

MEMORANDUM
TO:		Bob Kelly, U.S. Environmental Protection Agency
FROM:  	Eastern Research Group, Inc.
DATE:  	March 28, 2012
--------------------------------------------------------------------------------
SUBJECT:  	BART Control Cost and Emission Reduction Estimates for the Virgin Islands 

Background
Section 169A of the Clean Air Act requires sources affecting areas designated as Class I areas to reduce emissions to eliminate all anthropogenic obscuration of visibility, with the goal of reaching natural background levels of visibility by 2064. The Virgin Islands National Park on the island of St. John is a designated Class I area.  Therefore, a Regional Haze State Implementation Plan (SIP) is being developed by EPA to address the need to reduce emissions to provide reasonable progress toward reducing regional haze in the Virgin Islands National Park. 

As part of the analysis needed to develop the SIP, the costs of applying Best Available Retrofit Technology (BART) to BART-eligible sources have been estimated using information provided by EPA and the VIDPNR.  This analysis has been conducted to estimate control costs and emissions reduction potential for controlling NOx, SO2, and PM.  The results of this effort are presented in this memo, including the estimated control costs, emissions reductions, and cost effectiveness of each evaluated control technology for each pollutant.

This memo is organized as follows:

I. 		Selected Controls and Control Efficiency Assumptions
II.		Emission Reductions
III.		Emission Control Costs
		A. Filling Data Gaps for Control Cost Inputs
		B. Cost Summary
IV.		Cost Effectiveness 
V.		References

I. 	Selected Controls and Control Efficiency Assumptions 

For SO2 and PM control, a duct sorbent injection and fabric filter (DIFF) combination was prescribed.  Duct sorbent injection is a control technique for SO2 control where a sorbent such as lime is injected into the duct upstream from the particulate matter control device.  The SO2 is absorbed, neutralized and/or oxidized by the alkaline reagent into a sold compound, either calcium or sodium sulfate.  The solid is then removed from the waste gas stream using the downstream particulate control equipment.  DIFF is a semi-wet flue gas desulfurization (FGD) process, with additional water added due to quench demand.  The water is used to humidify and cool the gas stream to the desired reaction temperature.  In this instance, we have assumed a fabric filter is the particulate matter control device that collects the sorbent medium (and any particulate formed directly from the combustion process).  

According to the Clean Air Technology Center (CATC) Flue Gas Desulfurization fact sheet[1], dry sorbent injection is 50% to 60% efficient for SO2 removal when using calcium-based sorbent. For our emission reduction estimates, we have assumed a 55% removal efficiency.

For PM removal, fabric filter efficiencies typically range from 95% to 99.9%, with newer equipment ranging from 99% to 99.9%[2]. We have therefore assumed a 99% PM removal efficiency for installed fabric filters.

For NOX control, selective non-catalytic reduction (SNCR) and selective catalytic reduction (SCR) were considered. In an SNCR system, a nitrogen-based reducing agent, or reagent, such as ammonia or urea, is injected into the post-combustion flue gas through nozzles mounted on the wall of the combustion unit.  In an SCR system, the nitrogen-based reagent is injected downstream of the combustion unit, then the gas enters a reactor containing a catalyst, through which the hot flue gas and reagent diffuse. In the presence of the catalyst, the reagent reacts selectively with NOX. SNCR is used on a wide range of boiler configurations; for large gas turbines, however, SCR is most commonly used. 

In conjunction with combustion controls, SNCR NOX removal efficiencies range from 65% to 75%.[3] For the purposes of estimating control costs and emission reductions, we have conservatively assumed a 65% removal rate in case combustion controls are not in place or are not feasible in some cases. 
SCR system removal efficiencies for NOX typically range from 70% to 90%[4], so we have assumed an efficiency of 80% for our calculations.

II. 	Emission Reductions 

Table 1 shows the emission reductions resulting from the installation of controls discussed above. Baseline emissions are based on potential to emit and design data as provided by EPA Region II. Total reduction estimates, based on efficiencies described above, can be summarized as follows:
	
Installing DIFF on all units would result in approximately 4,600 tons per year of SO2 removal and 780 tons per year of PM removed. 

