### Questions on FCPP modeling files for APS proposal Scott Bohning Scott Bohning to: Kostrova, Olga 12/17/2010 10:36 AM

Cc: "Paine, Bob", Anita Lee

Olga -

Hello! This week I have finally been able to examine the modeling files from the disk you sent the other week, and I have a few questions for you... sorry to drop this on you so near the holidays. (Please forward if you are not the right person to ask about this.)

1 . Particular modeling output files relied on Particular modeling output files relied on

I wanted to confirm exactly which outputs were used as the basis for conclusions and the graphic (attached) in the APS proposal, since there are various modeling files on the disk and not all of them were used (e.g. c2 files for LNB not used). I would appreciate if you could check that I have this right.

The following lists what I found, in this format: My conclusion for the scenario in the bar chart graphic CALPOST input file name for arches for 2001 POSTUTIL concentration output file used as CALPOST input POSTUTIL input file name: CALPUFF.DAT a.k.a.. MODDAT file(s) used as POSTUTIL input

All the units in base case were used in "Baseline" in APS Proposal graphic calpost\am1_c0\ct_fcpp_c0_am1_arch_01.inp postutil\am1\pu_fcpp_c0_am1_01.con am1\pu_fcpp_c0_am1_01.inp: 1 calpuff\cf_fcpp_c0_u123_01.con am1\pu_fcpp_c0_am1_01.inp: 2 calpuff\cf_fcpp_c0_u45_01.con

Just units 4&5 in base case were used in "Units 4 & 5 Baseline" in APS Proposal graphic calpost\am1_c0_u45\ct_fcpp_c0_am1_arch_01.inp postutil\am1\pu_fcpp_c0_am1_u45_01.con am1\pu_fcpp_c0_am1_u45_01.inp: 1 calpuff\cf_fcpp_c0_u45_01.con

All the units in SCR & PM control case were used in "EPA BART Case: SCR/PM Controls (Units 1-5 ON)" in APS Proposal graphic calpost\am1_c5\ct_fcpp_c5_am1_arch_01.inp postutil\am1\pu_fcpp_c5_am1_01.con am1\pu_fcpp_c5_am1_01.inp: 1 calpuff\cf_fcpp_c5_u123_01.con am1\pu_fcpp_c5_am1_01.inp: 2 calpuff\cf_fcpp_c5_u45_01.con

Just units 4&5 in SCR & PM control case were used in "Units 4 & 5 SCR/PM Controls" in APS Proposal graphic calpost\am1_c5_u45\ct_fcpp_c5_am1_arch_01.inp postutil\am1\pu_fcpp_c5_am1_u45_01.con am1\pu_fcpp_c5_am1_u45_01.inp: 1 calpuff\cf_fcpp_c5_u45_01.con

2 . Basis for emissions Basis for emissions

The emissions used by AECOM for "EPA BART" (c5) do not appear to match the emissions that EPA used to model the effect of SCR (c3) and of PM controls (c1); see comparison in attached spreadsheet (seenotes at its top and yellow highlighting in its ratio table ). ( The emissions used for scenarios c 0 base

case, and c2 LNB do match EPA's, though.) Am I looking in the wrong place, or can you explain why the numbers differ? Can you provide details on where those emission numbers came from, such as the nice spreadsheets ENSR/AECOM originally provided way back when?

3 . CMAQ ammonia scenario CMAQ ammonia scenario

This one we don't need an answer on, but I thought you would like to know. It appears to me that the POSTUTIL files under Monthly_Ave_CMAQ all use both the u123 and the u45 CALPUFF results, whereas I would have expected them to have just u45 (units 4 & 5) to show results of APS proposal. The do not have "u45" in their names, so I see that this actually is consistent with how file names were used for the other scenarios (i.e. no "u" means all the units)... maybe this is a non-problem, since use of these outputs would be for effect "EPA BART", not for the APS proposal.

Thanks for any help you can provide.

- Scott B.

