Proposed coal-fired electric-generation

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Jennifer Cora Russell
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feature em Proposed coal-fired electric-generation projects in the eastern United States must adopt creative approaches to mitigate future and existing adverse impacts on designated Class I areas.

1 feature em Proposed coal-fired electric-generation projects in the eastern United States must adopt creative approaches to mitigate future and existing adverse impacts on designated Class I areas. Class I areas (e.g., wilderness areas and national parks) are classified by Congress as those areas that are areas afforded the least deterioration in air quality. These projects face a unique situation in that the region s abundant reserves of high-sulfur coal are generally located in or adjacent to states with several Class I areas. Projects that choose to locate close to the coal reserves, to minimize fuel transportation costs and thus make the project The Longview Power Project s selected BACT produced compliance with all air quality impacts, except for Class I visibility and acid deposition. more financially viable, are faced with being located within the modeling range of several Class I areas. The proposed Longview Power Project is one such project. Located near Morgantown, WV, it is adjacent to several coal reserves and within 300 km of four Class I areas: Dolly Sods Wilderness, Otter Creek Wilderness, James River Face Wilderness, and Shenandoah National Park. One approach for improving air quality in Class I areas that is gaining attention and proving to be effective is the Louis M. Militana, QEP, is managing partner with AAQS Inc. in Lincoln University, PA; Cindy Huber is an air resource specialist with the U.S. Department of Agriculture, Forest Service; Christopher Colbert is vice president of coal development with GenPower; Chris Arrington is an air quality modeler with the West Virginia Department of Environmental Protection, Division of Air Quality; and Don Shepherd is an environmental engineer with the U.S. Department of Interior, National Park Service. lmilitana@aaqsinc.com. implementation of emissions cap-and-trade programs. Examples of successful trading programs include the acid rain program and the nitrogen oxides (NO x ) budget program. More recently, the U.S. Environmental Protection Agency (EPA) proposed a cap-and-trade program as an alternative to the current nitrogen dioxide (NO 2 ) Prevention of Significant Deterioration (PSD) increment for attainment in unclassified and Class I areas (70 FR 8880; February 23, 2005). This article describes a similar approach for acid deposition and visibility impacts from the proposed Longview Power Project in four Class I areas. Part I discusses the air quality impacts of the proposed project. Part II (to be published in next month s EM) discusses the mitigation plan developed to reconcile the gap between generally acceptable emissions limits and the predicted adverse visibility and acid deposition impacts on Class I areas. PERMITTING REQUIREMENTS The proposed Longview Power Project is a 600-MW coalfired power plant to be located in Maidsville, WV, near Morgantown. The plant s design features a pulverized coal 30 em july 2005 Copyright 2005 Air & Waste Management Association awma.org

Figure 1. Location of Class I areas. (PC) supercritical boiler with a once-through, balanced-draft, single reheat steam turbine/generator burning 2.5% sulfur (nominal) bituminous coal.

2 Figure 1. Location of Class I areas. (PC) supercritical boiler with a once-through, balanced-draft, single reheat steam turbine/generator burning 2.5% sulfur (nominal) bituminous coal. The project began the preconstruction air quality permitting process in February 2003 with the submittal of a PSD permit application to West Virginia Department of Environmental Protection (WVDEP). The permit application contained a Best Available Control Technology (BACT) demonstration and a demonstration of compliance with all air quality impacts (i.e., National Ambient Air Quality Standards [NAAQS] and PSD increments), except for Class I visibility and acid deposition. The project s predicted sulfur dioxide (SO 2 ) emissions showed potential impacts well above the Federal Land Managers (FLM) thresholds for visibility and acid deposition. Under the PSD preconstruction permitting regulations, BACT applies to major new sources or major modifications to existing sources located in attainment areas that result in a significant increase of regulated pollutant emissions. The Longview Power Project triggered PSD review because (a) the project area is in attainment or not classifiable for all criteria pollutants, (b) the plant is listed as a 100 t/yr major stationary source under 40 CFR 52.21, and (c) its potential to emit (at least) one criteria pollutant is greater than 100 t/yr. Consequently, the project s developers were required to prepare and submit a PSD permit application to WVDEP (the local permitting agency), including BACT and air quality impact analyses for Class I and Class II areas. Each of these is discussed below. The PSD permitting regulations provide for a system of area classifications, which affords states an opportunity to identify local land use goals. Class I areas are allowed only a small degree of air quality deterioration, while Class II areas can accommodate normal wellmanaged industrial growth. BACT ANALYSIS The BACT analysis for the Longview Power Project followed EPA s top-down approach, outlined in its Draft New Source Review Workshop Manual. 1 BACT determinations were conducted for emissions of SO 2, particulate matter (PM), PM less than or equal to 10 micron (PM 10 ), carbon monoxide (CO), NO x, volatile organic compounds (VOCs), sulfuric acid (H 2 SO 4 ), and beryllium (Be). BACT determinations are case-by-case analyses that involve an assessment of the availability of applicable technologies capable of sufficiently reducing the emissions of a specific pollutant, as well as the economic, energy, and environmental impacts of each technology. The results of the initial BACT analysis for the Longview Power Project and a comparison of the BACT emissions limits awma.org Copyright 2005 Air & Waste Management Association july 2005 em 31

