Document ID: EPA-R03-OAR-2010-0386-0004
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2010-06-18T04:00Z

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

REGION III

	1650 Arch Street

	Philadelphia, Pennsylvania  19103

DATE:	May 25, 2010

SUBJECT:	Technical Support Document (TSD) 

		 EPA-R03-OAR-2010-0386; Notice of Proposed Rulemaking – Revision to
Emission Limitations for R. Paul Smith Power Station

FROM:	Marilyn Powers, Environmental Engineer /s/

Office of Air Program Planning 

TO:		File

THRU:	Cristina Fernandez,   /s/

		Associate Director, Office of Air Program Planning 

A.  BACKGROUND

On September 4, 2008 (73 FR 51599), EPA approved COMAR regulation
26.11.27 – Emission Limitations for Power Plants into Maryland’s
State Implementation Plan (SIP).  This regulation, adopted to implement
the statutory requirements of Maryland’s Healthy Air Act (HAA),
established emission limits for annual nitrogen oxides (NOx), ozone
season NOx, and annual sulfur dioxides (SO2) for the 15 largest electric
generating units (EGU) in the State located at seven power plants,
including units 3 and 4 at R. Paul Smith Power Station in Washington
County, Maryland.

Maryland’s HAA has an exception that allows R. Paul Smith units 3 and
4 to operate without complying with the emission reduction requirements
set forth in the HAA if PJM Interconnection Inc. (PJM) determines that
the termination of operation of the facility will adversely affect the
reliability of electrical service in the PJM region.  Subsequent to
Maryland’s adoption of COMAR 26.11.27 and EPA’s approval of the rule
into the Maryland SIP, PJM determined that the R. Paul Smith facility is
needed to maintain electricity reliability in the State.  The HAA
requires that if R. Paul Smith units 3 and 4 are allowed to operate
without complying with the emissions limitations established in the
statute, certain conditions must be met.  These conditions require that
the facility not operate at emissions levels greater than the highest
level measured at the facility during the calendar years from 2000
through 2004, and that the Maryland Department of the Environment (MDE)
must review the operations of the facility, then adopt regulations to
establish an alternative emissions requirement for the facility.  In
accordance with these statutory requirements, MDE revised COMAR 26.11.27
to establish alternate emission limits for these two EGUs at R. Paul
Smith.  

	On November 20, 2009 (74 FR 60199), EPA determined that the
Martinsburg-Hagerstown area had attained the 1997 PM2.5 standard on the
basis of monitored air quality data from the three year period from 2006
through 2008.  

B.  EPA REQUIREMENTS

	Section 110(l) of the Clean Air Act (CAA) dictates that the EPA
Administrator shall not approve a revision of a plan if the revision
would interfere with any applicable requirement concerning attainment
and reasonable further progress (RFP) or any other applicable
requirement of section 110.  

	Maryland submitted COMAR 26.11.27 to EPA as one of the measures it is
relying on to attain the 1997 8-hour ozone and PM2.5 NAAQS in
nonattainment areas throughout the State.  Washington County is part of
the Hagerstown-Martinsburg, MD-WV metropolitan statistical area, which
is in attainment of the 1997 8-hour ozone standard but was designated as
nonattainment for the 1997 PM2.5 standard.  Washington County’s
attainment of the 8-hour ozone standard is based on an Early Action
Compact (EAC), approved on August 17, 2005 (70 FR 48283), that included
an action plan to assure the area continues to attain the standard
through 2012.  Washington County is also now attaining the PM2.5
standard, and has submitted a PM2.5 Attainment Plan for EPA’s
approval.  For EPA to approve this SIP revision for R. Paul Smith,
Maryland is required to demonstrate that the revised emission limits do
not impact either of these plans or any other programs under section
110.

C.  STATE’S SUBMITTAL:

On December 15, 2009, the MDE submitted a revision to the Maryland SIP
(Maryland revision #09-04) pertaining to the establishment of revised
NOx and SO2 emission limits for the EGUs located at R. Paul Smith. 
These revised limits are set forth in Regulations .02 and .03 under
COMAR 26.11.27.  The submittal includes documentation that the revisions
were properly adopted via the State’s administrative procedures,
including public notice and opportunity for a public hearing.  The only
comments submitted were from EPA Region 3.  On January 27, 2010, EPA
determined that the submittal was administratively and technically
complete.

