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 Application for South Eastern 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 Corporation dated January 19, 2000. The PSD permit

application is for the proposed construction of an~~I¢ctntg~Jl~a~g.pl!lQ~·F~nsistingof either six

simple cycle or combined cycle combustion turbines (CTs), depending on the outcome ofa

pending Georgia Department ofNatural Resources water permit. 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) 7FA units

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 steam turbine 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 other than 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 ifSouth Eastern 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 a policy statement that both

combined cycle and simple cycle combustors are subject to a 112(g) case-by-case MACT

determination ifHAP emissions exceed the major source thresholds.

Inlemel Addl1lss (URL) • http://www.epa.gov

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2. The applicant proposed a best available control technology (BACT) NO" emission limit

of 25 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 Power in 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" emissionsfrom the 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, on page 4-8 ofthe Combined Cycle BACT Analysis (Attachment 7

ofthe application), that there are technical concerns regarding the use of SCONOxTM 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 combustion turbine. Region 4 therefore

considers this control method technically feasible for the South Eastern Energy's

combined cycle CTs. Accordingly, ADEM should require South Eastern Energy to

provide a project-specific BACT analysis for SCONOxTM (economics, environmental

impacts, and energy use) before issuing a final permit. .

4. Region 4 asks that ADEM check the PM10 emission rate (22 lb/hr) during simple cycle

operation and PM10 emission rate (23.1Iblbr) during combined cycle operation. These

rates appear higher than previous Region 4 projects (approximately 10 lb/hr when 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 SCR cost analysis specifically.

a. The most recent version ofthe OAQPS Control Cost Manual"cites an interest rate

of7% instead ofthe 1OOJ'o interest rate used throughout the coSt analyses in ~s

permit application~ Ifthe 10% interest rate is appropriate for South Eastern

Energy, supporting documentation should be provided.

EPA4PER070533

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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 Cost Manual, documentation should be provided.

d. The cost analysis 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 of about

45 percent, which is lower than the control efficiencies we have previously seen

for SCR controL including the combined cycle analysis in the South Eastern

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 South Eastern Energy 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 .

emission rate of0.048 gls was used in the impact modeling and appears in Tables 4-1 and

4-2. Based on the short-term CO emission rate provided in Attachment 4, the CO hourly

emission rate should be 0.575 gls.

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Thank you for the opportunity to comment on the PSD permit application for South

Eastern Energy Corporation. Ifyou 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