### 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.

### GENERAL COMMENT:

Arizona Public Service Company (APS) owns or operates a number of fossil fuel-fired power

plants, including two large coal -fired power plants. APS strongl y supports aggressive research

and development of viable methods for carbon ca pture and sequestration ( CCS) projects and for

reuse CO2 from fossil generation plants. APS has worked with Westcarb and other Arizona

utilities on a DOE funded project to drill an experimental CO2 sequestration test well at our

Cholla Power Plant near Holbrook, Arizona. APS has also recently received funding from DOE

to study the feasibility of reusing CO2 from the pl ant to grow algae that later can be processed

into liquid transportation fuels.

APS supports EPA’s proposal to adopt a flexible waiver process to allow for CO2 sequestration

above and between underground sources of drin king water (USDWs). 74 Fed. Reg. at 44810. In

Arizona we are just beginning to investigate the potential for geol ogic storage sites. In the case

of the project at our Cholla Power Plant, CO2 injection was planned below any USDW.

However, to the north of our plant favorable geologic storage sites may be located between

USDWs. The data on water quality is sparse in these deeper units. Allowing for a waiver gives

us increased flexibility to pursue good storag e sites that are not beneath all USDWs.

Because of the importance of the waiver propo sal APS asks that EPA consider requiring the

inclusion of this waiver provisi on, rather than leaving the adopti on of an injection depth waiver

process to the discretion of the individual UI C Program Directors. 74 Fed. Reg. 44811. Inclusion

of a waiver provision would sti ll leave UIC Program Directors free to decline to grant any

waivers where not necessary or appropriate.A subsidianj of Pinnacle West Capital Corporation

Scott L. Davis

Director

Environmental Health & Safety

Department



### VIA ELECTRONIC DELIVERY

October 15, 2009

Water Docket

U.S. Environmental Protection Agency

Mail Code: 4101 T

1200 Pennsylvania Avenue, N.W.

Washington, DC 20460



### Attn: Docket ID 

### No. EPA-HQ-OW-2008-0390 Tel. 602-250-3225 Mail Station 8376

Fax 602-250-3872 PO Box**~i3999** e-mail Scott.Davis@aps.comPhoenix.Arizona 85072-3999



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

Under the Underground Injection Control (UIC) Program for Carbon

Dioxide (C0 2 ) 

### Geologic Sequestration (GS) Wells (74 Fed. Reg. 44802

dated Aug. 31, 2009)

To Whom It 

### May Concern:

Arizona Public Service Company (APS) submits these comments in response to

the Environmental Protection Agency (EPA) request for public input regarding the

Notice of Data Availability and Request for Comment ("NOD A") relating to the

proposed Federal Requirements Under the Underground Injection Control (UIC) Program

for Carbon Dioxide (C02) Geologic Sequestration Wells. APS is the largest electric

utility in Arizona serving over a million customers. APS owns or operates a number of

fossil fuel-fired power plants, including two large coal-fired power plants. Over the last

two years APS has worked with Westcarb and other Arizona utilities on a DOE funded

project to drill an experimental CO 2 sequestration test well on our Cholla Power Plant

property near Holbrook, Arizona. APS also recently received funding from DOE to

study the feasibility of a fully integrated energy system for beneficial CO 2 use. The CO 2

produced by the power plant is fed directly to an algae farm, which consumes CO 2

. The

algae will then be processed into liquid transportation fuels (e.g. biodiesel, ethanol, and

military fuel), constituting a beneficial reuse of CO 2

.

APS strongly supports aggressive research and development of viable methods for

carbon capture and sequestration (CCS) projects and for reuse CO 2 from fossil generation

plants. EPA predicts that the electric power sector "will most likely be the largest

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

CO 2 

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

(July 30, 2008). As a result of our involvement in this research and because of the

potential for impact to our industry APS believes we have the knowledge and perspectiveArizona Public Service Company Comments

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

October 15,2009 Page 2 of2



### to provide meaningful comments on the development of EPA's UIC regulations for CO 2

geologic sequestration.

APS appreciates EPA's careful approach to the development of the C02 g(;:ologic

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

the technology is still being developed and may not be commercially deployed for many

years, it is essential that the rule be flexible in order to accommodate later developments

in information and technology. Performance based standards allow for requirements that

can be tailored for the differences in geology and other site characteristics across the

country.

APS supports EPA's proposal to adopt a flexible waiver process to allow D)r CO 2

sequestration above and between underground sources of drinking water (USDWs). 74

Fed. Reg. at 44810. In Arizona we are just beginning to investigate the potential fDr

geologic storage sites. In the case of the project at our Cholla Power Plant, C02 injection

was planned below any USDW. However, to the north of our plant favorable geologic

storage sites may be located between USDWs. The data on water quality is sparse in

these deeper units. Allowing for a waiver gives us increased flexibility to pursue good

storage sites that are not beneath all USDWs.

Because of the importance of the waiver proposal APS asks that EPA consi.der

requiring the inclusion of this waiver provision, rather than leaving the adoption of an

injection depth waiver process to the discretion of the individual UIC Program Directors.

74 Fed. Reg. 44811. Inclusion of a waiver provision would still leave UIC Progrmn

Directors free to decline to grant any waivers where not necessary or appropriate.

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

for an injection depth waiver process. If you have any questions regarding these

comments, please contact me at (602) 250-3225 or by email atScott.Davis@aps.com.