The changes to COMAR 26.11.27 involve the removal of the existing R.
Paul Smith caps from the statewide total cap and the addition of new
sections that set forth the higher caps, as follows:

- A new section C was added to Regulation .02 – Applicability and
Exemptions, which stipulates that the R. Paul Smith facility is subject
to the NOx and SO2 emissions in revised sections B(8) and C(3) of
Regulation .03 – General Requirements.

- Section B(8) changes the NOx annual tonnage limits for R. Paul Smith
from 416 tons to 1390 tons starting with the January 1, 2009 through
December 31, 2009 control period, and the NOx ozone season tonnage limit
from 140 tons to 545 tons starting with the 2009 ozone season.  

- Section C(3) changes the SO2 annual tonnage from 1002 tons to 4590
tons starting with the January 1, 2010 through December 31, 2010 control
period.

It is noted that COMAR 26.11.27 also includes revisions to section D of
Regulation .03.  Maryland’s December 15, 2009 letter expressly
submitted only the NOx and SO2 limits in sections B and C as a SIP
revision.  As section D has not previously been approved as part of the
Maryland SIP, the revisions to Section D are excluded from this action.

D.  EVALUATION OF STATE SUBMITTAL:

	As noted previously, Maryland is relying on COMAR 26.11.27 as one of
the measures to help it attain the PM2.5 NAAQS in the Washington County
nonattainment area.  Section 110(l) requires that the revision not
interfere with any applicable requirement pertaining to attainment for
this area.

	In response to an EPA comment regarding the section 110(l)
requirements, Maryland submitted a demonstration to show that the
increase in caps for NOx ozone season, NOx annual and SO2 annual
emissions at R. Paul Smith do not impede Washington County’s
attainment of the 1997 NAAQS.  The demonstration is based on air
monitoring data, emissions analysis, and information from the attainment
modeling that was done by MANE-VU for this area.

	For 8-hour ozone, the State maintains that Washington County’s
attainment of the 1997 8-hour ozone standard is not affected by the
emission limit changes for R. Paul Smith contained in this SIP revision.
 The EAC for 8-hour ozone showed attainment starting in 2007, with an
Early Action Plan (EAP) to assure maintenance of the standard through
2012.  Because the EAC program pre-dated the adoption of the HAA
regulation, the emission limits originally required by COMAR 26.11.27
for R. Paul Smith were not reflected in the emission reductions relied
upon for the EAC, and are not relied upon for maintenance through 2012. 
A review of the EAC and EAP showed that the projection of maintenance
for the five-year period from 2007 – 2012 does not include the HAA as
either a control measure or a contingency measure that is relied upon or
this facility.

	Likewise, for PM2.5, Maryland asserts that Washington County’s
attainment of the 1997 PM2.5 standard is not affected by this SIP
revision.  The State notes that Washington County has been attaining the
1997 annual and 24-hour standard since 2000, and has continued to meet
the standard through 2008.  As part of its section 110(l) demonstration,
Maryland included data from the Washington County attainment plan which
shows annual PM2.5 design values of 14.8 micrograms per cubic meter
(µg/m3) for the 2000 – 2002 period, with design values equal to or
less than 14.1 µg/m3 in the intervening years up to 2008.  Maryland
also provided information from the MANE-VU modeling which shows R. Paul
Smith emissions in 2009 as 1335 tons of NOx and 5426.8 tons of SO2..  On
this basis, the State asserts that the total NOx and SO2 emissions
projected for 2009, 6761.8 tons, is actually 11 percent higher than the
total NOx and SO2 emissions that would be allowed for R. Paul Smith by
this SIP revision, 5,980 tons.  Table 1 shows this comparison.