--

=+=+=+=+=+=+=+=+=+=+=+=+=+=+= "Scott Bohning" <bohning.scott@epa.gov> U.S. EPA Region 9, AIR-7

415/947-4127 fax-3579

P.S. I hope you will have some good time off!

Attachment: "APS Proposal graphic", the bar chart on p.5 of file "FINAL EPA-BART LETTER ED FOX.pdf", Nov. 24, 2010 Attachment: spreadsheet comparison of AECOM emissions for APS proposal and "EPA BART" to emissions used by EPA

aps_rh_impacts_barchart.png aps_rh_impacts_barchart.png emissions_APS_alt.xlsx emissions_APS_alt.xlsx

### RE: Questions on FCPP modeling files for APS propos al

Kostrova, Olga

to: Scott Bohning

12/17/2010 12:42 PM

Cc: "Paine, Bob", Anita Lee

Show Details

Scott,

Thanks for reviewing the files I sent to you. I wil l respond to all of your questions on Monday. Regar ding the emissions: we used the lb/MMBtu directly from the T SD’s Table ES- 1 and multiplied them by the heat input rates
you used in the ANPR modeling, instead of applying a percent reduction to the baseline emissions.

Regards,
Olga

From: Bohning.Scott@epamail.epa.gov [ mailto:Bohning.Scott@epamail.epa.gov ]

Sent: Friday, December 17, 2010 1:36 PM

To: Kostrova, Olga

Cc: Paine, Bob; Lee.Anita@epamail.epa.gov Subject: Questions on FCPP modeling files for APS proposal

Olga -

Hello! This week I have finally been able to exa mine the modeling files from the disk you sent the other week, and I have a few questions for you... sorry to drop this on you so near the holidays. (Please forward if you are not the right person to ask about this.)

1. Particular modeling output files relied on

I wanted to confirm exactly which outputs were used as the basis for conclusions and the graphic (atta ched) in the APS proposal, since there are various modeling file s on the disk and not all of them were used (e.g. c 2 files for LNB not used). I would appreciate if you could che ck that I have this right.

The following lists what I found, in this format: My conclusion for the scenario in the bar chart gra phic CALPOST input file name for arches for 2001
POSTUTIL concentration output file used as CALPOST input
POSTUTIL input file name: CALPUFF.D AT a.k.a.. MODDAT file(s) used as POSTUTIL input

All the units in base case were used in "Baseline" in APS Proposal graphic
calpost\am1_c0\ct_fcpp_c0_am1_arch_01.inp
postutil\am1\pu_fcpp_c0_am1_01.con
am1\pu_fcpp_c0_am1_01.inp: 1 calpuff\cf_fcpp_c0_u123_01.con
am1\pu_fcpp_c0_am1_01.inp: 2 calpuff\cf_fcpp_c0_u45_01.con

Just units 4&5 in base case were used in "Units 4 & 5 Baseline" in APS Proposal graphic
calpost\am1_c0_u45\ct_fcpp_c0_am1_arch_01.inp
postutil\am1\pu_fcpp_c0_am1_u45_01.con 

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...am1\pu_fcpp_c0_am1_u45_01.inp: 1 calpuff\cf_fcpp_c0_u45_01.con

All the units in SCR & PM control case were used in "EPA BART Case: SCR/PM Controls (Units 1-5 ON)" in APS
Proposal graphic
calpost\am1_c5\ct_fcpp_c5_am1_arch_01.inp
postutil\am1\pu_fcpp_c5_am1_01.con
am1\pu_fcpp_c5_am1_01.inp: 1 calpuff\cf_fcpp_c5_u123_01.con
am1\pu_fcpp_c5_am1_01.inp: 2 calpuff\cf_fcpp_c5_u45_01.con

Just units 4&5 in SCR & PM control case were used i n "Units 4 & 5 SCR/PM Controls" in APS Proposal gra phic

calpost\am1_c5_u45\ct_fcpp_c5_am1_arch_01.inp
postutil\am1\pu_fcpp_c5_am1_u45_01.con
am1\pu_fcpp_c5_am1_u45_01.inp: 1 calpuff\cf_fcpp_c5_u45_01.con

2. Basis for emissions

The emissions used by AECOM for "EPA BART" (c5) do not appear to match the emissions that EPA used to model the effect of SCR (c3) and of PM controls (c1 ); see comparison in attached spreadsheet (see note s at its top and yellow highlighting in its ratio table). (The emissions used for scenarios c0 base case, and c2 LNB do match EPA's, though.) Am I looking in the wrong pl ace, or can you explain why the numbers differ? Ca n you provide details on where those emission numbers cam e from, such as the nice spreadsheets ENSR/AECOM originally provided way back when?

