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.Comments on Proposed Rule 40 CFR Parts 144 and 146 Federal Requirements Under the Underground Injection Control (UIC) Program for

Carbon Dioxide (CO 2 ) Geologic Sequestration (G S) Wells: As published in the Federal Register July 25, 2008

James J Dooley

Senior Staff Scientist Joint Global Change Research Institute Pacific Northwest National Laboratory December 9, 2008

PNNL-18059

Comments on the proposed Class VI GS CO 2 storage proposal are divided into three sections. “Tier 1 Comments” address large th ematic issues that cut across many sections of the proposed rule. “Tier 2 Comments” are comments on narrower topics within the proposed rule, while “Tier 3 Comments” ar e less consequential comments including suggestions for word changes to improve the clarity of the proposed rule.

1

# Tier 1 Comments

Proposed Requirement of Computational Models to Support Permit Is Extremely Appropriate Requirement The USEPA should be commended for requiring the use of computa tional models as a part of the permitting process and for the renewal of permits as well as a means of demonstrating compliance with the permit. These computational models are sufficiently well developed at this point in time that they can provide a ro bust set of technical information that will be needed for issuing Class VI permits. While the use of these models is a highly technical en terprise and will most likely be something that permitees will contract out, the cost of using these models is trivial compared to the capital cost of a complete end to end CCS system or the co st of purchasing enough emissions offsets to

cover the CO 2 emissions from something like a large power plant over its multidecade lifetime if that facility chose not to implement CCS. It is extremely appropriate to require the use of these sophisticated st ate of the art modeling tools.

Page 43506. The USEPA should also be commended for explicitly ruling out the use of simple “fixed radius or simple mathema tical computations” to compute the AOR for large scale GS projects. S ophisticated computational t ools exists which can do AOR calculations while taking into account a larg e number of key variable and processes.

These tools and not a back of the envelope calculation should be required. It is appropriate for EPA to explicitly forbid the use of these simple methodologies for Class VI AOR. By disallowing these si mple methods, the USEPA is not materially increasing the cost of employing CCS. While this argum ent might be put forward by others as a reason to keep these simple AOR tools, it is extremely hard to imagine a private sector firm risking billions to tens of billions of dollars of capital needed to construct and operate a CCS-enabled power pl ant or industrial facility w ithout employing sophisticated geochemical/geomechanical tools to assess a pr ospective GS reservoir. So the USEPA is simply asking for access to data that will most likely already exists with the applicant and is therefore not creating a ne w cost for CCS deployment.

Page 43507. The USEPA specifically asks for comments on the appropriateness of allowing proprietary models to be used in s upport of a Class VI permit. There is nothing wrong with using proprietary models. The test as to whether it is appropriate to use proprietary models (or “open community” mode ls) should be whether these models are seen by the USEPA and the technical commun ity as providing robust, accurate, and useful results. It is much more important to understand a model’s tr ack record in this regard than to ask for documentation of “code assumptions, relevant equations, and

scientific basis.” Given th e inherent complexity of these models, asking for “code assumptions, relevant equations, and scientific basis” could result in the submittal of an extremely long technical document that is so dense it will not be read or the submittal of a very superficial treatment of the model. The USEPA s hould -- without delay -- begin deliberations on methodologies that could be used to transparently establish the

robustness of these models and their results/outputs. This could be done – for example –

2through formal model intercomparisons using a set of test cases and repeating this process every couple of years. It will be fa r more useful to invest the time, thinking and if need be resources now to help estab lish which models are useful and for what applications than to request that each Class VI permit application include a detailed 100- 1000 page description of the model used and how key geomechanical/geophysical processes were parameterized. USEPA is str ongly encouraged to ch ange the focus here from a process oriented assessment of how these models work to a more outcome oriented measure of the perceived useful ness and robustness of these models by the technical community and other stakeholders (e.g., Wall Street) as useful tools for GS.

Filling in the Missing Linkages between Class VI Rule and a Larger National Climate Policy It is clear from the draft Class VI storage ru le that the USEPA was constrained to issuing the rule under the existing authorities it ha s via the Safe Drinking Water Act (SDWA). The federal employees who put together the cu rrent draft Class VI storage rule did an admirable job of staying within the confines of the author ities granted by the SDWA and in doing so produced a draft rule for CO 2 storage that helps to answer many key questions

about how CO 2 storage will be regulated w ithin the United States.

However, there are still many, many critical issues that need to be addressed that go beyond the statutory authority granted by the SDWA. If EPA does not begin to address these issues, the resulting lack of clarity is potentially as large of a stumbling block for the commercial deployment of CCS technologies as would be the case if there was not this well thought out draft of the Class VI rule.

One simple to articulate but difficult /complex to answer question that must be resolved

is: Is compliance with the requirements of a Class VI well rule sufficient to establish

that CO 2 has not been emitted to the atmosphere for the purposes of accounting for a firm’s annual CO 2 emissions and therefore a ssessing that firm’s compliance with future climate policy?

It is clear that the answer to this question is not a simple “yes” or “no.” For example, there are good GS reservoir management practices that could lead to the intentional,

controlled release of some previously injected CO 2 that would not be consistent with creating verified CO 2 emissions reductions.

As the USEPA revises and finalizes this draf t Class VI rule, it must begin to devote significant attention to these issues an d begin to communicate and dialogue with

numerous classes of stakeholde rs to get their input on how compliance with the Class VI rule will be integrated into a larger national climate policy.

Page 43520. As correctly noted by the USEPA in the draft Class VI rule, the financial responsibility requirements of the SDWA do not extend to activiti es not related to

3protection of USDWs. So this is another example of the need to understand what else is

needed to take this Class VI rule and make it part of a national climate policy.

On the Issue of Primacy: An Example of the Challenge Inherent in “Filling in the Missing Linkages between Class VI Rule and a Larger National Climate Policy” Given the need to link the issuance and comp liance with a Class VI injection permit to a larger national climate policy and eventually the need to link that U.S. national climate policy to an international climate policy regi me, careful consideration should be given about how high the bar should be set for gr anting primacy to States, Territories, and Tribes. There is a significant imperative to make sure that CCS derived emissions reductions are comparable (and more precise ly fungible) with GHG emission reductions obtained by implementing other greenhouse gas mitigation technologies and measures. A delicate balance must be sought between the desi re to delegate authority to the local level with a need to preserve a sufficient level of national uniformity in how CO 2 storage is carried out in practice . At a very minimum, the USEPA needs to recognize and reject as insufficient such reasoning that says becau se a state has shown that it can handle the Class II program they should also be given pr imacy for Class VI wells. The requirements to eventually integrate this proposed Class VI rule which in its present form is bounded by the SDWA into a much larger climate prot ection regulatory structure implies that the decision to grant primacy must be deliberate and must explicitly take account of how it would complicate the smooth and efficient functioning of a national climate policy.

The degree to which EPA changes what is pr oposed as a common fe deral rule for Class

VI CO 2 storage wells because some states might be further along in the development of

their own CO 2 storage regulations (see for exampl e discussion of “Who implements the UIC program” p. 43497) must also take into account the need for an owner/operator of CCS infrastructure to eventually be able to take CO 2 injected under a class VI permit in Ohio, Georgia, Michigan, California, Washi ngton State, etc. and turn that into a tradable/fungible emissions reduction credit (or a verified non-emi ssion) that could be used to satisfy the requirements of a nationa l climate policy. The degree to which the

federal class VI CO 2 storage policy should be amended to allow for discrepancies in how

individual states are currently planning on regulating CO 2 storage must take into account the need to create an economically efficient national climate change policy. This consideration goes well beyond the boundaries of the SDWA but it must be addressed by the USEPA as a whole if this proposed Class VI storage rule is to be put into practice (e.g., if this issue is not resolved it is ha rd to see the private sector motivation for deploying CCS technologies even if the Class VI rule is in place).

Page 43504 . In laying out its reasoning for why it did not select Regulatory Alternative Number 1 as the basis of the proposed Cla ss VI rule, the USEPA correctly notes that there is value in having a common federal approach as there are many potential CCS adopters that will operate faciliti es in numerous different states . This is true and it is appropriate for USEPA to note this . It is also important to realize that there are numerous reasons for pursuing a common federal approach and that decision will cascade through

4numerous parts of the proposed rule and how it is implemented in practice and how it is integrated into a future national climate policy.

On Allowing Class II EOR and Class VI GS to Evolve on Parallel Tracks: An Example of the Challenge Inherent in “F illing in the Missing Linkages between Class VI Rule and a Larger National Climate Policy”

The USEPA is to be commended for resis ting numerous calls from a number of

stakeholders to fit GS CO 2 storage into the existing framework for CO 2 -driven enhanced oil recovery (EOR). It is cr itically important that all st akeholders understand that these are very different processes with distinct infrastructures and operating practices and which are driven by different economic motives. The fact that they both inject CO 2 into the deep subsurface is not a sufficient reason to treat CO 2 -driven EOR and GS CO 2 storage in the same regulatory manner (s ee page 43502, “Why is EPA Proposing to Develop a New Class of Injection Well for GS of CO 2 ?” as well as the section on that same page “How Would this Proposal Aff ect Existing Injection Wells Under the UIC Program?)

Page 43502 . Again, the USEPA should be commende d for critically thinking through the extent to which Class II EOR pr actices and future Class VI CO 2 storage are similar in practice. Allowing for the possibility of conve rsion of Class II wells into Class VI wells is a reasonable step to take which might, in a very limited number of instances in specific regions of the U.S., lower the cost of comply ing with the proposed Class VI rule. And the proposed Class VI rule is correct in clearly stating that only the construction requirements could be grandfathered assumi ng that all other aspects of the proposed Class VI rule are fulfilled (e.g., identifying and remediating all ar tificial penetrations within the AoR). This is a clear demonstration that the USEPA understands that simply injecting CO 2 into the deep subsurface does not mean that Class II CO 2 driven EOR and Class VI GS are the same thing. However, it is not clear if the USEPA has gone far enough in differentiating between these two pr actices. In particul ar, the proposed Class VI rule should be explicit as to whether hydrocarbon recovery will still be allowed for wells/fields that have been permitted under Clas s VI. That is, a class VI well that is injecting CO 2 in order to drive oil or natural gas towards adjacent production wells is not completely consistent with the overarching goal of the Class VI rule of permanently isolating CO 2 from the atmosphere (i.e., some of the injected CO 2 will come up with the produced oil or gas, in some cases significant quantities of the injected CO 2 will come up the production wells). The USEPA should consid er whether it should explicitly state that the “grandfathering” of the construction requirem ents for Class II wells is also contingent upon the cessation of hydrocarbon production proce sses. Should this grandfathering only be allowed in depleted oil and gas fields that are no longer go ing to be used for enhanced hydrocarbon recovery and will exclusively be used for CO 2 storage? This issue of grandfathering of Class II wells must also be a part of EPA’ s needed deliberations about what else it needs to do in terms of rule ma king that lies outside of the SDWA to make

CO 2 stored in accord with the Class VI rule into something that can be used in the accounting framework of a na tional climate policy program.

