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### Medina, Dayana

From: Medina, Dayana

Sent: Wednesday, August 21, 2013 2:17 PM

To: pettyjohn

Cc: Donaldson, Guy

Subject: Region 6 Comments on AEP Flint Creek BART analysis

Hi Mary,

We have no further comments on the SO2 BART analysis for AEP Flint Creek and appreciate the effort put forth and the

additional information that has been provided to address our previous concerns with that analysis. We have the

following comments on the NOx BART analysis. While we believe our remaining concerns are not major, we would be

happy to set up a meeting with ADEQ and AEP/SWEPCO if either party would like to meet with Tom Diggs to expedite

resolution of the remaining issues. If either party is interested in having a meeting, please let me know and we will work

with ADEQ to set up and coordinate the meeting.

LNB/OFA and SCR Cost Estimates

 It appears that the cost estimate for LNB/OFA was escalated to 2017

‐ 2018 dollars while the cost estimate for SCR

was escalated to 2016 dollars. The CCM approach, recommended by the BART Guidelines, explicitly excludes future

escalation as cost comparisons are made on a current real dollar basis. Inflation is not included in cost effectiveness

analyses as they rely on the most accurate information available at current prices and do not try to extrapolate

those prices into the future. ADEQ should ensure that any escalation to future years is excluded from the cost

estimates.

 While 20 years is used as the equipment life for SCR in an example in the CCM, we apologize for the confusion and

wish to clarify that the use of 20 years was merely an assumption for purposes of presenting an example of cost

estimation for SCR installation and operation in the CCM. The CCM actually requires that the capital recovery factor

(CFR) be based on the actual (or anticipated) service life of the equipment. The lifetime of an SCR, which is a metal

frame packed with catalyst modules, is equal to the lifetime of the boiler, which might easily be over 60 years. Many

utilities routinely specify 30+ year lifetimes in requests for proposal and to evaluate proposals. We believe a 30

‐ year

service life is consistent with actual experience with existing SCRs and with the nature of the equipment.

 We continue to believe that an equipment life of 30 years rather than 15 is more representative of the anticipated

service life of LNB/OFA, and that this should be used to calculate the CFR and cost

‐ effectiveness of this control.

However, even assuming a 15 year equipment life, we believe that the estimated cost of LNB/OFA is within the

range of what we generally consider cost

‐ effective.

 While we have the above concerns regarding the SCR cost calculation, it is unlikely that the additional visibility

benefits will justify the additional cost of the control.

NOx BART emission limit

 Based on the actual NOx performance obtained from CAMD and compiled by AEP/SWEPCO, it appears that

PacifiCorp Wyodak is the EGU most similar to AEP Flint Creek Unit 1 in terms of the pre

‐ controlled NOx emissions

averages. Since June 2011, two months following the operation of LNB/OFA, the monthly average NOx emissions at

Wyondak have consistently remained at no more than 0.21 lb/MMBtu. In addition, except for one isolated instance,

AEP Welsh Unit 2 has had monthly average NOx emissions no greater than 0.191 lb/MMBtu since May 2005, when

LNB/OFA controls began operating. According to the B&W proposal, AEP Flint Creek Unit 1 is a duplicate of AEP

Welsh Unit 2. Further, according to the B&W proposal, the expected controlled NOx emission rate for AEP Flint

Creek at full load conditions based on a 4

‐ hour test period is 0.145

– 0.20 lb/MMBtu with Aire Jet Burners or 0.165

–

0.218 lb/MMBtu with DRB

‐ 4Z Burners. While we believe that the analysis adequately supports the selection of

OFA/LNB as BART, we believe based on the information provided a lower emission limit than 0.23 is likely

appropriate and should be considered.2 Thank you,

Dayana Medina

U.S. Environmental Protection Agency, Region 6

Multimedia Planning and Permitting Division

Air Planning Section (6PD

‐ L)

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