Scott L. Davis,

Director Environmental Health and Safety, APSLetter ID: 0363

Commenter: Scott L. Davis

Organization: Arizona Public Service Company (APS), Environmental Health and Safety

Letter ID: 0363 Comment ID: 28269 Letter Lines: 17 to 21

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

Comment: Arizona Public Service Company (APS) owns or operates a number of fossil fuel

‐

fired power plants, including two large coal

‐ fired power plants. APS strongly

supports aggressive research and development of viable methods for carbon

capture and sequestration (CCS) projects and for reuse CO2 from fossil

generation plants. APS has worked with Westcarb and other Arizona utilities on a

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: 0363 Comment ID: 28270 Letter Lines: 21 to 25

Comment Code: 2400 2.4. Other Research Offered by Commenters (seeking comment)

Comment: generation plants. APS has worked with Westcarb and other Arizona utilities on a

DOE funded project to drill an experimental CO2 sequestration test well at our

Cholla Power Plant near Holbrook, Arizona. APS has also recently received

funding from DOE to study the feasibility of reusing CO2 from the plant to grow

algae that later can be processed into liquid transportation fuels.

Individual Response: EPA acknowledges the submittal. EPA is aware of the Cholla GS project described

and will continue to review studies of this nature. EPA intends to continue to collect data on GS and to

incorporate such data and information as it implements its adaptive approach to the GS rulemaking to

incorporate new research, data, and information about GS. For more information on the adaptive

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

Letter ID: 0363 Comment ID: 28273 Letter Lines: 65 to 72

Comment Code: 2400 2.4. Other Research Offered by Commenters (seeking comment)Comment: coal

‐ fired power plants. Over the last two years APS has worked with Westcarb

and other Arizona utilities on a DOE funded project to drill an experimental CO2

sequestration test well on our Cholla Power Plant property near Holbrook,

Arizona. APS also recently received funding from DOE to study the feasibility of

a fully integrated energy system for beneficial CO2 use. The CO2 produced by the

power plant is fed directly to an algae farm, which consumes CO2. The algae will

then be processed into liquid transportation fuels (e.g. biodiesel, ethanol, and

military fuel), constituting a beneficial reuse of CO2.

Individual Response: EPA acknowledges the submittal. EPA is aware of the Cholla GS project described

and will continue to review studies of this nature. EPA intends to continue to collect data on GS and to

incorporate such data and information as it implements its adaptive approach to the GS rulemaking to

incorporate new research, data, and information about GS. For more information on the adaptive

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

Letter ID: 0363 Comment ID: 28274 Letter Lines: 74 to 90

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

Comment: APS strongly supports aggressive research and development of viable methods for

carbon capture and sequestration (CCS) projects and for reuse CO2 from fossil

generation plants. EPA predicts that the electric power sector "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). As a result of our involvement

in this research and because of the potential for impact to our industry APS

believes we have the knowledge and perspective to provide meaningful comments on

the development of EPA's UIC regulations for CO2 geologic sequestration.

APS appreciates EPA's careful approach to the development of the C02 geologic

sequestration regulations, including this most recent release of additional

data. Because the technology is still being developed and may not be

commercially deployed for many years, it is essential that the rule be flexible

in order to accommodate later developments in information and technology.

Performance based standards allow for requirements that can be tailored for the

differences in geology and other site characteristics across the country.

Individual Response: 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 dataas it implements its adaptive approach to GS rulemaking. 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.

For additional information on the adaptive approach and site specific requirements, see the responses

to comments on the proposed rule in the rulemaking docket.

The other portion of 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: 0363 Comment ID: 28275 Letter Lines: 92 to 100

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

Comment: APS supports EPA's proposal to adopt a flexible waiver process to allow for CO2

sequestration above and between underground sources of drinking water (USDWs).

74 Fed. Reg. at 44810. In Arizona we are just beginning to investigate the

potential for geologic storage sites. In the case of the project at our Cholla

Power Plant, C02 injection was planned below any USDW. However, to the north of

our plant favorable geologic storage sites may be located between USDWs. The

data on water quality is sparse in these deeper units. Allowing for a waiver

gives us increased flexibility to pursue good storage sites that are not beneath

all USDWs.

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. EPA agrees that a flexible, site

‐ specific approach to waiver

determinations (and all Class VI permitting decisions) is appropriate. Site

‐ specific demonstrations of

injection zone integrity along with proper well construction, operation, monitoring, and post closure site

care are the best way to ensure USDW safety while allowing flexibility for GS above or between USDWs.

EPA believes that the additional requirements that apply to owners or operators of Class VI wells

granted a waiver of the injection depth requirements will provide additional considerations for the

owner or operator and Director when permitting such wells to ensure protection of all USDWs.

The Agency believes the waiver approach: 1) responds to concerns about local and regional geologicstorage 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: 0363 Comment ID: 28276 Letter Lines: 102 to 107

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

Comment: Because of the importance of the waiver proposal APS asks that EPA consider

requiring the inclusion of this waiver provision, rather than leaving the

adoption of an injection depth waiver process to the discretion of the

individual UIC Program Directors. 74 Fed. Reg. 44811. Inclusion of a waiver

provision would still leave UIC Program Directors free to decline to grant any

waivers where not necessary or appropriate.

Individual Response: EPA clarifies that adoption of the waiver process remains at the discretion of

individual UIC programs. Therefore, States, Territories, and Tribes seeking primacy for Class VI wells are

not required to provide for injection depth waivers in their UIC regulations and may choose not to make

this process available to Class VI wells under their jurisdiction. 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 in a specific State, Tribe, or Territory 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.