5On the Appropriateness of Allowing CO 2 Storage above a USDW It seems that the overriding principle should be does the proposed Class VI rule help protect the wellbeing of humans and the health of the environment. Framing the issue in this way makes it clear that there is an e xplicit tradeoff being made about the use of

USDWs for CO 2 storage or the use of water beari ng bodies that have more than 10,000

TDS but are shallower than another formati on which has waters with less than 10,000

TDS. This calls for a flexible and site or region specific approach as opposed to an arbitrary criterion like “thousa nds of feet between the inj ection zone and overlying and underlying USDWs” ... ( page 43512 ) If there are adequate caprocks above and below the “water bearing bodies that have more than 10,000 TDS but are shallower than another

formation which has waters with less th an 10,000 TDS” that should be a key (and explicitly noted in the final Class VI rule) criterion for deciding whether to allow a

formation to be used for CO 2 storage.

The USEPA, as a whole, and not just the Office of Water that administers the UIC program, will likely need to create a transp arent methodology for deci ding whether it is better to use some specific deep saline-water bearing formations (total dissolved solids exceeding 10,000 mg/L) as repositories for anthropogenic CO 2 or not. This is a complex decision that goes beyond the confines of the SDWA as one would not only need to consider the potential human uses for these waters (e.g., as a potential source of potable water via desalinization) or as a CO 2 storage formation. Th is methodology should also

take into account whether th ere are other potential large scale and economic means of reducing CO 2 emissions that could be employed to offset potential emissions and whether

there are other bodies of water that could be treated to prov ide a more economical source of potable water. The methodology should be broader and more meaningful than simply asserting that either CO 2 is injected into a given form ation or it is vented to the atmosphere. The calculus here is more complex and nuanced.

The USEPA should also explain what authority it has (or needs to be given) to ensure that any future wells (oil, gas, water, injection) that drill through a wa ter bearing formation with greater than 10,000 TDS which ha s previously been used for CO 2 storage are built to withstand the higher pressures and acidit y of these formations without becoming pathways for the migration of previously stored CO 2 out of the target storage formation. If the USEPA has no way of regulating the construction of production wells that penetrate through a water bearing form ation that has been used for CO 2 storage and if it believes that it will not be granted this author ity, then this needs to bear on decisions to allow storage in formations that are shallower than a USDW.

Lastly, it is important to note that my rese arch group has performed preliminary analysis which sheds light on the extent to which this might be a significant issue. We have included a copy of this research along with our comments on the class VI rule. There are two points that are worth summarizing briefly here.

o First, these are preliminary results. We st ress that point because there is a lack of high quality and detailed data that would be needed to present a more rigorous analysis. This lack of high quality data is likely to persist for a very long time.

6o Second, it is clear to us from this anal ysis that the nation’s ability to cost effectively address climate change will not be significantly impacted regardless of whether the USEPA allows injection into formations that are shallower than the lowermost USDW or not, as the vast majority of the nation’s geologic CO 2 storage capacity is in formations that do not fall into this category (i.e., most DSF storage formations lie below the lowermost USDW). Having said that, it is clear that certain regions of the country might see their ability to deploy CCS

constrained if the USEPA disallows the use of formations shallower than an USDW. While these impacts will be localized and region-specific it could be consequential for certain regions, firms, st ates and could narrow their portfolio of options for reducing CO 2 emissions to the atmosphere.

o This research of ours is documented in:

 CL Davidson, Dooley JJ, and RT Dahowski. 2008. "Assessing the Impacts of Future Demand for Saline Groundwater on Commercial Deployment of CCS in the United States." In the Proceedings of the 9thInternational Conference on Greenhouse Gas Technologies. PNNL-SA63047, Pacific Northwest National Laboratory, Richland, WA.

 CL Davidson, JJ Dooley, SA Finne, RT Dahowski. February 2008. "How do salinity constraints impact the U.S. CO 2 storage resource?" Joint Global Change Research Institute, Pacific Northwest National Laboratory. Richland, Washington. PNNL-SA-58998.

On page 43503 , the EPA requests comment on whether GS CO 2 storage in coal seams which lie above a USDW should be categoric ally prohibited. In keeping with the discussion above, it seems that a more robus t set of metrics and a broader framework should be employed rather than a blanket prohib ition. If there is a suitable coal seam that is isolated above and below by strong caprock s and if EPA has the ab ility to influence / control how drilling th rough this formation in the future might occur then there’s no obvious reason to prohibit a Class VI application. It would be more rigorous and more in keeping with the spirit of the SDWA to establ ish a set of technical benchmarks that need to be satisfied rather than seemingly ruling certain GS applications out. This comment also applies to the proposed prohibition on injection into “Other Formations” ( p. 43503 ); rather than creating an inflexible prohibit ion USEPA should work to establish rigorous

benchmarks and thresholds that woul d need to be satisfied to allow CO 2 storage in these

formations. If these benchmarks are difficu lt to satisfy because there is solid reasoning for creating higher thresholds, then that woul d have the same impact as a prohibition but still leave the door open for technologi cal progress to make it feasible.

In the actual text of the proposed rule’s definition of key terms ( page 43535 ), a geologic storage project is specifically defined as one in which wells are used to “emplace a

carbon dioxide stream beneath the lowermost US DW.” Was this inte ntional to rule out these other practices that are mentioned in the preamble as items that are still under discussion, by defining a GS project in this narrow manner in the draft rule language?

7Costs of Compliance with Class VI Rule Seem Methodologically Problematic On page 43524 EPA acknowledges that there is a need to revisit the Cost Analysis. EPA is commended for recognizing this need and is encouraged to consider fundamentally modifying large aspects of the Cost Analysis of this proposed class VI rule in subsequent revisions. The following is a selection of methodol ogical issues in th e economic analysis of this rule that argue in favor of re thinking the approach used here and making significant revisions for subseque nt versions of the proposed Class VI rule. Suggestions to consider when revising th e cost analysis include:

o Page 43525 . I see no rigorous basis for asser ting that 22 projects will deploy in 25 years. It would be far better to pr esent costs for a range (high, medium and low) of CCS deployment scenarios and then explain the basis of these scenarios.

o Page 43527. I also do not understand the rationa le for assuming that a power plant would only capture half of its lifetime emissions. Why was that deemed to be an appropriate assumption to make?

o Page 43527. This page includes a reference to a research paper from my technical group as the basis for “we can use a long term average estimate of $3/tonCO 2 ” for transportation costs. This research pape r of ours does not speak to that specific monetary figure so I am not sure where that number comes from. There could be many instances where the cost of CO 2 transport via a pipeline falls outside this $3/tonCO 2 range.

o Page 43528 . The conclusion that “monitoring requirements account for 60 percent of the incremental regulatory costs, of which 70 percent is incurred for the construction, operation, and maintenance of monitoring wells” is likely heavily influenced by the assumption that there would be three monitoring wells for each injector well. The assumption that ther e are three monitoring wells per injector well is a significant cost driver. It is not clear that this would hold true in a field with multiple injector wells; for example a five spot injection pattern would require 15 monitoring wells, which could be excessive. For GS projects that have very large injection fields with numerous injector wells there is no reason to

believe that this 3:1 ratio would hold tr ue. USEPA should consider modeling out a number of different deployment scenarios to see how robust this assertion is.

This seems to be a worthwhile effort as this is the largest cost component caused by this Class VI rule and therefore this es timated cost is one that could receive a good deal of attention. My sense is that ad hering to this 3:1 ratio exaggerates the cost of the proposed Class VI rule.

o Page 43530 . It is important to note that th e determination as to whether this proposed rule will cost the public and or the private sectors more than $100 million in any given year is a function of the pace of CCS deployment which is something that will be driven by future climate policy. If there is no future national climate policy, then the cost of co mplying with this new rule should be close to $0. If there is a very tight / constraining clim ate policy, the cost could be significant. The USEPA is encouraged to model out a number of different climate policies and then assess what the incrementa l cost of complying with this rule is rather than basing the cost on assumptions about there only being 22 pilot projects over the next 25 years. Without doing this calculation, there is no way of

8knowing how robust the assertion is that th e cost of complying with the proposed rule will not exceed $100 million in any given year.

o Page 43527 . The text here says that it is “unlikely that all coal plants would deploy CCS simultaneously.” Not only is it “unlikely” it is simply impossible. There is no reason to hypothesize such a future deployment scenario and the computed results are meaningless for the purpose of public policy making. There is also no need to approach this particular calculation in this manner. My research group has completed a number of studies (as have other research groups) that could bound realistic CCS deployment rates. It is far better to use something within the realm of the possi ble as a basis for informing / justifying this important rule making. See for example:

o MA Wise and JJ Dooley. 2008. “The Value of Post-Combustion Carbon Dioxide Capture and Storage Technologies in a World with Uncertain Greenhouse Gas

Emissions Constraints.” International Journal of Greenhouse Gas Control. In

press.

o Dooley JJ, RT Dahowski, and CL Da vidson. 2008. "Comparing Existing Pipeline Networks with the Potential Scale of Future U.S. CO 2 Pipeline Networks." In the Proceedings of the 9th International Conference on Greenhouse Gas Technologies. PNNL-SA-62187, Pacific Northwest National Laboratory, Richland, WA.

o Wise MA, JJ Dooley, RT Dahowski, and CL Davidson (2007). “Modeling the impacts of climate policy on the deployment of carbon dioxide capture and geologic storage across electric power regions in the United States." International Journal of Greenhouse Gas Control. Volume 1, Issue 2, April 2007, Pages 261-270. doi:10.1016/S1750-5836(07)00017-5

o Dooley, James, J.; Davidson, Casie L.; Wise, Marshall A.; Dahowski, Robert T. “Accelerated Adoption of Carbon Dioxide Capture and Storage within the United States Electric Utility Industry: the Impact of Stabilizing at 450 ppmv and 550 ppmv.” In, ES Rubin, DW Keith and CF Gilboy (Eds.), Greenhouse Gas Control Technologies, Volume I (pp. 891-899). Elsevier Science, 2005.

Demonstrating Sufficient CO 2 Storage Capacity Page 43536. The draft Class VI rule states that the applicant is requi red to identify “An injection zone of sufficient areal extent, thickness, porosity, and permeability to receive the total anticipated volume of the carbon dioxide stream.” This is a good requirement but it is incomplete. There needs to be some time element here. That is the proposed rule needs to address “total anticipated volume” over what period of time. There is no need to establish an arbitrary quanti tative figure here (e.g., “over 40 years”). Rather the calculation could be predicated on the expected lifetime of the facility, the duration of the injection permit, etc. It would be prudent to modify this sentence to explicitly

communicate that the USEPA was not consider ing “the total anticip ated volume of the carbon dioxide stream” for any given year of operations.

9Lack of Clarity throughout Dra ft Rule with respect to the “CO 2 Stream” Page 43493 and 43535 . The draft Class VI rule has not adequately specified the critical concept of the “CO 2 Stream.” There are many instances in the rule where critical decisions are made with respect to the “CO 2 stream,” but this term itself is not well

defined nor does it seem to be consistently used.

o Page 43497 . Under “Potential USDW Impacts” the text says that the “CO 2 stream” may contain other impurities and lists as an example H 2 S.

o Page 43493 . The Definition of “Geologic Sequestration” only speaks to CO 2 being injected.

o Page 43496 contains a discussion about whether CO 2 is a commodity or a pollutant. This issue of whether CO 2 is a commodity or a pollutant is a red herring as far as this Class VI GS rule is concerned and EPA should be commended for saying that its ability to regulate CO 2 injection under the SDWA is not contingent on determini ng whether it is a commodity or a pollutant. However, the rule is neve r very clear about what an acceptable

“CO 2 stream” is.

o Pages 43503 and 43504. Are a bit clearer on what is and is not a “CO 2 stream” in the context of a Class VI well but it still is not clear what is

allowed and what is not.

o Page 43535. Defines the “carbon dioxide stream” as CO 2 from an anthropogenic source “plus incidental a ssociated substances derived from the source materials and the capture process” as well as any tracer s. This is more precise as it clearly would rule out the intentional co mingling of other gaseous waste products that were not derive d from the primary anthropogenic CO 2 point source. Yet it still hinges on the rather vague concept of “incidental”.

