Prepared for: Prepared by: TransCanada AECOM Ravenswood, NY Westford, MA 60158987 

### Environment



# Five Factor BART Analysis for TransCanada Ravenswood Generating Station

### Environment



# Five Factor BART Analysis for TransCanada Ravenswood Generating Station

______________________ ______________________________________________ Prepared By Olga Kostrova

_________________________________ Reviewed By Robert J. Paine Prepared for: Prepared TransCanada AECOM Ravenswood, NY Westford, 60158987 

### Environment



# Five Factor BART Analysis for TransCanada Ravenswood

Station

______________________________________________

Robert Hall Seemantini

_________________________________ Prepared by: AECOM Westford, MA 60158987

______________________________________________ ___________ Seemantini DeshpandeAECOM Environment

Five Factor BART Analysis for TransCanada Ravenswoo d Generating Station September 2010 i



# Contents

Executive Summary ................................

................................................... ....................... ES-1

1.0 Introduction ......................................

................................................... ........................... 1-1

1.1 Location of Source vs. Relevant Class I Areas .....

................................................... .......... 1-1

1.2 Organization of Report Document ...................

................................................... ................. 1-1



### 2.0 Background Data ...................................

................................................... ..................... 2-1

2.1 Overview of BART Emission Units ...................

................................................... ................ 2-1

2.2 Existing Control Technologies .....................

................................................... ..................... 2-1

2.3 Baseline Emissions ................................

................................................... ........................... 2-1



### 3.0 Emission Control Alternatives .....................

................................................... ............. 3-1

3.1 Candidate SO 2 Emissions Control ................................

................................................... ... 3-1

3.2 Candidate NOx Emission Controls ...................

................................................... ................ 3-1
3.2.1 Effectiveness of Technically Feasible NOx Controls ........................................... 3-2
3.2.2 Analysis of Alternative NOx Controls ..............

................................................... .. 3-3

3.3 Candidate PM Emission Controls ....................

................................................... ................ 3-5



### 4.0 Meteorological Data used in Visibility Improvement Modeling ................................. 4-1

4.1 Elements of the Refined Analysis ..................

................................................... .................. 4-1



### 5.0 CALPUFF Modeling Procedures .......................

................................................... ........ 5-1

5.1 CALPUFF Modeling Domain and Receptors .............

................................................... ...... 5-1

5.2 Model Version .....................................

................................................... .............................. 5-1

5.3 Background Air Quality Data .......................

................................................... ..................... 5-1

5.4 Light Extinction and Haze Impact Calculations .....

................................................... .......... 5-1



### 6.0 CALPUFF Modeling and BART Determination Results ... .......................................... 6-1

6.1 Modeled Control Scenarios .........................

................................................... ..................... 6-1

6.2 Modeling Results for Baseline Emissions ...........

................................................... ............. 6-1

6.3 Modeling Results for the Advanced Combustion Contro l Case ......................................... 6- 3

6.4 Conclusions and BART Recommendation ...............

................................................... ....... 6-3AECOM Environment

Five Factor BART Analysis for TransCanada Ravenswoo d Generating Station September 2010 ii



### 7.0 References ........................................

................................................... .......................... 7-1



# List of Appendices

Appendix A Cost Effectiveness Calculations

Appendix B Quotation from Fuel Tech for LNB/SOFA a nd SNCR

Appendix C Modeling Archive



# List of Tables

Table ES-1 Summary of BART Analysis................

................................................... ......................... ES-4

Table 2-1: Ravenswood Baseline Emissions (100% Oil-Firing) ...

................................................... ... 2-3

Table 2-2: Ravenswood Stack Parameters .......................

................................................... .............. 2-3

Table 3-1: Control Efficiency of Technically Feasible NOx Cont rol Options ...................................... 3-3

Table 3-2: Total Capital and Annual Costs Associated with LNB/ SOFA SNCR, SCR, and Fuel

Switching for Ravenswood Units, 10, 20, and 30 ....

................................................... ...... 3-3

Table 3-3: Summary of Non Air Quality Environmental Effects ..

................................................... .... 3-4

Table 3-4: Control Efficiency of Technically Feasible PM Contr ol Options........................................ 3-7

Table 3-5: Cost Effectiveness of Technically Feasible PM Contr ol Options ...................................... 3 -7

Table 3-6: Ravenswood NOx Advanced Combustion Controls Emissio ns (Control Case 1) ........... 3-8

Table 4-1: Comparison of the AECOM and VT DEC CALMET User-Defi ned Settings .................... 4-3

Table 5-1: References to the New IMPROVE Equation CALPOST Inpu ts ....................................... 5-2

Table 6-1: Regional Haze Impacts due to Baseline Emissions ...

................................................... ... 6-2

Table 6-2: Regional Haze Impacts due to Advanced Combustion Co ntrols (Control Option 1) ....... 6-3

Table 6-3: Cost Effectiveness and Visibility Improvement Assoc iated with Control Option 1 ........... 6-4



# List of Figures

Figure 1-1: Location of the Class I Areas in Relation to the Ra venswood Generating Station .......... 1-2
Figure 4-1: Ravenswood CALMET Modeling Domains ................

................................................... .... 4-2AECOM Environment

Five Factor BART Analysis for TransCanada Ravenswoo d Generating Station September 2010 ES-1



# Executive Summary

TransCanada, LLC owns the Ravenswood Generating Sta tion (“RGS”) in Queens, New York. The Ravenswood Generating Station is a 2,480 megawatt ( MW) power plant that consists of multiple units, including boilers. It supplies electrical generati ng capacity to meet 26% of New York City’s demand. As such, Ravenswood must also meet a reliability re quirement as per the New York Independent System Operator, Inc. (NYISO) 1 for standby fuel oil firing in order to prevent a system impact in the event that the natural gas supply is interrupted.

Both Unit 10 and Unit 20 commenced commercial opera tion in 1963 and Unit 30 in 1965, thus meeting the in-service date for BART eligibility. Over the past several years, the plant has had emissions exceeding 250 tons per year of sulfur dio xide (SO 2 ) and nitrogen oxide (NOx). Therefore, the plant is BART-eligible. All three units are ta ngential-fired boilers manufactured by Combustion Engineering. Units 10, 20, and 30 are fired with n atural gas and/or No.6 fuel oil and have maximum heat input rates of 4,204, 4,171, and 9,379 MMBtu/h r, respectively. The plant burns primarily natural gas, but also uses residual fuel oil as indicated b y NYISO’s reliability requirements (I-R3, the “Minimum Oil Burn Rule”). The No.6 fuel oil has a maximum sulfur content of 0.3%.

The New York State BART rules require that sources that are subject to BART perform a site-specific BART analysis including a control technology review and CALPUFF modeling to assess the visibility impact of the emission units. Additionally, for la rge Electric Generating Units (EGUs) affected by th e rule, the source is required to meet presumptive co ntrol levels for NOx and SO 2 unless it is demonstrated that alternative control levels are ju stified or equivalent in effectiveness.

The BART analysis was conducted for the 100% oil-fi ring case since this condition reflects the highest emission case for all haze-causing pollutants. The presumptive BART limit for NOx emissions for the Ravenswood units is 0.15 lb/MMBtu for NOx as a 24-h our average, based on NYSDEC policy. This presumptive BART limit is dictated by the New York Reasonably Achievable Control Technology or RACT rule. For SO 2 , the NYSDEC BART guidelines indicate that limiting the sulfur content of the fuel burned to 1.0% or less constitutes BART for SO 2 . The plant already has a fuel sulfur limit well b elow this level (0.3% sulfur).

