This comment letter response contains two parts:   

(1) The original submittal from the commenter.

(2) A data base printout of EPA’s response to each point raised by the commenter.

Notes about the response letters:

• The response letters were generated by a data base used to track the content of all public

comment submittals and ensure that the Agency responds to each. Each comment letter

was assigned a Letter ID that corresponds to the last four digits of the docket number of the

original comment (as posted on www.regulations.gov).

• Each response letter includes: comment text; an EPA‐assigned comment code; and an

individual response. These are described and explained below.  

• The data base contains Comment text from the letters submitted by commenters.  

Many hard copy letters were scanned into electronic format for inclusion in the data

base. As a result, there may be some typographical errors attributable to optical

character recognition issues.  However, all original submittals were reviewed in the

process of drafting responses to ensure that the comment content was understood and

appropriately addressed.

• The content of each comment letter was divided into topic areas and assigned a unique

Comment ID.  Additionally, one or more Comment Codes (i.e., unique topic area ID) was

assigned to each discrete point raised by a commenter. This information was added to

the data base. To inform final rulemaking decisions, all comments and information

received on a given topic were reviewed by technical experts in each rule area (e.g., on

construction requirements).  

• Following decisions on the final rule requirements, Individual responses were drafted

by topic area to ensure completeness and consistency of the responses with the final

rule and other responses to similar comments.  Each discrete point made by a

commenter was given a unique response.

• Upon completion of comment responses, all information was entered into the data base.

Each letter response is a compilation of each comment and its individual response,

compiled in the order of the original comment letter.  As a result of this process, there is

repetition in the response text.  The Agency believes this approach ensures completeness

and attention to each comment letter that was submitted.   

• All comments in a topic area were reviewed, evaluated, and responded to concurrently.  

Responses on each topic area are compiled and are also available in the rulemaking docket.
October 15, 2009

VIA ELECTRONIC DELIVERY

Water Docket

EPA Docket Center (EPA/DC)

Public Reading Room 3334

EPA West

1301 Constitution Avenue, N.W.

Washington, D.C. 

Attn: Docket ID No. EPA-HQ-OW-2008-0390

Re: Comments on Notice of Data Availability for Federal Requirements Under

the Underground Injection Control (UIC) Program for Carbon Dioxide

(CO2) Geologic Sequestration (GS) Wells (74 Fed. Reg. 44802 (Aug. 31,

2009)), Docket ID EPA-HQ-OW-2008-0390

Dear Sir or Madam:

NRG Energy Inc. (NRG) submits these comments on the Notice of Data Availability and

Request for Comment (“NODA”) relating to the proposed Federal Requirements Under the

Underground Injection Control (“UIC”) Program for Carbon Dioxide (“CO2”) Geologic

Sequestration Wells. 74 Fed. Reg. 44802 (Aug. 31, 2009). NRG Energy, Inc., a Fortune 500

company, owns and operates one of the country’s largest and most diverse power generation

portfolios. NRG’s 48 plants provide approximately 24,000 megawatts of generation capacity—

enough to power nearly 20 million homes. NRG believes that emissions of GHGs from power

generation and other sectors must be reduced, both domestically and internationally, to

successfully address climate change, and that commercially attractive, safe and environmentally

secure carbon capture and sequestration will be critical for that success. Headquartered in

Princeton, NJ, NRG is a member of the U.S. Climate Action Partnership (USCAP), a group of

business and environmental organizations calling for mandatory legislation to reduce greenhouse

gas emissions.

NRG appreciates the substantial efforts which have been part of this proposal

development governing CO2 injection for the purpose of GS. As a company, NRG is committed

to effectively addressing climate change, and believes that GS is a critical component for the

reduction of CO2 emissions. In general, NRG supports and commends the efforts of the EPA to

develop a rational approach that would (1) create a new category of injection wells (i.e., Class

VI) under the Underground Injection Control (UIC) Program and (2) establish Federal

regulations that are specifically tailored to CO2 injection for GS. NRG submitted comments last

December on EPA’s proposal to regulate CO2 GS under the UIC program. See 73 Fed. Reg.