The issue of how pure the “CO 2 stream” needs to be and whether trace or more significant quantities of other ga ses or liquids can be injected into a Class VI well is a

critical issue that will influence the over all economics of CCS and could impact the safety and efficacy of GS. Greater clarity on th is issue (while still a llowing for some sitespecific flexibility) would help the business community better understand what the cost of using CCS will be. The USEPA is encouraged to continue trying to narrow the

definition of the “CO 2 stream” in subsequent versions of the draft rule. While this is a

difficult issue and there is no obvious “corr ect answer”, USEPA is encouraged to continue research and dialogues with various stakeholders to see if a narrower definition of what degree of co-injection is allowable for a Class VI well. It is possible that it could take many years maybe even decades to finali ze this but it is important to begin pursuing

it now.

No Minimum Injection Depth Specified Page 43511. It is difficult to envision that there will be widescale deployment of CCS

that would utilize formations that are shallow enough to favor injection of CO 2 as a gas and not as supercritical fluid. It seems that a better way to approach this from a regulatory standpoint would be to require injection at depth th at would call for injection

10as a supercritical fluid but to allow the Dire ctor to waive that requirement for cause and that the waiver would be contingent on the Class VI permitee satisfying additional requirements designed to ensure that the overarching goals of the SDWA and other environmental policies are fulfilled.

It seems odd and inconsistent to not specify a minimum depth when CO 2 is being injected into a water bearing formation that is belo w the lower most USDW, but EPA is proposing

that there would need to be “thousands of feet between the injection zone and [BOTH] the overlying and underlying USDWs .” (p. 43512). The overarching goal of the Class VI rule making is to protect USDWs and human health and welfare. If CO 2 is buoyant and there are concerns about it migrating out of the target injection zone, it doesn’t seem consistent to specify a minimum depth in one relatively small s ubset of potential GS applications (injection of CO 2 into a formation above the lowermost USDW) but not define a minimum depth for the vast major ity of GS applications (injection of CO 2 below the lower most USDW).

Lastly, perhaps “depth” is t oo narrow of a concept of what is being discussed here. “Deeper than any USDW and not in communication (i.e., not connected hydrodynamically or via faults or other intrusions) with any USDW” or “Deeper than any

USDW and geochemically and geomechanically isolat ed under current and modeled coand post-injection conditions with any USDW” seems much closer to the mark in terms of protecting what society wants protected.

It is Appropriate to Utilize both a Fixed Time Frame and Performance Standard for Establishing the Period of Post Closure Monitoring Given humanity’s knowledge about GS deployed at the scale of millions of tons per year for decades at a given injection field is quite slim, the USEPA’s proposal of a fixed time frame in conjunction with a performance standa rd appears to be an appropriate balance between discharging its responsibilities to pr otect human health and the environment and not placing overly burdensome, unneeded re quirements on prospective GS owner / operators (pp 43519-43520). The 50 year time frame will allow owners / operators to budget for post site closure within the bounds of what is currently known. The performance standard is an assurance to the public that a site will not be released until it has reached a certain point of stability. Given where humanity is with GS, the USEPA should be commended for crafting this compro mise and should retain this language in subsequent versions of this draft Class VI rule.

Requirement to Document GS Sites and Pass that Information on to Future

Potential Users of the Land Above as we ll as any Subsurface Zones Is Appropriate Page 43541. It is appropriate for the USEPA to require that steps be taken to document

the CO 2 injection formation and to ensure that information is passed on into the future. The steps spelled out here ar e reasonable and not overly burdensome (e.g., survey plat

11and deed for land must include a notation that the deep subsurface was used for CO 2 storage). This language should be retained in subsequent ve rsions of the Class VI rule.

All Wells and “All Known Wells” are not the Same Page 43507 and 43517. The proposed Class VI rule needs to be much more precise in its use of language in a couple of key areas. Th e rule requires an applicant for a Class VI permit to “identify all artificial penetrations.” What exactly does this mean? Is it all

known artificial penetrations (the rule speak s to the operator “review(ing) available information”)? What is the test for what is a known well or available information (does it require detailed field surveys or does one only need to do a qu ick search of a database of wells drilled in the area)? If on the othe r hand it means literally all human penetrations, then one must ask if this is technologically possible (e .g., are there technologies which

would allow for the identification of a small diameter non-steel walled well that has no visible surface features)? Is there a danger in asking for something that can not actually be delivered? One can guess what was likely meant by “identify all artificial penetrations” in terms of drafting this rule but it is not at all cl ear how this would be opperationalized at actual pr ospective GS sites.

More importantly on Page 43535 under “144.55 Co rrective Action”, the rule says that owners/operators need to identify the locat ion of “all known wells” which seems to be a

lesser standard. In the actual text of the rule (page 43526), the applicant is told “Only information of public record is required to be included on this ma p.” Given how many times the rule and its preamble talk about old wells being a potential conduit for CO 2 release from the storage formation, this seem s like an overly lax threshold. It would seem appropriate to require the applicant survey the actual site itself for artificial penetrations that might not be in the public record (the survey could include a number of different methods / tools). Further on in th is section, the applicant is asked to submit a

“tabulation of all wells within the area of review which penetrate the injection or confining zones.” Again, “all wells” and “all known wells” and how much work does one need to do to determine if they have tried to find “all the wells” must be better

articulated in the final rule. This same kind of language shows up on page 43537 within

the discussion of the Area of Review and Corrective Action.

Lastly, given the large amounts of money involved in a commercial CO 2 storage project,

I would think that the electric production, oil and gas, or ot her large industrial company contemplating a large CCS-ena bled facility would want (or be required) to go beyond simply collecting existing data as a way of decreasing risk and uncertainty. In this context, the proposed “requirement” for goi ng beyond existing data could be imposed by

entities other than state or federal environmental regulat ors and could be imposed by shareholders, a public utility commission, or a fi rm’s own board of directors. In terms of abandoned wells, it seems likely that commerci al firms would see it to be in their own

best interest to do some ki nd of physical search / assessm ent of whether there are any

known or unknown wells within the area of review gi ven the relatively minor cost associated with something like an aerial magnetic survey versus the costs associated with

12loss of CO 2 and any fines, the cost associated with any required post-leak age activities, or simply the cost of litigation and or lo ss of good will associated with such sloppy management of a critical, capital in tensive pollution abatement facility.

In this same section (page 43526), the appli cant is asked to submit information on “the presence and depth of seismic sources” but this falls under a heading that is limited to the “proposed storage site and overlying formations .” So if a proposed GS site sat 10 cm, 10m or 10km north of any aspect of the New Madrid Fault, that would not be noted in the application. Limiting the scope of data colle ction to the boundaries of the project site might not be appropriate for data related to “the presence and depth of seismic sources”

It Should Be a Requirement to Periodically Revaluate Funds Set Aside for Well Plugging and Post-Injection Site Care Page 43520. The USEPA should mandate that ow ners / operators peri odically update the cost estimate for well plugging, post-injection s ite care, ect. Given how long GS projects are likely to last, there is no reason to believe that the am ount of money set aside at the start of the project even if it were invested in something that kept up with inflation would necessarily be sufficient to cover these costs. The US DOE Energy Information

Administration in its An nual Energy Outlook: 2007 (http://www.eia.doe.gov/oiaf/aeo/otheranalysis /cecei.html) documented how drilling and

other associated costs have esca lated at a rate that is far a bove the core inflation rate for the economy as a whole. On page 43522, the draft rule says “Trying to determine the cost for post injection site care, possible 30 to 50 years in the future, could be difficult...” Yes, it is difficult to understand what anyt hing would cost 50 years in the future. However, one can figure out what it would co st to do those things now and then one could periodically reassess thos e costs. That is quite straightforward and the USDOE’s EIA maintains a Oil and Gas Lease Equipmen t and Operating Costs Index which could easily be used to true up these costs as needed to account for inflation (see http://www.eia.doe.gov/pub/oil_gas/natural _gas/data_publications/c ost_indices_equipme nt_production/current/cost study.html). The Oil and Gas Jour nal also publishes indices of

construction costs which could be used to tr ue up these costs over the life time of a GS project. Again, there are many reasons to mandate that these costs be revised periodically and if need be the correspondi ng financial assurance mechanisms should be revalued.

90% of the Injection Zone or the Caprock’s Fracture Pressure Page 43510 under “Proposed Injection Well Operating Requirements.” Citing the IOGCC report and the expert op inion of permit writers is no t the most rigorous basis for asserting that injection pressure can not exceed 90% of fracture pressure for all GS applications. Perhaps in a Notice of Data Availability (NODA) for this rule, USEPA could ask for data or studies that would help establish a firmer basis for this threshold. This is an important criteria as it directly impacts how much CO 2 can be put down a given well and therefore how many wells will be needed to handle the anthropogenic CO 2

13from a given facility. The number of injector wells is a key determinant of the cost of

CO 2 storage. On page 43538, this same language is found in the proposed rule text (i.e., not in the preamble).

More importantly did the USEPA intend to tie th is 90% pressure threshold to the fracture pressure of the “ injection zone ” or the fracture pressure of the “primary caprock / seal above the injection zone”? If a GS project was injecti ng at the bottom of a 500 meter

thick interval of a sandstone , is there any harm in allowing for some amount of deformation to areas near the injection point in the target formation? In many areas, the caprocks are stronger than the injection z ones based on the rock types, degree of cementation etc. In such cases, it may be good to have a mechanism where you can stimulate the injection zone more aggressive ly to increase permeability / injectivity. Fracturing of the injection zones may be cri tical in improving inje ction performance and even in making some of the marginal injectivity sites into viable sites.

It Is Appropriate to Require Class II Fields to be Recertified before Conversion to

Class VI Fields Page 43512. It is appropriate for the USEPA to require a new aquifer exemption for a formerly Class II injection field if there is a desire to use that field for GS. EPA should retain this requirement in the final rule . Just because a formation was deemed appropriate for Class II activit ies, does not guarantee that it is suitable for GS and therefore EPA is right to ask fo r more fact finding and potentia lly remediation of artificial penetrations before allowing the formation to be exempted and used for GS.

Allowing the Director the Discretion to Ask for Additional Fact Finding on Supplemental Confining Layers Page 43505-43506. EPA specifically asks for comments on allowing the Director to require that additional confining zones be id entified for certain proj ects. Assuming that the Director uses this authority to require more fact finding for cause (i.e., it is not a capricious request), then it seem s as if USEPA has struck an appropriate balance here and should retain this flexibility in the final rule . Given the capital cost of something like an IGCC+CCS, it does not seem unreasonable to as k that cores be taken from a second or third overlying caprock if there is some reason to want to ensure that there are additional containment systems beyond the caprock immedi ately above the target injection zone. While the USEPA might receive comments sayi ng that this is potentially a significant unknown cost that could delay CCS deployment, th e cost of this additional fact finding islikely denominated in the millions of dollars or less while the rest of the complete end-toend CCS facility could be worth tens of billions of dollars. Again assuming that this flexibility is only used when needed and for cause, it seems to be an appropriate and cost effective tool for ensuring the overall goals of the Class VI program are fulfilled.