3. CMAQ ammonia scenario

This one we don't need an answer on, but I thought you would like to know. It appears to me that the P OSTUTIL files under Monthly_Ave_CMAQ all use both the u123 and the u45 CALPUFF results, whereas I would have expected them to have just u45 (units 4 & 5) to sho w results of APS proposal. The do not have "u45" i n their names, so I see that this actually is consistent wi th how file names were used for the other scenarios (i.e. no "u" means all the units)... maybe this is a non-problem , since use of these outputs would be for effect "E PA BART", not for the APS proposal.

Thanks for any help you can provide.

- Scott B.

--

=+=+=+=+=+=+=+=+=+=+=+=+=+=+= "Scott Bohning" <bohning.scott@epa.gov> U.S. EPA Region 9, AIR-7
415/947-4127 fax-3579

P.S. I hope you will have some good time off!

Attachment: "APS Proposal graphic", the bar chart o n p.5 of file "FINAL EPA-BART LETTER ED FOX.pdf", N ov. 24, 2010 Attachment: spreadsheet comparison of AECOM emissio ns for APS proposal and "EPA BART" to emissions use d
by EPA 

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...

### RE: Questions on FCPP modeling files for APS propos al

Kostrova, Olga

to: Scott Bohning

12/21/2010 08:24 AM

Cc: "Paine, Bob", Anita Lee, C.Mathai, "Kostrova, Olga"

Show Details

Scott,

Please find below our responses to your questions. In the future, it would be good for you to copy AP S on questions so that they are aware of your review

progress.

1. Particular modeling output files relied on

Your understanding of the modeling files in relatio n to the results graphic is correct. We also mode led a fifth case (not depicted on your graphic) with LN B/OFA on Units 4&5 and Units 1-3 shut down (c2). The graphs with that case included are attached ( “modeling results – 5 cases.bmp”)

2. Basis for emissions

There are actually two versions of the EPA Region 9 proposed BART emissions, associated with different averaging times. We selected for modelin g the version in the Technical Support Document Table 40, which are based on 30-day rolling average s for NOx and a 6-hour average for PM. However, in emission tables that you included on the hard dr ive containing the EPA Region 9 modeling files, there was a computation of NOx emissions associated with the SCR controls on Units 1-5 by applying

an 80% reduction to the worst

- case daily baseline NOx emissions. PM emissions associated wi th the ESP controls on Units 1-3 were computed by applying a 52% (on Unit 1) and 59% (on Units 2-3) reduction to the worst-case daily baseline PM emiss ions. These represent peak 24-hour average emissions, while the TSD Table 40 generally appears to represent lower emission rates associated with a longer (30-day) averaging time. We modeled the p eak 24-hour emissions for the baseline case and the 30-day rolling average emissions for the contro l cases. Therefore, our modeling results will like ly
overstate the benefits of SCR and PM controls.

3. CMAQ ammonia scenario

We used the CMAQ-derived ammonia values only for a sensitivity study to compare the results from Peak 24

- hour emissions 30

- day average emissions

NOx worst

case daily

average PM worst

- case

daily average NOx 30

- day

average PM 6

- hour

average

lb/MMBtu lb/MMBtu lb/MMBtu lb/MMBtu

0.17 0.014 0.16 0.012

0.14 0.017 0.13 0.012

0.13 0.015 0.12 0.012

0.13 0.025 0.10 0.015

0.11 0.012 0.10 0.015 

### Page 1 of 4

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...the baseline case and the EPA BART case. The EPA BA RT case includes modeling of all five units, not

just Units 4 and 5. Therefore, in POSTUTIL, we com bined the impacts from Units 1 -3 and units 4-5. However, if EPA is interested in the results of A PS emissions proposals using the CMAQ ammonia concentrations, these could be modeled.

