UNITED STATESENVIRONMENTAL PROTECTION AGENCY REGION 4 ATlANTA FEDERAL CENTER 61 FORSYTH STREET ATLANTA. GEORGIA 30303-8960 · '-

MAR 1 6 2000 4APT-ARB Mr. Timothy S. Owen Alabama Department ofEnvironmental Management P.O. Box 301463 1400 Coliseum Blvd. Montgomery, AL 36130-1463 SUBJ: PSD Permit Applicationfor SouthEastern Energy Corporation located in Randolph County, Roanoke, Alabama Dear Mr. Owen: Thank you for sending the prevention ofsignificant deterioration (PSD) permit application for South Eastern Energy Corporationdated January 19, 2000. The PSD permit application is for the proposed construction of**an~~I¢ctntg~Jl~a~g.pl!lQ~·F~nsisting** ofeither six simple cycle or combined cycle combustionturbines (CTs), depending on the outcome ofa pending Georgia Department ofNatural Resources waterpermit. Ifthe water permit is issued, the facility 

### will operate in combined cycle mode; otherwise, it will operate in simple cycle mode. The combustion turbines proposed for the facility will be either General Electric (GE) 7FAunits or Siemens Westinghouse SOIF units with a nominal generating capacity of 170 megawatts (MW) each. Ifthe plant operates in coInbined cycle mode, additional equipment will include the following: six fired heat recovery steam generators, two steamturbine generators. one auxiliary boiler and two mechanical draft cooling towers. The CTs and auxiliary boiler will combust pipeline quality natural gas only. Total emissions from the proposed project are above the thresholds requiring PSD review for nitrogen oxides (NOJ. carbon monoxide (CO), volatile organic compounds (YOC), and particulate matter (pMJPMlo)' Based on our review ofthe PSD permit application, we have the following comments on topics otherthan the air quality impact assessment. Air quality impact comments are provided at the end ofthis letter. 1. The potential to emit (PTE) ofapplicable hazardous air pollutants (especially formaldehyde) should be calculated to determine ifSouthEastern Energy is subject to the ·112(g) program. Recently, we have found that some facilities which operate several combustion turbines in simple cycle mode are subject to the 112(g) program. Furthermore, we understand that EPA will soon issue apolicy statement thatboth combined cycle and simple cycle combustors are subject to a 112(g) case-by-case MACT determination ifHAP emissions exceed the major sourcethresholds.

Inlemel Addl1lss (URL) • http://www.epa.gov**R.cycl~ecycl.bl** •• Printed**w~h** Vegelable Oil Based Inks on Recyc;Jed Paper \Minlmum**25~.** Postcon.ume,)2 

### 2. The applicant proposed abest available control technology (BACT) NO" emission limit of25 

### ppmvd (15% 

### oxygen) for natural gas firing to be achieved by use ofdry low-NOll combustion ifSiemens Westinghouse CTs are operated in simple cycle mode. Region 

### 4 has recently reviewed PSD permits (Palmetto Powerin Florida, Heard County Power in Georgia, and others) that involve Siemens Westinghouse simple cycle combustion turbine projects with a proposed BACT NO" emissions limit of 15 

### ppmvd. Ifthe South Eastern Energy facility is significantly different from these other facilities, documentation ofthis difference should be included in the Alabama Department ofEnvironmental Management (ADEM) preliminary determination and draft 

### PSD permit. Additionally, the applicant performed a cost analysis which considered using selective catalytic reduction (SCR) to control NO" emissions fromthe Siemens Westinghouse CTs.**f:ae;'apP~~!i~~cost an~ysis;caltUtafed"tntfco'SfeWear'f~n~s,jt>r:S(gR·to··bet$5~200ttOQ,;;{~m~Y~;,Q,';~O".**  

### This**cO,~t~effectiveness4$'within'tn€'range"'JconsUrirea';economicanY'f~ible·for:installation** 

### of.**SCR'5ri~;offi~fr'(j1'~projtis:** 3. 

### The applicant states, onpage 4-8 

### ofthe Combined Cycle BACT Analysis (Attachment 7 ofthe application), thatthere are technical concerns regarding the use ofSCONOxTM for the combined·cycle CTs, in part because ofunknown scale-up problems going from small CT to large CT systems. In 

### November 1999, ABB ALSTOM POWER announced the availability ofSCONOxTM systems for any size combustionturbine. Region 4 

### therefore considers this control method technically feasible for the SouthEasternEnergy's combined cycle CTs. Accordingly, ADEM should require SouthEastern Energy to provide a project-specific BACT analysis for SCONOxTM (economics, environmental impacts, and energy use) before issuing afinal 

### permit.

. 4. 