14Dialogue between the Regulated and Regulator Isn’t Obvious The draft Class VI rule and especially the pr eamble assert numerous times that a key to ensuring the safety and efficacy of geologi c sequestration is a well functioning dialogue between the regulated entity and the regulat ory agency. There are at least three intertwined concerns I have with the way the cu rrent draft Class VI rule is written that if left unresolved would hamper a robust, mean ingful dialogue between the regulated entity and the regulator has been created by this rule. 1) The concept that there is “working” re lationship between the permitee and the permit-granting agency doesn’t really come through here. This seems like a very arms length relationship. 2) The draft rule never establishes that the process of moving from initial site selection to permitting, to operations to renewal of permits to closure is an iterative one between the ope rator and the EPA or state permit writer (acting as stewards of the public’s welfare) as new data are generated and incorporated into the site management plan. That is, the rule could do a much better job of explaining that the permittee and the regul ator should be learning a great deal about how a particular geostorage field is operating in practice and that this knowledge will be factored into how the fiel d is regulated in the future (including decisions about post closure). 3) Data is collected but it is not clear how it is used by th e regulator nor is it clear who has access to this data. In particul ar, there appears to be only two instances (one at the very earliest stages of site selection and the other before site closure) where the public is invited to learn and comment on a GS project.

Given that humanity is in the early days/dec ades of CCS deployment, it seems to me that much could be learned by having closer and more frequent communication between the regulator and owner/operator of a GS project, and allowing for some dissemination of the massive amount of data generated by these pr ojects. A more transparent and meaningful dialogue between these two parties would also help with stakeholder acceptance of CCS.

Much Data Is Collected; But how is it used and who has access to the data?

o Page 43514 includes a requirement that m echanical integrity be demonstrated annually, but it does not say what is done w ith this information or what it is used for. How long is this data retained?

o Page 43514 includes a requirement that ow ners / operators report semi-annually on the injection pressure, flow rate, temper ature, volume and annular pressure and

on MIT test results. What is the data collection method and who will have access to these data? Is it an open website like the Toxic Report Inventory (TRI) where any citizen could view this information, or is it a single hard copy report locked in a state or regional EPA office that can only be seen via a FOIA request by members of the public or other stakeholders?

o Page 43514. EPA asks for “comments on the requirements for monitoring” but it is not clear that there are any require ments articulated here. The USEPA should require that data on the areal extent of the CO 2 plume and the pressure front as well as any other relevant data from MMV be reported to EPA on an annual /

15semi-annual basis. USEPA still must come to some consensus on how these data will be collected, who will have access to them, ect.

o Page 43514 under “Monitoring CO 2 Movement and Reservoir Pressure”, USEPA states that the owner/operator must compar e the results of monitoring to baseline data but the text of the pr oposed rule does not require that this information be shared with the USEPA or state permitting ag ency. Isn’t this critically important information on how GS is working at a si te? Isn’t that information needed by

USEPA to understand whether the Class VI rule is effective in protecting USDWs and the other goals of the SDWA? There should be a requirement that this data and comparison be shared with regulators.

o Page 43517 contains a requirement to repor t various data on the performance of GS on a semi-annual basis, but again it is not clear how these data will be used, retained, or who ha s access to them.

o Page 43538. Owners and operators of Class VI wells are required to install and use continuous recording de vices to monitor a number of critical performance

variables. The rule does not specify how long these data are to be retained and

who has access to them.

Who has access to reports on an ongoing GS project?

o Page 43517. It is asserted that the requirement for “monitoring, testing, AOR, and corrective action” plans will help establish “an ongoing dialogue between the operator and the permitting authority.” This reviewer just doesn’t see this “dialogue” in this rule. There is no di scussion of how these plans are used and

therefore this looks like a very distant and at arms le ngth process. I am 100% in support of there being an ongoing dialogue between the operator and the regulator and I believe that these additional plans are a wise requirement for Class VI GS

wells.

o Page 43517. Records retention of only 3 y ears after site closure. That seems incredibly short. Also it is not clear how this requirement to hold on to these data for three years after site closure is consistent with the owner operators requirement to discharge its respons ibilities under the pos t closure period including establishi ng that non-endangerment continue s to be the case. Wouldn’t access to baseline and data collected during the period of principal operations be needed to report out these findings during the period of post closure. This short record retention period also seems to undercut assertion of a open continuous dialogue being a center piece of how USEPA and any states that have Class VI primacy will ensure public safety.

o Page 43517. USEPA asks for comments on electronic reporting. Yes, electronic reporting should be mandatory. USEPA also needs to find a way to ensure that electronic reports are eventually consolid ated at a national level. Having the reports be submitted to a state but not having the reporting go any further will frustrate efforts to improve our knowle dge about how CCS works in practice and

it will frustrate efforts to cost effectiv ely include GS in to the structure of a national climate policy. Page 43529. The USEPA should consider whether a requirement of being granted primacy for Class VI wells would be a requirement

to share data collected at the state or Tribal area with the federal USEPA. EPA

16Stakeholder Input and the Periodi city of this Involvement

o Page 43520. The draft rule states “Duri ng this 50 year pe riod, the owner or operator would be required to submit peri odic reports...” What’s the periodicity of these reports? A layperson would likely see this as a more meaningful step to regulate GS if the periodicity was annually as opposed to once every 15 years. I do not intend to imply that annual reporti ng is the appropriate periodicity but by not specifying the interval the value of th is as a regulatory tool or a means of building public trust in nascent GS technologies is largely gutted.

o Page 43520. The draft rule seems to imply that the draft site closure plan would be made publically available. That is fi ne and appropriate, bu t the rule does not address what data will be made publically available when the GS project is being planned or during its operational phase. I do not see how the USEPA can be silent on this point.

o Pages 43522-43523 contain an explicit discu ssion of public involvement in GS projects. This passage says that a summary of this pre-construction public involvement activity would become part of the public record. So the rule says that something at the very earliest stages of a GS project and something at the very end are public documents, but it is not clear what data during the 30-50 year operational life of the project are publically available.

Page 43523. EPA explicitly asserts that because it (or a state that has primacy) has such a rigorous on-going dialogue with owners/operators that it is prudent to issue injection permits “for the life of the GS project includ ing the post-injection site care period.” This very consequential decision hinges upon wh ether or not there truly is an ongoing dialogue that is substantive and happens with enough frequency to allow problems to be detected and remediated quickl y. I am not sure that I see this dialogue as being that

robust.

Page 43528. The proposed Class VI rule states “The information gathered as a result of this proposed rule .... allows the Agency to verify throughout the life of the injection project that UIC protective requirements are in place and that USDWs are protected.” At the end of the day, this is indeed the figure of merit. Does this rule allow for sufficient exchange of information between the owners/ operators of GS projec ts and regulators and stakeholders (?). This reviewer is not c onvinced that this metric is satisfied by the proposed rule.

17

# Tier II Comments

• Page 43497. To the extent that EPA will revise this preamble language, please consider ending the section on “Potential US DW Impacts” with a new sentence that reaffirms that the purpose of this proposed rule is to put in place regulations, best practices, enforcement mechanisms, etc. to ensure that all of the previously mentioned bad things that could go wrong with a CO 2 storage project do not take place. This reviewer thinks that given the nega tive tone of much of the material in this section it is appropriate for the USEPA to re inforce the point that the purpose of this

rule is to ensure that CO 2 storage is done safely thus significantly reducing if not eliminating the extent to which a ny of these things actually happen.

• Page 43495 under “Why is Geologic Sequestra tion Under Consideration...”. Please change sentence which says in part “The capture and storage of CO 2 would enable the

continued use of coal in a manner that ...” The first deployments of CCS are not going to be at coal fired elec tric power plants. There is no reason for this rule to be overly focused on coal based CCS applications and is not appropriate for this Class VI UIC rule since it is bounded by the SD WA which means that the source of CO 2 is not a critical aspect of this rule. Focusing on coal can also bring in a lot of ancillary (although important) issues surrounding the us e of coal like mining practices that do

not need to be discussed within the bounda ries of a proposed Class VI UIC rule. CCS is more than just coal.

• Page 43498. Second paragraph on that page. “However, some CO 2 releases from injection activities have been documented.” Crystal Geyser is not an “injection activity” as that term is used in the context of this Class VI rule . The text in that paragraph makes it clear that the CO 2 which erupts from Crystal Geyser is from “improper well plugging.” It is technically inaccurate, misleading and prejudicial to start off this paragraph by saying “some CO 2 releases from injection activities have

been documented.”

• Page 43498. The USEPA is to be commended for the passage here on Lake Nyos and Lake Monoun and in particular for the forcef ulness with which the draft Class VI rule makes it clear that these are not analogous to CO 2 injected into a deep geologic

formation.

• Page 43498, section on “Seismic Events.” The first sentence in this section is clearly speaking to the potential for CO 2 injection to cause seismic activity in the future when commercial deployment of CCS becomes more common place. However, the second sentence and the subsequent discussion of induced seismicity at the Rocky Mountain

Arsenal are not related to CO 2 injection. To be clear, it was not CO 2 that was being injected into deep geologic formations be neath the Rocky Mountain Arsenal. If this section of the preamble is re tained in future versions of this proposed rule, this

section must be rewritten to make it clear th at the technical literature suggests that

18poorly managed CO 2 injection could in the future induce small scale seismic activity. And then if there is a need to discuss previ ous instances where injection of fluids that

were not CO 2 triggered seismic activity the language needs to be clear and explicit so

the reader understands that these are not past instances of poor CO 2 injection.

• Page 43503. While it is a widely held belief that much more is known about depleted oil and gas (DOG) fields within the US as opposed to DSFs, it is not at all clear if this is true or significant in terms of the proposed Class VI rule or in terms of the decision making process a private firm would use to decide whether to utilize DOG or DSF

fields in a commercial CO 2 storage project. To the ex tent that there is more known about DOG fields, much of this data is proprietary and is in the hands of oil companies and oil field service companies. For more than a decade members of the CCS community have been seeking access to this presumed treasure trove of geologic

data to build a national CO 2 storage reservoir data base with this presumably high quality data. But the data have not been released, likely due to legitimate private

sector concerns over protec ting valuable proprietary information or perhaps this wealth of easily exploitable high quality data do not exist at these firms. So if the data exist but are not available, it seems immaterial to assert here that a significant cost savings could be had by exploiting DOG fields. This has not been proven in practice and I believe it might not ever be proven out in practice.

• Page 43509, last full paragraph on that page. The text here seems to imply that the

cement used for CO 2 storage wells will be eaten away by “acid” in one week. This is one example of a number of places in the rule where – perhaps inadvertently in the editing process – it seems as if text was deleted that would ha ve helped a reader understand that “we are now discussing a sc ientific study that has some bearing on the topic at hand but isn’t exactly like GS ” and “now are switching to an explicit discussion of what the USEPA will require of owners and operators of GS projects.” If this text is retained in subsequent in terations of the Class VI rule it would be good to explain why this study is germane to regulating GS in the United States and whether the same thing is expected to happe n in practice. If cements in wells are going to fail in a week, then there isn’ t much point in promulgating this rule.

• Page 43511. The USEPA does a good job of explaining why the cost of requiring

down hole shut off valves should not be seen as being overly burdensome for potential operators of GS sites. While the logic and data presented here seem convincing and make the point, it seems that a cost/benefit calculation might be a secondary issue. If the USEPA believes that these down hole shut off valves are needed to discharge its responsibilities under the SDWA (i.e., protect USDWs) then that should be the primary reason. The USEPA should not need to defend requirements needed to carry out its responsibilities under the SDWA with cost/benefit analyses.

