EGU MACT -- Interagency Request for Comment 

 Higgins, Cortney 

 to: RobertJ Wayland 

 03/15/2011 07:28 PM 

 Cc: Bill Maxwell, Peter Tsirigotis, Kevin Culligan 

Hi Bob, 

 

I’ve heard from interagency reviewers that had a chance to review the 

response to comment documents. The list below highlights those issues 

that they want to make sure have request for comments, and a second list 

of issues that were not addressed that the suggest be considered for the 

final rule. Can you make sure the first list is addressed in the 

preamble? 

 

Thanks, 

Cortney 

Issues that should be highlighted for comment: 

* EPA should seek public comments on the approach (99% UPL) used to 

account for variability of emissions during different unit operating 

loads. 

* EPA appears to have made several assumptions to come to a conclusion 

that installation of 65 GW of FGD retrofits can be accomplished 

within planned outages for all affected units. Some of these 

assumptions, e.g., whether many units have spare absorbers, must be 

confirmed by the industry. It is true that several of the older FGD 

installations have multiple scrubbers, but they may usually be designed 

to have multiple vessels with each less than 100% capacity (e.g., 2x50%). 

Upgrade of these vessels may still require partial outages, affecting 

availability. We are recommending that EPA clearly show their 

assumptions with regards to FGD upgrades in the preamble and solicit 

public comments on them. 

* It is recommended that, in addition to EPA’s further review of the 

issues raised regarding the use of baghouses, EPA should seek information 

and public comments on these issues (primarily, is there sufficient space 

for retrofits). 

* The number of units affected and controls installed for CAIR were 

totally different than what is required by the Toxic Rule. EPA’s 

analysis does not address the issues involved with the resources required 

for this rule. This is another important issue where EPA should seek 

information/comments from public to obtain the information needed to 

perform a proper analysis for the final rule. 

* It is critical that EPA perform comprehensive modeling of the impact 

that all proposed rules for all media (316b, NSPS for GHG, CCW, and any 

others) would have on coal plant retirements. Retirement decisions will 

not be made on a single rule but on the total expected investment 

required for compliance. We recommend that EPA seek public comments on 

coal retirement issue. 

 

Comments that were not responded to but EPA should consider while 

drafting the final rule: 
OMB File: Summary of Interagency Working Comments on draft EGU MACT 

under EO 12866 Interagency Review_ 03 10 2011_Response_031411.doc 

1. Page 6 – Response to Comment on Page 10, Last Paragraph: We agree 

with the use of a baghouse with a 6.0 A/C ratio for the ACI service. 

However, if the baghouse is being used in the service of trona-based DSI 

system, an A/C ratio of 4.0 would be required. 

2. Page 7 – Response to Comment on Page 13, Table 5-18: Please add the 

size-cost correlation factors as a note to this table. EPA has done this 

for all other technologies. This is necessary for a proper review of 

these costs, especially for smaller units. 

3. Page 7 – Response to Comment on Page 15, Last Paragraph: EPA has not 

addressed the main concern expressed in this comment. No basis for the 

$100/kW cost has been provided. This represents a major cost and it 

should be supported by a study and/or references to the costs incurred at 

actual retrofit projects. 

4. Page 8 – Response to Comment on Page 5, Table 1: Please revise Table 

1 to show the FGD upgrades resulting from EPA’s analysis. In addition, 

EPA appears to have made several assumptions to come to a conclusion that 

installation of 65 GW of FGD retrofits can be accomplished within planned 

outages for all affected units. Some of these assumptions, e.g., whether 

many units have spare absorbers, must be confirmed by the industry. It 

is true that several of the older FGD installations have multiple 

scrubbers, but they may usually be designed to have multiple vessels with 

each less than 100% capacity (e.g., 2x50%). Upgrade of these vessels may 

still require partial outages, affecting availability. We are 

recommending that EPA clearly show their assumptions with regards to FGD 

upgrades in the preamble and solicit public comments on them. 

5. Page 9 – Response to Comment on Pages 12 to 14: EPA’s response does 

not address the issues raised in the comment. First, the document 

listing the project completion times should be revised to reflect correct 

times (this will also change some of the text). Second, work done for 

CAIR has a relationship to the work required for the Toxic Rule only for 

the units planning to install FGD controls. A lot more planning is 

required to confirm the technologies that would be required to comply 

with the emission limits in the Toxic rule. EPA cannot make an 

assumption that plants will be able to complete all preliminary 

engineering work before the final rule and will be ready to award the 

equipment contracts right after the final rule is issued. It would be 

more appropriate for EPA to use conservative assumptions, given the 

complexity of this rule and the fact that the final rule may contain 

changes requiring selection of different compliance approaches. 

6. Page 11 – First Bullet Item: EPA has not done any analysis to show 

that combining multiple units to share a single control will result in 

any cost saving or will be possible for a significant number of affected 

units. Lack of a proper space to place common controls, costs of long 

ductwork, increased auxiliary power loads, reliability issues, and the 

potential need for a new stack may not allow such an option to be 

exercised on a significant scale. Please also note that a common 

baghouse for multiple units may not reduce costs significantly, since the 

baghouses use air-to-cloth ratios for design. 

OMB File: Summary of Interagency Working Comments on draft EGU MACT 

under EO 12866 Interagency Review_ 03 04 _Response_031411.doc 
* Page 27 – Comment on Page 466, Section V.M, Last Paragraph: It is 

agreed that there are some options that can be installed for improving an 

existing ESP performance. However, we also believe that the level of ESP 

performance required to achieve the emission limits for this rule would 

not be met with such options. It also appears that EPA has done no 

analysis to back its claim on this issue.