43492 (July 25, 2008).
Water Docket 

October 15, 2009

Page 2

NRG recognizes that the development of a viable carbon capture and sequestration

(“CCS”) regulatory program has been cited by many as a prerequisite to the implementation of

energy reform initiatives involving carbon reduction measures on both the federal and state level.

EPA predicts that the electric power sector, including NRG, “will most likely be the largest

potential market for [CCS] technologies,” and predicts that CCS technology could lead to CO2

reductions of approximately 80-90% at a single plant. 73 Fed. Reg. 44354, 44492 (July 30,

2008). NRG believes that the agency’s decades of involvement with the management of fossil

fuel combustion materials as well as our members’ experiences in the field provide us with a

valuable knowledge base and perspective from which to provide meaningful input on the

development of EPA’s UIC regulations for CO2 GS.

At the outset, NRG applauds EPA’s careful approach to the development of CO2 GS

regulations, including this most recent release of additional data. Because the technology

contemplated in the CO2 GS proposal will not be commercially deployed for many years, it is

essential the Final Rule be flexible enough to accommodate developments in information and

technology related to carbon sequestration. It is critical that EPA develop a regulatory regime

incorporating performance-based standards in order to allow for site-tailored requirements that

will reflect the vast differences among various potential CO2 GS sites. 

NRG supports EPA’s suggestion to adopt a flexible waiver process to allow for CO2 GS

injection above and between underground sources of drinking water (USDWs). 74 Fed. Reg. at

44810. As stated in the NODA, EPA’s original proposal to define Class VI injection wells as

those used for injection of CO2 beneath the lowermost formation containing a USDW (73 Fed.

Reg. at 43511) would preclude injection of CO2 into zones between and above USDWs, thereby

restricting or rendering impossible CO2 GS sites in large areas of the country with deep USDWs.

74 Fed. Reg. at 44808. The proposal would also prohibit CO2 injection into many shallow

formations such as coal seams and basalts. 73 Fed. Reg. at 43512. As the NODA observes, a

number of states have indicated that regions with very deep and layered USDWs could not

undertake CO2 GS projects because injectors could not comply with the proposed injection depth

and well construction requirements. 74 Fed. Reg. at 44809. 

EPA addresses these concerns by the proposal set forth in the NODA to keep the

originally proposed injection depth requirement but allow owners or operators to apply for a sitespecific waiver from those injection depth requirements upon making a demonstration that such

injection can be undertaken in a manner that prevents the endangerment of public health from

USDW contamination. Id. at 44810. NRG believes that such a flexible approach would ensure

adequate protection of USDWs while recognizing the vast geographic and topographic

differences between potential CO2 GS sites throughout the country, allowing for maximization of

safe CO2 storage capacity nationwide. 

While NRG supports the flexible injection depth waiver proposal described above, NRG

urges EPA to consider requiring the inclusion of such a waiver provision, rather than leaving the

adoption of an injection depth waiver process to the discretion of the individual UIC Program

Directors. Id. at 44811. While it is true that deep USDWs do not exist in every state and that

states without USDWs may choose not to grant waivers, inclusion of a waiver provision would

still leave UIC Program Directors free to decline to grant any waivers where not necessary or
Water Docket 

October 15, 2009

Page 3

appropriate. See id. CO2 GS technology is rapidly developing; because this experience with and

information regarding this technology is growing rapidly, it is prudent to structure a regulatory

framework that is flexible enough to respond to developments in the field.

We appreciate the opportunity to comment on this new data and EPA’s new proposal for

an injection depth waiver process. If you have any questions regarding these comments, please

contact Mr. Jeffrey Davis at (713) 795-6207.

Sincerely,

Verne Shortell

Executive Director,

Environmental Business
Letter ID: 0360  

Commenter: Verne Shortell  

Organization: NRG Energy, Inc.  