This report documents the case-by-case BART analysi s conducted for NOx, SO 2 , and PM 10 emissions from Units 10, 20, and 30. This analysis addresses the five statutory factors required by Section 169 A (g) (7) of the Clean Air Act that States must consi der in making BART determinations:

(1) the costs of compliance,

(2) the energy and non-air quality environmental im pacts of compliance,

(3) any existing pollution control technology in us e at the source,

1 New York Independent System Operator, Inc., Docket No. ER07-748-000, Issued May 11, 2007 by the Feder al Energy Regulatory Commission.AECOM Environment

Five Factor BART Analysis for TransCanada Ravenswoo d Generating Station September 2010 ES-2

(4) the remaining useful life of the source, and,

(5) the degree of improvement in visibility which m ay reasonably be anticipated to result from the use of such technology.

The following emission scenarios were evaluated for the Ravenswood BART analysis:

• Baseline Case (2005-2009 period – the most recent 5 years): maximum daily emissions of SO 2 , NOx as well as particulate matter were provided b y TransCanada. The maximum daily heat input rates were based on the Part 75 monitori ng data for the period of 2005-2009. Condensable particulate matter emissions for the th ree units were based on AP-42 emission factors for No.6 oil-fired boilers.

• NOx Control Case involves combustion control optim ization. This option would include installation of low NOx burners (LNB) and separated overfire air (SOFA) and other combustion modifications. These retrofit controls are capable of achieving a NOx emissions level of 0.17 lb/MMBtu which will limit NOx emissio ns to 3,018 lb/hr for all three units combined on a 24-hour rolling average basis.

Additional NOx and PM 10 control cases were considered for cost effectivene ss and feasibility and they are discussed in Section 3. Based on either an exc essively high cost (NYSDEC considers a cost of $5,000 per ton as excessive), physical space constr aints, infeasibility of the controls, or legal contractual conditions making the option infeasible , other NOx and PM 10 emission control cases were dismissed as not applicable for BART. Consequently , they were not modeled for determining visibility impacts. In general, non-sulfate-related PM 10 visibility impacts are marginally higher than the 0.1 delta-dv threshold and were hence dismissed from fu rther consideration. Moreover, post-combustion control equipment for oil-fired units is generally not feasible.

As noted above, Ravenswood Units 10, 20, and 30 bur n fuel oil with the maximum sulfur content of 0.3%. Per NYSDEC guidance, fuel oil with a sulfur content of 1.0% or less meets BART requirements for SO 2 and, therefore, no further BART review is necessar y for this haze-causing pollutant. However, we present a cost analysis in Section 3 that indica tes that the control cost associated with fuel switching to an even lower sulfur fuel oil is well above $5,000 per ton removed for NOx and PM 10
.
CALPUFF modeling of baseline emissions indicates th at the maximum visibility impact from each unit exceeds the 0.1 delta-deciview (delta-dv) significa nce threshold at one or more Class I areas. Therefore, a BART analysis was conducted. CALPUFF modeling results due to application of the advanced combustion NOx controls (low NOx burners a nd separated overfire air) showed modest visibility improvements at the Class I areas modele d. The most heavily affected Class I area is the Brigantine Wilderness. The NOx control costs for a dvanced combustion controls are approximately $1,600/ton NOx removed and the visibility improveme nt costs are at least $22,000,000/deciview. NYSDEC has noted that control costs above $5,000 pe r ton are excessive and can be used to dismiss BART candidate options from further conside ration.

This BART option of installing advanced combustion controls on the units is not cost effective with regard to visibility (dollars/dv is excessively hig h). However, advanced combustion controls are proposed as BART by TransCanada for controlling NOx emissions based on NY RACT requirements and the dollars/ton cost effectiveness.AECOM Environment

Five Factor BART Analysis for TransCanada Ravenswoo d Generating Station September 2010 ES-3

As can be seen in Table ES-1, switching to low sulf ur distillate oil has associated costs well in exce ss of the NYSDEC guideline of $5,000 per ton removed f or NOx and PM 10 control. Furthermore, the incremental cost of retrofitting the units with an SNCR or an SCR post application of the advanced combustion controls are found to be excessive. We conclude as a result of this BART analysis that none of the additional retrofits considered beyond advanced combustion controls (including switching to distillate oil fuel) are cost-effective for NOx.AECOMEnvironmentFive Factor BART Analysis for TransCanada Ravenswood Generating StationSeptember 2010ES-4Table ES-1: Summary of BART AnalysisStep 1Step 2Step 3Step 4aStep 4bStep 5IdentifyControlTechnologiesFeasibleControlTechnology?EvaluateControlEffectivenessfor TechnicallyFeasibleControlTechnologiesCalculate CostEffectiveness forControlTechnologiesDetermineNon-Air QualityEnvironmentaland EnergyImpactsEvaluateVisibilityChanges ofControls vs.baselineIdentify BART EvaluationResultsNOx Controls:AdvancedCombustionControls: LowNOx burners,separatedoverfire airYesNOx Outlet =0.17 lb/MMBtu,~30% NOxreduction frombaseline levelsof 0.24lb/MMBtuAnnualized cost =$2.62 MM;$1,612/ton removedbased on potentialemissionsNo significantimpactsAveragevisibilityimprovement=0.06 delta-dvInstallation of LNB/SOFA(NOx = 0.17 lb/MMBtu) isBART for Ravenswood Units10, 20 and 30NOx Controls:SNCRYesNOx Outlet =0.15 lb/MMBtu,~ 10-15% NOxreduction frompost LNB/SOFAlevels of 0.17lb/MMBtuAnnualized cost =$7.7 MM;$10,924/ton removedbased on potentialemissionsModest energyimpacts,ammoniaemissionsn/aCosts for this option are toohigh; not considered furtherfor BARTNOx Controls:SCRYesEstimated NOxOutlet = 0.025lb/MMBtu, ~85% NOxreduction fromthe postLNB/SOFAlevels of 0.17lb/MMBtuAnnualized cost =$90 MM; $25,829/tonremoved based onpotential emissionsTransportingammoniaI inNYC; addition ofammoniastorage andhandlingsystems,ammoniaemissions,increasessulfuric acid mistn/aCosts for this option are toohigh; not considered furtherfor BARTAECOMEnvironmentFive Factor BART Analysis for TransCanada Ravenswood Generating StationSeptember 2010ES-5Step 1Step 2Step 3Step 4aStep 4bStep 5IdentifyControlTechnologiesFeasibleControlTechnology?EvaluateControlEffectivenessfor TechnicallyFeasibleControlTechnologiesCalculate CostEffectiveness forControlTechnologiesDetermineNon-Air QualityEnvironmentaland EnergyImpactsEvaluateVisibilityChanges ofControls vs.baselineIdentify BART EvaluationResultsemissionsNOx Controls:Switch tolower sulfurNo. 2 oilYesNOx Outlet =0.10 lb/MMBtu,~ 58% NOxreduction fromresidual oil NOxlevel of 0.24lb/MMBtuAnnualized cost =$104 MM,$62,000/ton removedNo significantimpactsn/aCosts for this option are toohigh; not considered furtherfor BARTNOx Controls:100% NaturalGasNo; MinimumOil Burn Rulefor reliabilityrules out thisoptionn/a n/a n/a n/aInfeasible option; notconsidered further for BARTBART for NOx for Ravenswood Unit 10, 20 and 30Installation of LNB/SOFA(NOx = 0.17 lb/MMBtu) isBART for Ravenswood Units10, 20 and 30SO2Controls:Switch tolower sulfurNo. 2 oilYes, but 0.3%sulfur is belowthe NYSDECSO2BARTthreshold of1% sulfurcontentn/a n/a n/a n/aSince combustion of fuelwith a sulfur content of<=1% is considered BARTfor SO2 and the annualincremental cost of burningdistillate oil is excessivelyhigh, this option was notconsidered further.AECOMEnvironmentFive Factor BART Analysis for TransCanada Ravenswood Generating StationSeptember 2010ES-6Step 1Step 2Step 3Step 4aStep 4bStep 5IdentifyControlTechnologiesFeasibleControlTechnology?EvaluateControlEffectivenessfor TechnicallyFeasibleControlTechnologiesCalculate CostEffectiveness forControlTechnologiesDetermineNon-Air QualityEnvironmentaland EnergyImpactsEvaluateVisibilityChanges ofControls vs.baselineIdentify BART EvaluationResultsBART for SO2for Ravenswood Unit 10, 20 and 30Combustion of 0.3% Sresidual fuel oil is BART forSO2for Ravenswood Units10, 20 and 30PM10Controls:Install FabricFilterNo n/a n/a n/a n/aNot feasible for oil-firedunits.PM10Controls:Install DryESPYesEngineeringestimate –99.9% controlAnnualized cost =$166 MM,$178,000/ton removedUtilizes electricityadding to the loadon the facilityn/aCosts for this option are toohigh; not considered furtherfor BARTPM10Controls:Install WetESPYesEngineeringestimate –99.9% controlAnnualized cost =$229 MM,$246,000/ton removedUtilizes electricityadding to the loadon the facility,wastewatertreatment issuesn/aCosts for this option are toohigh; not considered furtherfor BARTPM10Controls:Switch tolower sulfurNo. 2 oilYesPM10Outlet =0.014 lb/MMBtu,~ 65% NOxreduction fromresidual oil PM10level of 0.04lb/MMBtuAnnualized cost =$104 MM,$175,000/ton removedn/a n/aCosts for this option are toohigh; not considered furtherfor BARTAECOMEnvironmentFive Factor BART Analysis for TransCanada Ravenswood Generating StationSeptember 2010ES-7Step 1Step 2Step 3Step 4aStep 4bStep 5IdentifyControlTechnologiesFeasibleControlTechnology?EvaluateControlEffectivenessfor TechnicallyFeasibleControlTechnologiesCalculate CostEffectiveness forControlTechnologiesDetermineNon-Air QualityEnvironmentaland EnergyImpactsEvaluateVisibilityChanges ofControls vs.baselineIdentify BART EvaluationResultsBART for PM for Ravenswood Unit 10, 20 and 30Combustion of 0.3% Sresidual fuel oil with thecurrent configuration isBART for PMforRavenswood Units 10, 20and 30AECOM Environment