3 Figure 2. Modeling domain boundaries. to the permits limits of other recent and comparable projects are shown in Tables 1 and 2, respectively. The initial BACT emissions limits were used in the air quality impact analysis for Class I areas. This is discussed below. AIR QUALITY IMPACT ANALYSIS An assessment of potential adverse impacts on visibility and other air quality-related values in Class I areas is required by all PSD applicants. Air quality impacts at Class I areas must be assessed under PSD regulations if they are within 100 km of the source or if the source is judged to have a potential adverse impact on Class I areas at distances over 100 km. Four Class I areas are located within 300 km of the proposed Longview Power Project site: Dolly Sods Wilderness (91 km southeast), Otter Creek Wilderness (78 km south-southeast), James River Face Wilderness (237 south-southeast), and Shenandoah National Park (173 km southeast). Figure 1 shows the locations of the Class I areas relative to the proposed project site. The model used in the Class I area air quality modeling analysis was the EPA-approved air dispersion model, CALPUFF. The procedures used in conducting the modeling analysis followed the requirements outlined in EPA Guideline on Air Quality Models; 2 Federal Land Managers Air Quality Related Values Workgroup (FLAG), Phase I Report; 3 Interagency Workgroup on Air Quality Modeling, Phase 2 Report; 4 and guidance provided by the West Virginia Division of Air Quality and FLM. Brief descriptions of the selected air quality model, input data, and modeling procedures are presented in the following sections. Air Quality Model The CALPUFF air dispersion modeling system, which includes CALMET and CALPOST, 5 was used to predict air quality impacts at the four Class I areas. CALPUFF is a multilayered, non-steady-state puff dispersion model and is routinely used to evaluate long-range transport and Class I area impacts. The CALMET program generates the three-dimensional meteorological data used by CALPUFF, while the CALPOST program processes the CALPUFF model outputs and calculates the visibility impacts, concentration levels, and deposition amounts. CALPUFF was used with the default dispersion settings contained in the Phase 2 Report. 4 The model was also used in a refined mode in a manner that is consistent with the guidance, 3,4 except that it was agreed that only one year of meteorological data would be sufficient for analysis in this case. 32 em july 2005 Copyright 2005 Air & Waste Management Association awma.org