• Page 43513. EPA should not requir e that tracers be used in all GS applications across the very heterogeneous set of deep geologic formations that could be used to store

CO 2 in the USA. The USEPA (and in partic ular the Office of Air and Radiation)

19might want to consider doing full life-cycle analyses of the manufacture, storage, use and potential leakage of trac ers to help better inform the technical community about the cost / benefits of using this one class of MMV technologies.

• Page 43515. It strikes this reviewer as odd to cite only one study (Burton et al, 2007) to support the statement that “current monitoring technologies are more than adequate for monitoring pressure in a GS project.” It is not clear if by including this in the preamble to the draft rule whether EPA shares this assessment or not. This seems like an awfully broad and sweeping statement. Consider rewording. Consider being explicit as to whether EPA shares this view or if part of any NODA associated with this rule making should try to collect information that goes beyond this one study to confirm or refute this assertion that pr essure monitoring technologies which exist today are sufficient to meet any GS need in any kind of formation anywhere and at any time across all regions of the USA.

• Page 43516. It is not clear if the USEPA is asserting that usi ng “seismic crosswell methods” are “costly and time consuming” or if that is a finding of the GEO-SEQ (2004) report mentioned at the start of this paragraph. If it is the latter then it is important to clearly attribute that statement to the authors of the GEO-SEQ report. Otherwise, it appears that the USEPA is calling into question the cost effectiveness and utility of a technique that has yet to be robustly tested with respect to GS. That would seem to be a premature assumption based only on the results of the GEO-SEQ project, since crosswell seismic could be a preferred option for some sites where alternative options are impractical or economi cally infeasible. This section contains a number of implicit references to cost/benef it calculations for m onitoring technologies.

If the USEPA believes that these tec hniques are needed to discharge its responsibilities under the SDWA, then that should be stated and these techniques should be required. The text could say so mething about encouraging technological progress in the hopes of coming up with less costly but equally effective monitoring technologies, but it does not seem appropr iate to try and justify some actions by alluding to cost benefit analyses as the basis for decision making.

• Page 43519. Consider explicitly referencing the work laid out by Benson to support the statement that physical and geochemi cal trapping mechanisms will help to improve the integrity of storage as time moves forward. This is a critically important – but widely misunderstood – point about how GS will work in practice. It would be good to include at least one citation to tech nical work to back up this point.

o OTC 19244. Multi-Phase Flow and Trapping of CO 2 in Saline Aquifers. Sally M. Benson, SPE, Stanford Universi ty. Copyright 2008, Offshore Technology Conference This paper was prepared for presentation at the 2008 Offshore Technology Conference held in H ouston, Texas, U.S.A., 5–8 May 2008.

• Page 43521. The text here briefly mentions on going analysis of “pay-in periods for

trust funds” in the context of financial a ssurance. I do not un derstand the statement here that says “EPA is considering a gui dance approach that would recommend a pay in period of three years for GS projects.” “Three years” seems completely arbitrary.

20What would be the basis for the fee paid in those three years? Would it be a charge of $1/tonCO 2 or $50/tonCO 2 ? There is no way to unders tand the utility of a three year pay-in period without knowing much more about what costs this fund was supposed to cover, how the fee would be asse ssed, at what level would the fee be set, etc... We have recently completed an anal ysis that sheds light on a number of issues specifically related to trust f unds applied to GS and I beli eve it is potentially relevant to the USEPA’s ongoing evaluation of these issues. Please see:

o Dooley JJ, C Trabucchi, and L Patton. 2008. “Tipping Fees Can't Save us from the Tipping Point: The Need to Create Rational Approaches to Risk Management that Motivate Geologic CO 2 Storage Best Practices.” To be published in the Proceedings of th e 9th International Conference on Greenhouse Gas Technologies. Oc tober 2008. PNWD-SA-8349, Pacific Northwest National Laboratory, Richland, WA.

o Page 43530. The draft rule corr ectly states “S equestering CO 2 via injection wells is a voluntary action that would only be undertaken by an entity if it were in its interest compared to other alternatives it may have.” This point is worth repeating a number of times in this proposed rule. In par ticular, this might be worth repeating in discussions of what is required for Class VI wells and the cost of meeting these requirements. At times, it seems as if the USEPA is apologizing for requiring compliance with measures designed to protect USDWs. The USEPA should ask for the public and other stakeholders to perf orm a thorough and rigorous review of any proposed requirements but there is no need to apologize. As the draft Class VI rule makes clear, no one is being required to use GS. That is important to remember and likely bears repeating.

o What if any are the construction requiremen ts and mechanical integrity requirements for monitoring wells?

o Page 43531. The USEPA invites the public to identify peer reviewed studies that

assess the effects on infants and toddlers w ho are exposed to drinking water that has been degraded “by geologic sequestration of carbon dioxide.” The wording here seems to assume a number of key steps that I am not sure one can assert given where humanity is in terms of the commercial deployment of GS. This request for

information would be better if it requested information on studies that speak to the impact of drinking contaminated water by infants and toddlers caused by processes

that could result from a poorly functioning GS project at some point in the future. I do not see how there can be existing studies that show negative impacts on children from drinking water contaminated by a malfunctioning GS proj ect. It is worth comparing the language here with the far more balanced and accurate language on page 43532 where the USEPA forcefully asserts that the proposed rule will not have a disproportionate impact on minor ity and low-income populations.

o Page 43540 under “Post-injection site care a nd site closure.” The USEPA should ask for a seismic image or other data that depi cts the current extent and placement of the

CO 2 plume. The current language asks for “the predicted position.” If the EPA

21would like modeling of the predicted position for some purpose that is fine but there

is no reason not to ask for data that shows where the plume really is.

22

# Tier III Comments

• Page 43493, in the “Definitions.” Consider ation should be given to breaking the

definition of EOR/EGR into two different short paragraphs. The physical processes

as well as economic drivers involved in EOR and EGR are not strictly similar and it is not clear that these should be lumped togeth er in something like a federal regulation.

• Page 43495, third column, under “II What is EPA Proposing?” I believe the IPCC Special Report on Carbon Dioxide Capt ure and Storage (IPCC SR on CCS) and/or more recent peer reviewed papers can shed light on the timeframes under which primary and secondary trapping mechan ism begin to operate. Adding some quantification to this point would likely help stakeholde rs better understand and be

more familiar with CO 2 storage. Consider adding something like “Some of these trapping mechanisms begin as soon as the CO 2 is injected into the host formation while others take hundred to thousands of y ears to run their course.” I believe one

could cite the IPCC SR on CCS to substantiate that point.

• Page 43497 under “What are the risks associated with CO 2 GS?” I do not see any reason to include the modifier “likely” in the first sentence of “Potential USDW Impacts.” Under what set of circumstances would CO 2 injected into a water-bearing deep geologic formation not come into contact with formation waters? Delete “likely” from this sentence. It does not help readers understand CCS or how EPA will regulate CO 2 storage.

• Page 43497 under what are the “Potential USDW Impacts.” Please consider adding at the very end of this section a sentence that reaffirms for the reader that the fundamental purpose of the proposed Class VI ru le is to make sure that the bad things

above enumerated do not occur.

• Page 43502, third sentence under “How W ould this Proposal Affect Existing Injection Wells Under the UIC Program?” Pl ease consider being specific as to what kind of “production” is being discussed here. From the context of this sentence it would seem to be “production of oil” or perhaps “production of hydrocarbons” but it would not seem to cover “production of brackish waters for the purpose of desalination to provide pota ble water.” The phrase “a ny production” seems overly

vauge.

• Page 43505 within the discussion of CO 2 storage in coal seams. It is incorrect to state that “the process of CO 2 adsorption to the coal has not been proven.” This is well

established. I think what USEPA inte nded to say was something like “the commercial application of coal-based CO 2 storage has not been proven.” The fundamental principle of CO 2 adsorbing on the coal surface is established. Whether this is going to work in situ and at commercial scale has not been established / proven. Please consider rewording.

2324 • Page 43516. “Simulations discussed in the manual confirm seismic and ...” What

“manual”? It is not clear wh at is being discussed here.

• Page 43538. Does the USEPA (or states that have primacy for Class VI wells) really want to take physical possession of cores from prospective GS sites? The rule currently states “The owner or operator mu st take and submit to the Director whole cores or sidewall cores of the injection zone and confining system and formation fluid samples from the injection zone(s).” I unde rstand the requirement that the Class VI permit applicant needs to take cores and needs to perform tests upon them but wouldn’t it be more meaningful for the “Director” to receive a written summary of those tests and a description of the methodolog ies used in the testing of the cores than to literally take physical possession of the cores themselves? The USEPA should consider rewording this passage.

## This document is not availabl e in Regulations.gov since it contains copyrighted material that may not be reproduced without consent of the copyright holder.

Contact the EPA Docket Center, Public Read ing Room to view or receive a copy of this docu ment. Requests for copies may be

made as follows:

In person/writing: Environmental Protection Agency, Docket Center 1301 Constitution Ave NW, 2822T, Room 3334 Washington, DC. 20004

Telephone:

202-566-1744

Fax:

202-566- 9744

Email: docket-customerservice@epa.gov

## This document is not availabl e in Regulations.gov since it contains copyrighted material that may not be reproduced without consent of the copyright holder.

Contact the EPA Docket Center, Public Read ing Room to view or receive a copy of this docu ment. Requests for copies may be

made as follows:

In person/writing: Environmental Protection Agency, Docket Center 1301 Constitution Ave NW, 2822T, Room 3334 Washington, DC. 20004

Telephone:

202-566-1744

Fax:

202-566- 9744

Email: docket-customerservice@epa.gov

## This document is not availabl e in Regulations.gov since it contains copyrighted material that may not be reproduced without consent of the copyright holder.

Contact the EPA Docket Center, Public Read ing Room to view or receive a copy of this docu ment. Requests for copies may be

made as follows:

In person/writing: Environmental Protection Agency, Docket Center 1301 Constitution Ave NW, 2822T, Room 3334 Washington, DC. 20004

Telephone:

202-566-1744

Fax:

202-566- 9744

Email: docket-customerservice@epa.govLetter ID: 0156 Commenter: James Dooley Organization: Joint Global Change Research In stitute, Pacific Northwest National Laboratory

Letter ID: 0156 Comment ID: 22616 Letter Lines: 40 to 70

Comment Code: 3310 2.2.1.1 Comments in favor of requiring computational models to delineate the AoR (seeking comment)

Comment: Proposed Requirement of Computational M odels to Support Permit Is Extremely Appropriate Requirement

The USEPA should be commended for requiring the use of computati onal models as a part of the permitting process and for the renewal of permits as well as a means of demonstrating compliance with the pe rmit. These computational models are sufficiently well developed at this point in time that they can provide a robust set of technical information that will be needed for issuing Class VI permits. While the use of these models is a highl y technical enterprise and will most likely be something that permitees will contract out, the cost of using these models is trivial compared to the capital cost of a complete end to end CCS system or the cost of purchasing enough emissions offsets to cover the CO2 emissions from something like a large pow er plant over its multidecade lifetime if that facility chose not to implemen t CCS. It is extremely appropriate to require the use of these sophisticated state of the art modeling tools.