Please let me know if you have any questions.

Regards, Olga

Olga Kostrova Air Quality Specialist

Environment

D 978.589.3174 olga.kostrova@aecom.com

AECOM 2 Technology Park Drive, Westford, MA 01886-3140

T 978.589.3174 F 978.589.3312 http://www.aecom.com/ " title="blocked:: http://www.aecom.com/ "> www.aecom.com

 Please consider the environment before printing this e-mail

From: Bohning.Scott@epamail.epa.gov [ mailto:Bohning.Scott@epamail.epa.gov ]

Sent: Friday, December 17, 2010 1:36 PM

To: Kostrova, Olga

Cc: Paine, Bob; Lee.Anita@epamail.epa.gov Subject: Questions on FCPP modeling files for APS proposal

Olga -

Hello! This week I have finally been able to exa mine the modeling files from the disk you sent the other week, and I have a few questions for you... sorry to drop this on you so near the holidays. (Please forward if you are not the right person to ask about this.)

1. Particular modeling output files relied on

I wanted to confirm exactly which outputs were used as the basis for conclusions and the graphic (atta ched) in the APS proposal, since there are various modeling file s on the disk and not all of them were used (e.g. c 2 files for LNB not used). I would appreciate if you could che ck that I have this right.

The following lists what I found, in this format: My conclusion for the scenario in the bar chart gra phic CALPOST input file name for arches for 2001
POSTUTIL concentration output file used as CALPOST input
POSTUTIL input file name: CALPUFF.D AT a.k.a.. MODDAT file(s) used as POSTUTIL input

All the units in base case were used in "Baseline" in APS Proposal graphic
calpost\am1_c0\ct_fcpp_c0_am1_arch_01.inp
postutil\am1\pu_fcpp_c0_am1_01.con
am1\pu_fcpp_c0_am1_01.inp: 1 calpuff\cf_fcpp_c0_u123_01.con
am1\pu_fcpp_c0_am1_01.inp: 2 calpuff\cf_fcpp_c0_u45_01.con 

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...Just units 4&5 in base case were used in "Units 4 & 5 Baseline" in APS Proposal graphic

calpost\am1_c0_u45\ct_fcpp_c0_am1_arch_01.inp
postutil\am1\pu_fcpp_c0_am1_u45_01.con
am1\pu_fcpp_c0_am1_u45_01.inp: 1 calpuff\cf_fcpp_c0_u45_01.con

All the units in SCR & PM control case were used in "EPA BART Case: SCR/PM Controls (Units 1-5 ON)" in APS
Proposal graphic
calpost\am1_c5\ct_fcpp_c5_am1_arch_01.inp
postutil\am1\pu_fcpp_c5_am1_01.con
am1\pu_fcpp_c5_am1_01.inp: 1 calpuff\cf_fcpp_c5_u123_01.con
am1\pu_fcpp_c5_am1_01.inp: 2 calpuff\cf_fcpp_c5_u45_01.con

Just units 4&5 in SCR & PM control case were used i n "Units 4 & 5 SCR/PM Controls" in APS Proposal gra phic

calpost\am1_c5_u45\ct_fcpp_c5_am1_arch_01.inp
postutil\am1\pu_fcpp_c5_am1_u45_01.con
am1\pu_fcpp_c5_am1_u45_01.inp: 1 calpuff\cf_fcpp_c5_u45_01.con

2. Basis for emissions

The emissions used by AECOM for "EPA BART" (c5) do not appear to match the emissions that EPA used to model the effect of SCR (c3) and of PM controls (c1 ); see comparison in attached spreadsheet (see note s at its top and yellow highlighting in its ratio table). (The emissions used for scenarios c0 base case, and c2 LNB do match EPA's, though.) Am I looking in the wrong pl ace, or can you explain why the numbers differ? Ca n you provide details on where those emission numbers cam e from, such as the nice spreadsheets ENSR/AECOM originally provided way back when?