Installing SNCR on all boilers would result in a NOX reduction of approximately 4,000 tons per year.

Installing SCR on all turbines would result in a NOX reduction of approximately 7,400 tons per year.


III. 	Emission Control Costs

This section presents the costs that were estimated for DIFF, SNCR, and SCR.

A. 	Filling Data Gaps for Control Cost Inputs
Costs were calculated using algorithms based on those presented in the OAQPS Control Cost Manual5 as well as algorithms previously developed for regulatory development. In order to use these algorithms, input values for heat input, flow rate, operational hours, and other parameters were required for each unit. Unit-specific data were limited, so data gaps were filled based on the assumptions described below. Resulting input values are presented in Appendix A.
Stack data including temperature, velocity, and diameter, were provided for all units except for those at the WAPA St. Thomas facility. For the WAPA St. Thomas boilers, we assumed the same values as those provided for the two boilers at the WAPA St. Croix facility. For the WAPA St. Thomas turbines, we used data from Hovensa unit GT1(G-1101E), since these appeared to be similar units. 
Stack velocity, diameter, and temperature were then used to calculate actual flow rate (acfm) where no flow rate data were available. 
Average moisture and oxygen values were based on moisture and oxygen values assigned to specific fuel categories in the boiler database. [6][,7] Data pulled from the boiler database is listed in Appendix B. Fuel categories were assigned to the Hovensa and WAPA units based on reported fuel types. Because several units reported multiple fuel types, an average of the corresponding moisture and/or oxygen values was calculated for each unit.
Average pollutant concentrations at 7% O2 were based on the emissions data and the oxygen value determined as discussed above. Average dry flow rates were calculated using the moisture values obtained as discussed above.
For the Hovensa units, operational hours were based on data for the same units in the boiler database. For the WAPA units, averages from comparable units in the boiler database were used.
   
B.  	Emission Control Costs
The capital and annual costs for the emission controls were estimated in dollars ($) on a 2008 basis, and annualized costs assumed an interest rate of 7 percent. Downtime costs for the retrofits were assumed to be negligible.  Each unit is assumed to have adequate space to install an emission control system.  Appendix A contains a summary of the parameters used for each unit (e.g., heat input rate, stack gas flow rate, incinerator operating hours, and concentrations). 

Capital and annual control costs for each unit are provided in Table 2.  Total capital and annual control costs for all BART-eligible units are summarized in Table 3. The total capital cost to install DIFF for all boilers and turbines is estimated at approximately $750 million, and the total annual cost for DIFF is approximately $203 million per year. The cost for applying SNCR at all boilers is estimated at $29.1 million in capital costs and $3.3 million annually. For SCR, the capital cost to install for all turbines is estimated at $83.0 million, and the total annual cost is estimated at $13.0 million per year. Cost details are discussed below.

   1. Adding duct sorbent injection/fabric filter (DIFF).
   Calculations were based on an algorithm consistent with that used for the boiler NESHAP.[8] Calculations are presented in Appendix C.  DIFF capital costs per unit range from approximately $4.8 million to $55.4 million, and annual costs range from approximately $1.1 million/yr to $15.3 million/yr.
   
   2. Adding a selective non-catalytic reduction (SNCR) system.
   The cost algorithm for installing an SNCR system is presented in Appendix D and is based on algorithms in the OAQPS Control Cost Manual.5  The SNCR capital costs range from approximately $2.1 million to $3.0 million, and annual costs range from approximately $234,000/yr to $330,000/yr. 
   
   3. Adding a selective catalytic reduction (SCR) system.
   The cost algorithm for installing an SCR system is presented in Appendix E and is based on algorithms in the OAQPS Control Cost Manual.5  The SCR capital costs range from approximately $7.0 million to $8.7 million, and annual costs range from approximately $1.1 million/yr to $1.4 million/yr. 


IV. 	Cost Effectiveness

Table 2 summarizes the pollution control cost effectiveness for each unit for each control type (DIFF for all units, SNCR for the boilers and SCR for the turbines).  Appendix F contains details on how these data were derived.

