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### New Hampshire Regional Haze SIP Revision Responses to AMC’s Comments

On June 26, 2009, the New Hampshire Department of E nvironmental Services (NHDES) received comments from Georgia Murray, staff scient ist from the Appalachian Mountain Club (AMC), on New Hampshire’s draft final Regional Haze SIP, May 22, 2009. Many of AMC’s comments supported the decisions and methodologies employed in development of the SIP and do not require a response. For specific comments t hat do need responses, NHDES provides the following. Comments are written in italics and responses are written in regular font.

MANE-VU Ask. AMC urges NH to include federally enforceable contr ols in its SIP to meet its commitment of a 90% reduction in SO 2 emissions under the Targeted EGU Strategy. Preferably, NH should add a specific commitment to reduce SO 2 emissions at NT1, a BARTeligible source, by 90%. NH should exhaust all pos sible options (fuel switching to natural gas, earlier use of 0.5%-S fuel oil, and/or an increase in enforceable reduction at Merrimack station to greater than 90%) to reduce the overall emission s for the 3 targeted stacks by 90%. AMC provides the following table to clarify the differe nce between the emission reduction targets from the MANE-VU Ask and the NH SIP. We recognize that NH and other states are provided some flexibility in meeting their regional haze obl igations, and that NH has worked extensively to achieve the planned reductions included in this draft. However, it would be a missed opportunity to further improve NH air quality to no t require 90% reduction of SO 2 from each target EGU. Furthermore, the example put forth in NH’s RH SIP commitments will provide our state important leverage as we ask other states to control emissions that impact visibility in

our Class I airsheds.

 NHDES Response: NHDES recognizes the need for enfo rceable control measures. Enforceable provisions for SO 2 emission reductions are in place for Units MK1 and MK2 and are in progress for Unit NT1. However, bec ause of its low utilization rate and capacity factor, retrofitting Unit NT1 for flue gas desulfurization is not economically feasible. Consequently, the only prac tical means of reducing SO 2 emissions at this plant is to control the sulfur co ntent of fuels used. NHDES has prepared a draft rule that will limit SO 2 emissions from Unit NT1 to 0.50 lb/MMBtu – a limitation that will require the operator to regu late and monitor fuel sulfur content. While this provision will not achieve the desired 9 0 percent SO 2 reduction from this facility that was sought under the Ask, there are a t least two mitigating circumstances to consider. First, the 90-percent reduction for U nits MK1 and MK2 is a minimum

. The actual reduction is expected to exceed this val ue; and, in fact, meeting thePage 2 of 3

maximum sustainable rate is a requirement of the fa cility’s draft Title V operating permit. Second, emissions from Unit NT1 have been trending lower since 2002 because of the plant’s low usage. For example, rep orted SO 2 emissions were 586 tons in 2008, a nearly 90 percent reduction from the 200 2 base year. The combination of these circumstances is likely to put total SO 2 emission reductions from the three units at or below the 90 percent target.

New Hampshire, in concert with the other MANE-VU st ates and the Ozone Transport Commission, is contemplating further controls to re duce SO 2 emissions across the region. One important initiative focuses on emissi on controls for industrial, commercial,

and institutional boilers. NHDES is committed to a thorough reevaluation of the 167 EGU strategy and related SO 2 control measures as part of the regional haze midcourse review circa 2013 to ensure that New Hamp shire is doing its part to achieve established visibility goals.

Section 11.4.3. Table 11.1 The final column in this table appears t o have incorrect values for

NT1 2018 SO 2 Emissions and the Total Emissions for 2018.

 NHDES Response : The errors in the table have been corrected.

Section 11.8. Page 133 NH DES should clarify in this section, as they did in section 10.3, that

the alternative method was used to calculate baseli ne and natural visibility.

 NHDES Response : The following sentence has been added to the tex t pertaining to 2000-2004 baseline and natural visibility values: “Note that both natural conditions and baseline visibility for the 5-year period were calculated in conformance with an alternative method recommended by the IMPROVE Steer ing Committee.”

Page 134 The 3rd bullet states that the glide slope was “created by linear interpolation between the 20 percent worst visibility baseline va lue in 2004 and the 20 percent worst visibility value under natural conditions in 2064.” The glide slope should be based on linear interpolation between the average 20 percent worst visibility baseline value from 2000-2004 and the 20 percent worst visibility value under nat ural conditions in 2064. It is difficult to read the values off the graph and determine what the act ual glide slope is (in dv/year) and therefore difficult to determine what method was actually use d by NH DES. The agency correctly refers to the baseline visibility average values (2000-200 4) throughout the SIP, however it needs to clarify what was used to calculate the glide slope and what the actual rate of change is.

 NHDES Response : The distinction regarding linear interpolation i s noted and the text has been revised accordingly. Also, the follo wing sentence has been added under the bullet for the glide slope (straight gree n line): “Visibility values used for the calculation of uniform rate of progress may be found in Table 10.1.”

Section 11.11. Page 140-141 NH DES discusses its obligation to ens ure that control measures are federally enforceable to comply with the RHR re quirements. Earlier in the SIP NH states that existing NOx and PM controls are considered BA RT; however, it is unclear that these controls will be federally enforceable with the inf ormation and attachments provided. This can be resolved by NH DES submitting as part of the RH SIP the appropriate Title V permits that provide federally enforceable requirements for oper ation of the SCR and ESP. While year round SCR is currently expected due to NOx RACT req uirements, it is important to see thePage 3 of 3

permit documents that identify this. We recognize that NH does not have a merged construction and Title V permitting program, but th e Temporary Permit referred to (TP-0008) does not identify enforcement of NOx and PM control s.

 NHDES Response : PSNH Merrimack Station Units MK1 and MK2 will be subject

to SO 2 , NOx, and PM emission limitations specified in its Title V operating permit (TV-0055; Attachment HH). Similarly, PSNH Newingto n Station Unit NT1 will be subject to SO 2 , NOx, and PM emission limitations specified in its Title V operating permit (TV-OP-054; Attachment II). Units MK2 and N T1 must also meet the enforceable BART provisions described in Tables 9-6 and 9-7, added to Section 9 of the SIP. These tables include references to propos ed rulemaking Chapter Env-A 2300 Mitigation of Regional Haze (Attachment GG). Also, stricter fuel sulfur standards developed as part of the MANE-VU Ask have been inco rporated into proposed

revisions to Env-A 1604 Sulfur Content Limitations for Liquid Fuels (Attachment FF).