STATE OF MARYLAND

OFFICE OF THE GOVERNOR



### November 20,2015

Shawn M. Garvin

Regional Administrator

U.S. Environmental Protection Agency

Region Ill 

### (3RAOO)

1650 Arch Street

Philadelphia, PA 19103-2029

Dear 

### Mr. Garvin: LARRY HOGAN

GOVERNOR

STATEHOUSE

100 STATE CIRCLE

ANNAPOLIS

, MARYLAND 21401-1925

(410) 974-3901

(TOLL FREE) 1-800-811-8336

TTY USERS CALL VIA MD RELAY



### Thank you for your letter to Maryland Department of the Environment (MDE) Secretary Ben

Grumbles on March 20, 2015. The U.S. Environmental Protection Agency (EPA) notified

Maryland of the settlement agreement between the EPA, Sierra Club and the Natural Resources

Defense Council over the new sulfur dioxide (S0

2 ) 

### standard and the aggressive schedule

included in that agreement.

Maryland appreciates the opportunity to present the EPA with a recommendation for the

designation of areas under the 2010 primary, 1-hour National Ambient Air Quality Standard

(NAAQS) for SO :

. Maryland recommends that EPA designate the Herbert A. Wagner

Generating Plant ("Wagner") area as "attainment" with respect to the new**so ~**  

### standard.

Between 2007 and 2010, Maryland power generators invested an estimated $2 billion in air

pollution controls to reduce**SO~** 

### emissions. As shown in Attachments 1 and 2, these reductions

in S02 emissions resulted in dramatic reductions in 1-hour SO z concentrations across the State.

A summer 2013 air monitoring study regarding 1-hour S0

2 

### levels around the Wagner area shows

that 

### SOz levels are generally below the new standard. Attachment 3 summarizes the data from

the 2013 air monitoring study.

As shown in Attachment 4, preliminary air quality modeling also demonstrates that the Wagner

area can attain the new 

### SOz standard. In mid-April2015, the owners of the Wagner facility,

Raven Power

, began to use a lower sulfur coal at Wagner unit number 2 as a method of

compliance with the federally enforceable Mercury and Air Toxics Standards. Modeling current

emissions, adjusted for the reduced sulfur content of the new coal

, results in S0

2 

### concentrations

below the new standard.

### Shawn M. Garvin

Regional Administrator

Page 2

As EPA knows, this kind of technical modeling analysis is complicated and takes significant

time and resources to complete. Because of the late, March 20' h notification, the final modeling

analysis will be submitted as expeditiously as possible under separate cover by MDE Secretary

Grumbles.

In early 2016, Raven Power will also be adding a dry sorbent injection (DSI) system to unit

number 3 at the Wagner facility to comply with the Mercury and Air Toxics Standards. DSI

control technology can also help reduce S0 2 emissions. The modeling described in Attachment 5

will capture the benefits from both the 2015 and 2016 emission reduction efforts at the Wagner

plant.

Maryland is not making a designation area boundary recommendation at this time. Maryland

recognizes, though

. that this designation recommendation submittal is only the first step in the

S02 designation process and looks forward to working with the EPA and Maryland stakeholders

during the remaining steps of the process. Maryland is requesting routine coordination calls with

EPA on issues related to the designation of the Wagner area. For more details, please see

Attachment 6, which is a timeline.

Please note that Maryland's submission of this designation recommendation letter is consistent

with 

### § 1 07( d)( 1) of the Clean Air Act. It 

### is also consistent with Consent Decree, Case No. 3: 13-

cv-03953-SI, 

### Sierra Club and Natural Resources Defense Council v. Gina McCarthy,

Administrator, United States Environmental Protection Agency.