Table 3 summarizes the overall pollution control cost effectiveness. The cost effectiveness for each control was calculated based on the total annual control costs for all units for which the control was assigned and the estimated annual emission reductions resulting from the application of those controls. 

For NOX control using SNCR for boilers, the overall cost effectiveness was estimated at $834 per ton of pollutant removed.

For NOX control using SCR for turbines, the overall cost effectiveness was estimated at $1,734 per ton of pollutant removed.

For PM and SO2 control using DIFF for all units, the overall cost effectiveness was estimated at $38,064 per ton of pollutant removed.

The overall cost effectiveness of using these three controls to reduce NOx, PM, and SO2 emissions from all units is $13,153 per ton of pollutant removed.

V. References

   1.    "Air Pollution Control Technology Fact Sheet: Flue Gas Desulfurization (FGD) - Wet, Spray Dry, and Dry Scrubbers." http://www.epa.gov/ttn/catc/dir1/ffdg.pdf.
   2.     "Air Pollution Control Technology Fact Sheet: Fabric Filter" http://www.epa.gov/ttn/catc/dir1/ff-shaker.pdf, http://www.epa.gov/ttn/catc/dir1/ff-pulse.pdf, http://www.epa.gov/ttn/catc/dir1/ff-revar.pdf. 
   3.    "Air Pollution Control Technology Fact Sheet: Selective Non-Catalytic Reduction (SNCR)." http://www.epa.gov/ttn/catc/dir1/fsncr.pdf.
   4.    "Air Pollution Control Technology Fact Sheet: Selective Catalytic Reduction (SCR)." http://www.epa.gov/ttn/catc/dir1/fscr.pdf.
   5.    U.S. Environmental Protection Agency. January 2002. OAQPS Control Cost Manual, Sixth Edition. Publication Number EPA/452/B-02-001.
   6.    Survey Database containing Results of the 2008 Questionnaire for Boilers, Process Heaters, & Other Combustion Units (ICR No. 2286.01) (Version 3)
   7.    Emissions Database for Boilers and Process Heaters Containing Stack Test, CEM, & Fuel Analysis Data Reported under ICR No. 2286.01  & ICR No. 2286.03 (Version 7).
   8.    40 CFR 63, subpart DDDDD, National Emission Standards for Hazardous Air Pollutants for Major Sources: Industrial, Commercial, and Institutional Boilers and Process Heaters.
Table 1. Emission Reductions for Selected Controls
                                   Facility
                                   Location
                                   Unit Type
                                   Unit No.
                           Baseline Emissions (TPY)
                               Reductions* (TPY)
                           Resulting Emissions (TPY)
                                       
                                       
                                       
