxide and other pollutant regulation: "Instead of litigating the question of whether TransAlta is subject to BART, Ecology and TransAlta were able to agree and move forward on a BART determination for NOx that meets the requirements of the federal Regional Haze Rule."

Regarding mercury emissions, TransAlta's comment on the agreement notes that they were "preparing to comply with Ecology's proposal when the CAMR was overruled by a federal court." CAMR, the Clean Air Mercury Rule, was a Bush-era attempt to exempt utilities from the stringencies of the Clean Air Act, so the news that TransAlta was "preparing to comply" with lesser requirements is a little disingenuous.

That said, no business wants to invest millions to meet regulatory goals only to have the goalposts move. While most states are just standing around waiting for the EPA to come up with new mercury regulations, twelve have mandated strict reductions of up to 90 percent. Washington, led by Governor Gregoire, is choosing not to join that group. Gregoire has also fought stoutly to maintain TransAlta's $4-milllion-per-year tax exemption, which she says she needs as a bargaining chip.

Centralia itself is likely divided on the issue. The Department of Ecology's news release mentions that "more than 370 union and non-union employees work for TransAlta and more than 300 full-time contractors support Centralia’s ongoing operation. The average salary for a TransAlta employee in 2007 was $88,520." It does not bother to add up the cost of mercury contamination of the fish supply, or asthma treatment, to name two more obvious externalities. 

Washington Toxics Coalition staff scientist Erika Schreder notes, "Mercury is a persistent toxic chemical that doesn't break down in the environment, and in fact builds up in the food chain. One of the biggest concerns we have about mercury is that exposure during fetal development can harm the nervous system."

The U.S. EPA RfD for methyl mercury is 0.1 µg/kg body weight/day, and the EPA estimates that "more than 300,000 newborns each year may have increased risk of learning disabilities associated with in utero exposure to methylmercury."

UPDATE: The Department of Ecology's Alan Newman got back to me with the mercury emission data from 2008 (306 lbs.) and 2009 (354 lbs.). The previous 400-lb. annually figure was an estimate, but these measurement came from monitoring the plant stack emissions. Newman also confirmed that state's mediation agreement is superseded by the EPA's upcoming Boiler regulations, which on a national scale would prevent, it's estimated, "between 2,000 and 5,200 premature deaths, and about 36,000 asthma attacks a year."