The Sierra Club and Montana Environmental Information Center sent the owners of the coal-fired Colstrip power plant a July 25 letter that serves as official notice that they plan to file suit over alleged violations of the Clean Air Act at the plant.
The letter was sent to the plant co-owners, including PPL Montana LLC, Avista Corp., Puget Sound Energy, Portland General Electric, NorthWestern Energy and PacifiCorp.
Colstrip is a four-boiler coal-fired plant, with Units 1 and 2 at 307 net MW each, and Units 3 and 4 at 740 net MW each, the letter noted. Each of these four units releases numerous air pollutants, including SOx, NOx, CO2, carbon monoxide (CO), mercury, particulate matter, and others. The Sierra Club and MEIC are alleging violations of the Clean Air Act’s prevention of significant deterioration (PSD) requirements, violations of the Montana State Implementation Plan’s (SIP) requirement that the plant apply Best Available Control Technology (BACT), violations of requirements related to Part 70 Operating Permits, and violations of provisions regulating the opacity of emissions in the SIP and the Part 70 Operating Permit.
Under the PSD accusations, the groups said a number of physical changes have occurred at Colstrip that would result in emission increases of sulfur dioxide, nitrogen oxide, and particulate matter (including PM, PM10, and PM2.5). These changes include: a Unit 1 overhaul in 2012 that included the replacement of an economizer, condenser, V-Bottom tubes, a generator-exciter, and 3 ID fans; in 2008, the replacement of the HP/IP turbines for Unit 2; and in 2007, the replacement of the HP turbine for Unit 3. Air quality permits were never obtained for these modifications, the letter claimed.
The Title V applications and compliance certifications for Colstrip failed to identify PSD requirements (including BACT limits) as applicable requirements, incorrectly certified compliance with all applicable requirements and failed to propose a compliance schedule to meet PSD requirements (including BACT requirements), the letter claimed.
The plant’s own opacity data shows numerous violations of opacity limits over a period of time, the notice said. “We are giving you notice of each 6-minute period for which the average opacity exceeded the applicable opacity limitation as a separate, discrete violation of that limitation and the Clean Air Act,” it said. “The exact date and time(s) of each such violation is readily available to you. You reported the violations set forth above based on opacity monitoring equipment that you have at the Colstrip plant and that was used to compile and certify the plant’s emissions to the state agency.”
A brochure on the PPL Montana website says that Colstrip is one of the cleanest-emitting, coal-fired power plants in the U.S. It said, for example, that Unit 1 and 2 are in the top 25% of coal-fired plants for lowest SO2 emissions. In 2010, these units became one of the first coal-fired facilities in the country to control mercury achieving about 90% reduction in mercury emissions.