3. CMAQ ammonia scenario

This one we don't need an answer on, but I thought you would like to know. It appears to me that the P OSTUTIL files under Monthly_Ave_CMAQ all use both the u123 and the u45 CALPUFF results, whereas I would have expected them to have just u45 (units 4 & 5) to sho w results of APS proposal. The do not have "u45" i n their names, so I see that this actually is consistent wi th how file names were used for the other scenarios (i.e. no "u" means all the units)... maybe this is a non-problem , since use of these outputs would be for effect "E PA BART", not for the APS proposal.

Thanks for any help you can provide.

- Scott B.

--

=+=+=+=+=+=+=+=+=+=+=+=+=+=+= "Scott Bohning" <bohning.scott@epa.gov> U.S. EPA Region 9, AIR-7
415/947-4127 fax-3579

P.S. I hope you will have some good time off! 

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...Attachment: "APS Proposal graphic", the bar chart o n p.5 of file "FINAL EPA-BART LETTER ED FOX.pdf", N ov.

24, 2010 Attachment: spreadsheet comparison of AECOM emissio ns for APS proposal and "EPA BART" to emissions use d
by EPA 

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...

### presentation of CALPUFF v. 6.4 to FLMs

Paine, Bob

to: Scott Bohning

12/22/2010 10:30 AM

Cc: Anita Lee, "Kostrova, Olga", C.Mathai, Ann.Becker

Show Details

Scott, attached is a copy of the presentation that Joe Scire made on December 10 to the FLMs in Lakewood, CO on CALPUFF v. 6.4. The FLMs were p leased to receive this presentation and will be working with EPA to “expedite” the review and implementation for this i mproved version of CALPUFF.

Olga reminded me that we have included some CALPUFF 6.4 modeling runs in addition to the CALPUFF version 5.8 modeling runs on the DVD that y ou received.

Please let us know if you have any additional quest ions on the modeling files. Hope you have a peaceful and joyous holiday!

Bob 

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### RE: Questions on FCPP modeling files for APS propos al

Paine, Bob

to: Scott Bohning

12/23/2010 06:50 AM

Cc: Anita Lee, "Kostrova, Olga", C.Mathai, Ann.Becker

Show Details

Scott, to help you interpret the results of our CAL PUFF modeling, I am attaching a document that has b ar graph

results and tables of emissions used. The model co mbinations are CALPUFF v. 5.8 and also v. 6.4 with two sets of ammonia background: the IWAQM default 1.0 ppb a nd also the AECOM values that were used in the 2008
BART analyses.

The five emission cases that we modeled are tabulat ed, and they include:

Case 1) The baseline emissions that you used in you r modeling
Case 2) The proposed EPA BART emissions as publishe d in the Federal Register
Case 3) An alternative baseline case that has no em issions from Units 1-3 Case 4) Case 3 with LNB/OFA installed on Units 4-5
Case 5)Case 2 with Units 1-3 shut down.

You will notice that the relative visibility impact and the effectiveness of the emission cases to imp rove visibility
vary considerably depending the choice of the CALP UFF version and the ammonia background assumed.

Bob 

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...

### RE: Questions on FCPP modeling files for APS proposal Questions on FCPP modeling files for APS proposal Scott Bohning Scott Bohning to: Paine, Bob 12/27/2010 11:05 AM

Cc: Anita Lee, Ann.Becker, C.Mathai, "Kostrova, Olga"

Bob & Olga -

Thank you for those bar charts, and for the previous spreadsheets and explanations. The main point I was concerned about, difference between "worst case" and proposed FIP 30-day average limit for NOx, I understand now and should have been able to get from what you had already sent.

Sorry if I am being dense , but I still do not see how the EPA proposed PM limits were used in the modeling. We may not need to resolve this, since EPA will likely have our own version of the effect of the new APS proposal, but if you have other details you might send them.