Five Factor BART Analysis for TransCanada Ravenswoo d Generating Station September 2010 1-1



# 1.0 Introduction

The Ravenswood Generating Station (Ravenswood), ope rated by TransCanada, has been identified by NYSDEC as a source that is eligible for consider ation of BART controls for SO 2 , NOx, and PM 10
. This document describes the procedures by which a m odeling analysis and a BART engineering review have been conducted for the BART-eligible Ra venswood Units 10, 20, and 30.



### 1.1 Location of Source vs. Relevant Class I Areas

Figure 1-1 shows the location of the Ravenswood Gen erating Station relative to the seven Class I areas to be considered for New York BART reviews. The BART modeling analysis has been conducted for each of the seven Class I areas in ac cordance with the NYSDEC guidance. The seven Class I areas are as follows:

1. Brigantine National Wildlife Refuge (NJ), locate d about 143 km from Ravenswood;
2. Lye Brook Wilderness Area (VT), located about 2 50 km from Ravenswood;
3. Presidential Range Dry River Wilderness (NH) , l ocated about 425 km from Ravenswood;
4. Great Gulf Wilderness (NH), located about 450 km from Ravenswood;
5. Dolly Sods Wilderness Area (WV), located about 5 00 km from Ravenswood;
6. Otter Creek Wilderness Area (WV). located about 515 km from Ravenswood;
7. Acadia National Park (ME), located about 570 km from Ravenswood.



### 1.2 Organization of Report Document

This report documents the case-by-case BART analysi s conducted for SO 2 , NOx and PM emissions from Units 10, 20, and 30 at the Ravenswood Generat ing Station. Section 2 provides a description of Ravenswood Units 10, 20, and 30 and their baseline emissions. Section 3 provides a discussion of SO 2 , NOx and PM control technologies. The available m eteorological data and the CALPUFF modeling procedures are described in Sections 4 and 5, respectively. The results of the visibility improvement modeling using CALPUFF are presented in Section 6. References are listed in Section 7.AECOM Environment

Five Factor BART Analysis for TransCanada Ravenswoo d Generating Station September 2010 1-2

Figure 1-1: Location of the Class I Areas in Relati on to the Ravenswood Generating StationAECOM Environment

Five Factor BART Analysis for TransCanada Ravenswoo d Generating Station September 2010 2-1



# 2.0 Background Data

2.1 Overview of BART Emission Units

The BART-affected emission units at the Ravenswood Generating Station are the three No. 6 oil/natural gas fired boilers designated as Units 1 0, 20, and 30. Units 10 and 20 commenced commercial operation in 1963 and Unit 30 became ope rational in 1965. Since all three units began operation during the time period (1962-1977) target ed by the Regional Haze BART Rule, they are subject to this rule. Units 10, 20, and 30 are tan gential-fired boilers manufactured by Combustion Engineering.



### 2.2 Existing Control Technologies

Units 10, 20, and 30 has dual-fired capability with either a natural gas and/or No.6 fuel oil and have rated heat input rates of 4,204, 4,171, and 9,379 M MBtu/hr, respectively. The plant burns primarily natural gas, with occasional use of residual fuel o il as requested by NYISO’s reliability requirements (IR3, the “Minimum Oil Burn Rule”). The No.6 fuel oi l has a maximum sulfur content of 0.3%. Ravenswood Units 10, 20, and 30 are equipped with C lose Coupled Over Fire Air (CCOFA) systems to control NOx emissions. All three units currentl y burn natural gas and No. 6 oil with a maximum sulfur content of 0.3% to control SO 2 emissions. Currently, there are no PM controls on the units.



### 2.3 Baseline Emissions

For the purposes of determining BART eligibility, t he SO 2 , NOx, and PM filterable baseline emissions for the 100% oil firing case were determined using maximum daily emissions during the most recent 5-year period (2005 through 2009). For Units 10, 2 0, and 30, the maximum NOx emission rates were 668 lb/hr, 526 lb/hr, and 1,449 lb/hr, respectively

.
Speciation of the particulate matter emissions into filterable and condensable PM 10 components was determined using the following approach:

• The total filterable PM emission rate was obtained from stack tests.

• The filterable PM 10 portion of the total filterable PM was calculated using the cumulative size distributions given in AP-42 Table 1.3-4 (uncontrol led size fractions). The total filterable PM 10 is 71% of the filterable PM. The fine PM 10 was calculated as the total filterable PM * 0.52. The coarse PM 10 was calculated as the difference between the total PM 10 and the fine PM 10
.

• Elemental carbon or black carbon was estimated to be 7.4% of fine PM 10 based on the best estimates for industrial petroleum in Table 6 of “C atalog of Global Emissions Inventories and Emission Inventory Tools for Black Carbon”, William Battye and Kathy Boyer, EPA Contract No. 68-D-98-046, January 2002. Fine soil is the di fference between fine total and fine EC.

