### Clean Air Act Section 110(l) Demonstration to Support Amendments to
COMAR 26.11.27 Emission Limitations for Power Plants

This is a Clean Air Act section 110(l) demonstration prepared in response to the comments received from the United States Environmental Protection Agency (EPA) regarding Maryla nd’s amendment to COMAR 26.11.27 Emission Limitations for Power Plants. The EPA’s comments were received by the Maryland Department of the Environment on May 28, 2009.

This demonstration shows that the increase in the emissions at R. Paul Smith facility will have no impact on Wash ington County attaining the 1997 annual PM2.5 standard.

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### Clean Air Act Section 110(l) Demonstration to Support Amendments to
COMAR 26.11.27 Emission Limitations for Power Plants

OVERVIEW The Maryland Department of the Environm ent (MDE) has prepared a revision to COMAR 26.11.27, Emission Limitations for Power Plants also known as the Healthy Air Act (HAA). The emission limits at R. Paul Smith facility for annual and ozone season NO X emissions and annual SO 2 emissions have been revised. This revision is to abide by the exception provision of the Hea lthy Air Act (HAA) which states: should PJM Interconnection, Inc. (PJM Inc. ) determine that the termina tion of operation of the R. Paul Smith facility would adverse ly affect the reliability of electrical services in the PJM region then MDE is authorized to allow units 3 and 4 at R. Paul Smith facility to operate without complying with the emissions requirements of the HAA . The Healthy Air Act is a part of the Washington County PM2.5 SIP.

Section 110(l) of the Clean Air Act states th at the Administrator (of the United States Environmental Protection Agency) shall not approve a revision of a plan (State Implementation Plan or SIP) if the revisi on would interfere with any applicable requirement concerning attainment or reasona ble further progress (of a National Ambient Air Quality Standard). To address this an ti-backsliding provision, MDE has prepared a demonstration that shows that the revision to the emissions limits for R. Paul Smith Facility will not interfere with the applicab le requirements concerni ng attainment of the National Ambient Air Quality Standards for fine particles.

BACKGROUND The Maryland Healthy Air Act was developed with the purpose of bringing Maryland into attainment with the National Ambien t Air Quality Standards (NAAQS) for ozone and fine particulate matter by the federal d eadline of 2010. The H ealthy Air Act and the subsequent regulations also require the reduction of mercury emissions from coal-fired electric generating units and significantly reduce atmospheric depositio n of nitrogen to the Chesapeake Bay and other waters of the State. The HAA regulati ons became effective on July 16, 2007 and require reducti ons in nitrogen oxide (NO X ), sulfur dioxide (SO 2 ), and mercury emissions from large coal burning power plants. The R. Paul Smith Facility is a 62 year old power plant owned and operated by the Allegheny Energy Supply Company, LLC. The f acility is located in Washington County, Maryland and operates two coal-fired boile rs, units 3 and 4. Unit 3’s particulate emissions are controlled by a single cold-s ide electrostatic precipitator (ESP) and NO X emissions are controlled by low NO X burner technology. Unit 4’ s particulate emissions are controlled by a primary cold-side ESP a nd an electrostatically enhanced bag-house and NO X emissions are controlled by low NO X burners and a separate over-fire air system.

23 The Maryland Department of the Environment recently revised the emissions limitations for the R. Paul Smith facility for the reas ons outlined in the Hea lthy Air Act’s exception provision (see attached addendum). These amen dments were submitted to the U. S. EPA for approval as a revision to Maryland’s St ate Implementation Plan. In accordance with the HAA, the guidelines for revisi ng the emissions at R. Paul Smith facility establish that should units 3 and 4 be allowed to operate without complying with the emissions limitations of the HAA then the following conditions must be met:

1. The facility may not operate at an em issions level greater than the highest level measured at the facility dur ing the calendar years 2000 through 2004 and;

2. The Department shall review the ope rations of the facility and adopt regulations to establish an altern ative emissions requirement for the facility.

The above mentioned conditions have been me t with the revised emission limits for R. Paul Smith facility. NOx: 1,390 tons per year; 545 tons per ozone season SO2: 4,590 tons per year

DEMONSTRATION In order to support the revision to the emissi ons limits for R. Paul Smith facility, MDE has prepared a demonstration to meet the re quirements of Section 110 (l) of the Clean Air Act. Reasonable Further Progress (RFP) is not required for the PM2.5 SIPs, therefore the demonstration will focus on the attainment of the National Air Quality Standards (NAAQS). This demonstration is supported by air monitoring data, emissions analysis and MANE-VU modeling. Air monitoring data shows that Washingt on County is in attainment of the PM 2.5 annual and 24-hour standards (see Figures 1 and 2 belo w). The data from the area’s monitors show that the area has been in compliance with the 1997 annual fine particle standard since 2000. Historically, Washington County has never exceeded the 1996 24-hour design value of 65 μ g/m 3 (see Figure 2 below). Currently th e 24-hour design value for 2006-2008 is 30 μ g/m 3 approximately 14% below the 2006 24-hour PM 2.5 standard of 35 μ g/m 3