Page 43506. The USEPA should also be comm ended for explicitly ruling out the use of simple "fixed radius or simple ma thematical computations" to compute the AOR for large scale GS projects. Sophisti cated computational t ools exists which can do AOR calculations while taking into ac count a large number of key variable and processes. These tools and not a back of the envelope calc ulation should be required. It is appropriate for EPA to explicitly forbid the use of these simple methodologies for Class VI AOR. By disallowing these simple methods, the USEPA is not materially increasing th e cost of employing CCS. While this argument might be put forward by others as a reason to keep these simple AOR tools, it is extremely hard to imagine a private sector firm risking billions to

tens of billions of dolla rs of capital needed to construct and operate a CCSenabled power plant or industrial fac ility without employing sophisticated geochemical/geomechanical tools to assess a prospective GS reservoir. So the USEPA is simply asking for access to data that will most likely already exists with the applicant and is therefore not creating a new cost for CCS deployment.

Individual Response: EPA acknowledges the commenter’s suppor t and believes th at predicting the complex multiphase, buoyant flow of the CO 2, co-injectates, and compounds that may be mobilized due to injection requires the sophistica tion of computational models, as required at 146.84(c)(1). Models can predict CO2 fate and tr ansport, as well as changes in formation

1pressure, in three dimensions, as a function of ti me in order to delineate the subsurface storage site and the AoR. Models can account for site-specific and predicted operating conditions as well as geologic heterogeneities a nd potential migration through fau lts, fractures, and artificial penetrations.

Letter ID: 0156 Comment ID: 22617 Letter Lines: 72 to 96

Comment Code: 3350 2.2.1.5 Use of proprietary models for GS sites (seeking comment)

Comment: Page 43507. The USEPA specifically asks fo r comments on the appropriateness of allowing proprietary models to be used in support of a Class VI permit. There is nothing wrong with using proprietary m odels. The test as to whether it is appropriate to use proprietary models (o r "open community" models) should be whether these models are seen by the US EPA and the technical community as providing robust, accurate, and useful result s. It is much more important to

understand a model’s track record in this regard than to ask for documentation of "code assumptions, rele vant equations, and scien tific basis." Given the inherent complexity of these models, asking for "code assumptions, relevant equations, and scientific basis" could re sult in the submittal of an extremely long technical document that is so dense it will not be read or the submittal of a very superficial treatmen t of the model. The USEPA should -- without delay -- begin deliberations on methodologies that could be used to transparently

establish the robustness of these models and their results/out puts. This could be done - for example - through formal model intercomparisons using a set of test cases and repeating this process every couple of years. It will be far more useful to invest the time, thinking and if need be resources now to help

establish which models are useful and for wh at applications than to request that each Class VI permit application include a detailed 100-1000 page description of the model used and how key geomecha nical/geophysical processes were parameterized. USEPA is strongly encouraged to change the focus here from a process oriented assessment of how these m odels work to a more outcome oriented measure of the perceived usefulness a nd robustness of thes e models by the technical community and other stakeholders (e.g., Wall Street) as useful tools

for GS.

Individual Response: EPA agrees that some of the availa ble proprietary models may meet the needs for calculating the AoRs of GS sites. EPA will allow their use in meeting the requirements for the GS regulation, but clarifies that GS well operators using proprietary models are required to disclose, to the Director's sa tisfaction, the code assumptions, re levant equations, and scientific basis. EPA acknowledges that several proprietary models have been used by petroleum-reservoir engineering professionals as we ll as in peer-reviewed studies to model CO2 sequestration. EPA

adds that its Confidential Business Informati on requirements at 40 CFR 144.5 will apply to the use of proprietary models.

EPA does not plan to initiate a formal review of models or modeling methodologies, as the commenter suggests. Instead, EPA believes that it is appropriate to allow operators the flexibility

2to select modeling techniques that are most appropr iate to site conditions and available types and amounts of data. The owner or operator must de monstrate, in the proposed AoR and corrective action plan required at §146.84(b), to the satisfac tion of the Director, that the modeled AoR will be based on detailed geologic data collected on th e site. EPA anticipates that any model that does this in a satisfactory manner wi ll be approved by the Director . EPA acknowledges that modeling technology is expected to continuously improve , and encourages and expects owners or operators to use the best available multiphase computational models to determine the AoR. Reliance on improved models will likely incr ease the accuracy and quality of the AoR characterization, resulting in better pr otection of USDWs from endangerment.

Letter ID: 0156 Comment ID: 22618 Letter Lines: 98 to 114

Comment Code: 1430 1.2.1.2 Support EPA's authority to regulate CO2 injection

Comment: Filling in the Missing Linkages between Class VI Rule and a Larger National Climate Policy

It is clear from the draft Cl ass VI storage rule that the USEPA was constrained to issuing the rule under the existing au thorities it has via the Safe Drinking Water Act (SDWA). The federal employees who put together the current draft Class VI storage rule did an admirable job of staying within the confines of the authorities granted by the SDWA and in doing so produced a draft rule for CO2 storage that helps to answer many key que stions about how CO2 storage will be regulated within the United States.

However, there are still many, many critical issues that need to be addressed that go beyond the statutory authority gr anted by the SDWA. If EPA does not begin to address these issues, the resulti ng lack of clarity is potentially as large of a stumbling block for the commercial deployment of CCS technologies as

would be the case if there was not this well thought out draft of the Class VI

rule.

Individual Response: EPA clarifies that the scope of the GS regulation is limited to injection of CO2, and that all requirements in the GS rule are designed for the purpose of protecting USDWs from endangerment. The SDWA does not provide th e UIC Program with the authority to develop regulations for all areas related to GS, such as releases to the atmosphere.

EPA acknowledges that GS falls within the broade r context of CCS and the need for regulatory clarity to ensure that USDWs are protected from endangerment. In develo ping the final GS rule,

the Office of Water coordinated with other Agency program offices and across federal agencies (e.g., with the Department of Energy; United Stat es Geological Survey; Bureau of Ocean Energy Management, Regulation, and Enforcement, formerly the Minerals Management Service; Bureau of Land Management). The Agency continues to eval uate areas of potential applicability of other Federal environmental statutes including, but not limited to: the Clean Air Act; the Resource Conservation and Recovery Act; the Comprehe nsive Environmental Response, Compensation,

3and Liability Act; and the Marine Protection, Resear ch and Sanctuaries Act to various aspects of GS and CCS. The Agency will continue to coordinate on GS and CCS related issues to minimize redundancy and maximize efficiencies for owners or operators. For additional information, please see the discussion entitle d "How Does This Rulemaking Relate to Other Federal

Authorities and GS and CCS Activities?" in the preamble to the final GS rule.

Letter ID: 0156 Comment ID: 22619 Letter Lines: 116 to 131

Comment Code: 1540 1.2.3.2 Climate change legislation

Comment: One simple to articulate but difficult /com plex to answer question that must be resolved is: Is compliance with the re quirements of a Class VI well rule

sufficient to establish that CO2 has not been emitted to the atmosphere for the purposes of accounting for a firm’s annual CO2 emissions and therefore assessing that firm’s compliance with future climate policy?

It is clear that the answer to this ques tion is not a simple "yes" or "no." For example, there are good GS reservoir manageme nt practices that c ould lead to the intentional, controlled releas e of some previously injected CO2 that would not be consistent with creating veri fied CO2 emissions reductions.

As the USEPA revises and finalizes this dr aft Class VI rule, it must begin to devote significant attention to these i ssues and begin to communicate and dialogue with numerous classes of stak eholders to get their input on how compliance with the Class VI rule will be integrated into a larger national climate policy.

Individual Response: EPA acknowledges that carbon cred iting and greenhouse gas accounting are important issues. However, these issues are outside of the UIC Program's authority under the Safe Drinking Water Act and outside the scope of this rulemaking. The UIC requirements are designed to ensure that where GS is employed, it is done in a manner that protects USDWs from endangerment.

EPA acknowledges that GS falls within the broade r context of CCS and the need for regulatory clarity to ensure that USDWs are protected from endangerment. In develo ping the final GS rule,

the Office of Water coordinated with other Agency program offices and across federal agencies (e.g., with the Department of Energy; United Stat es Geological Survey; Bureau of Ocean Energy Management, Regulation, and Enforcement, formerly the Minerals Management Service; Bureau of Land Management). The Agency continues to eval uate areas of potential applicability of other Federal environmental statutes including, but not limited to: the Clean Air Act; the Resource Conservation and Recovery Act; the Comprehe nsive Environmental Response, Compensation, and Liability Act; and the Marine Protection, Resear ch and Sanctuaries Act to various aspects of GS and CCS. The Agency will continue to coordinate on GS and CCS related issues to minimize redundancy and maximize efficiencies for owners or operators. For additional information, please see the discussion entitle d "How Does This Rulemaking Relate to Other Federal

Authorities and GS and CCS Activities?" in the preamble to the final GS rule.

4In a separate rulemaking under authority of th e Clean Air Act, EPA is amending the Greenhouse Gas (GHG) Reporting Program at 40 CFR Part 98 to add reporti ng requirements for facilities that conduct GS (subpart RR) a nd all other facilities that in ject CO2 underground (subpart UU). For additional information, see the section of the final GS rule preamble entitled, "How Does Mandatory Reporting of Greenhouse Gases (GHGs) Relate to This Rulemaking?” and the GHG Reporting Program rulemaking and docket.

Letter ID: 0156 Comment ID: 22620 Letter Lines: 133 to 137

Comment Code: 5430 2.9.1 Comments on proposed financia l responsibility requirements (40 CFR 146.85)

Comment: Page 43520. As correctly noted by the USEP A in the draft Class VI rule, the financial responsibility requirements of the SDWA do not extend to activities not related to protection of USDWs. So this is another example of the need to

understand what else is needed to take this Class VI rule and make it part of a national climate policy.

Individual Response: EPA clarifies that the Class VI GS requirements are designed to ensure that, where deployed, GS is conducted in a ma nner that protects USDWs from endangerment. The requirements apply to owners or operators of injection wells used to inject CO2 for permanent storage. The Class VI GS rulemaki ng is promulgated under Safe Drinking Water Act authority and does not relate to any endangerm ent and cause or contribute findings under the Clean Air Act. The Class VI GS requirement s do not depend upon, and are unaffected by, Clean Air Act endangerment and cause or contribute findings.

Letter ID: 0156 Comment ID: 22621 Letter Lines: 139 to 177

Comment Code: 1540 1.2.3.2 Climate change legislation

Comment Code: 5600 2.11 Comments related to UIC Program primacy for Class VI wells

Comment: On the Issue of Primacy: An Example of th e Challenge Inherent in "Filling in the Missing Linkages between Class VI Rule and a Larger National Climate Policy"

Given the need to link the issuance and compliance with a Class VI injection permit to a larger national climate policy and eventually the need to link that U.S. national climate policy to an intern ational climate policy regime, careful consideration should be given about how high the bar should be set for granting primacy to States, Territories, and Trib es. There is a significant imperative

to make sure that CCS derived emissions reductions are comparable (and more precisely fungible) with GHG emission reductions obtaine d by implementing other greenhouse gas mitigation technologies and m easures. A delicate balance must be sought between the desire to delegate aut hority to the local le vel with a need to preserve a sufficient level of national uniformity in how CO2 storage is

5carried out in practice. At a very mini mum, the USEPA needs to recognize and reject as insufficient such reasoning that says because a state has shown that it can handle the Class II program they s hould also be given primacy for Class VI wells. The requirements to eventually integrate this proposed Class VI rule which in its present form is bounded by th e SDWA into a much larger climate protection regulatory structur e implies that the decision to grant primacy must be deliberate and must explicitly take account of how it would complicate the smooth and efficient functioning of a national climate policy.