• The condensible PM emission factor was based on AP -42 Table 1.3-2 (1.5 lb/1000 gal) for #6 oil-fired boilers. All inorganic condensable PM 10 was assumed to be sulfates (i.e. no soil component).AECOM Environment

Five Factor BART Analysis for TransCanada Ravenswoo d Generating Station September 2010 2-2

Table 2-1 provides a summary of the SO 2 , NOx, and PM baseline emissions that were used in the modeling analysis. Table 2-2 provides the stack pa rameters that were used in the baseline and advanced controls conditions modeling analysis.AECOMEnvironmentFive Factor BART Analysis for TransCanada Ravenswood Generating StationSeptember 20102-3Table 2-1: Ravenswood Baseline Emissions (100% Oil-Firing)Table 2-2: Ravenswood Stack ParametersUnit No.SourceLatitude(deg)SourceLongitude(deg)Base Elevation(m)Stack Height(m)Stack Diameter(m)Flue Gas Temperature(°K)Flue Gas Velocity(m/s)10 40.76 -73.95 0.0 152.1 4.1 399.8 48.220 40.76 -73.95 0.0 152.1 4.1 399.8 48.230 40.76 -73.95 0.0 152.1 7.2 405.4 34.1AECOM Environment

Five Factor BART Analysis for TransCanada Ravenswoo d Generating Station 3-1



# 3.0 Emission Control Alternatives

The visibility impairing pollutants discussed in th is section include NOx, SO 2 , and PM. Information on control of these pollutants through application of a control device, combination of devices, and/or operational change is provided.



### 3.1 Candidate SO 2 

### Emissions Control

SO 2 emissions are directly related to the sulfur conte nt of the fuel burned. Natural gas inherently has low sulfur content, so only the oil firing scenario is subject to BART review for SO 2 emissions reductions. Reducing the amount of sulfur in the f uel oil, or switching entirely to natural gas is th e only practical way to reduce SO 2 emissions. However, the Minimum Oil Burn rule pre vents a switch to exclusively firing natural gas when the NYISO invok es the rule. The guidance put forth by NYSDEC regarding presumptive BART for SO 2 indicates that burning fuel with a sulfur content of 1% or less constitutes BART. Ravenswood generating station bur ns residual oil with a sulfur content of 0.3% and hence satisfies the BART requirements for SO 2 . Therefore, no further analysis was required for this pollutant.



### 3.2 Candidate NOx Emission Controls

Several emission control options for NOx are discus sed below. The current NOx controls for the three BART-eligible boilers consist of close-coupled over fire air systems and low NOx burners.

Combustion Controls: Firing Configuration and Firin g Practices

Firing configuration and firing practices can resul t in a reduction in NOx formation, with the reducti on percentage being very boiler-specific. Firing conf iguration is a design characteristic of the boiler. Firing practices include such things as low excess air, staged combustion, low NOx burners, and fuel substitution/alteration. Ravenswood Units 10, 20 an d 30 are currently equipped with these controls.

Operating at low excess air involves reducing the a mount of combustion air to the lowest possible level while maintaining efficient and environmental ly compliant boiler operation. NOx formation is inhibited because less oxygen is available in the c ombustion zone. These methods may change the normal operation of the boiler and the effectivenes s is boiler-specific. Implementation of these techniques may also reduce operational flexibility; however, they may reduce NOx by 10-20% from uncontrolled levels.

Low NOx burners are designed to control fuel/air mi xing and increase heat dissipation. These alternative burners can be installed on new boilers or retrofitted on older units, and this is an opti on being considered for the BART analysis.

Fuel substitution requires burning fuel with a lowe r nitrogen content to inhibit the production of fue l NOx. The lower the content of nitrogen in a fuel, the lower the resultant NOx emissions will be. One candidate option for this control is the use of low er-nitrogen fuel oil. A switch to natural gas firi ng only is not allowed due to the need for Ravenswood to be available for system reliability and the Minimum Oil Rule.AECOM Environment

Five Factor BART Analysis for TransCanada Ravenswoo d Generating Station 3-2

Overfire Air

Overfire air involves injecting a portion of the to tal combustion air above the burners. Overfire air limits NOx by (1) suppressing thermal NOx by partia lly delaying and extending the combustion process resulting in less intense combustion and co oler flame temperatures; (2) a reduced flame temperature that limits thermal NOx formation, and/ or (3) a reduced residence time at peak temperature which also limits thermal NOx formation . Overfire air can reduce NOx emissions for both oil and natural gas firing by 20-30%. Separated ov erfire air systems introduce the injected combustion air some distance above the burners, whi le close-coupled overfire air systems (currently installed) introduce the air immediately above the burners.

Selective Non-Catalytic Reduction (SNCR)

SNCR is a post-combustion technique that involves i njecting ammonia or urea into specific temperature zones in the upper furnace or convectiv e pass. The ammonia or urea reacts with NOx in the flue gas to produce nitrogen and water. The ef fectiveness of SNCR depends on the temperature where reagents are injected; mixing of the reagent in the flue gas; residence time of the reagent with in the required temperature window; ratio of reagent t o NOx and the sulfur content of the fuel that may create sulfur compound that deposit in the downstre am equipment. In general, SNCR results in NOx reductions on the order of 25-40% from high uncontr olled emission rates.

Selective Catalytic Reduction (SCR)

SCR is another post-combustion technique that invol ves injecting ammonia into the flue gas in the presence of a catalyst to reduce NOx to nitrogen an d water. The SCR reactor can be located at various positions in the process including before a n air heater and particulate control device, or downstream of the air heater, particulate control d evice, and flue gas desulfurization systems.

The performance of SCR is greatly influenced by flu e gas temperature, fuel sulfur content, ammonia to NOx ratio, inlet NOx concentration, space veloci ty, and catalyst condition. NOx emission reductions of 75-90% have been achieved through the use of SCR on oil-fired boilers operating in the U.S.

Use of Distillate Oil

Distillate oil has inherently less fuel-bound nitro gen than residual oil. The resultant NOx emission rate for switching to distillate oil is about 0.10 lb/MM Btu (with the use of Low NOx Burners).



### 3.2.1 Effectiveness of Technically Feasible NOx Con trols

Based on information provided by equipment vendors, it is estimated that LNB/SOFA will reduce NOx emissions to a 24-hour averaged emission level of a pproximately 0.17 lb/MMBtu. Due to the lower inlet NOx concentrations, it is estimated that the addition of SNCR will reduce NOx emissions by another 15% (post advanced combustion controls), wh ich corresponds to a NOx emission level of approximately 0.15 lb/MMBtu. SCR is estimated to r educe NOx emissions to approximately 0.025 lb/MMBtu. Table 3-1 presents the control efficienc ies of the technically feasible NOx control options

.AECOM Environment

Five Factor BART Analysis for TransCanada Ravenswoo d Generating Station 3-3

Table 3-1: Control Efficiency of Technically Feasib le NOx Control Options

Control Option Control

Technology Inlet NOx

(lb/MMBtu) Outlet NOx

(lb/MMBtu) Control Efficiency (%)

1 LNB/SOFA 0.24 0.17 29%

2 LNB/SOFA and

SNCR 0.17 0.15 12% from 0.17 lb/MMBtu

3 LNB/SOFA and

SCR 0.17 0.025 85% from 0.17 lb/MMBtu

4 Low sulfur

distillate fuel oil 0.24 0.1 58%



### 3.2.2 Analysis of Alternative NOx Controls

The alternative control technologies available to c ontrol NOx emissions from Units 10, 20, and 30 are LNB/SOFA, SNCR, SCR, and switching to distillate fu el oil. This section documents the economic, non-air environmental, and energy impacts associate d with applying LNB/SOFA, LNB/SOFA and SNCR as well as LNB/SOFA and SCR to Ravenswood Unit s 10, 20, and 30. Incremental annual operating costs associated with switching to distil late oil are also reviewed in this section.