Table 1.  Comparison of emission caps to modeled values	

Plant ID	Plant Name	2009 Projected Emissions	Revised Caps – this SIP
revision

043-0005	Allegany Energy Supply LLC – R. Paul Smith	NOx	SO2	NOx	SO2

1335	5426.80	1390	4590

	

	As shown in Table 1, the revised NOx limit for this facility, 1,390
tons, is actually higher than the 2009 model year NOx emission value,
1,335 tons, by 55 tons.  However, the SO2 limit for this facility, 4590
tons, is lower than the 2009 model year emissions, 5426.80 tons, by
836.8 tons.  EPA looked to the Washington County PM2.5 attainment plan
submitted by Maryland to evaluate this situation.  In order to address
the contingency measures required to be included in the attainment plan,
Maryland evaluated the equivalency of reductions for precursors of PM2.5
to see if the excess SO2 reductions were adequate to offset the
insufficient number of NOx reductions.  The evaluation of relative
impacts of reductions of NOx and SO2 for this area was based on the
modeling that was performed.  Section 10.1.2 of the attainment plan
explains how the relative reduction factor was derived:

“The recommended approach is to review existing data and sensitivity
studies performed as part of photochemical modeling to estimate the
relative impact of reductions in different precursors on PM
concentrations. Basing an equivalency ratio on relative reduction
factors as generated by the Community Multiscale Air Quality (CMAQ)
modeling results in a ratio of 1.1 to 1.4 tons of NOx for each ton of
SO2 . . . . Using sensitivity analyses created by Visibility Improvement
of State and Tribal Association of the Southeast (VISTAS) and Georgia
Tech . . ., equivalency ratios range from 3.3 to 3.6 tons of NOx for
each ton of SO2.”

A relative reduction factor ranging from 1.1 to 3.6 tons of NOx for each
ton of SO2 is adequate to of offset the higher NOx value.  At the most
conservative ratio of 1.1, 55 tons of NOx is equivalent to 50 tons of
SO2.

	A further look at the air quality data for Washington County for 2009
is useful to inform this section 110(l) analysis, particularly as the
revised caps for R. Paul Smith became effective beginning in 2009. 
Although not yet certified or quality-assured, monitored 2009 ambient
air quality concentration data for both 8-hour ozone and PM2.5 for the
Hagerstown – Martinsburg, MD-WV area continues to show attainment of
both standards, as can be seen in Table 2 and 3 below.  The data shown
in these tables is from the EPA Air Quality System (AQS), and the raw
data reports, from which the tabular data is derived, are included in
the docket for this action.  

 

Table 2.  2009 Monitored Values for Annual PM2.5, in µg/m3 

Site ID	City 	County 	State	First Quarter

2009	Second Quarter 2009	Third Quarter 2009	Fourth Quarter 2009

240430009	Hagerstown	Washington Co	MD	10.79	9.62	10.64	7.35

540030003	Martinsburg	Berkeley Co	WV	14.02	11.35	12.47	10.38

Table 3.  2009 Monitored Values for 8-hour Ozone, in ppb

Site ID	City	County	State	4th highest value in 2009 	Highest value in
2009

240430009	Hagerstown	Washington Co	MD	65	70

540030003	Martinsburg	Berkeley Co	WV	65	70

	Finally, one other factor to consider is that Maryland’s Clean Air
Interstate Rule (CAIR) is in effect throughout the State, and applies to
units 3 and 4 at the R. Paul Smith facility.  Maryland’s CAIR SIP
revision was approved on October 30, 2009 (74 FR 56117).  Under the CAIR
program, R. Paul Smith is allocated 191 tons of NOx allowances for the
ozone season trading program, 454 tons of NOx allowances for the annual
trading program, and 175 allowances for annual SO2. These CAIR ozone
season and annual allocations are less than the limits imposed in this
SIP revision, however, regardless of any emission limits established by
the State for these units, R. Paul Smith must comply with the NOx and
SO2 allowance holding requirements of CAIR – i.e. emissions that
exceed its allocations would need to be covered on a one-to-one basis by
obtaining additional allowances from the CAIR allowance market.  This
SIP revision therefore does not impact the CAIR trading program.  

	

F.  CONCLUSIONS AND RECOMMENDED AGENCY ACTION

	EPA’s analysis of the impacts of this SIP revision concludes that it
does not negatively affect the attainment requirements for either the
PM2.5 or 8-hour ozone standards.  It is recommended that a notice of
proposed rulemaking be prepared approving the SIP revision.

 Annotated Code of Maryland Environment Title 2 Ambient Air Quality
Control Subtitle 10 Health Air Act Sections 2-1001 - 2-1005.

 Washington County, MD PM2.5 State Implementation Plan and Base Year
Inventory, February 29, 2008.

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