                                       
                                     PM10
                                      SO2
                                      NOX
                                     PM10
                                      SO2
                                      NOX
                                     PM10
                                      SO2
                                      NOX
                                    Hovensa
                                   St Croix
                                    Boiler
                                  1 (B-1151)
                                     40.6
                                     330.1
                                     450.6
                                     40.2
                                     181.5
                                     292.9
                                     0.41
                                     148.5
                                     157.7
                                    Hovensa
                                   St Croix
                                    Boiler
                                  3 (B-1153)
                                     40.6
                                     330.1
                                     450.6
                                     40.2
                                     181.5
                                     292.9
                                     0.41
                                     148.5
                                     157.7
                                    Hovensa
                                   St Croix
                                    Boiler
                                  4 (B-1154)
                                     39.7
                                     322.5
                                     443.5
                                     39.3
                                     177.4
                                     288.3
                                     0.40
                                     145.1
                                     155.2
                                    Hovensa
                                   St Croix
                                    Boiler
                                  5 (B-1155)
                                     60.7
                                     484.9
                                     676.9
                                     60.1
                                     266.7
                                     440.0
                                     0.61
                                     218.2
                                     236.9
                                    Hovensa
                                   St Croix
                                    Boiler
                                  6 (B-3301)
                                     40.6
                                     330.8
                                     435.3
                                     40.2
                                     182.0
                                     282.9
                                     0.41
                                     148.9
                                     152.3
                                    Hovensa
                                   St Croix
                                    Boiler
                                  7 (B-3302)
                                     40.6
                                     330.8
                                     435.3
                                     40.2
                                     182.0
                                     282.9
                                     0.41
                                     148.9
                                     152.3
                                    Hovensa
                                   St Croix
                                    Boiler
                                  8 (B-3303)
                                     78.6
                                     640.1
                                     559.8
                                     77.8
                                     352.1
                                     363.9
                                     0.79
                                     288.0
                                     195.9
                                    Hovensa
                                   St Croix
                                    Boiler
                                  9 (B-3304)
                                     78.6
                                     640.1
                                     559.8
                                     77.8
                                     352.1
                                     363.9
                                     0.79
                                     288.0
                                     195.9
                                    Hovensa
                                   St Croix
                                    Turbine
                                 GT1 (G-1101E)
                                     12.2
                                     135.5
                                     805.7
                                     12.0
                                     74.5
                                     644.6
                                     0.12
                                     61.0
                                     161.1
                                    Hovensa
                                   St Croix
                                    Turbine
                                 GT2 (G-1101F)
                                     12.2
                                     135.5
                                     805.7
                                     12.0
                                     74.5
                                     644.6
                                     0.12
                                     61.0
                                     161.1
                                    Hovensa
                                   St Croix
                                    Turbine
                                 GT3 (G-1101G)
                                     12.2
                                     135.5
                                     805.7
                                     12.0
                                     74.5
                                     644.6
                                     0.12
                                     61.0
                                     161.1
                                    Hovensa
                                   St Croix
                                    Turbine
                                 GT4 (G-3404)
                                     12.9
                                     161.0
                                     809.5
                                     12.8
                                     88.5
                                     647.6
                                     0.13
                                     72.4
                                     161.9
                                    Hovensa
                                   St Croix
                                    Turbine
                                 GT5 (G-3405)
                                     12.9
                                     161.0
                                     766.5
                                     12.8
                                     88.5
                                     613.2
                                     0.13
                                     72.4
                                     153.3
                                    Hovensa
                                   St Croix
                                    Turbine
                                 GT6 (G-3406)
                                     12.9
                                     161.0
                                     766.5
                                     12.8
                                     88.5
                                     613.2
                                     0.13
                                     72.4
                                     153.3
                                    Hovensa
                                   St Croix
                                    Turbine
                                 GT7 (G-3407)
                                     12.9
                                     161.0
                                     766.5
                                     12.8
                                     88.5
                                     613.2
                                     0.13
                                     72.4
                                     153.3
                                    Hovensa
                                   St Croix
                                    Turbine
                                 GT8 (G-3408)
                                     15.1
                                     167.6
                                    1002.1
                                     14.9
                                     92.2
                                     801.7
                                     0.15
                                     75.4
                                     200.4
                                    Hovensa
                                   St Croix
                                    Turbine
                                 GT9 (G-3409)
                                     14.0
                                     52.2
                                     150.2
                                     13.9
                                     28.7
                                     120.2
                                     0.14
                                     23.5
                                     30.0
                                    VI WAPA
                                   St Thomas
                                    Boiler
                                      11
                                     60.0
                                     646.0
                                     371.0
                                     59.4
                                     355.3
                                     241.2
                                     0.60
                                     290.7
                                     129.9
                                    VI WAPA
                                   St Thomas
                                    Boiler
                                      13
                                     28.0
                                    1116.0
                                     670.0
                                     27.7
                                     613.8
                                     435.5
                                     0.28
                                     502.2
                                     234.5
                                    VI WAPA
                                   St Thomas
                                    Turbine
                                      12
                                     15.0
                                     381.0
                                    1288.0
                                     14.9
                                     209.6
                                    1030.4
                                     0.15
                                     171.5
                                     257.6
                                    VI WAPA
                                   St Thomas
                                    Turbine
                                      14
                                     16.0
                                     392.0
                                    1326.0
                                     15.8
                                     215.6
                                    1060.8
                                     0.16
                                     176.4
                                     265.2
                                    VI WAPA
                                   St Croix
                                    Boiler
                                      10
                                     45.0
                                     396.0
                                     359.0
                                     44.6
                                     217.8
                                     233.4
                                     0.45
                                     178.2
                                     125.7
                                    VI WAPA
                                   St Croix
                                    Boiler
                                      11
                                     81.0
                                     712.0
                                     646.0
                                     80.2
                                     391.6
                                     419.9
                                     0.81
                                     320.4
                                     226.1
                                                                          Total
                                     782.2
                                    8322.6
                                    15350.1
                                     774.4
                                    4577.4
                                    11371.4
                                      7.8
                                    3745.2
                                    3978.7
* Control Efficiencies are based on typical efficiencies listed in EPA Clean Air Technology Center fact sheets for dry sorbent injection, fabric filters, selective non-catalytic reduction, and selective catalytic reduction. See Section I of this memorandum for details.