### Region 4 

### asks that ADEM checkthe PM10 

### emission rate (22 lb/hr) during simple cycle operation and PM10 

### emissionrate (23.1Iblbr) during combined cycle operation. These rates appear higherthan 

### previous Region4 projects (approximately 10 lb/hrwhen burning natural gas for the 

### same size CT). 

### 5. In 

### Section 3.1 BACT 

### Analysis, there are no PMlPM10 

### BACT emission rates listed in conjunction with 

### the BACT determination ofGood Combustion Practices for control of PMlPM10 

### emissions. The appropriate emission rates (those used in calculating the PTE) should be included in

### the draft 

### PSD permit. 6. Listed below are several comments regarding the permit application's economic analysis. in general, and SCRcost analysis specifically.

a. The most recentversion ofthe OAQPS Control CostManual"cites an interest rate of7% instead ofthe 1OOJ'o interest rate used throughout the coSt analyses in**~s** 

### permit**application~** If

### the 10% interest rate is 

### appropriate for SouthEastern Energy, supporting documentation should be provided.



### EPA4PER070533 o.**',~,..'**b. .3 The applicant includes a Lost Power Generation (pressure drop from catalyst bed) term in the cost analyses. Although it is appropriate to calculate the cost ofusing additional natural gas.to compensate for the lost power resulting from pressure drops across the catalyst bed, lost revenue should not be included in the cost analysis.

.**.~** c. The contingency fee is listed as 20% ofthe direct capital costs. Ifthere is reason to suggest the need for a 20% contingency fee instead ofthe 3% contingency fee cited in the OAQPS Control CostManual, documentation should be provided. d. The costanalysis for SCR (GE 7FAs in simple cycle mode) uses NO" emissions of9 ppm as the baseline and calculates the cost effectiveilessofusing SCR with controlled NO" emissions at an assumed level of5 ppm. In other words, the applicant does not base tons per year reduced on a specific control efficiency value. We note that the applicant's approach yields a control efficiency ofabout 45 percent, which is lowerthan the control efficiencies we have previously seen for SCR controL including the combined cycle analysis in the SouthEastern Energy application, which proposes a NO" emission limit of3.5 ppm when SCR is installed. In terms ofthe 

### air quality impact assessment, the following provides our review comments on the SouthEasternEnergy PSD permit application. These review comments were discussed with ADEM on March 9,2000. I. Cooling Towers

- Emissions (i.e., PMlPM10 and toxies) and potential impacts from the two mechanical draft cooling towers should be addressed in the permit application. 2. VOC Emissions

- VOC emissions from the proposed.project are greater than 100 TPY. Ambient ozone preconstruction monitoring and current ozone conditions in the area. should be addressed in the PSD permit application. 3. Visibility Impairment· The assessment ofvisibility impairment is not limited to Class I areas. This assessment should be performed in the impact area with particular emphasis at locations ofsensitive receptors (e.g., scenic vistas, nearby airports, etc
...). 4. Emergency Generator CO Emission Rates

- The short-term CO emergency generator
. emissionrate of0.048 gls was used in the impact modeling and appears in Tables 4-1 and 4-2. Based on the short-termCO emission rate provided in Attachment 4, the CO hourly emission rate should be 0.575 gls.

......

### __..

# __..

## _-- ----- --_._._--_...-_ •...4 

### Thank you for the opportunity to comment on the PSD permit application for South Eastern Energy Corporation. If

### you have any questions regarding these comments, please direct them to either Katy Forney at 404-562-9130 or Jim Little at 404-562-9118. Sincerely,

# 6)~~ 

# Ilu.ft;r
R. 

### Douglas Neeley Chief Air and Radiation Technology Branch Air, Pesticides and Toxics

Management Division



## EPA4PER878535