The U.S. Environmental Protection Agency is proposing a Federal Implementation Plan (FIP) to address regional haze in the state of Montana following the state’s decision in 2006 to not submit a regional haze State Implementation Plan (SIP) revision.
EPA said in a March 20 decision document, which is due to be published in the Federal Register, that the FIP satisfies requirements of the Clean Air Act (CAA) that require states, or EPA in promulgating a FIP, to assure reasonable progress towards the national goal of preventing any future and remedying any existing man-made impairment of visibility in mandatory Class I areas.
Public hearings are planned in Helena, Mont., on May 15, and in Billings, Mont., on May 16.
EPA noted in the 305-page finding that Montana identified a number of sources to be Best Available Retrofit Technology (BART)-eligible and that it has agreed to find these facilities as BART-eligible: Ash Grove Cement Co.; Cenex Harvest States Cooperative, Laurel Refinery; PPL Montana LLC, Colstrip power plant coal Units 1 and 2; PPL Montana, JE Corette coal plant; Columbia Falls Aluminum Co. LLC; ExxonMobil Refining & Supply Co., Billings Refinery; Holcim (US) Inc.; Montana Sulfur & Chemical Co.; and Smurfit-Stone Container Enterprises Inc., Missoula Mill. The two other Colstrip coal units are not subject to BART. PPL Montana is a unit of PPL Corp. (NYSE:PPL).
The BART Guidelines in the Regional Haze rule requires that EPA address SO2, NOx, and direct PM (including both coarse particulate matter (PM10) and PM2.5) emissions as visibility-impairing pollutants.
Colstrip Units 1-2. These boilers have a nominal gross capacity of 333 MW each. The boilers began commercial operation in 1975 (Unit 1) and 1976 (Unit 2) and are tangentially fired pulverized coal boilers that burn Powder River Basin (PRB) sub-bituminous coal as their exclusive fuel.
For Colstrip Unit 1, EPA proposes that the NOx BART emission limit should be based on what can be achieved with separated overfire air (SOFA) plus selective non-catalytic reduction (SNCR). The proposed BART emission limit of 0.15 lb/MMBtu allows for a sufficient margin of compliance for a 30-day rolling average limit that would apply at all times, including startup, shutdown, and malfunction.
Colstrip Unit 1 is already controlled by wet venturi scrubbers for simultaneous particulate and SO2 control. The venturi scrubbers utilize the alkalinity of the fly ash to achieve an estimated SO2 removal efficiency of 75%. EPA proposes that the SO2 BART emission limit for Unit 1 should be based on what can be achieved with lime injection with an additional scrubber vessel. The proposed BART emission limit of 0.08 lb/MMBtu allows for a sufficient margin of compliance for a 30-day rolling average limit that would apply at all times, the agency said.
At Colstrip Unit 2, EPA said the NOx BART emission limit should be based on what can be achieved with SOFA plus SNCR. The proposed BART emission limit of 0.15 lb/MMBtu allows for a sufficient margin of compliance for a 30-day rolling average limit that would apply at all times.
Colstrip Unit 2 is already controlled by wet venturi scrubbers, which are identical to the Colstrip Unit 1 scrubbers, for simultaneous particulate and SO2 control. EPA proposes that the SO2 BART emission limit for Colstrip Unit 2 should be based on what can be achieved with lime injection with an additional scrubber vessel. The proposed BART emission limit for SO2 is 0.08 lb/MMBtu.
Again, EPA found that the particulate BART limit for Unit 2 can be met with the existing venturi scrubbers.
Corette. PPL Montana’s Corette plant consists of one unit with a nominal gross capacity of 162 MW. The boiler began commercial operation in 1968 and is a tangentially fired pulverized coal boiler that burns PRB sub-bituminous coal as the exclusive fuel. Although the gross capacity of Corette is below the 750 MW cutoff for which use of the BART Guidelines is mandatory, EPA said it nonetheless followed the guidelines as they provide useful advice in implementing the BART provisions of the regional haze rule.
The Corette boiler has existing low-NOx burners and close-coupled overfire air system. The unit is subject to an annual NOx emission limit of 0.4 lb/MMBtu. The cost of further controls is not justified by the regional haze visibility improvement, EPA decided.