Table 2. Cost Effectiveness for Selected Controls
                                   Facility
                                   Location
                                   Unit Type
                                   Unit No.
                               Reductions* (TPY)
                          Annual Control Cost ($/yr)
                      Cost Effectiveness ($/ton reduced)
                                       
                                       
                                       
                                       
                                     PM10
                                      SO2
                                      NOX
                                     DIFF
                                     SNCR
                                      SCR
                                     DIFF
                                     SNCR
                                      SCR
                                    Hovensa
                                   St Croix
                                    Boiler
                                  1 (B-1151)
                                     40.2
                                     181.5
                                     292.9
                                  $8,591,292
                                   $235,848
                                       
                                    $38,749
                                     $805
                                       
                                    Hovensa
                                   St Croix
                                    Boiler
                                  3 (B-1153)
                                     40.2
                                     181.5
                                     292.9
                                  $8,591,292
                                   $235,848
                                       
                                    $38,749
                                     $805
                                       
                                    Hovensa
                                   St Croix
                                    Boiler
                                  4 (B-1154)
                                     39.3
                                     177.4
                                     288.3
                                  $8,588,093
                                   $234,532
                                       
                                    $39,640
                                     $814
                                       
                                    Hovensa
                                   St Croix
                                    Boiler
                                  5 (B-1155)
                                     60.1
                                     266.7
                                     440.0
                                  $6,253,161
                                   $313,100
                                       
                                    $19,136
                                     $712
                                       
                                    Hovensa
                                   St Croix
                                    Boiler
                                  6 (B-3301)
                                     40.2
                                     182.0
                                     282.9
                                  $5,819,344
                                   $234,477
                                       
                                    $26,197
                                     $829
                                       
                                    Hovensa
                                   St Croix
                                    Boiler
                                  7 (B-3302)
                                     40.2
                                     182.0
                                     282.9
                                  $5,819,344
                                   $234,477
                                       
                                    $26,197
                                     $829
                                       
                                    Hovensa
                                   St Croix
                                    Boiler
                                  8 (B-3303)
                                     77.8
                                     352.1
                                     363.9
                                  $11,589,590
                                   $312,326
                                       
                                    $26,959
                                     $858
                                       
                                    Hovensa
                                   St Croix
                                    Boiler
                                  9 (B-3304)
                                     77.8
                                     352.1
                                     363.9
                                  $11,589,590
                                   $312,326
                                       
                                    $26,959
                                     $858
                                       
                                    Hovensa
                                   St Croix
                                    Turbine
                                 GT1 (G-1101E)
                                     12.0
                                     74.5
                                     644.6
                                  $12,389,903
                                       
                                  $1,172,745
                                   $143,149
                                       
                                    $1,819
                                    Hovensa
                                   St Croix
                                    Turbine
                                 GT2 (G-1101F)
                                     12.0
                                     74.5
                                     644.6
                                  $12,389,903
                                       
                                  $1,172,745
                                   $143,149
                                       
                                    $1,819
                                    Hovensa
                                   St Croix
                                    Turbine
                                 GT3 (G-1101G)
                                     12.0
                                     74.5
                                     644.6
                                  $12,389,903
                                       
                                  $1,172,745
                                   $143,149
                                       
                                    $1,819
                                    Hovensa
                                   St Croix
                                    Turbine
                                 GT4 (G-3404)
                                     12.8
                                     88.5
                                     647.6
                                  $12,395,811
                                       
