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KDHE – Bureau of Air Response to the National Park Conservation Association 

Comments on the Kansas Regional Haze SIP

December 1, 2011

The NPCA comments can essentially be summarized as stating that KDHE did not perform an 

acceptable five factor analysis for the Kansas BART sources, thus resulting in emission rates in the 

agreements that were not low enough to be considered BART. In some cases, the comments stated 

that additional control equipment should be required to be installed. In other cases, the comments

suggest that the control equipment to be installed should be capable of achieving a lower emission 

rate. It is KDHE’s position that in all cases an acceptable five factor analysis was performed for the 

BART affected units. KDHE believes these statutory factors have been met for these BART sources

in accordance with the provisions of 40 CFR 51, Regional Haze Regulations and Guidelines for BART. 

KDHE does not agree with these comments; however, to address them, dispersion modeling using 

the CALPUFF model was conducted. The modeling used the same inputs that were used when the 

original Regional Haze SIP modeling was conducted as part of the BART technical analysis, except 

for changes to the emission rates to address the NPCA comments. Each of the original modeling 

runs was repeated with lower rates in order to evaluate the incremental visibility benefits that 

would result from lower SO2 and NOX rates than those currently in the Regional Haze agreements 

with KCP&L and Westar Energy. The rates that were selected were based on NPCA comments and 

on recent BACT determinations. These rates are more stringent than required by the BART process. 

BACT and BART are not equivalent. BACT is applied to new sources while BART is applied to existing 

sources. The emission rates that can be achieved at a new source will be more stringent than those 

that can be achieved by retrofitting an existing source. The modeled emission rates, the model 

results, and the cost of supplemental controls are included in an attached table.

Upon completion of the current modeling, the differences in the modeled visibility impacts on the 

five Class I areas that were evaluated in the SIP were determined. KDHE also obtained or developed 

annualized costs for the additional equipment that would be required to be installed in order to 

achieve the lower emission rates. For NOX, the modeling and associated costs were determined for 

SNCR and SCR at Jeffrey Energy Center (JEC) Units 1 and 2 as well as La Cygne Unit 2. For SO2 , the 

modeling and associated costs were determined for installation of new scrubbers at JEC Units 1 and 

2, and for operation of new scrubbers at a lower rate at La Cygne. The metric suggested by NPCA in 

their comments, cost per deciview of visibility improvement, was used to evaluate the results of the 

modeling. The results are included in the attached table. 

Jeffrey Energy Center Units 1 and 2 - NOX

The BART analysis for JEC Units 1 and 2 identified various potential controls that were feasible for 

retrofit on these units. The control technologies were ranked and it was determined based on this 

ranking that low NOX burner systems and SCR systems were the most effective at NOX reductions. 
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Because these two technologies were ranked highest for removal efficiencies, their cost 

effectiveness was evaluated first. During the cost evaluation it was determined that LNB costs were 

reasonable and this was ultimately the technology chosen as BART. SCR was further evaluated for 

incremental cost improvements and this technology was excluded as BART based on the high 

incremental cost and low incremental visibility improvements. The cost analysis for SCR was 

performed based on the BART emission limit of 0.10 lb/MMBtu, which is within the range of 

effectiveness one could expect as a retrofit control on these older units. The analysis assumed a 

removal rate of approximately 80%. KDHE believes this is reasonable for a retrofit control. 

The NPCA comments that the costs used in the analysis are inflated and that the cost used in the 

JEC analysis should reflect the best possible reductions that SCR can achieve. The cost is reflective 

of the assumed emission rate limit of 0.10 lb/MMBtu. The NPCA comments suggest that the cost 

used in this analysis should reflect an emission rate of 0.05 lb/MMBtu. The 0.05 lb/MMBtu rate is 

consistent with current BACT rates for new facilities, not retrofitting 35 year old existing facilities. 