If you have any questions about this submission, please do not hesitate to contact Ben Grumbles,

Secretary, Maryland Department of the Environment at 410-537-3084.

cc: Ben Grumbles, Secretary, Maryland Department of the Environment

Enclosures

### 1 

## Attachment 1

Annual Reductions in Sulfur Dioxide (SO 2 

## ) from the Healthy Air Act

0 50,000 100,000 150,000 200,000 250,000 300,000

2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014SO2Emissions(tonsperyear)

Note: Graph includes units reporting SO

2 emissions to EPA's Clean Air Markets Division 

# SO

2 

# Annual Emissions from

Electric Generating Units in Maryland

Healthy Air Act

SO 2 

### Reductions

January, 2010

### 2 

## Attachment 2

One-Hour SO 2 

## trends, after the Healthy Air Act

(Note: the 1-hour SO 2 standard is 75 ppb)



### SO 2 

### Emissions and Air Monitoring Concentrations in the Wagner Area, 2007-2014

SO 2 Emissions (Tons/Year) SO 2 Concentrations at Essex (ppb)

Year Total Brandon Shores Wagner Crane Design Value* Max 1

‐ hour

2007 92,931 42,041 20,259 30,631 99 173

2008 79,282 39,924 15,006 24,352 86 66

2009 60,391 32,821 15,093 12,477 80 56

2010 15,877 1,260 9,028 5,589 43 33

2011 17,518 2,829 9,007 5,682 34 53

2012 12,494 2,848 7,473 2,173 22 26

2013 16,020 2,870 10,178 2,972 22 31

2014 14,643 3,145 9,610 1,887 22 44

*The design value for the 1

‐ hour SO 2 standard is the 99th percentile of the 1

‐ hour daily maximum concentrations, averaged over 3

years. The 1

‐ hour SO 2 standard is 75 parts per billion (ppb), calculated the same way. 0 40 80 120 160 200

2004 2006 2008 2010 2012 2014 2016SO2(ppb) 

# Annual Maximum 1

‐ hour SO

2

Essex Piney Run HU

‐ Beltsville

Google earth Phase 1 SO 2

controls under

the Healthy Air

Act in 2010 

## SO2 Monitors

in Maryland S O 2 

## M o n i t o r s

i n M a r y l a n d

Note: Monitor names are in

yellow.

### 3 

## Attachment 3

Summer 2013 Air Monitoring Study Results

A 2013 two-month monitoring study of SO 2 

### concentrations was conducted around Raven Power’s Brandon

Shores, Herbert A. Wagner, and C.P. Crane Generati ng Plants. Peak daily 1- hour maximum monitored SO 2 

### values were typically well below the 75 ppb 1-hour SO 2 

### NAAQS.



## Monitoring Sites Used in the 2013 Study

Note: Monitoring sites are in yellow on the map; the generating stations are in green.



### Monitored Values

Table 1. Top Five Monitored 1-Hour SO 2 

### Values during the 2013 Study

Peak Daily 1

‐ Hour Maximum Monitored Value (ppb)

Note: the 1

‐ hour SO 2 standard is 75 ppb.