4 Receptor Grid The CALPUFF receptor grid comprised multiple air quality modeling receptors located at 500-m intervals within the Dolly Sods, Otter Creek, and James River Face Class I areas, and at 1000-m intervals within Shenandoah National Park. The elevation for each receptor was determined by selecting the maximum elevation falling within the area, extending halfway to the neighboring receptors. U.S. Geological Survey digital elevation model data (90-m spacing) and a geographical information system were used to determine the maximum elevation for each receptor. A total of 129 receptors were used for Dolly Sods, 305 for Otter Creek, 132 for James River Face, and 840 for Shenandoah National Park. Meteorological Data CALPUFF requires an extensive array of meteorological data to successfully perform its dispersion modeling calculations. Multiple meteorological data sources were used for this analysis, including Four Dimensional Data Assimilation (FDDA) Mesoscale Meteorological (MM) data, representative National Weather Service (NWS) data, and Clean Air Status Table 1. Summary of initial BACT determination for the Longview Power Project. Emissions Limit / Pollutant Averaging Period BACT SO lb/mmbtu / 3-hr Wet FGD average 0.12 lb/mmbtu / 24-hr average PM/PM lb/mmbtu / Baghouse (Total 6-hr average filterable and condensable) CO 0.11 lb/mmbtu / Proper boiler design and good combustion practice 3-hr average NO x 0.08 lb/mmbtu / Dry low-no x burners with SCR 24-hr average VOC lb/mmbtu / Proper boiler design and good combustion practice 3-hr average H 2 SO lb/mmbtu / DSI/baghouse 24-hr average Be and As 99% control DSI/baghouse Hg 80% control SCR and DSI/baghouse and WFGD HCl, HF 99% control DSI/baghouse and WFGD Benzene NA Proper boiler design and good combustion practice NA = Not applicable; WFGD = wet flue gas desulfurization; SCR = selective catalytic reduction; DSI = dry sorbent injection. and Trends Network (CASTNET) data. One year s worth of Mesoscale Meteorological Model 5 (MM5) 36-km grid data (1996), in combination with all concurrent NWS and CASTNET meteorological data (both surface and upper air stations) within the modeling domain, were used as input Table 2. Comparison of the Longview Power Project s emissions limits to other recent PSD permits. SO 2 PM NO x Emissions Emission Emissions Facility Name/Location Boiler Capacity Limits Control Limits Control Limits Control Type (MW) (lb/mmbtu) Type (lb/mmbtu) Type (lb/mmbtu) Type Longview Power Project, WV PC WFGD FF 0.08 SCR Black Hills Power-Wygen, WY PC DFGD FF 0.09 LNB/SCR Bull Mountain-Roundup, MT PC DFGD FF 0.07 LNB/SCR Kansas City P&L-Hawthorne, KC PC DFGD FF 0.08 SCR LS Power-Five Forks Energy, VA PC 2x WFGD FF 0.10 SCR LS Power-Plum Point Energy, AR PC 2x DFGD FF 0.10 SCR Mustang, NM PC CDS FF 0.09 SCR N. American Power-Mid PRB, NM PC 1x DFGD FF SCR Prairie State Gen, IL PC 2x WFGD WFGD/ 0.09 LNB/SCR WESP Rocky Mountain Power-Hardin, MT PC WFGD WFGD 0.09 SCR Santee Cooper Cross 3&4, SC PC 2x WFGD FF 0.07 SCR Thoroughbred, KY PC 2x WFGD WFGD/ 0.09 SCR WESP Tucson Electric Power, AZ PC 2x DFGD NA 0.15 NA Two Elk #2, WY PC 1x DFGD FF SCR Rawhide PC DFGD NA NA NA NA Bonanza PC WFGD NA NA NA NA InterMountain W-DB-PC WFGD FF 0.07 LNB/SCR STEAG-Desert Rock PC WFDG FF 0.06 SCR NA = Not applicable; PC = pulverized coal; WFGD = wet flue gas desulfurization; DFGD = dry flue gas desulfurization; W-DB-PC = WFGD, dry bottom, pulverized coal; WFGD/ WESP = WFGD with wet electrostatic precipitator; CDS = circulating dry scrubber; FF = fabric filter; SCR = selective catalytic reduction; LNB/SCR = low-no x burners with SCR. awma.org Copyright 2005 Air & Waste Management Association july 2005 em 33

5 Table 3. PSD increment analysis for the Longview Power Project. Maximum Predicted Air Quality Concentration (µg/m 3 ) James River Shenandoah Significance PSD Pollutant Otter Creek Dolly Sods Face National Park Level Increment SO 2 3-hr E hr Annual PM hr Annual NO 2 Annual for CALMET. The CALMET program also requires a boundary to the modeling domain, grid cell size, and the number of layers for the meteorological variables. The boundaries of the domain were developed following the guidance in the Phase 2 Report, 4 including extending the domain 50 km beyond the outer receptors and the project site. The boundaries are shown in Figure 2. Class I Impacts The CALPOST program was used to determine the PSD increment consumption, changes in visibility, and deposition of nitrogen (N) and sulfur (S) compounds for the receptors in the Class I areas. The guidance outlined in the Phase I Report 3 was used to determine background levels for visibility and natural conditions were used as reference levels. The predicted changes Table 4. Visibility analysis for the Longview Power Project. Change in 24-hr β extinction James River Shenandoah Visibility Otter Creek Dolly Sods Face National Park Threshold Max Change (%) No. of Days > 5% NA No. of Days >10% NA NA = Not applicable. in the reference levels due to emissions from the proposed project were calculated. Initially, the value for maximum relative humidity (RHMAX) was set at 98% to cap the relative humidity adjustment factor [f(rh)] used to calculate the change in extinction. The measurement of visibility degradation is the extinction of light in the atmosphere. The change in extinction is calculated to evaluate the potential impact a source may have on current or natural background visibility conditions. Additional Table 5. Deposition analysis for the Longview Power Project. Maximum Deposition (kg/ha/yr) Deposition Shenandoah Analysis Otter Creek Dolly Sods James River Face National Park Threshold S N modeling was performed using a value of 95% for RHMAX. All S and N species were included in CALPOST to evaluate acid deposition, which was calculated in units of kg/ha/yr. PSD Increment. The CALPUFF model was used to predict ambient air concentrations for the Class I areas. The peak short- and long-term average concentrations of SO 2, PM 10, and NO 2 are summarized in Table 3. These results indicate that BACT emissions from the project will not cause an exceedance of the Class I increments for SO 2, PM 10, and NO 2, and in fact, the predicted impacts were below the Class I significance levels for NO 2 and PM 10. Class I significance levels are pollutant and averaging specific air quality concentrations below which it has been determined that a source cannot cause or significantly contribute to a model predicted exceedance of a NAAQS and/or a PSD increment. Visibility. The predicted change in visibility for the Class I areas are presented in Table 4. The predicted change in visibility (from natural background levels) are compared to thresholds of 5% and 10% change in extinction to evaluate the impact of the proposed project on visibility in the Class I areas. As shown in Table 4, the project s estimated BACT emissions were predicted to cause an exceedance of the 5% change in extinction threshold level for 13 days per year in Shenandoah National Park, 12 days in Otter Creek, and 20 days in Dolly Sods. An exceedance of 1 day per year 34 em july 2005 Copyright 2005 Air & Waste Management Association awma.org