The incremental cost associated with an SCR at tangential-fired units such as JEC Units 1 and 2 is 

significantly higher than for a wall-fired boiler, as reflected in the significantly different EPA 

presumptive rates of 0.15 lb/MMBtu versus 0.23 lb/MMBtu. In response to the NPCA comments, 

KDHE obtained an annualized cost for SNCR control on Jeffrey Units 1 and 2 from Westar Energy. 

The annualized cost for SCR control on Jeffrey Units 1 and 2 was obtained from the original Westar 

BART analysis, Tables 5.4 and 5.5. 

KDHE does not agree with the NPCA comments; however, to evaluate the incremental benefit of an 

SCR installed at JEC Units 1 and 2, a CALPUFF run was performed with a rate of 0.08 lb/MMBtu. The 

base SO2 rate used when conducting the SNCR and the SCR modeling runs for NOX at Jeffrey Unit 1 

was kept at the same rate as the original BART modeling rate (0.86 lb/MMBtu). The base SO2 rate 

used when conducting the SNCR and the SCR modeling runs for NOX at Jeffrey Unit 2 was kept at 

the same rate as the original BART modeling rate (0.88 lb/MMBtu). The change in modeled impact 

between the SCR scenario (0.08 lbs NOx /MMBtu) and the LNB scenario (0.15 lbs NOx /MMBtu) at 

Hercules Glade was less than 0.05 deciview. The difference in the cumulative impact of all five Class 

I Areas for this scenario is 0.16 deciview. The differences in visibility impact between an SCR and 

LNB for Jeffrey Unit 1 are insignificant when compared to the differences in impact between the 

LNB scenario and the pre-BART scenario. The differences for Jeffrey Unit 2 under these scenarios 

are even lower than for Unit 1.

For SNCR, no further evaluation was performed in the original analysis due to the low overall 

ranking of estimated control efficiency. To address this NPCA comment and evaluate the 

incremental benefit that would result from requiring that an SNCR be installed at JEC Units 1 and 2, 

a CALPUFF run was performed with a NOX rate of 0.10 lb/MMBtu. For Jeffrey Unit 1, the change in 

modeled impact between the SNCR scenario (0.10 lb NOx /MMBtu) and the LNB scenario (0.15 lb 

NOx /MMBtu) at Hercules Glade, was 0.03 deciview. The difference in the cumulative impact of all 

five Class I areas for this scenario is only 0.09 deciview. The differences in visibility impact between 
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an SNCR and LNB for Jeffrey Unit 1 are even lower than those for the SCR scenario, as expected. The 

results for Unit 2 are nearly identical. It is KDHE's conclusion that the additional NOX reduction costs 

for the incremental visibility improvements for Jeffrey Units 1 and 2 are too high and do not 

warrant changes to the Kansas Regional Haze Westar Agreement or the SIP.

Jeffrey Energy Center Units 1 and 2 – SO2

The BART analysis for JEC Units 1 and 2 for SO2 resulted in the decision that rebuilding existing wet 

scrubber units and meeting a rate of 0.15 lb/MMBtu was BART. The NPCA comments suggest that 

retrofit technology should be required to meet BACT level emission rates. The 0.05 lb/MMBtu rate 

suggested by NPCA is consistent with current BACT rates for new facilities, not retrofitting 35 year 

old existing facilities. This is not how the BART rates are established and the NPCA has offered no 

justification for lower rates specific to these units. Although KDHE does not agree with these NPCA 

comments; to evaluate the incremental cost and visibility improvement of requiring a lower SO2

emission rate, KDHE conducted a CALPUFF run for the installation of a new scrubber for each of the 

two JEC units instead of the rebuilt scrubbers determined by KDHE to be BART.

The CALPUFF runs were performed with a rate of 0.05 lb/MMBtu for a new scrubber. The base NOX

rate used when conducting the new scrubber modeling run for SO2 at Jeffrey Unit 1 was kept at the 

same rate as the original BART modeling rate (0.49 lb/MMBtu). The base NOX rate used when 

conducting the new scrubber modeling run for SO2 at Jeffrey Unit 2 was kept at the same rate as 

the original BART modeling rate (0.48 lb/MMBtu). In response to the NPCA comments, KDHE 

obtained annualized costs for new scrubbers on Jeffrey Units 1 and 2 from Westar Energy. 

