CITY OF PH ILADELPHIA Department of Public Health

Environmental Protection Division Air Management Services



### InterOffice Memo

To: File

From: Kassahun Sellassie & Edward Wiener

Date: Nov 11, 2014

Subject: 8-Hour RACT Analysis for Exelon Generating Company - Schuylkill Station

Introduction:

The Clean Air Act (CAA) requires that moderate (or worse) ozone nonattainment areas implement reasonably available control technology (RACT) controls on all major sources of Volatile Organic Compounds (VOC) and Nitrogen Oxides (NOx). Philadelphia County is part of the Philadelphia-Wilmington-Atlantic City moderate ozone nonattainment area for the 1997 8-hour ozone NAAQS. This document presents the findings of the reevaluation of NOx RACT for the 1997 8-hour ozone standard for this facility

Company Description:

Exelon Generation Company - Schuylkill Station owns and oper ates an electric utility in Philadelphia, Pennsylvania. Equipment used at the facility includes two (2) simple cycle combustion turbines and one (1) emergency generator. The facility was owned by PECO Energy Company at the tim e of the original RACT plan approval, but changed to ownership to Exelon in October 2000.

Applicability for NOx and VOC RACT:

Exelon - Schuylkill Station is a major source of NOx due to having potential NOx emissions greater than 100 tons per year, the major source threshold in Philadelphia County that is applicable to NOx RACT for the 1997 8-hour ozone NAAQS. They are not a major so urce of VOC, due to having potential VOC emissions not greater than 50 tons per year, the major source threshold in Philadelphia County that is applicable to NOx RACT for the 1997 8-

hour ozone.

Process Descriptions:

Exelon - Schuylkill Station currently has two simple cycle combustion turbines and one emergency generator. One combustion turbine is rated 233 MMBTU/hr, one rated 284 MBTU/hr, both burn #2 oil and kerosene. The emergency generator is rated 2.75 MW and burns #2 oil or kerosene.

The facility had one boiler in the original RACT plan approval that was rated 1,530 MMBTU/hr and burned No. 6 oil as the primary fuel and No. 2 oil as the ignition fuel. This boiler was shutdown in 2012 and is expected to be permanently retired.

NOx RACT Analysis for the 8-hour Ozone Standard:

Each combustion turbine accepted a 5% an nual capacity factor in the RACT Pl an Approval (PA Pe rmit Number 51- 4904) dated July 11, 2001 and is covered under the presumptive RACT limitations of 25 PA Code Section 129.93(c)(5). The emergency generator was given an op erating limit of less than 500 hours per rolling 12-month period in the same RACT Plan Approval and is covered under the presumptive RACT requirements of 25 PA Code Section 129.93(c)(5). Theref ore, the only remaining significant NOx sources at the facility (the combustion turbines and emergency generator) are covered by Pennsylvania’s presumptive RACT. No further analysis is needed for 8-

hour RACT.

Conclusions and Recommendations:It is recommended that the 1-hour ozone RACT in the RACT Plan Approval (PA Permit Number 51-4904) dated July 11, 2001 still be considered to represent NOx RACT for the 8-hour ozone standard for the Exelon - Schuylkill

Station.

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Edward Wiener, Chief of Source Registration Date