The degree to which EPA changes what is proposed as a common federal rule for Class VI CO2 storage wells because some states might be further along in the development of their own CO2 storage regul ations (see for example discussion of "Who implements the UIC program" p. 43497) must also take into account the need for an owner/operator of CCS infrastructure to eventually be able to take CO2 injected under a class VI permit in Oh io, Georgia, Michig an, California, Washington State, etc. and turn that into a tradable/fungible emissions reduction credit (or a verified non-emission) that could be used to satisfy the requirements of a national climate polic y. The degree to which the federal class VI CO2 storage policy should be ame nded to allow for discrepancies in how individual states are currently planni ng on regulating CO2 storage must take

into account the need to create an economically efficient national climate change policy. This consideration goes well beyond the boundari es of the SDWA but it must be addressed by the USEPA as a whole if this proposed Class VI storage rule is to be put into practice (e.g., if this issue is not resolved it is hard to see the private sector moti vation for deploying CCS technologies even if the Class VI rule is in place).

Individual Response: EPA agrees that it is important to balance flexibility and national consistency. EPA clarifies that the primacy appr oval processes for Class II and Class VI differ. The SDWA directs EPA to grant primary enforcem ent responsibility (or primacy) to the States through two statutory provisions . The first provision, under Sec tion 1422, provides for States to demonstrate that their proposed UIC program is at least as stringent as the minimum Federal requirements in order to prevent endangerment of USDWs. The second provision, under Section 1425, allows States to submit an alternative demo nstration for their Class II programs (oil and gas) where the State only has to demonstrate th at its proposed Class II program is an effective program to prevent underground inj ection that endangers USDWs.

EPA acknowledges the expertise of state oil and gas agencies that have been regulating Class II

wells for decades under section 1425 of SDWA. These agencies already understand many of the issues pertaining to Class VI wells and ha ve experience with CO2 injection, subsurface operations, and pipeline transport, as well as familiarity with local interests and the SDWA. EPA assumes that this experience, along with the agencies' familiarity with UIC permitting requirements, will help facilita te the adoption of Class VI pr imacy programs and assumes that many states with Class II programs will choose to have the Class II primacy agency implement the Class VI program. However, EPA clarifies th at, while there are many similarities between Class II and Class VI wells, addition al requirements are needed to fully address the unique nature

6of Class VI wells for CO2 GS, and because GS wells are not oil and gas wells, they must be regulated under authority of Section 1422 of SDWA.

EPA believes that the requireme nt that states' regulations meet the minimum federal requirements will promote national consistency. To further ensure the final rule is applied consistently, EPA is developing guidance documents for states that describe the process of applying for and receiving primary enforcement re sponsibility (primacy) for GS Class VI wells under Section 1422 of SDWA, as we ll as the technical and admini strative issues on developing GS regulations that are the equivalent of minimum federa l criteria and requirements.

EPA acknowledges that some states and tribes ar e developing statutory frameworks, regulations, technical guidance, and strategi es for addressing broader issues related to CCS and GS, and encourages states to seek primacy for Cl ass VI wells to further these efforts.

EPA acknowledges that carbon crediting and gree nhouse gas accounting are important issues. However, these issues are outside of the UIC Program's authority under the Safe Drinking Water Act and outside the scope of th is rulemaking. The UIC requirement s are designed to ensure that where GS is employed, it is done in a manner that protects USDWs from endangerment. All of the requirements of the GS rule are for the purpose of protecting USDWs from endangerment, consistent with the UIC Progr am's authority under SDWA.

In a separate rulemaking under authority of th e Clean Air Act, EPA is amending the Greenhouse Gas (GHG) Reporting Program at 40 CFR Part 98 to add reporti ng requirements for facilities that conduct GS (subpart RR) a nd all other facilities that in ject CO2 underground (subpart UU). For additional information, see the section of the final GS rule preamble entitled, "How Does Mandatory Reporting of Greenhouse Gases (GHGs) Relate to This Rulemaking?” and the GHG Reporting Program rulemaking and docket.

Letter ID: 0156 Comment ID: 22622 Letter Lines: 179 to 187

Comment Code: 1540 1.2.3.2 Climate change legislation

Comment Code: 2320 1.7.2 Comments on Alternative 1

Comment: Page 43504. In laying out its reasoning fo r why it did not select Regulatory

Alternative Number 1 as the basis of the proposed Class VI rule, the USEPA correctly notes that there is value in ha ving a common federal approach as there are many potential CCS adopters that w ill operate facilities in numerous

different states. This is true and it is appropriate for USEPA to note this. It is also important to realize that th ere are numerous reasons for pursuing a common federal approach and that decisi on will cascade through numerous parts of the proposed rule and how it is implemente d in practice and how it is integrated into a future national climate policy.

Individual Response: As described above, EPA agrees that a consistent approach to regulating GS activities across the United States is important.

7EPA believes that the technical requirements in Regulatory Alternative 3 build upon the existing UIC regulatory framework for deep wells and ar e appropriately tailored to address the unique nature of full-scale CO2 GS, including the vol umes of CO2 being anticipated for long-term storage, the buoyant and mobile na ture of the injectate, and its corrosivity in the presence of

water.

This approach provides a foundation for nationa l consistency in permitting of GS projects, promotes USDW protection, incorporates flexibil ity or the discretion of the permitting authority when appropriate, and seeks to limit burden on ow ners or operators and permitting agencies. The tailored approach in this alternative (and the final GS rule) modifies the existing UIC requirements for site characterization, area of review, well construction, mechanical integrity testing, monitoring, well plugging, post -injection site care, and site closure, to address full-scale

GS.

Letter ID: 0156 Comment ID: 22623 Letter Lines: 189 to 209

Comment Code: 2046 1.5.2.3 Continuing to classify CO2 in jection for EOR/EGR as Class II/ dividing line between Class II and Class VI (seeking comment)

Comment: On Allowing Class II EOR and Class VI GS to Evolve on Parallel Tracks: An Example of the Challenge Inherent in "F illing in the Missi ng Linkages between Class VI Rule and a Larger National Climate Policy"

The USEPA is to be commended for resis ting numerous calls from a number of stakeholders to fit GS CO2 storage into the existing framework for CO2-driven enhanced oil recovery (EOR). It is cri tically important that all stakeholders understand that these are very different pr ocesses with distinct infrastructures and operating practices and which are driven by different economic motives. The fact that they both inject CO2 into the deep subsurface is not a sufficient

reason to treat CO2-driven EOR and GS CO 2 storage in the same regulatory manner (see page 43502, "Why is EPA Proposing to Develop a New Class of Injection Well

for GS of CO2?" as well as the secti on on that same page (How Would this Proposal Affect Existing Injecti on Wells Under the UIC Program?)

Page 43502. Again, the USEPA should be commended for critically thinking through the extent to which Class II EOR practices and future Class VI CO2 storage are similar in practice. Allowing for the possibility of conversion of

Class II wells into Class VI wells is a r easonable step to take which might, in a very limited number of instances in specific regions of the U.S., lower the cost of complying with the proposed Cla ss VI rule. And the proposed Class VI

Individual Response: EPA agrees that tailored requirements for Class VI wells are necessary to address the unique nature and risk s associated with injecting larg e volumes of CO2 and to ensure that USDWs are protected from endangerment. The GS rule contains tailored requirements for

8the permitting, geologic site characterization, AoR and corrective action, well construction, operation, mechanical integrity te sting, monitoring, we ll plugging, post-injection site care, and site closure of GS wells that directly address issues unique to the natu re of large-scale CO2 injection for GS.

EPA also agrees that the risk s posed by long term storage of CO2 for GS cannot be addressed under existing UIC requirements, such as those fo r Class II wells. EPA believes that there are significant differences between how projects are operated, as well as the risks posed by these different injection activities. The new tailored a pproach of the GS rule was designed to address the general risks deep injection may pose to USDW s and was tailored specifically to address the risks posed by long term storage of CO2 (i.e., very large volum es, very long time-periods, and reservoir pressure conditions).

The final Class VI regulations re quire that any owner or operato r injecting CO2 for the primary purpose of long term storage obtain a Class VI pe rmit with some special consideration for the fact that they are transitioning from a well not or iginally designed to meet Class VI requirements. The Director has the authority to determine at wh at point a Class VI permit is required for those projects that are transitioning from the primar y purpose of EOR to long term storage of CO2. The final regulation provides a set of technical factors for the Direct or to evaluate in making this determination, at §144.19. EPA believes that this approach provides su fficient protection of

USDWs when there is an increased risk to USDWs as compared to traditi onal Class II operations while allowing for site-specific flexibility. For more information, please see the discussion on transition of Class II wells in the preamble to the final GS rule.

Letter ID: 0156 Comment ID: 22624 Letter Lines: 210 to 234

Comment Code: 2064 1.5.3.2 Grandfathering construction of Class II wells (seeking comment)

Comment: rule is correct in clearly stating that only the construction requirements could be grandfathered assuming that all other aspects of the proposed Class VI rule are fulfilled (e.g., identifying and remedi ating all artificia l penetrations within the AoR). This is a clear demons tration that the USEPA understands that simply injecting CO2 into the deep subs urface does not mean that Class II CO2

driven EOR and Class VI GS are the same thing. However, it is not clear if the USEPA has gone far enough in differentia ting between these tw o practices. In particular, the proposed Class VI rule should be explicit as to whether hydrocarbon recovery will still be allowe d for wells/fields that have been permitted under Class VI. That is, a class VI well that is injecting CO2 in order to drive oil or natural gas to wards adjacent producti on wells is not completely consistent with the overarc hing goal of the Class VI rule of permanently isolating CO2 from the atmosphere (i.e., some of the injected CO2 will come up with the produced oil or gas, in some cases significant quantities of the injected CO2 will come up the production wells). The USEPA should

consider whether it should explicitly state that the "grandfathering" of the construction requirements for Class II wells is also contingent upon the cessation of hydrocarbon production processe s. Should this grandfathering only

9be allowed in depleted oil and gas fields that are no longer going to be used for enhanced hydrocarbon recovery and will exclusively be used for CO2 storage? This issue of grandfathering of Class II wells must also be a part of EPA’s

needed deliberations about what else it need s to do in terms of rule making that

lies outside of the SDWA to make CO2 stor ed in accord with the Class VI rule into something that can be used in the accounting framework of a national climate policy program.

Individual Response: EPA agrees that a cautious approach to grandfathering is appropriate, particularly given that the convert ed well will be used for a substa ntially different process, which involves increased reservoir pre ssures associated with large volumes of stored CO2 and the corrosivity of CO2 in the presence of water. Th e final GS rule provides for the construction of these wells to be grandfathered (per 146.81(c)). EPA has included a requirement in the final GS rule that owners or operators seeking to c onvert existing wells for long term storage must demonstrate to the Director that the grandfathe red wells were engineered and constructed meet the requirements at §146.86(a) and ensure prot ection of USDWs, in lieu of requirements at §146.86(b) and §146.87(a).

EPA adds that, following re-permitting as Class VI wells, these projects must be subject to the operational, MIT, monitoring, reporting, plugging, a nd post-injection site ca re and site closure requirements in the final GS rule. EPA belie ves this is necessary, because following repermitting of the project as GS, many of the uniqu e factors of GS sites (e.g., increased reservoir pressures associated with large volumes of st ored CO2 and the corrosivity of CO2 in the presence of water) will result in an increased risk profile, warrant ing the specific requirements in

the final GS rule.