The change in modeled impact between the new wet scrubber scenario (0.05 lb SO2/MMBtu) and 

the BART Agreement rebuilt scrubber (0.15 lb SO2/MMBtu) was less than 0.05 deciviews for Jeffrey 

Unit 1 at Wichita Mountains. The difference in the cumulative impact of all five Class I Areas for this 

scenario is 0.17 deciview. The differences in visibility impact between the new scrubber and the 

BART Agreement scrubber for Jeffrey Unit 1 are insignificant when compared to the differences in 

impact between the BART Agreement scrubber and the pre-BART scenario. The differences for 

Jeffrey Unit 2 under these scenarios are even lower than for Unit 1. It is KDHE's conclusion that the 

additional SO2 reduction costs for the incremental visibility improvements for Jeffrey Units 1 and 2 

are too high and do not warrant changes to the Kansas Regional Haze Westar Agreement or the SIP.

La Cygne Units 1 and 2 – NOX

The BART analysis for La Cygne Units 1 and 2 for NOX resulted in the decision that establishing a 

combined emissions limit for both units with a rate of 0.13 lb/MMBtu was BART. The SCR at Unit 1 

was constructed while the Regional Haze SIP development process was underway and was an 

existing unit when the SIP was adopted and submitted to EPA. Unit 1 is a cyclone design, which has 

a much higher initial NOX emission rate. This is reflected in the fact that the BART presumptive limits 

were not based on boiler modifications such as low NOX boiler systems, but rather an SCR. It is not 
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technically feasible for an older cyclone boiler to be retrofit to achieve NOX rates that are consistent 

with current BACT rates for wall fired boilers as NPCA suggests. KDHE reviewed the CAMD and EIA 

databases at the time the Regional Haze SIP was being developed to review emissions data for 

cyclone boilers equipped with SCR technology. A relatively small number of cyclone boilers were so 

equipped at that time and their emission rates varied both above and below the presumptive NOX

rate.

NPCA commented that a lower NOX emission rate for Unit 2 should be required and could be 

achieved at the same cost provided in the analysis. The costs will be directly associated with the 

designed emissions rate of the SCR and the lower the rate the higher the cost. NPCA commented 

that KDHE afforded KCP&L flexibility in the technology used to reach the rates agreed to in the 

Regional Haze Agreement. In the La Cygne BART analysis, pages 5-10, KCP&L proposes SCR on Unit 

2 along with further study on combustion controls. The combined rate for the two units cannot be 

achieved without the installation of an SCR on Unit 2. KCP&L has applied to KDHE for a permit to 

install an SCR on Unit 2. For SNCR, no further evaluation was performed due to the low overall 

ranking of estimated control efficiency and because of the low combined NOX emission rate in the 

KCP&L agreement. 

Although KDHE does not agree with these NPCA comments, CALPUFF modeling was conducted to 

evaluate the incremental visibility improvement that would result from requiring a lower emission 

rate in the KCP&L agreement. The change in modeled impact between the BART agreement NOx

controls (0.23 lb NOx /MMBtu) and the Unit 2 SCR scenario (0.08 lb NOx /MMBtu) was 0.08 deciview 

for Upper Buffalo. The difference in the cumulative impact of all five Class I Areas for this scenario is 

0.25 deciview. These differences in impact are very low, as expected.

The change in modeled impact between the BART agreement NOx controls (0.23 lb NOx/MMBtu)

and the Unit 2 SNCR scenario (0.14 lb NOx /MMBtu) was 0.03 deciview for Upper Buffalo. The 

difference in the cumulative impact of all five Class I Areas for this scenario is 0.12 deciview. These 

differences in impact are very low, as expected.