Rank Cianbro MDYC Shining Star MD Marina Essex

1 101.7 53.2 34.6 13.1 31.3

2 42.2 37.8 28.7 10.5 24.5

3 34.4 37.3 26.8 10.3 24.0

4 31.5 29.6 23.6 10.1 20.7

5 23.9 20.7 21.4 9.5 17.4 Essex

Site

Cianbro

Site Crane

Generating Plant Shining Star

MD

Marina

Site

Ft. Smallwood

Generating Plant

MDYC

Site4Table 2. All 1-Hour Daily Maximum SO2Data during the 2013 Study1‐hourSO2DailyMaximumConcentration(ppb)Note:1‐hourSO2standardis75ppb.Theblankcellsweredatesbeforeamonitorstartedrunning,duetodelaysinobtainingaleaseagreementtoplacethemonitor.InvicinityofBrandon&WagnerPlantsInvicinityofC.P.CranePlantInvicinityofBrandon&WagnerPlantsInvicinityofC.P.CranePlantDateCianbroMDYCShiningStarMDMarinaEssexDateCianbroMDYCShiningStarMDMarinaEssex7/25/20130.70.48/25/201322.32.00.78.710.57/26/201322.04.78/26/20131.11.45.34.61.97/27/20130.59.28/27/20138.629.62.41.22.17/28/201321.910.58/28/20130.51.61.10.01.07/29/20131.71.58/29/20132.02.40.60.01.97/30/20131.21.48/30/20130.61.81.10.58.77/31/20131.613.48/31/20130.92.47.74.57.68/1/20130.50.04.09/1/201313.41.66.33.29.38/2/20132.27.20.02.99/2/20132.97.16.710.14.48/3/20131.01.50.01.39/3/20132.837.31.50.32.48/4/20132.03.80.01.79/4/201315.913.05.83.83.08/5/201317.00.30.62.79/5/20134.320.72.31.32.48/6/20130.70.00.21.59/6/201323.911.119.50.38.48/7/20130.62.10.41.39/7/2013101.72.421.710.55.28/8/20131.03.17.411.89/8/20132.37.43.81.92.38/9/20130.74.00.73.79/9/201342.24.932.713.15.98/10/201334.411.90.42.59/10/20131.32.66.01.95.58/11/201320.44.026.813.09/11/201321.317.610.15.531.38/12/20136.26.30.01.69/12/20131.85.04.03.05.58/13/20131.414.32.63.42.19/13/20131.953.21.40.01.68/14/20132.96.41.43.02.79/14/20131.58.81.40.00.88/15/20138.53.31.32.20.99/15/20137.61.85.23.12.08/16/20132.43.11.23.21.49/16/20131.34.13.94.71.68/17/20132.01.91.82.52.99/17/20131.75.31.52.22.08/18/20130.61.30.71.90.59/18/201319.91.417.60.01.08/19/20130.62.11.62.52.09/19/20135.71.85.23.82.68/20/201331.519.924.99.56.29/20/20131.62.510.910.320.78/21/20130.83.22.02.88.79/21/20130.72.71.50.03.48/22/20131.86.45.56.22.29/22/20131.613.71.60.01.28/23/20131.114.40.62.41.79/23/20131.12.41.60.01.48/24/20131.21.40.90.00.7The hourly SO2levels were typicallywell below the 1-hour SO2NAAQS. Peak daily 1-hour maximum monitored SO2values ranged from9.5 to 53.2 ppb except on one day during the 2-month study when the Cianbro monitor reached a level of 101.7 ppb. Overall, the studysuggests that the Wagner areacan attain the 1-hour SO2NAAQS.

### 5 

## Attachment 4

Preliminary MDE Modeling Analyses

Preliminary AERMOD (Version 15181) dispersion modeling shows that the Wagner area is attaining the 2010

1-hour SO 2 

### standard. The modeling uses 2012 - 2014 actual emi ssions data, including th e reductions presently

being seen from the use of low-sulfur coal for complia nce with the Mercury and Air Toxics Standards (MATS)

at Wagner’s unit 2 (see graph below). MDE modeling incl udes all of the emission units of Raven Power/Talen

Energy (Wagner, Brandon Shores, and Crane Plants), and other nearby sources (Wheelabrator and Energy

Answers). The background concentration calculation wa s based on season and hour-of-day approach included

in EPA guidance. MDE is working with EPA to finaliz e this modeling. Attachment 5 provides a summary of

how the modeling is being conducted.



## Predicted Hourly SO 2 

## Levels*

(Note: The 1-hour SO 2 standard is 75 ppb, or 196.20 μg/m 3 )

* Additional reductions are expected in 2016 as new controls required by MA TS at Wagner 3 become operational.

**Brandon Shores, Crane, Wheelabrator and Energy Answers

0.00 10,000.00 20,000.00 30,000.00 40,000.00 50,000.00 60,000.00

0 500 1000 1500 2000 2500 3000 3500SO2(lbs)GrossLoad(MW‐h) 

# Emissions Reductions at Wagner 2, May

‐ Sept. 2015,

After MATS Compliance

Gross Load (MW

‐ h)

SO2 (lbs) 

## 4 th 

## Highest

Concentration (μg/m 3 

## ),

Without Background Percentage

Contribution (%

contribution to total) Total with

Background

(μg/m 3 

## )

Wagner Unit 1 0.009 Negligible

193.47 Wagner Unit 2 26.47 15

Wagner Unit 3 95.26 53

Wagner Unit 4 21.53 11

All other nearby sources** 37.61 21

Switch

to lowsulfur

coal

### 6 

## Attachment 5

MDE Modeling

MDE is working with EPA Region III, the facility and ot her interested parties to finalize sophisticated SO 2 