3.2.2.1 Control Costs
Table 3-2 summarizes the total capital and annual c osts associated with applying LNB/SOFA, SCR, and SNCR to Units 10, 20 and 30 together. The cost s presented in this section were provided by TransCanada,

Table 3-2: Total Capital and Annual Costs Associate d with LNB/SOFA SNCR, SCR, and Fuel Switching

for Ravenswood Units, 10, 20, and 30

3.2.2.2 Non Air Quality Environmental Issues
One of the most significant consequences of retrofi tting SCR at the facility is the addition of ammonia storage and handling systems. An accidenta l release of ammonia would pose a risk to workers and the public (especially in a highly urba nized area, as around the Ravenswood plant vicinity), and is reportable to local, state, and f ederal agencies. If ammonia at a concentration greater than 19% is stored at the site, Ravenswood would need to develop, implement, and Control Option Control

Technology Total

Capital Cost ($) Annual Fixed

Costs ($/yr) a Annual O&M

Costs ($/yr) Total Annual

Costs ($/yr) NOx

Controlled (tons/year) Overall Cost

Effectiveness ($/ton removed) Incremental Cost

Effectiveness from Option 1 ($/ton removed)

1 LNB/SOFA $13,808,000 $2,518,000 $102,000 $2,620,000 1,62 6 $1,612

2 LNB/SOFA and SNCR $24,527,000 $4,473,000 $3,244,000 $7,717,000 2,092 $3,68 8 $10,924

3 LNB/SOFA and SCR $458,808,000 $88,193,326 $1,796,341 $89,989,666 5,008 $1 7,968 $25,829

4 Low sulfur distillate fuel oil --- --- $104,338,496 $104,338,496 3,266 $31,947 $62,009

(a) Annualized capital costs based on a CRF of 0.14 24, assuming an interest rate of 7% and amortizatio n period of 10 years.AECOM Environment

Five Factor BART Analysis for TransCanada Ravenswoo d Generating Station 3-4

maintain a Risk Management Plan (RMP) and Process S afety Measures (PSM) Program. Risk communication to the general public typically inclu des a worst-case analysis with potential effects possible at up to a mile from the facility.

Theoretically, one mole of ammonia will react with one mole of NOx, forming elemental nitrogen and water in both SCR and SNCR. In reality, not all th e injected reagent will react due to imperfect mixi ng, uneven temperature distribution, and insufficient r esidence time. These physical limitations may be compensated for by injecting a larger amount of amm onia than stoichiometrically required and essentially achieving lower NOx emissions at the ex pense of ammonia slip (unreacted ammonia). Typically, the average guaranteed ammonia slip asso ciated with SCR is approximately 2 to 10 ppmvd at 3% O 2 , while that associated with SNCR is approximately 5 ppmvd to 20 ppmvd at 3% O 2 . This excess ammonia may react with SO 3 or H 2 SO 4 in the flue to form ammonium bisulfate ((NH 4 ) 2 HSO 4 ) and ammonium sulfate ((NH 4 ) 2 SO 4 ). These ammonium salts may condense as the flue g ases cool and can lead to increased emissions of both PM 10 and PM 2.5 . Furthermore, in SCR systems, the catalyst promotes partial oxidation of SO 2 to SO 3 , which in turn increases the formation of ammonium bisulfate and ammonium sulfate. The enhanced forma tion of these ammonia salts further increases the potential emissions of PM 10 and PM 2.5
.
Table 3-3 summarizes the non-air quality environmen tal effects associated with the proposed BART control options.

Table 3-3: Summary of Non Air Quality Environmental Effects

Control Alternative Summary of Non

- Air Quality Environmental Effects LNB/SOFA • No significant impacts. SNCR • Deliveries of the reagent will result in NOx, VOC, CO, CO 2 , and PM 10 air emissions.

• Excess ammonia slip reacts with SO 3 or H 2 SO 4 in the flue to form ammonium bisulfate (NH 4 )HSO 4 and ammonium sulfate (NH 4 ) 2 SO 4 resulting in increased PM 10 emissions.

• Ammonium bisulfate and ammonium sulfate in the flu e gas can cause various power plant operating and maintenance probl ems including fouling and corrosion of heat transfer surfaces in the air pre-heater. SCR • Addition of ammonia handling systems. Ammonia is considered dangerous to human health, and accidental releases must be reported to local, state, and federal agencies.

• SCR will increase sulfuric acid mist emissions.

• Excess ammonia slip reacts with SO 3 or H 2 SO 4 in the flue to form ammonium bisulfate (NH 4 )HSO 4 and ammonium sulfate (NH 4 ) 2 SO 4 resulting in increased PM 10 emissions.

• Ammonium bisulfate and ammonium sulfate in the flu e gas can cause various power plant operating and maintenance probl ems including fouling and corrosion of heat transfer surfaces in the air pre-heater.

• The site must develop, implement, and maintain a R isk Management Plan (RMP) and Process Safety Measures (PSM) Progra m.

• Deliveries of ammonia will result in NOx, VOC, CO, CO 2 , and PM 10 air emissions.AECOM Environment

Five Factor BART Analysis for TransCanada Ravenswoo d Generating Station 3-5

3.2.2.3 Energy Impacts
SCR would consume significantly more electrical ene rgy than any of the other BART options, including SNCR. The higher electrical energy consu mption for SCR is primarily due to the increased fan static pressure required to overcome the pressu re drop across the catalyst bed, as well as for pumps and evaporator blower. For example, assuming a pressure drop of 14 inches water gauge (W.G.) across new duct work and the catalyst bed, S CR applied to all three units could consume approximately 1% of the total power generation of t he plant for each hour of operation. The increased emissions of pollutants required to maintain the ne t electrical output is a negative aspect of SCR deployment.

3.2.2.4 Remaining Useful Life
TransCanada anticipates that the Ravenswood Units 1 0, 20 and 30 will remain in operation for at least the next 10 years. A 10-year amortization pe riod was used for purposes of the cost effectiveness for the BART analysis which is consis tent with the procedures outlined in NYSDEC’s Air Guide 20 (Economic and Technical Analysis for R easonably Available Control Technology). Note that for an SCR, the catalyst has a shorter us eful life of 5 years. Hence, the catalyst replacement cost was amortized over a 5 year period

. Emissions of NOx post LNB/SOFA (Control case 1) are presented in Table 3-6.



### 3.3 Candidate PM Emission Controls

The PM control technologies identified as available for retrofit to the Ravenswood Units 10, 20, and 3 0

are:

• Fabric Filter (Baghouse)

• Dry Electrostatic Precipitator (ESP)

• Wet Electrostatic Precipitator (WESP)

• Switching to Low Sulfur Distillate Oil
These control technologies are reviewed below in th e context of their effectiveness in further reducin g PM emissions.

Fabric Filter

In a fabric filter, flue gas passes through a tight ly woven or felted fabric, causing particles in the gas to be collected on the fabric by sieving, electrostati c attraction, and other mechanisms. Fabric filters may be in the form of sheets, cartridges or, most commo nly, bags. The dust cake that forms on the filter from the collected PM can significantly increase co llection efficiency. Fabric filters are frequently referred to as baghouses because the fabric is usua lly configured in cylindrical bags. Groups of bags are placed in isolable compartments to allow cleani ng of the bags or replacement of some of the bags without shutting down the entire fabric filter.

Because of the sticky and hygroscopic nature of res idual oil fly ash, fabric filters have never been applied to oil-fired units, unless the bags are fir st pre-conditioned by means of dry sorbent injectio n upstream of the baghouse for SO 2 control. A fabric filter baghouse, therefore, is not considered technically feasible for application to the Ravensw ood BART units.AECOM Environment

Five Factor BART Analysis for TransCanada Ravenswoo d Generating Station 3-6

Dry Electrostatic Precipitator

An ESP uses electrical forces to move particles ent rained within the exhaust stream onto collector plates. The entrained particles are given an elect rical charge when they pass through the corona, a region where gaseous ions flow. Electrodes in the center of the gas stream are maintained at high voltage and generate the electrical field that forc es the particles to the collector plates. The coll ector plates are periodically knocked or "rapped" by vari ous mechanical means to dislodge the particulate, which slides downward into a hopper and is collecte d. The collection hopper is evacuated periodically, as it becomes full. The particulate is removed through a rotary valve into an ash-handl ing system, such as a pneumatic conveyor, and is then d isposed of.

