Summary	of	Interagency	Working	Comments on	the	Draft	Language	under	

EO12866/13563	Interagency	Review.	Subject	to	Further	Policy	Review.

ENVIRONMENTAL PROTECTION AGENCY (EPA)

Updated Version of 111(b) RIA and Response to Interagency Comments

General Comments

1) Reviewer recommends clarifying whether the sentence on page 1-4 which includes “new noncompliant natural gas-fired combustion turbine units” is referring to simply cycle combustion 

turbine units.

Response: Sentence revised for clarity.

2) Reviewer recommends clarifying whether the reference on page 4-4 to AEO 2013 should instead 

refer to 2014.

Response: This is correct. The regional cost factors within the current version of IPM were 

developed using AEO 2013. These are not updated with each new version of AEO.

3) Reviewer recommends clarifying page 4-11, in the notes under figure 4-1, whether the 

renewables list should include wind.

Response: Wind is identified independently in the figure, so not included in the list. Category 

revised from “renewables” to “other renewables” for clarity.

4) Reviewer recommends clarifying whether the reference to “cofiring with 14 percent natural gas” 

on page 5-19 is correct.

Response: Corrected – analysis assumes 34% natural gas co-firing.

Technical Comments

1) Reviewer recommends updating page ES-2 to reflect the revised preamble.

a. Specifically the sentence about “BSER for natural gas-fired stationary combustion 

turbines” and the “1,080 lb CO2/MWh” reference

Response: Revisions made.

2) Reviewer recommends updating table ES-1 to reflect the revised preamble.

Response: Revisions made. Also revised Table 1-1.

3) Reviewer recommends reconciling the note under Table 4-3 to ensure consistency with the 

definition of “high economic growth” scenario in Table 4-4.

Response: Revisions made.

4) Reviewer recommends reconciling the notes under figure 5-1 about NG co-firing of 43% with the 

text in the paragraph above.

Response: Revisions made.
Summary	of	Interagency	Working	Comments on	the	Draft	Language	under	

EO12866/13563	Interagency	Review.	Subject	to	Further	Policy	Review.

5) Reviewer recommends clarifying the accounting for the greenhouse gas benefits of biomass 

energy in the RIA. Reviewer notes that the EPA SAB stated that it was not scientifically valid to 

assume that all biogenic feedstocks are carbon neutral, not is it scientifically valid to equate full 

stack emissions from biomass combustion with fossil sources. Despite this, EPA assumes a 

biomass emission factor of 195, equivalent to the direct stack emissions from biomass 

combustion. This is an inconsistency between the RIA and the language of the rule.

Response: The table in the RIA presents the emission factors contained in the Integrated 

Planning Model. This part of the industry profile is simply meant to informative and does not 

influence the conclusions of the RIA. The policy aspects of this question will be addressed in the 

preamble.

Typographical Comments All revisions made.

1) Reviewer recommends editing the sentence on page 1-2 which reads “has explained in detail 

how emissions of CO2 from the source category here cause or contribute significantly to the air 

pollution which endangers.”

2) Reviewer recommends editing the sentence on page 2-8 to read “Transmission is the term used 

to describe the bulk transfer of electricity”. 

3) Reviewer recommends editing page 2-26 to refer to “highly efficient coal-fired designs” rather 

than “highly efficiency”. 

4) Reviewer recommends editing page 4-8 to delete “projection is” in the sentence including 

“reference case is ‘projection is a business-as-usual...” 

5) Reviewer recommends editing page 4-8 to delete “in” from “2030 in is projected to...”

6) Reviewer recommends editing page 4-12 to replace “than” with “that” in the bullet titled State 

Renewable Portfolio Standards (RPS). 

7) Reviewer recommends adding “in” on page 4-25 to the sentence including “For technologies 

that are included in the IPM Base Case...”

8) Reviewer recommends rewording the sentence on page 5-14 that reads “In this scenario, we 

expect some compliance costs if a new NGCC unit...”