### modeling by early 2016. MDE’s modeling considers met hodologies used by the Sier ra Club and Raven Power

in their independent modeling of SO 2 

### levels in the Wagner area:

Preliminary MDE modeling us ed the following inputs:

 AERMOD Version 15181

 Actual 1-hour SO 2 

### emissions data for 2012-2014

 Background 1-hour SO 2 

### concentrations from the MDE Howard University (HU) -Beltsville air

monitoring station

 Building heights based on Google Earth

 Meteorological data, including Baltimore Washington International Airport (BWI) surface data, and

Sterling, Virginia upper air data



###  The seasonal and hour-of-day approach consistent with the methodology found in section 8,

“Background Concentrations,” of the “Draft SO 2 

### NAAQS Designations Modeling Technical

Assistance Document” (EPA, December 2013)



### Ongoing modeling includes consideration of the following potential refinements:

 The use the non-regulatory “LOWWIND3” option (BETA option) in AERMOD to address issues with

model over-prediction under low wind speed conditions.

 Merged plumes/one stack for Brandon Shores when both units were running simultaneously, following

EPA guidance

 The use of enhanced tools to evaluate plume rise. Work performed by AECOM, has assessed the effects

of plume rise adjustments in the AERMOD modeling system by applying the concepts of moisture in

plume modeling versus dry plume modeling. AE RMOD treats the final plume rise based on the

assumption of a “dry” plume, where the chimney plume is far from being saturated and carries no liquid

water load. However, the “dry” plume rise in AERMOD might be affecting the final plume rise height in

the model. AECOM has developed a moist plume rise model (IBJpluris) to estimate plume rise by

modifying and adjusting the standard Briggs (1975) plume rise formula used in AERMOD. AECOM has

implemented IBJpluris Ver. 2.7 in the AERMOIST pre-processor. The AERMOIST pre-processor uses a

set of temperature and RH ranges to automatically build a stack-specific wet plume rise model based on

the IBJpluris prediction.

 The use of LIDAR to more accurately estimate the building dimensions to be used as the inputs in the

Building Profile Interface Program (BPIP) model of the AERMOD modeling system. Correct building

dimensions are very important to estimate the effect s of building downwash on the pollutant concentration

at the facility. This LIDAR technique can be used to accurately measure the building length, width, and

height, and stack height, for modeling purposes. The modeling may also use this technique in estimating

the elevation of ground level for input in AERMAP, the terrain pre processor in the AERMOD model.

The LIDAR technique is also helpful in plume mapping that depicts the plume rise and spread in the real

time analyses.

 MDE is also looking at other potential surface meteor ological data sites as input into AERMOD, in

addition to surface data currently being used from th e Baltimore-Washington International (BWI) airport.

### 7 

## Attachment 6

SO 2 

## Attainment Designation Timeline

 2015: Maryland submits its designation recommendati on letter for the Wagner area to EPA Region III.

 2015 – Early 2016: MDE Secretary Ben Grumbles s ubmits to EPA further emissions and modeling

analyses and information to support the attain ment designation or an updated designation

recommendation.

 2015 - 2018: Monthly calls between MDE and EPA to coor dinate on the status of activities related to

the designation of the Wagner area.

 January 15, 2016: MDE identifies federally enforceable emissions limits or permit conditions that may

be needed to support the attainment designation, and MDE forwards this information to EPA. EPA’s

120-day letters, in which EPA notifie s states concerning any intended m odifications to their designation

recommendations, are expected on or about January 22, 2016.

 January 2018: Maryland’s target date for providing documentation that the Wagner area is attaining the

1-hour SO 2 

### NAAQS including any federally enforceable em ission limits or permit conditions that may

be required to insure attainment. Note: If Ma ryland were to submit a nonattainment area state

implementation plan (SIP) to EPA to comply with the 1-hour SO 2 

### NAAQS for the Wagner area, then

January 2018 would be the date by which sources would be required to come to agreement, with states,

to implement controls in time for a 1-hour SO 2 

### nonattainment area to attain the SO 2 

### NAAQS. This is

ahead of that schedule.