                                  $1,173,950
                                   $122,333
                                       
                                    $1,813
                                    Hovensa
                                   St Croix
                                    Turbine
                                 GT5 (G-3405)
                                     12.8
                                     88.5
                                     613.2
                                  $12,395,811
                                       
                                  $1,160,377
                                   $122,333
                                       
                                    $1,892
                                    Hovensa
                                   St Croix
                                    Turbine
                                 GT6 (G-3406)
                                     12.8
                                     88.5
                                     613.2
                                  $12,395,811
                                       
                                  $1,160,377
                                   $122,333
                                       
                                    $1,892
                                    Hovensa
                                   St Croix
                                    Turbine
                                 GT7 (G-3407)
                                     12.8
                                     88.5
                                     613.2
                                  $12,395,811
                                       
                                  $1,160,377
                                   $122,333
                                       
                                    $1,892
                                    Hovensa
                                   St Croix
                                    Turbine
                                 GT8 (G-3408)
                                     14.9
                                     92.2
                                     801.7
                                  $15,316,917
                                       
                                  $1,402,611
                                   $142,990
                                       
                                    $1,750
                                    Hovensa
                                   St Croix
                                    Turbine
                                 GT9 (G-3409)
                                     13.9
                                     28.7
                                     120.2
                                  $15,295,348
                                       
                                  $1,135,171
                                   $359,186
                                       
                                    $9,447
                                    VI WAPA
                                   St Thomas
                                    Boiler
                                      11
                                     59.4
                                     355.3
                                     241.2
                                  $1,168,675
                                   $256,705
                                       
                                    $2,818
                                    $1,065
                                       
                                    VI WAPA
                                   St Thomas
                                    Boiler
                                      13
                                     27.7
                                     613.8
                                     435.5
                                  $2,416,194
                                   $330,397
                                       
                                    $3,766
                                     $759
                                       
                                    VI WAPA
                                   St Thomas
                                    Turbine
                                      12
                                     14.9
                                     209.6
                                    1030.4
                                  $6,217,806
                                       
                                  $1,117,227
                                    $27,709
                                       
                                    $1,084
                                    VI WAPA
                                   St Thomas
                                    Turbine
                                      14
                                     15.8
                                     215.6
                                    1060.8
                                  $6,219,588
                                       
                                  $1,132,200
                                    $26,873
                                       
                                    $1,067
                                    VI WAPA
                                   St Croix
                                    Boiler
                                      10
                                     44.6
                                     217.8
                                     233.4
                                  $1,128,352
                                   $254,743
                                       
                                    $4,301
                                    $1,092
                                       
                                    VI WAPA
                                   St Croix
                                    Boiler
                                      11
                                     80.2
                                     391.6
                                     419.9
                                  $2,353,506
                                   $327,269
                                       
                                    $4,988
                                     $779
                                       
                                                                          Total
                                     774.4
                                    4577.4
                                    11371.4
                                 $203,711,047
                                  $3,282,047
                                  $12,960,525
                                    $38,064
                                                                           $834
                                                                         $1,743
* Reductions are based on typical efficiencies listed in EPA Clean Air Technology Center fact sheets for dry sorbent injection, fabric filters, selective non-catalytic reduction, and selective catalytic reduction. See Section I of this memorandum for details.


Table 3. Total Control Costs and Cost Effectiveness
                                    Control
                            Total Capital Cost ($)
                           Total Annual Cost ($/yr)
                        Total Emission Reductions (tpy)
                 Cost Effectiveness 
($/tpy pollutant reduced)
DIFF
                                                                   $750,566,946
                                                                   $203,711,047
                                                                          5,352
                                                                        $38,064
SNCR
                                                                    $29,146,033
                                                                     $3,282,047
                                                                          3,937
                                                                           $834
SCR
                                                                    $82,692,433
                                                                    $12,960,525
                                                                          7,434
                                                                         $1,743
Overall
                                                                   $862,405,412
                                                                   $219,953,619
                                                                         16,723
                                                                        $13,153