Letter ID: 0360 Comment ID: 28237 Letter Lines: 44 to 48  

Comment Code: 6000 6. Other Comments that are Out of Scope for the NODA  

Comment: 20 million homes. NRG believes that emissions of GHGs from power generation and  

other sectors must be reduced, both domestically and internationally, to  

successfully address climate change, and that commercially attractive, safe and  

environmentally secure carbon capture and sequestration will be critical for  

that success. Headquartered in Princeton, NJ, NRG is a member of the U.S.  

Individual Response: This comment is outside the scope of the Notice of Data Availability and the UIC

Program’s authority under the GS rulemaking.  

Letter ID: 0360 Comment ID: 28238 Letter Lines: 53 to 62  

Comment Code: 5000 5. Comments on the Proposed Rule (out of NODA Scope)  

Comment: NRG appreciates the substantial efforts which have been part of this proposal  

development governing CO2 injection for the purpose of GS. As a company, NRG is  

committed to effectively addressing climate change, and believes that GS is a  

critical component for the reduction of CO2 emissions. In general, NRG supports  

and commends the efforts of the EPA to develop a rational approach that would  

(1) create a new category of injection wells (i.e., Class VI) under the  

Underground Injection Control (UIC) Program and (2) establish Federal  

regulations that are specifically tailored to CO2 injection for GS. NRG  

submitted comments last December on EPA’s proposal to regulate CO2 GS under the  

UIC program. See 73 Fed. Reg. 43492 (July 25, 2008).  

Individual Response: This comment pertains to EPA’s proposed GS rule (73 FR 43492) and is outside the

scope of the Notice of Data Availability. Please see responses to comments on the proposed rule for

EPA’s response to similar comments.  
Letter ID: 0360 Comment ID: 28239 Letter Lines: 77 to 84  

Comment Code: 1000 1. General Comments on the Notice of Data Availability  

Comment Code: 5000 5. Comments on the Proposed Rule (out of NODA Scope)  

Comment: At the outset, NRG applauds EPA’s careful approach to the development of CO2 GS  

regulations, including this most recent release of additional data. Because the  

technology contemplated in the CO2 GS proposal will not be commercially deployed  

for many years, it is essential the Final Rule be flexible enough to accommodate  

developments in information and technology related to carbon sequestration. It  

is critical that EPA develop a regulatory regime incorporating performance‐based  

standards in order to allow for site‐tailored requirements that will reflect the  

vast differences among various potential CO2 GS sites.  

Individual Response: EPA believes that the final rule is based on the most recent GS‐related data,

information, and scientific research available. EPA intends to continue to collect data on GS and to

incorporate such data as it implements its adaptive approach to GS rulemaking to incorporate new

research, data, and information about GS. The Agency believes that an adaptive approach provides Class

VI owners or operators the flexibility to use and apply newly developed technologies for GS as they

become available in the future. EPA plans to, every six years, collect and review data on GS projects to

determine whether the appropriate amount and types of information and appropriate documentation

are being collected, and to determine if modifications to the requirements are appropriate or necessary.

EPA agrees with the commenter that a site‐specific approach to permitting GS sites is important. The

final rule provides Class VI owners or operators the flexibility to select technologies appropriate for a

specific site and affords the Director flexibility to establish permit requirements on the basis of site‐

specific characteristics. For additional information on the adaptive approach and site‐specific

requirements, see the responses to comments on the proposed rule in the rulemaking docket.  

Letter ID: 0360 Comment ID: 28241 Letter Lines: 86 to 108  

Comment Code: 3210 3.2.1. Comments Generally in Support of the Approach  

Comment: NRG supports EPA’s suggestion to adopt a flexible waiver process to allow for  

CO2 GS injection above and between underground sources of drinking water  

(USDWs). 74 Fed. Reg. at 44810. As stated in the NODA, EPA’s original proposal  

to define Class VI injection wells as those used for injection of CO2 beneath  

the lowermost formation containing a USDW (73 Fed. Reg. at 43511) would preclude  

injection of CO2 into zones between and above USDWs, thereby restricting or  

rendering impossible CO2 GS sites in large areas of the country with deep USDWs.  
74 Fed. Reg. at 44808. The proposal would also prohibit CO2 injection into many  

shallow formations such as coal seams and basalts. 73 Fed. Reg. at 43512. As  

the NODA observes, a number of states have indicated that regions with very deep  

and layered USDWs could not undertake CO2 GS projects because injectors could  

not comply with the proposed injection depth and well construction requirements.  