Although dry ESPs have been attempted for applicati on to oil-fired utility boilers, they routinely experience problems in dislodging the particles fro m the collection plates because of the sticky and hygroscopic nature of the fly ash. Ash generated b y residual oil combustion is rich in elemental carbon (soot) which has a low resistivity. As a re sult, the ash particles do not adhere to the plates as well and re-entrainment issues occur. Furthermore, the high capital and operating costs of this contr ol technology make it economically infeasible (see Tab le 3-4).

Wet Electrostatic Precipitator

A wet ESP collects particles based on the same theo ry as a dry ESP, where negatively charged particles are collected on positively charged surfa ces. In a wet ESP, however, the collecting surface s are wet instead of dry and are flushed with water t o remove the particulate. Typically, a wet ESP is installed downstream of an existing wet flue gas de sulfurization (FGD) system where the flue gas is already saturated to minimize water consumption. T he particulate collection efficiency is enhanced by preventing re-entrainment after contact with the we t walls, compared with re-entrainment due to rapping on a dry ESP. Due to this feature, wet ESP s are well suited for the removal of fine particula te or acid mist from the gas stream.

Several major hurdles exist with the use of a wet E SP. First, the flue gas must be saturated with moisture prior to entering the wet ESP to allow the unit to work as desired. This requires that a quenching system be installed to add water to the f lue gas to reduce the flue gas temperature to the saturation point. Without the presence of a wet FG D system, the wet ESP adds additional cost, increases water demand on the plant, and generates a visible moisture plume at the stack outlet. The removed particulate would also be contained in a wa stewater stream that is generated by the wet ESP. In addition to this issue, the capital and op erating cost of a wet ESP is very high as compared to other technologies due to the high cost of the allo y materials required. A higher grade of material i s required to withstand the highly corrosive conditio ns presented by the wet and acidic flue gas stream (Table 3-5).

Because the flue gas must be saturated before enter ing a wet ESP, these devices are usually applied to combustion installations equipped with either a Venturi scrubber for PM control or a wet FGD system for acid gas control. Consequently, wet ESP s have never been applied to oil-fired boilers as standalone units.AECOM Environment

Five Factor BART Analysis for TransCanada Ravenswoo d Generating Station 3-7

Switching to Distillate Fuel Oil

Distillate oil has a much lower sulfur content that residual oil and consequently has lower PM emissions as compared to those resulting from resid ual oil combustion. This option is technically feasible for the control of PM emissions from the R avenswood units.

Table 3-4 presents the control efficiencies of the technically feasible PM control options. Table 3-5 presents the cost effectiveness ($/ton) of the tech nically feasible PM control options.

Table 3-4: Control Efficiency of Technically Feasib le PM Control Options

Control Option Control Technology Control Efficienc y (%)

1 Dry Electrostatic Precipitator (1) 99%

2 Wet Electrostatic Precipitator (2) 99%

3 Switching to Distillate Fuel Oil (3) 65%
(1) Control efficiency of Dry ESPs based on EPA's A ir Pollution Control Technology Fact Sheet (EPA452/F-03-028). (2) Control efficiency of Wet ESPs based on EPA's A ir Pollution Control Technology Fact Sheet (EPA452/F-03-029). (3) Based on AP-42 PM Emission Factors for residual oil combustion and distillate oil combustion (Tabl e 1.3-1).

Table 3-5: Cost Effectiveness of Technically Feasib le PM Control Options

Control Option Control

Technology Control Efficiency (1) (%) Annual Cost

($/year) Tons PM

Controlled (tons/year) Cost

Effectiveness ($/ton)

1 Dry Electrostatic Precipitator (2) 99% $122,071,000 920 $132,650

2 Wet Electrostatic Precipitator (3) 99% $166,831,200 920 $181,280

3 Switching to Distillate Fuel Oil (4) 65% $109,338,500 596 $174,970

(1) For the dry and wet ESPs, a conservatively high control efficiency of 99% was assumed for conducti ng the cost effectiveness analysis. (2) Annualized cost of Dry ESPs (all three units co mbined) based on EPA's Air Pollution Control Techno logy Fact Sheet (EPA-452/F-03-028). Detailed calculations pre sented in Appendix A. (3) Annualized cost of Wet ESPs (all three units co mbined) based on EPA's Air Pollution Control Techno logy Fact Sheet (EPA-452/F-03-029). Detailed calculations pre sented in Appendix A. (4) Annual incremental cost of using distillate oil based on Annual Energy Outlook 2010, Report No. DO E/EIA-0383 2010, Reference Case, http://www.eia.doe.gov/oiaf/aeo/index.html . Detailed calculations presented in Appendix A.AECOMEnvironmentFive Factor BART Analysis for TransCanada Ravenswood Generating StationSeptember 20103-8Table 3-6: Ravenswood NOx Advanced Combustion Controls Emissions (Control Case 1)AECOM Environment

Five Factor BART Analysis for TransCanada Ravenswoo d Generating Station September 2010 4-1



# 4.0 Meteorological Data used in Visibility Improv ement Modeling

This section discusses two meteorological CALMET da tabases for year 2002 that were used for the Ravenswood BART modeling. The first CALMET databas e was prepared by AECOM and the second was prepared by the Vermont Department of Environme ntal Conservation (VT DEC). Both databases are approved by NYSDEC and the Federal Land Manager s (FLMs). NYSDEC requires that visibility impacts from BART eligible units are predicted usin g both CALMET databases.

The extents of the two CALMET domains are shown in Figure 4-1. Table 4-1 summarizes major differences between two databases.



### 4.1 Elements of the Refined Analysis

AECOM has recently developed a more refined CALMET database than the VT DEC CALMET database. The AECOM CALMET database is fully descr ibed in a separate document titled “Updated CALMET Modeling Procedures for BART Visibility Impr ovement Assessments in the MANE-VU RPO” , including a choice of the model critical settings , meteorological stations, geophysical and Fifth Generation Mesoscale Model (MM5) data. The VT DEC CALMET database is described in Appendix D of the document “Development of Parallel CALPUFF Dispersion Modelin g Platforms for Sulfate Source Attribution Studies in the Northeast U.)” . The document is available on the web at http://www.nescaum.org/documents/contributions-to-r egional-haze-in-the-northeast-and-midatlantic--united-states/

.
AECOM database has several major improvements over the VT DEC database, such the grid size resolution, vertical levels, and inclusion of the p rognostic MM5 data. CALMET database produced by VT DEC has a domain that covers approximately a 2,6 64 km (east-west) by 2,160 km (north-south) area with a 36-km grid resolution. This area cover s the entire eastern and part of central United States, but its large size limits the horizontal re solution of each grid element to 36 km. This coars e grid resolution, without further refinement, can be deemed appropriate for a screening-level analysis, but it would not be considered appropriate for a mo re refined analysis.

AECOM developed a refined meteorological database t hat included a modeling domain encompassing the seven Class I areas (required by N YSDEC) and the appropriate buffers around Class I areas for puffs recirculation. This domain covers approximately a 1,052 km (east-west) by 1,300 km (north-south) area, has a grid resolution of 4 km (9 times better than the VT DEC database in both east-west and north-south directions), and contains 11 vertical levels. In addition, the refi ned AECOM database utilizes the 12-km MM5 data and uses the latest official USEPA-approved CALMET Version 5.8, developed in year 2007. In contrast, VT DEC CALMET was run with the older version of the model, developed in year 2003.