The Corette boiler currently burns very low-sulfur PRB sub-bituminous coal with a sulfur content of 0.3% by weight. The boiler is subject to a fuel sulfur limit of 1 lb/MMBtu (as fired) on a continuous basis. EPA weighed technologies like dry sorbent injection to further control SO2, but concluded that no technology investment is justified by any visibility improvement. “In proposing a BART emission limit of 0.70 lb/MMBtu, we evaluated the existing emissions from the facility and determined this rate to allow for a sufficient margin of compliance for an annual average limit that would apply at all times, including startup, shutdown, and malfunction,” EPA said.
Corette currently has an electrostatic precipitator (ESP) for particulate control that is designed to achieve a 96% control efficiency, but is currently operating at 98.5%. The present emission annual average filterable particulate emission rate is 0.082 lb/MMBtu. The PM contribution to the baseline visibility impact for Corette is very small; therefore, any visibility improvement that could be achieved with improvements to the existing PM controls would be negligible, EPA noted. “We find that the BART emission limit can be achieved through the operation of the existing ESP.”
WildEarth Guardians goes wild over the FIP
WildEarth Guardians, a frequent critic of EPA and coal-fired power in general, slammed the proposed Montana FIP in a March 21 statement. “The EPA’s proposal lets dirty energy off the hook when it comes to safeguarding clean air in Montana,” said Jeremy Nichols, WildEarth Guardians’ Climate and Energy Program Director. “For a state defined by its skies, this proposal is a step backward.”
The EPA’s proposal was spurred by a lawsuit filed by WildEarth Guardians in 2011 over the agency’s failure to clean up haze pollution in National Parks and wilderness areas as required by the Clean Air Act, the environmental group said. Under the law, the EPA is required to ensure the oldest and dirtiest sources of air pollution be retrofitted with up to date emission controls, called BART Above all, the law requires that reasonable progress be made in reducing haze so that by 2064, natural visibility in restored.
The need to reduce haze is critical in Montana, with some of the state’s most iconic landscapes—including Glacier National Park, Yellowstone National Park, the Bob Marshall Wilderness Area, and more—being on average nine times hazier than normal. The same pollutants that form haze also negatively impact public health, the group said.
Under its FIP proposal, the EPA itself admits that the plan will not make reasonable progress in reducing haze in Montana’s National Parks and wilderness areas, the group said. The reason is because the agency proposed to control emissions at only a handful of sources of air pollution, and even then, proposed less stringent emission controls than have been adopted in other states.
“In Montana, the key sources of haze forming pollution are the state’s coal-fired power plants, including the 2,200 megawatt Colstrip power plant, which is the second largest coal-fired power plant west of the Mississippi River,” WildEarth Guardians said. “These plants release thousands of tons of haze forming nitrogen oxides and sulfur dioxide gases. Other sources include cement kilns.”
PPL describes regional haze history
PPL Corp.’s Feb. 28 annual Form 10-K report said about the regional haze issue facing PPL Montana. “In Montana, the EPA Region 8 is developing the regional haze plan as the Montana Department of Environmental Quality declined to develop a BART state implementation plan at this time. PPL submitted to the EPA its analyses of the visibility impacts of sulfur dioxide, nitrogen oxides and particulate matter emissions for Colstrip Units 1 and 2 and Corette. PPL’s analyses concluded that further reductions are not warranted. The EPA responded to PPL’s reports for Colstrip and Corette and requested further information and analysis. PPL completed further analysis and submitted addendums to its initial reports for Colstrip and Corette. In February 2009, PPL received an information request for data related to the non-BART-affected emission sources of Colstrip Units 3 and 4. PPL responded to this request in March 2009.”
In November 2010, PPL Montana received a request from the EPA Region 8, under the EPA’s Reasonable Further Progress goals of the Regional Haze rules, to provide further analysis with respect to Colstrip Units 3-4. PPL said it completed a high-level analysis of various control options to reduce emissions of SO2 and particulate matter for these units, and submitted that analysis to the EPA in January 2011. The analysis shows that any incremental reductions would not be cost effective and that further analysis is not warranted. PPL also concluded that further analysis for NOx was not justifiable as these units installed controls under a consent decree in which the EPA had previously agreed that, when implemented, would satisfy the requirements for installing the BART for NOx.