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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 White Bluff BART analysis

Hi Mary,

We have the following comments regarding minor issues that if resolved we believe would strengthen the SO2 and NOx

BART analyses for White Bluff Units 1, 2, and the auxiliary boiler.

NOx BART

 The 2012 S&L NOx Study identifies neural net system upgrades as a potential NOx control. However, this control

option is not evaluated by Entergy in the BART analysis for Units 1 and 2. While it appears that the added visibility

benefit of LNB/SOFA + SNCR compared to LNB/SOFA is too small to justify the added cost of installing SNCR, we

believe the added cost of LNB/SOFA + Neural Net System Upgrades compared to LNB/SOFA would likely be small

and may provide some visibility benefit. ADEQ should ensure that if a NOx emission limit more stringent than 0.15

lb/MMBtu could be expected from LNB/SOFA + Neural Net System Upgrades, this should be evaluated as a separate

control option in the BART analysis.

Cost Analysis for SO2 and NOx controls

 We are not providing an exhaustive line

‐ by

‐ line review of costs for SO2 and NOx controls because we do not

anticipate that further revisions to the cost numbers would change the ultimate BART determinations. However, we

wish to make clear that EPA disagrees that the Control Cost Manual (CCM) allows for AFUDC to be included in the

BART cost evaluation. AFUDC is the cost of capital that is incurred to finance the project during the construction

period. While AFUDC is a valid cost under the all

‐ in cost estimating methodology, it is not a valid cost under the CCM

methodology. The Regional Haze Rule states the CCM should be followed where possible, and the CCM uses

overnight costing methodology. The overnight cost method is the cost of a construction project if no interest is

incurred during construction, as if the project is completed overnight. Thus, AFUDC is never valid under the CCM

overnight cost approach. ADEQ should ensure that the cost estimates for all SO2 and NOx controls are revised to

exclude AFUDC in order to reflect an accurate estimate of cost

‐ effectiveness of controls.

Auxiliary Boiler (SN

‐ 05)

 The calculations provided indicate that average sulfur content over the 2009

‐ 2011 period and the average heat

content over this same period were utilized to estimate the modeled emission rate. The use of average values based

on a three year average of annual values is inconsistent with estimating the maximum 24

‐ hr emission rate from the

baseline period. Please provide additional information on the variability of sulfur content and heat content in order

to estimate the range of the maximum impact.

 The rationale for determining that no additional controls are required for this unit differs in the revised BART report

and the response to Region 6 comments you provided (comment 16). Please revise the BART report to be consistent

with your response to our comments, as the response provides an appropriate justification for no additional controls

at the auxiliary boiler.

Thank you,

Dayana Medina

U.S. Environmental Protection Agency, Region 62 Multimedia Planning and Permitting Division

Air Planning Section (6PD

‐ L)

214

‐ 665

‐ 7241