74 Fed. Reg. at 44809.  

EPA addresses these concerns by the proposal set forth in the NODA to keep the  

originally proposed injection depth requirement but allow owners or operators to  

apply for a site‐ specific waiver from those injection depth requirements upon  

making a demonstration that such injection can be undertaken in a manner that  

prevents the endangerment of public health from USDW contamination. Id. at  

44810. NRG believes that such a flexible approach would ensure adequate  

protection of USDWs while recognizing the vast geographic and topographic  

differences between potential CO2 GS sites throughout the country, allowing for  

maximization of safe CO2 storage capacity nationwide.  

Individual Response: EPA acknowledges the commenter's support of the waiver approach and site‐

specific flexibility in regulatory development and permitting as described in the NODA and Request for

Comment. The Agency acknowledges that there are some situations where injection into non‐USDW

formations above the lowermost USDW can be performed in a manner that protects USDWs. The final

GS rule at §146.95 establishes a process by which owners and operators can seek a waiver of the Class

VI injection depth requirements. The Agency believes the waiver approach: 1) responds to concerns

about local and regional geologic storage capacity limitations imposed by the proposed injection depth

requirements; 2) allows for a more site‐specific assessment of injection depth for GS projects; 3)

accommodates injection into different formation types; 4) allows for injection of CO2 for GS into non‐

USDWs above and/or between USDWs when appropriate and where it can be demonstrated that

USDWs will be protected; and 5) responds to concerns about the use of aquifer exemptions for GS.

Finally, EPA's approach to addressing injection depth variability through a waiver process responds to

concerns about future drinking water resource availability and the need to ensure that high quality

water remains available in sufficient quantities to supply drinking water needs.  

Letter ID: 0360 Comment ID: 28242 Letter Lines: 110 to 120  

Comment Code: 3390 3.3.9. Comments Regarding State Discretion to Adopt the Waiver Approach  

Comment: While NRG supports the flexible injection depth waiver proposal described above,  

NRG urges EPA to consider requiring the inclusion of such a waiver provision,  

rather than leaving the adoption of an injection depth waiver process to the  

discretion of the individual UIC Program Directors. Id. at 44811. While it is  
true that deep USDWs do not exist in every state and that states without USDWs  

may choose not to grant waivers, inclusion of a waiver provision would still  

leave UIC Program Directors free to decline to grant any waivers where not  

necessary or appropriate. See id. CO2 GS technology is rapidly developing;  

because this experience with and information regarding this technology is  

growing rapidly, it is prudent to structure a regulatory framework that is  

flexible enough to respond to developments in the field.  

Individual Response: EPA clarifies that adoption of the injection waiver process will remain at the

discretion of individual UIC programs. States, Territories, and Tribes seeking primacy for Class VI wells

are not required to provide for injection depth waivers in their UIC regulations. Although some

commenters asked EPA to require that waivers be applied nationally, the Agency believes that the

decision about whether a waiver program is appropriate should be made by each program. This

approach allows flexibility for individual program Directors to determine the appropriateness of allowing

for waivers based on regional or state‐specific conditions, such as the predominant geologic settings

anticipated to be used for GS or other land uses in the state while ensuring maximum protection of

USDWs. The final approach for injection depth waivers represents minimum Federal requirements. UIC

program Directors may adopt GS requirements that do not allow injection above or between USDWs if

they determine this to be appropriate (for conditions in their State, territory, Tribe, or Region) and

protective.

EPA recognizes that GS technologies are rapidly developing. For this reason, the Agency is adopting an

adaptive rulemaking approach. EPA plans, every six years, to collect and review data on GS projects,

including information on any Class VI wells granted a waiver of the injection depth requirements, to

determine whether the appropriate amount and types of information and appropriate documentation

are being collected, and to determine if modifications to the requirements are appropriate or necessary.