In summary, the tables in the Word document you just sent are consistent with the emission rates used in the AECOM modeling for the EPA proposed BART case, except that there is no PMC emission rate, and it is not clear how the FIP PM emission limits (e.g. 0.012 lb/MMBTU for units 1-3) were used to get the emission rates used in that table or the modeling.

FYI, here are some things that I checked.

The heat inputs (MMBTU/hr) and emission rates (lb/hr) in "Shut Down 123 in 2012 (11-29-10).xls" for the case "EPA Proposed BART" do not correspond to those used by EPA, nor to those in "FCPP charts and emissions_23dec10.doc" or in the actual CALPUFF files, so I don't know what to make of them... I won't worry about these in light of later tables supplied in the Word document "FCPP charts and emissions_23dec10.doc".

For "FCPP charts and emissions_23dec10.doc" there is a match between the emissions in Table 2 "Proposed FIP Emissions (from published proposal)" and those used by AECOM in the latest CALPUFF modeling for SO2, NOx, PMF, EC, SO4*98/96, and SOA.

The SO2, NOx, and PM lb/hr and lb/MMBTU are consistent with the proposed FIP limits, and give heat inputs consistent with what EPA assumed (units 1-5 in MMBTU/hr: 2349; 2352; 3032; 8000; 8051).

But it is not clear to me how the PM limit or emission rate lb /hr was used to derive the various PM components (PMC, PMF etc.) used for the AECOM modeling; I guess that is someplace else.

The table does not include a PMC/PM coarse emission rate, and the PMC rate used in CALPUFF does not correspond to (PM minus PM fine), or (PM minus PM fine and EC), or (PM minus everything else).

- Scott B.

--

=+=+=+=+=+=+=+=+=+=+=+=+=+=+= "Scott Bohning" <bohning.scott@epa.gov> U.S. EPA Region 9, AIR-7

415/947-4127 fax-3579

"Paine, Bob" 12/23/2010 06:50:45 AM Scott, to help you interpret the results of our CAL...

From: "Paine, Bob" <bob.paine@aecom.com>

To: Scott Bohning/R9/USEPA/US@EPA

Cc: Anita Lee/R9/USEPA/US@EPA, "Kostrova, Olga" <olga.kostrova@aecom.com>,

<C.Mathai@aps.com>, <Ann.Becker@pinnaclewest.com>Date: 12/23/2010 06:50 AM

Subject: RE: Questions on FCPP modeling files for APS proposal



### Scott, to help you interpret the results of our CALPUFF modeling, I am attaching a document that has
bar graph results and tables of emissions used. The model combinations are CALPUFF v. 5.8 and also v.
6.4 with two sets of ammonia background: the IWAQM default 1.0 ppb and also the AECOM values that
were used in the 2008 BART analyses.

The five emission cases that we modeled are tabulated, and they include:

Case 1) The baseline emissions that you used in your modeling
Case 2) The proposed EPA BART emissions as published in the Federal Register
Case 3) An alternative baseline case that has no emissions from Units 1-3 Case 4) Case 3 with LNB/OFA installed on Units 4-5
Case 5)Case 2 with Units 1-3 shut down.

You will notice that the relative visibility impact and the effectiveness of the emission cases to improve
visibility vary considerably depending the choice of the CALPUFF version and the ammonia background

assumed.

Bob[attachment "FCPP charts and emissions_23dec10.doc" deleted by Scott Bohning/R9/USEPA/US]

### Questions on FCPP modeling files for APS proposal

- updated response

Paine, Bob

to: Scott Bohning

01/03/2011 07:53 PM

Cc: "Kostrova, Olga", C.Mathai, Ann.Becker, Anita Lee

Show Details

Scott, in response to your questions posed on Decem ber 27 about the PM emissions that we modeled for the Four Corners Power Plant, I have checked wi th Olga Kostrova, and we have the following responses to your questions as well as attached fil es (Excel and Word) that will help to clarify what we modeled.

Bob

Comments and responses are provided here.