Table 4-1 summarizes critical CALMET settings used in the two databases.AECOM Environment

Five Factor BART Analysis for TransCanada Ravenswoo d Generating Station September 2010 4-2

Figure 4-1: Ravenswood CALMET Modeling DomainsAECOM Environment

Five Factor BART Analysis for TransCanada Ravenswoo d Generating Station September 2010 4-3

Table 4-1: Comparison of the AECOM and VT DEC CALME T User-Defined Settings

Variable Description AECOM CALMET Critical Settings VT DEC

CALMET Critical Settings

Version No. CALMET model version number Version 5.8, Level 070623 Version 5.53 , Level 030709

MREG Technical options must conform to USEPA

guidance 1 no

DGRIDKM Domain grid spacing 4 36

NX Number of X grid cells 263 74

NY Number of Y grid cells 325 60

NZ Number of vertical layers 11 8

IPROG Use MM5 data as an input to diagnostic

wind field 14 (MM5 used) 0 (MM5 not used)

RMAX1 Max surface over-land extrapolation radius

(km) 40 1000

RMAX2 Max aloft over-land extrapolation radius

(km) 40 1000

RMAX3 Maximum over-water extrapolation radius

(km) 100 1000

TERRAD Radius of influence of terrain features (km) 15 100

R1 Relative weight at surface of Step 1 field

and obs 5 1000

R2 Relative weight aloft of Step 1 field and obs 5 1000AECOM Environment

Five Factor BART Analysis for TransCanada Ravenswoo d Generating Station September 2010 5-1



# 5.0 CALPUFF Modeling Procedures

This section provides a summary of the modeling pro cedures that were used for the refined CALPUFF analysis conducted for the Ravenswood Generating St ation.



### 5.1 CALPUFF Modeling Domain and Receptors

AECOM used the latest EPA-approved version of CALPU FF (Version 5.8, Level 070623) with both meteorological databases.

The extents of the AECOM and VT DEC modeling domain s are shown in Figure 4-1. The CALPUFF modeling domains were made equal in size to the CAL MET domain (as described in Section 4.1) and they have sufficient buffer around the source and C lass I areas to account for puff re-circulations.

The receptors used for each of the Class I areas ar e based on the National Park Service database of Class I receptors, available at http://www.nature.nps.gov/air/maps/Receptors/index. cfm

.



### 5.2 Model Version

The EPA-approved version of CALPUFF was used to mod el the emissions, POSTUTIL was used to combine impacts from all three units and CALPOST wa s used to process the regional haze impacts with Method 8 (New IMPROVE equation). CALPUFF Vers ion 5.8, Level 070623; POSTUTIL Version 1.56, Level 070627; and CALPOST Version 6.221, Leve l 080724 were used.

These programs are available for download from TRC website http://www.src.com/calpuff/calpuff1.htm

. 

### 5.3 Background Air Quality Data

CALPUFF modeling was conducted with the hourly back ground ozone data that was developed for MANE-VU BART modeling. Ozone data collection and p rocessing is described in Appendix D, Section D.3.3.1 of the NESCAUM document titled “Development of Parallel CALPUFF Dispersion Modeling Platforms for Sulfate Source Attribution S tudies in the Northeast U.S”

.
As for ammonia, AECOM followed the IWAQM Phase 2 re port, where it is suggested to use a background ammonia concentration of 0.5 ppb in the forested areas. Since most Class I areas and the surrounding region are mainly covered by forest , an ammonia concentration of 0.5 ppb was used in accordance with the recommendations in IWAQM Pha se 2.



### 5.4 Light Extinction and Haze Impact Calculations

The FLAG 2008 document (dated June 26, 2008) provid es guidance on the recommended new IMPROVE equation application. CALPOST Version 6.22 1 defines this application as Method 8, Mode 5. The assessment of visibility impacts at the Cla ss I areas used CALPOST Method 8.

The CALPOST postprocessor was used for the calculat ion of the impact of the modeled source’s primary and secondary particulate matter concentrat ions on light extinction. In the new IMPROVE equation, the total sulfate, nitrate, and organic c arbon compound concentrations are each split into two fractions, representing small and large size di stributions of those components. New terms, suchAECOM Environment

Five Factor BART Analysis for TransCanada Ravenswoo d Generating Station September 2010 5-2

as sea salt (important for coastal locations), abso rption by NO 2 (only used where NO 2 data are available), and site-specific Rayleigh scattering h ave been added to the equation. The new IMPROVE equation for calculating light extinction i s shown below.

The FLAG 2008 document provides inputs to the new I MPROVE equation that are based on either the 20% best or annual average natural conditions. Per NYSDEC guidance, AECOM elected to use inputs that are based on the 20% best natural condi tions. Inputs to the CALPOST Method 8 calculations for each Class I area were obtained fr om the FLAG 2008 document tables referenced below.

Table 5-1: References to the New IMPROVE Equation C ALPOST Inputs

Sea salt concentration FLAG 2008 Table V.1-1 Raleigh scattering FLAG 2008 Table V.1-1 Monthly f L (RH) FLAG 2008 Table V.1-3 Monthly f S (RH) FLAG 2008 Table V.1-4 Monthly f SS (RH) FLAG 2008 Table V.1-5AECOM Environment

Five Factor BART Analysis for TransCanada Ravenswoo d Generating Station September 2010 6-1



# 6.0 CALPUFF Modeling and BART Determination Resul ts

This section provides a summary of the modeled visi bility impacts due to the current baseline emissions and visibility improvement as a result of BART controls on Ravenswood Units 10, 20, and 30. It also presents the results of the recommende d BART determination.



### 6.1 Modeled Control Scenarios

Both the AECOM and VT DEC CALMET databases were use d to model the baseline emissions along with the advanced combustion control emission case. Tables 2-1 and 3-6 present the emissions associated with the baseline and one BART control case, respectively.



### 6.2 Modeling Results for Baseline Emissions

CALPUFF modeling results of the baseline emissions at the seven Class I areas are presented in Table 6-1. Modeling was conducted with two CALMET databases for year 2002. For each Class I area and CALMET database, Table 6-1 lists the numbe r of days above 0.1, 0.5 and 1.0 delta-deciview due to plant baseline emissions as well as the maxi mum and the 8 th highest delta-deciview. Table 6-1 indicates that the higher visibility impacts occur at Brigantine Wilderness and they are due to that park’s relative proximity to Ravenswood. The resul ts also show that the visibility impacts predicted with the VT DEC CALMET database are much higher tha n with the AECOM CALMET database. As discussed in Section 4.1, VT DEC CALMET database is not as refined as the AECOM database. We conclude that the visibility impacts predicted with the AECOM database are more realistic.

In general, however, even the AECOM database region al haze impacts using CALPUFF are overstated, for the reasons noted below.