.Figure 1 - Annual PM 2.5 Design Values for Hagerstown, MD from 2002-2006. Data from EPA Air Trends Design Valu es website at: http://www.epa.gov/airtrends/values.html

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### Hagerstown, MD Monitor Annual PM2.5 Design Value (2002-2006)

13.9 14.1 14.1

13.8 14.8

13.2 13.4 13.6 13.8

14 14.2 14.4 14.6 14.8

15 15.2

2000-2002 2001-2003 2002-2004 2003-2005 2004-2006Design Value (ug/m3))

Annual PM2.5 Design Value (ug/m3) Annual PM2.5 Standard (15 ug/m3)

Figure 2 - 24-hour PM 2.5 Design Values for Hagers town, MD from 2001-2006. Data from EPA Air Trends Design Valu es website at: http://www.epa.gov/airtrends/values.html

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### Hagerstown, MD Monitor 24-Hour PM2.5 Design Value (2001-2006)

40.0 39.0

36.0
34.0 41.0

30 35 40 45 50 55 60 65 70

2000-2002 2001-2003 2002-2004 2003-2005 2004-2006Design Value (ug/m3))

24-Hour PM2.5 Design Value (ug/m3) 24-Hour PM2.5 Standard (65 ug/m3)

4Additionally, it should be noted that Washington County is attaining the PM 2.5 standard well before the Healthy Air Act provisions take effect in 2009. The annual 2009 design value for Washington County is predicted by accepted EPA modeling platforms to range between 11.5-11.8 μ g/m 3 . Original modeling demonstrations for the PM2.5 standard were conducted by MANE-VU for the Wash ington County, MD State Implementation Plan. The emissions value used for R. Paul Smith for model year 2009 was 6761.8 tons per year of NO X and SO 2 combined (see Table 1). The newly proposed emission cap for R. Paul Smith (RPS) is 5980 tons per year NO X and SO 2 combined (see Table 2). The modeled MANE-VU emissions are 11% greate r than the proposed emissions limits for RPS under the HAA revision. Based on the MA NE-VU modeling, the ar ea will attain the PM2.5 standard. The revised lower emission lim its for R. Paul Smith will not affect the county’s attainment of the PM 2.5 NAAQS.

Washington County, Maryland was designated nonattainment for the PM2.5 standard primarily because of violations in Berkel ey County, West Virginia. Based on the modeling performed for the region using the sa me emissions inventory for R. Paul Smith as above, the 2009 design value for Berkeley County, West Virginia is predicted to range between 12.8 and 13.1 μ g/m 3 . The revised lower emission limits for R. Paul Smith will not affect Berkeley County, West Virginia’s attainment of the PM 2.5 NAAQS.

Table 1 - MANE-VU Projected Emissions R. Paul Smith facility (August 10, 2006) Source: MANE-VU

Projected Emissions (tons/yr) PLANT_ID POINT_ID PLANT_NAME SCC

NOX SO2

043-0005 1 & 2 ALLEGANY ENERGY SUPPLY LLC - R. PAUL SMITH 10100202 & 10100212 1,335 5,426.80

Table 2 - Revised Emissions R. Paul Smith facility (March 2009)

Revised Emissions (tons/yr) PLANT_ID POINT_ID PLANT_NAME SCC NOX SO2

043-0005 1 & 2 ALLEGANY ENERGY SUPPLY LLC - R. PAUL SMITH 10100202 & 10100212 1,390 4,590

The areas attainment of the NAAQS for 8-hour ozone will not be affected by the change in the emissions limitations for R. Paul Sm ith. Washington County’s 8-hour Ozone Early Action Compact (EAC) showed attainment of the 1997 8-hour standard by 2007 and maintenance through 2012. The HAA is not a part of the Washington County Early Action Plan. Therefore the revised emission li mits for R. Paul Smith will not affect the county’s attainment status unde r the 8-hour Ozone standard.

56 MDE has made revisions to R. Paul Smith’s allowable emissions limits which fall within the range of the guidelines under the Healthy Air Act. These emissions modifications were made in accordance with the Healthy Ai r Act which is a part of the Washington County PM2.5 SIP. This 110(l) demonstration il lustrates that the revision to the emission limits for the R. Paul Smith facility will not in terfere with the attainment of the National Ambient Air Quality Standards in Washingt on County. The demonstration is supported by modeling results, monitoring data and emissions analysis

. Consequently, the revision to the emission limits at the R. P. Smith f acility cannot be considered backsliding under section 110(l) of the Clean Air Act.