1) Scott Bohning:

In summary, the tables in the Word document you jus t sent are consistent with the emission rates used in the AECOM modeling for the EPA proposed BART cas e, except that there is no PMC emission rate,

and it is not clear how the FIP PM emission limits (e.g. 0.012 lb/MMBTU for units 1-3) were used to ge t
the emission rates used in that table or the modeli ng.

AECOM Response:

We are attaching a clarifying Excel and a Word vers ion of the emissions with PMC emissions included as well as details regarding the computation of the emission rates. The Excel file is based upon the file you sent us, with the red edits created by EPA’s re view and changes to the original BART Excel spreadsheet submitted by AECOM with the 2008 BART a nalysis.

2) Scott Bohning:

FYI, here are some things that I checked.

The heat inputs (MMBTU/hr) and emission rates (lb/h r) in "Shut Down 123 in 2012 (11-29-10).xls" for the case "EPA Proposed BART" do not correspond to t hose used by EPA, nor to those in "FCPP charts and emissions_23dec10.doc" or in the actual CALPUFF files, so I don't know what to make of them... I won't worry about these in light of later tables su pplied in the Word document "FCPP charts and emissions_23dec10.doc".

AECOM Response:

Please use the updates to the December 23 documents that are attached for comparison to the modeling files. The only changes in the attached f iles from those sent on December 23 are

clarifications to the PM emissions rates. Note tha t the emissions used in the modeling correspond to those in the Excel spreadsheets that you provided t o us, as well as EPA’s BART proposal as found in 

### Page 1 of 4

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...Table 40 of the Technical Support Document. Also n ote that the baseline emissions represent peak

24-hour NOx emissions, while the BART options corre spond to 30-day rolling average emission rates. Due to the inherently higher emission rate for the peak 24-hour average vs. the 30-day rolling average

, the modeled visibility improvement will be an overe stimate of the actual visibility improvement that would be realized if consistent emission averaging times were considered.

3) Scott Bohning:

For "FCPP charts and emissions_23dec10.doc" there is a match between the emissions in Table 2 "Proposed FIP Emissions (from published proposal)" and those used by AECOM in the latest CALPUFF modeling for SO2, NOx, PMF, EC, SO4*98/96, and SOA.

AECOM Response:

Those values are not changed in the attached inform ation provided, so they will continue to match.

4) Scott Bohning:

The SO2, NOx, and PM lb/hr and lb/MMBTU are consist ent with the proposed FIP limits, and give heat inputs consistent with what EPA assumed (units 1-5 in MMBTU/hr: 2349; 2352; 3032; 8000; 8051).

But it is not clear to me how the PM limit or emiss ion rate lb/hr was used to derive the various PM components (PMC, PMF etc.) used for the AECOM model ing; I guess that is someplace else.

AECOM Response:

The table does not include a PMC/PM coarse emission rate, and the PMC rate used in CALPUFF does not correspond to (PM minus PM fine), or (PM minus PM fine and EC), or (PM minus everything else).

AECOM Response:

The attached documents will address these questions

.

Regards,

Bob Paine, CCM, QEP

Technical Director
AECOM Environment The attached documents will clarify what we used fo r the PM modeling. Note that:

• For a dry bottom boiler fired with bituminous coal and equipped with a scrubber (Units 1-3), total filterable PM10 is 71% of filterable PM and fine filterable PM10 is 51% of filterable PM based on AP-42, Table 1.1-6.

• For a dry bottom boiler fired with bituminous coal and equipped with a baghouse (Units 4-5), total filterable PM10 is 92% of filter able PM and fine filterable PM10 is 53% of filterable PM based on AP-42, Table 1.1-6.

5) Scott Bohning: 

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...D 978.589.3164

mailto:bob.paine@aecom.com ">bob.paine@aecom.com

AECOM 2 Technology Park Drive Westford, MA 01886

T 978.589.3000 F 978.589.3100 http://www.aecom.com/ " title="blocked:: http://www.aecom.com/ "> www.aecom.com

From: Bohning.Scott@epamail.epa.gov [ mailto:Bohning.Scott@epamail.epa.gov ]
Sent: Monday, December 27, 2010 2:05 PM

To: Paine, Bob
Cc: Lee.Anita@epamail.epa.gov; Ann.Becker@pinnaclewest .com; C.Mathai@aps.com; Kostrova, Olga Subject: RE: Questions on FCPP modeling files for APS propo sal

Bob & Olga -

Thank you for those bar charts, and for the previou s spreadsheets and explanations. The main point I was concerned about, difference between "worst case " and proposed FIP 30

- day average limit for NOx, I understand now and should have been able to get f rom what you had already sent.