1) The CALPUFF base case modeled scenario is always a worst-case emission rate which is assumed to occur every day. The actual emissions are often lower, and so the modeled improvement is an overestimate.
2) The manner in which the daily haze predictions a re accounted for in the CALPOST output overstates the impact for even a perfect model. Th e way CALPOST works is that the peak 24-hour prediction anywhere in a Class I area is the only information saved fo r each predicted day. The predicted impact for each day is effectiv ely assumed to be a) always in the same place, and b) in all portions of the Class I area s imultaneously. In reality, for each individual receptor, there could be many days of very low or e ven zero concentrations that are not properly accounted for. Therefore, the 98 th percentile day’s prediction is often comprised of impacts in 8 different places that are all assumed to be co-located. For very small Class I areas, this is not as big of a concern as for large Class I areas.
3) It is well known that CALPUFF is not a perfect m odel, and that transport during a full diurnal cycle (or especially during evenings) in which sign ificant wind direction shear can occur (and is not properly accounted for by CALPUFF) can resul t in plumes that are too compact.
4) We know that nitrate predictions are often overs tated, especially in winter, unless appropriately low ammonia background values are sel ected for the currently approved version of CALPUFF.AECOM Environment

Five Factor BART Analysis for TransCanada Ravenswoo d Generating Station September 2010 6-2

5) The rate of plume dispersion default option is t echnically flawed. A better option for CALPUFF is the “turbulence-based” dispersion. Ther e are many reasons why it is technically superior, but the older Pasquill-Gifford dispersion provides higher impacts because the plume reaches the ground in stable conditions much faster , so it is therefore preferred by EPA and the FLMs.

NYSDEC recommends that the maximum visibility impac t from each source should be compared to the threshold of 0.1 deciviews to determine if a so urce contributes to visibility impairment. NYSDEC also recommends using the maximum and 98 th -percentile statistic for comparing visibility improvements due to BART control options. On an an nual basis, the 98 th percentile value implies the 8 th highest day at each modeled Class I area.

The results of the baseline emissions analysis indi cate that each Ravenswood unit and all three units combined have predicted visibility changes relative to natural background exceeding 0.1 deciviews in at least one Class I area. Therefore, the Ravenswo od Generating Station is presumed to be subject to BART because its emissions may reasonably be ant icipated to cause or contribute to visibility impairment at a relevant Class I area. Candidate B ART controls are discussed in Section 3. The results of the visibility improvement modeling for the candidate controls are discussed in the next section.

Table 6-1: Regional Haze Impacts due to Baseline Em issionsAECOM Environment

Five Factor BART Analysis for TransCanada Ravenswoo d Generating Station September 2010 6-3



### 6.3 Modeling Results for the Advanced Combustion Co ntrol Case

Maximum daily CALPUFF modeling results for the BART control option at the seven Class I areas due to emission from Ravenswood Units 10, 20, and 3 0 separately and combined are presented in Table 6-2. Consistent with the baseline results re ported above, modeling was conducted with two CALMET databases for the calendar year 2002. Per N YSDEC recommendation, in addition to the highest visibility impacts, the 8 th highest delta-deciview results were summarized in Table 6-2. Emission rates that were used in this modeling are presented in Table 3-1.

The results show that with the installation of LNB/ SOFA controls, the maximum visibility improvement would be about 0.12 delta-deciview (relative to the baseline case, at Lye Brook Wilderness). The maximum change in visibility (for each Class I area and over the two CALMET databases) from the current operations was combined with the cost impac t of controls relative to current operations to calculate the dollars per deciview cost. These res ults are presented in Table 6-3.

Table 6-2: Regional Haze Impacts due to Advanced Co mbustion Controls (Control Option 1)



### 6.4 Conclusions and BART Recommendation

Table 6-3 presents the visibility improvements offe red by LNB/SOFA at the seven Class I areas and the associated costs of applying the control techno logy (dollars/deciview).AECOM Environment

Five Factor BART Analysis for TransCanada Ravenswoo d Generating Station September 2010 6-4

Table 6-3: Cost Effectiveness and Visibility Improv ement Associated with Control Option 1

Installation of LNB/SOFA offer modest visibility im provements at the seven Class I areas. Even though retrofitting the boilers with LNB/SOFA is no t cost effective, this option is accepted by TransCanada for controlling NOx emissions based on NY RACT requirements and the rea sonable $/ton cost effectiveness. Therefore, BART for NOx is installation of advanced combustion controls (LNB/SOFA) to limit emissions to 3,018 lb/hr (0.17 lb/MMBtu) for all three units combined on a 24- hour rolling average basis.,

BART for SO 2 is burning residual oil with a sulfur content of 0 .3% which is well below the NYSDEC BART guideline which is 1.0% S.
BART for PM is burning residual oil with a sulfur c ontent of 0.3% and the current permit limit. Class I Area Control Option Max Deltadeciview Annualized

Cost for Units 10,20,30 ($/year) Deciview Reduction

Relative to Baseline (dv) Cost Effectiveness

Relative to Baseline ($/dv)

Baseline 3.82 - $ - -

LNB&SOFA 3.75 2,620,000 $ 0.07 35,890,411 $

Baseline 3.11 - $ - -

LNB&SOFA 3.07 2,620,000 $ 0.04 74,857,143 $

Baseline 3.14 - $ - -

LNB&SOFA 3.02 2,620,000 $ 0.12 21,652,893 $

Baseline 3.30 - $ - -

LNB&SOFA 3.27 2,620,000 $ 0.04 67,179,487 $

Baseline 2.02 - $ - -

LNB&SOFA 1.99 2,620,000 $ 0.03 77,058,824 $

Baseline 1.98 - $ - -

LNB&SOFA 1.94 2,620,000 $ 0.03 77,058,824 $

Baseline 4.08 - $ - -

LNB&SOFA 4.02 2,620,000 $ 0.06 46,785,714 $ Acadia National Park

Dolly Sods Wilderness

Brigantine Wilderness Great Gulf
Wilderness

Lye Brook Wilderness

Presidential Range - Dry River Wilderness

Otter Creek
WildernessAECOM Environment

Five Factor BART Analysis for TransCanada Ravenswoo d Generating Station September 2010 7-1



# 7.0 References

ENSR, Updated CALMET Modeling Procedures for BART V isibility Improvement Assessments in the MANE-VU RPO. April 2009.

ERM, Development of Parallel CALPUFF Dispersion Mod eling Platforms for Sulfate Source Attribution Studies in the Northeast U.S (Appendix D), ERM, May 2006.

Environmental Protection Agency (EPA), AP 42, Fifth Edition, Compilation of Air Pollutant Emission Factors, Volume 1: Stationary Point and Area Source s, January, 1995.

Environmental Protection Agency (EPA), Guidance for Tracking Progress Under the Regional Haze Rule, EPA-454/B-03-003, Appendix A, Table A-3, Sept ember, 2003a.

Environmental Protection Agency (EPA), Guidance for Estimating Natural Visibility Conditions Under the Regional Haze Program, EPA 454/B-03-005, Septem ber 2003b.

Environmental Protection Agency (EPA), Interagency Workgroup on Air Quality Modeling (IWAQM) Phase 2 Summary Report and Recommendations for Mode ling Long Range Transport Impacts, EPA454/R-98-019, December, 1998.

EPRI. Estimating Total Sulfuric Acid Emissions fro m Stationary Power Plants, EPRI, Palo Alto, CA: 2008. 1016384.

New York Independent System Operator, Inc., Docket No. ER07-748-000, Issued May 11, 2007 by the Federal Energy Regulatory Commission.

Regional Haze Regulations and Guidelines for Best A vailable Retrofit Technology (BART) Determinations; Final Rule (FR Vol. 70, No. 128 pub lished July 6, 2005).

Regional Haze Regulations; Revisions to Provisions Governing Alternative to Source-Specific Best Available Retrofit Technology (BART) Determinations ; Final Rule (FR Vol. 71, NO. 198 published October 13, 2006).AECOM Environment

Five Factor BART Analysis for TransCanada Ravenswoo d Generating Station September 2010 

# Appendix A

Cost Effectiveness CalculationsAECOM Environment

Five Factor BART Analysis for TransCanada Ravenswoo d Generating Station September 2010 

# Appendix B

Quotation from Fuel Tech for LNB/SOFA and SNCRAECOM Environment

Five Factor BART Analysis for TransCanada Ravenswoo d Generating Station September 2010 

# Appendix C

Modeling Archive