REFERENCES 1. Draft New Source Review Workshop Manual; U.S. Environmental Protection Agency (EPA): Washington, DC, 1990. 2. Guideline on Air Quality Models; 40 CFR Part 51 Appendix W, 2003. 3.

6 REFERENCES 1. Draft New Source Review Workshop Manual; U.S. Environmental Protection Agency (EPA): Washington, DC, Guideline on Air Quality Models; 40 CFR Part 51 Appendix W, Federal Land Managers Air Quality Related Values Workgroup, Phase I Report; U.S. Forest Service: Washington, DC, December Interagency Workgroup on Air Quality Modeling, Phase 2 Report; U.S. Environmental Protection Agency (EPA): Washington, DC, A User s Guide for the CALPUFF Dispersion Model; Earth Tech Inc.: Long Beach, CA, was determined for James River Face. It was predicted that the 10% change in extinction threshold level was exceeded for a total of 10 days per year among all four Class I areas. A change in extinction greater than 10% was predicted to occur for 6 days per year in Otter Creek, 3 days in Dolly Sods, and 1 day in Shenandoah National Park. There were no days predicted with a change in extinction greater than 10% in the James River Face area. The maximum predicted change in extinction due to project emissions was 14.5%, which was predicted for Otter Creek (located closest to the project site). Deposition. The CALPUFF model was used to predict the annual wet, dry, and total deposition amounts for S and N compounds. Deposition analysis thresholds (DATs) for S and N in Class I areas established by the National Park Service were used in this assessment. For eastern Class I areas, the DATs for both S and N are 0.01 kg/ha/ yr. Predicted deposition amounts lower than these thresholds are considered unlikely to cause adverse impacts in Class I areas. The total N deposition amount was calculated by determining the wet and dry nitrate and nitric acid deposition and dry NO 2 deposition amounts and multiplying each component by the ratio of the individual molecular weight to the molecular weight of N. A similar methodology was used for the S deposition calculations. The maximum S and N deposition amounts are shown in Table 5. The total S deposition was predicted to be between three and four times the DAT; while the total N deposition was predicted to be the same or less than the DAT. In summary, the estimated BACT emissions limits for the proposed Longview Power Project showed adverse impacts on Class I areas that were three to four times the acceptable S deposition levels and three times the visibility threshold, but were well below the PSD Class I increments and below the Class I significance levels for NO x and PM 10. MITIGATION PLAN Once the analysis was complete, a mitigation plan was proposed to reconcile the gap between BACT emissions limits and predicted S deposition and visibility impacts. The mitigation plan is described in Part II of this article, which will be published in the August 2005 issue of EM. Diesel Exhaust Partnering with Stakeholders to Reduce Emissions October 6-7, 2005, Oak Brook, IL In the last 15 years, air quality agencies have increasingly focused on the regulation of diesel emissions. In that time, diesel engine emissions and technology have significantly improved. Yet, further advances will be necessary to attain the 2007 standards announced by the U.S. Environmental Protection Agency and the California Air Resources Board. This conference will provide an overview of the following developments in the regulatory, policy, and scientific arenas: New 2007 emissions standards Government programs that affect the industry New perspectives on health issues related to old diesel technology Evaluating new diesel exhaust technology Visit for more information. ACKNOWLEDGMENTS The authors thank Robert Karpovich of AAQS Inc. for the air quality modeling analysis and graphical support for this article. em awma.org Copyright 2005 Air & Waste Management Association july 2005 em 35

Naughton Power Plant. Chapter 6, Section 2 Construction Permit Application. Submitted to the Wyoming Air Quality Division And Prepared by

Naughton Power Plant. Chapter 6, Section 2 Construction Permit Application. Submitted to the Wyoming Air Quality Division And Prepared by Naughton Power Plant Chapter 6, Section 2 Construction Permit Application Submitted to the Wyoming Air Quality Division And Prepared by 1407 West North Temple Salt Lake City, Utah 84116 March 2008 1.0