For KCPL, the change in modeled impact between the BART agreement controls and the Unit 2 SCR 

(0.08 lb NOx /MMBtu) Unit 1 and 2 new wet scrubbers (0.05 lb SO2/MMBtu) scenario was 0.17 

deciview for Upper Buffalo. The difference in the cumulative impact of all five Class I Areas for this 

scenario is 0.65 deciview. The cumulative differences in visibility impact for this scenario are larger 

than the JEC scenarios because the modeling was for two units combined. 

The annualized cost for SNCR control on KCP&L La Cygne Unit 2 was determined by using SNCR 

costs obtained from Jeffrey Energy Center Unit 1, and scaling the dollar amount using heat input 

and NOx rates. The annualized cost for SCR on KCP&L La Cygne Unit 2 was obtained from Table 5.5 

of the BART analysis. These costs were multiplied by 20% to estimate the incremental costs 

associated with achieving a substantially lower emission rate for the analysis. It is KDHE's conclusion 

that the additional NOX reduction costs for the incremental visibility improvements for La Cygne 
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Units 1 and 2 are too high and do not warrant changes to the Kansas Regional Haze KCP&L 

Agreement or the SIP.

La Cygne Units 1 and 2 – SO2

The BART analysis for La Cygne Units 1 and 2 for SO2 resulted in the decision that establishing a 

combined emissions limit for both units with a rate of 0.10 lb/MMBtu was BART. The NPCA 

comments suggest that retrofit technology should be required to meet BACT level emission rates. 

The rate suggested by NPCA is consistent with current BACT rates for new facilities, not retrofitting 

35 year old existing facilities. Unit 1 has an existing scrubber that will be modified to separate the 

PM control from the SO2 control with increased SO2 removal efficiency as the goal. Unit 2, which 

did not have an existing scrubber, will be fitted with a new scrubber. The combined BART emission 

rate chosen for SO2 controls are within the range of expected removal efficiencies, considering one 

unit is a retrofitted scrubber. 

Although KDHE does not agree with these NPCA comments, CALPUFF modeling was conducted to 

evaluate the incremental visibility improvement that would result from requiring a lower SO2 

emission rate in the KCP&L agreement. For Unit 1 scrubber at KCP&L, the change in modeled impact 

from the BART Agreement scenario (0.15 lb SO2/MMBtu) to a lower rate consistent with current 

BACT limits (0.05 lb SO2/MMBtu) was 0.01 deciview at Upper Buffalo. The difference in the 

cumulative impact of all five Class I Areas for this scenario is 0.12 deciview. These differences in 

impact are very low as expected. The Unit 2 scenario impact comparison is even lower. The 

incremental costs used to evaluate the cost effectiveness of a lower SO2 emission rate at La Cygne 

Units 1 and 2 were based on EPA AirControlNET costs. These costs were multiplied by 20% to 

estimate the incremental costs associated with achieving a substantially lower emission rate for the 

analysis. It is KDHE's conclusion that the additional SO2 reduction costs for the incremental visibility 

improvements for La Cygne Units 1 and 2 are too high and do not warrant changes to the Kansas 

Regional Haze KCP&L Agreement or the SIP.

The CALPUFF modeling conducted in response to NPCA’s comments in all cases shows that the 

modeled visibility improvements for the five Class I areas are extremely small relative to the 

visibility improvements achieved with the BART rates established for the four units under question. 

In addition, it is important to note that other electrical generating units in Kansas were also 

included in the Kansas Regional Haze SIP and significant reductions were achieved at these as well.

The majority of the issues raised by NPCA relate to a state’s ability to justify BART thresholds and 

limits while following the five statutory factors. KDHE acted within its authority in making the BART 

determinations in question and the NPCA has not provided any direct evidence that the BART 

determinations are not within the flexibility provided by the SIP development process. The 

attached table with the annualized cost factors for achieving emission rates equivalent to BACT 

rates shows the incremental costs to be extremely high when gauged by either of the two metrics 

used for the analysis. KDHE affirms that the BART determinations for the units in question follow 
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the statutory factors under the Clean Air Act and the regulatory requirements of the Clean Air 

Visibility Rule. They will result in significant, cost-effective visibility improvements to Class I areas 

affected by BART sources in Kansas.