Sorry if I am being dense , but I still do not see how the EPA proposed PM limits were used in the modeling. We may not need to resolve this, since E PA will likely have our own version of the effect o f the new APS proposal, but if you have other details you might send them.

In summary, the tables in the Word document you jus t sent are consistent with the emission rates used in the AECOM modeling for the EPA proposed BART cas e, except that there is no PMC emission rate,

and it is not clear how the FIP PM emission limits (e.g. 0.012 lb/MMBTU for units 1-3) were used to ge t
the emission rates used in that table or the modeli ng.

FYI, here are some things that I checked.

The heat inputs (MMBTU/hr) and emission rates (lb/h r) in "Shut Down 123 in 2012 (11-29-10).xls" for the case "EPA Proposed BART" do not correspond to t hose used by EPA, nor to those in "FCPP charts and emissions_23dec10.doc" or in the actual CALPUFF files, so I don't know what to make of them... I won't worry about these in light of later tables su pplied in the Word document "FCPP charts and emissions_23dec10.doc".

For "FCPP charts and emissions_23dec10.doc" there is a match between the emissions in Table 2 "Proposed FIP Emissions (from published proposal)" and those used by AECOM in the latest CALPUFF modeling for SO2, NOx, PMF, EC, SO4*98/96, and SOA.

The SO2, NOx, and PM lb/hr and lb/MMBTU are consist ent with the proposed FIP limits, and give heat inputs consistent with what EPA assumed (units 1-5 in MMBTU/hr: 2349; 2352; 3032; 8000; 8051).

But it is not clear to me how the PM limit or emiss ion rate lb/hr was used to derive the various PM components (PMC, PMF etc.) used for the AECOM model ing; I guess that is someplace else.

The table does not include a PMC/PM coarse emission rate, and the PMC rate used in CALPUFF does not correspond to (PM minus PM fine), or (PM minus PM fine and EC), or (PM minus everything else).

- Scott B.

--

=+=+=+=+=+=+=+=+=+=+=+=+=+=+= 

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..."Scott Bohning" <bohning.scott@epa.gov>

U.S. EPA Region 9, AIR-7

415/947-4127 fax-3579

Scott, to help you interpret the results of our CAL PUFF modeling, I am attaching a document that has bar graph results and tables of emissions used. Th e model combinations are CALPUFF v. 5.8 and also v. 6.4 with two sets of ammonia background: the IW AQM default 1.0 ppb and also the AECOM values that were used in the 2008 BART analyses.

The five emission cases that we modeled are tabulat ed, and they include:

Case 1) The baseline emissions that you used in you r modeling Case 2) The proposed EPA BART emissions as publishe d in the Federal Register Case 3) An alternative baseline case that has no em issions from Units 1-3 Case 4) Case 3 with LNB/OFA installed on Units 4-5 Case 5)Case 2 with Units 1-3 shut down.

You will notice that the relative visibility impact and the effectiveness of the emission cases to imp rove visibility vary considerably depending the choice o f the CALPUFF version and the ammonia background assumed.

Bob[attachment "FCPP charts and emissions_23dec10.d oc" deleted by Scott Bohning/R9/USEPA/US] From: "Paine, Bob" <bob.paine@aecom.com>

To: Scott Bohning/R9/USEPA/US@EPA

Cc: Anita Lee/R9/USEPA/US@EPA, "Kostrova, Olga" <olga.k ostrova@aecom.com>, <C.Mathai@aps.com>, <Ann.Becker@pinnaclewest.com>

Date: 12/23/2010 06:50 AM
Subject: RE: Questions on FCPP modeling files for APS propos al 

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