The final Class VI regulations re quire that any owner or operato r injecting CO2 for the primary purpose of long term storage obtain a Class VI pe rmit with some special consideration for the fact that they are transitioning from a well not or iginally designed to meet Class VI requirements. The Director has the authority to determine at wh at point a Class VI permit is required for those projects that are transitioning from the primar y purpose of EOR to long term storage of CO2. The final regulation provides a set of technical factors for the Direct or to evaluate in making this determination, at §144.19. EPA believes that this approach provides su fficient protection of

USDWs when there is an increased risk to USDWs as compared to traditi onal Class II operations while allowing for site-specific flexibility.

EPA is developing guidance on transitioning perm its from Class II to Class VI. The guidance will assist Directors in evaluating whether an in jection project should be transitioned from Class II where the primary purpose is oi l and gas production to Class VI where the primary purpose is long-term storage of large volumes of CO2. The guidance describes recommended methods the Director may use when determining changes in risk to USDWs from projects, and how the Director may determine whether a project should be regulated within th e Class II or Class VI UIC program. This guidance will be available on EPA’s website at http://water.epa.gov/type/groundwat er/uic/wells_se questration.cfm.

10EPA adds that GHG accounting and broader climate policy issues are outs ide the scope of the GS rulemaking.

Letter ID: 0156 Comment ID: 22625 Letter Lines: 236 to 311

Comment Code: 4410 2.4.4.3.1 Comments in favor of allowing injection above/between

USDWs in certain circumstances

Comment: On the Appropriateness of Allowi ng CO2 Storage above a USDW

It seems that the overriding principle shoul d be does the proposed Class VI rule help protect the wellbeing of humans and the health of the environment. Framing the issue in this way makes it clear that there is an explicit tradeoff being

made about the use of USDWs for CO2 stor age or the use of water bearing bodies that have more than 10,000 TDS but are sh allower than another formation which has waters with less than 10,000 TDS. This calls for a flexible and site or region specific approach as opposed to an arbitrary criterion like "thousands of feet between the injectio n zone and overlying and underlying USDWs" - (page 43512) If there are adequate caprocks above and below th e "water bearing bodies that have more than 10,000 TDS but are sh allower than another formation which has waters with less than 10,000 TDS" that should be a key (and explicitly noted in the final Class VI rule) criterion for deciding whether to allow a formation to be used for CO2 storage.

The USEPA, as a whole, and not just the Office of Water that administers the UIC program, will likely need to create a transparent methodology for deciding whether it is better to use some specifi c deep saline-water bearing formations (total dissolved solids exceeding 10,000 mg/L ) as repositories for anthropogenic CO2 or not. This is a complex decision that goes beyond the confines of the SDWA as one would not only need to consid er the potential human uses for these waters (e.g., as a potential source of potable water via desalinization) or as a CO2 storage formation. This methodology s hould also take into account whether there are other potential large scale and economic means of reducing CO2 emissions that could be empl oyed to offset potential em issions and whether there

are other bodies of water that could be treated to provide a more economical source of potable water. The methodology s hould be broader and more meaningful than simply asserting that either CO2 is injected into a given formation or it is vented to the atmosphere. The calcul us here is more complex and nuanced.

The USEPA should also explain what authority it has (or needs to be given) to ensure that any future wells (oil, gas, water, injection) th at drill through a water bearing formation with greater th an 10,000 TDS which has previously been used for CO2 storage are built to withsta nd the higher pressures and acidity of these formations without becoming pathwa ys for the migration of previously stored CO2 out of the target storage formation. If the USEPA has no way of regulating the construction of production wells that penetrate through a water

11bearing formation that has been used for CO2 storage and if it believes that it will not be granted this authority, then this needs to bear on decisions to allow storage in formations that are shallower than a USDW.

Lastly, it is important to note that my research group has performed preliminary analysis which sheds light on the extent to which this might be a significant issue. We have included a copy of this research along with our comments on the class VI rule. There are two points that are worth summarizing briefly here.

o First, these are preliminary results. We stress that point because there is a lack of high quality and deta iled data that would be n eeded to present a more rigorous analysis. This lack of high quali ty data is likely to persist for a very long time.

o Second, it is clear to us fr om this analysis that the nation’s ability to cost effectively address climate change will not be significantly impacted regardless of whether the USEPA allows injection into formations that are shallower than the lowermost USDW or not, as the vast majority of the nation’s geologic CO2 storage capacity is in formations that do not fall into this category (i.e., most DSF storage formations lie below the lowermost USDW). Having said that, it is clear that certain regions of the count ry might see their ability to deploy

CCS constrained if the USEPA disallows the use of formations shallower than an USDW. While these impacts will be locali zed and region-specific it could be consequential for certain regions, firm s, states and could narrow their portfolio of options for reducing CO 2 emissions to the atmosphere.

o This research of ours is documented in:

CL Davidson, Dooley JJ, and RT Dahowski. 2008. "Assessing the Impacts of

Future Demand for Saline Groundwater on Co mmercial Deployment of CCS in the United States." In the Proceedings of the 9th International Conference on Greenhouse Gas Technologies. PNNL-SA- 63047, Pacific Northwest National Laboratory, Richland, WA. [SEE PD F TO VIEW THIS DOCUMENT.]

CL Davidson, JJ Dooley, SA Finne, RT Da howski. February 2008. "How do salinity constraints impact the U.S. CO2 storage reso urce?" Joint Global Change Research Institute, Pacific Northwest National Laboratory. Richland, Washington. PNNLSA-58998. [SEE PDF TO VIEW THIS DOCUMENT.]

Individual Response: EPA recognizes that there is increa sing demand for water resources and that technology improvements may make high TDS aquifers viable drinking water sources. EPA believes these potential resources should be considered when inje ction depth waivers are sought. Therefore, the final GS rule at §146.95(b) requir es the Director to consider these issues in determining whether an injection depth waiver is appropriate.

EPA adds that the GS rule re quires that the Director, in ev aluating whether a waiver is

12appropriate, must consider planned needs, pot ential and/or future use of USDWs and nonUSDWs in the area; along with whether alternative injection s ites are available; community needs, demands, and supply from drinking water resources; and a plan for securing alternative resources or treating USDW formation waters in the event of contamination related to the Class VI injection activity.

EPA clarifies that the purpose of the GS rule is to protect any formations that meet the definition of a USDW where GS is to be employed. It is not the intent of the GS rule to evaluate the tradeoffs for the use of deep saline formations.

EPA is not changing the USDW definition; changing the definition of a USDW is outside the scope of the GS rulemaking. The GS rule focuse s on ensuring protection of USDWs, as required under the SDWA, by establishing regul ations to ensure the safe in jection of CO2 for long-term storage. For additional informati on on the waiver approach and aquifer exemptions for Class VI wells, please see the final rule and preamble, as well as EPA's responses to comments on the Notice of Data Availability and Request for Comment.

Letter ID: 0156 Comment ID: 22626 Letter Lines: 313 to 329

Comment Code: 4430 2.4.4.3.3 Injection into coal seams above USDWs (seeking comment)

Comment: On page 43503, the EPA requests comment on whether GS CO2 storage in coal

seams which lie above a USDW should be categoric ally prohibited. In keeping with the discussion above, it seems that a more robust set of metric s and a broader framework should be employed rather than a blanket prohibiti on. If there is a

suitable coal seam that is isolated ab ove and below by str ong caprocks and if EPA has the ability to influence / contro l how drilling through this formation in the future might occur then there’s no obvious reason to prohibit a Class VI application. It would be more rigorous a nd more in keeping w ith the spirit of

the SDWA to establish a set of technical benchmarks that need to be satisfied rather than seemingly ruling certain GS applications out. This comment also applies to the proposed prohibition on in jection into "Other Formations" (p. 43503); rather than creating an inflexible prohibition USEPA should work to establish rigorous benchmarks and thresholds that would need to be satisfied to allow CO2 storage in these formations. If these benchmarks are difficult to satisfy because there is solid reasoni ng for creating higher thresholds, then that would have the same impact as a prohibition but still leave the door open for technological progress to make it feasible.

Individual Response: The final GS rule does not categorica lly preclude or prohibit injection into any type of formation, including coal se ams. Instead, the requirements are designed to ensure protection of USDWs from endange rment through proper siting, well construction, operation, monitoring, and PISC at all sites selected for GS.

EPA recognizes that some types of formations, such as coal s eams and basalts, are typically

13shallow and above the lowermost USDW. EPA exp ects that most injection wells conducting GS in these shallow formations will be permitted as Class VI wells and such wells will be issued waivers, provided that their owners or operators can meet all of the requirements for an injection depth waiver at §146.95 and demonstr ate that such injection can be performed in a manner that protects USDWs, as long as appropriate protec tions are in place. The Class V experimental technology well classification, may, in some instan ces be an appropriate permitting alternative. This decision should be informed through a di scussion between the injection well owner or operator and the Director to determine the purpose and proper design of the well.

For additional information on the waiver approa ch and aquifer exemptions for Class VI wells, please see the final rule and pr eamble, as well as EPA's responses to comments on the Notice of Data Availability and Request for Comment.

Letter ID: 0156 Comment ID: 22627 Letter Lines: 331 to 336

Comment Code: 1220 1.1.1.1 Terminology and definitions

Comment: In the actual text of the proposed rule ’s definition of key terms (page 43535), a geologic storage project is specifically defined as one in which wells are used to "emplace a carbon dioxide stream beneath the lowermost USDW." Was this intentional to rule out these other practices that are mentioned in the preamble

as items that are still under discussio n, by defining a GS project in this

narrow manner in the dr aft rule language?

Individual Response: EPA disagrees with the suggested edit and retains the language: "emplace

a carbon dioxide stream beneath the lowermost USDW." EPA has modified the definition of geologic sequestration project to read as follows: “Geologic sequestration project means an injection well or wells used to emplace a carbon dioxide stream beneath the lowermost formation containing a USDW; or, wells used for geologic sequestration of carbon di oxide that have been granted a waiver of the inject ion depth requirements pursuant to requirements at §146.95; or, wells used for geologic sequestration of carbon di oxide that have received an aquifer exemption expansion. It includes the subsurface three-dime nsional extent of the carbon dioxide plume, associated pressure front, and displaced brine, as well as the surface area above that delineated region.”

Based on its evaluation of all public comments and input on the proposed rule and the NODA and Request for Comment EPA has made many revisions to the Cla ss VI GS rule. Please see the final rule and preamble for additional information.

Letter ID: 0156 Comment ID: 22628 Letter Lines: 338 to 363 ; 382 to 426

Comment Code: 6200 3.2 Comments on costing methodology

Comment: Costs of Compliance with Class VI Rule Seem Methodologically Problematic

14On page 43524 EPA acknowledges that there is a need to revisit the Cost Analysis. EPA is commended for recognizi ng this need and is encouraged to consider fundamentally modifying large as pects of the Cost Analysis of this proposed class VI rule in subsequent revi sions. The following is a selection of methodological issues in the economic analysis of this rule that argue in favor of rethinking the approach used here and making significant revisions for subsequent versions of the proposed Class VI rule. Suggestions to consider when revising the cost analysis include:

o Page 43525. I see no rigorous basis fo r asserting that 22 projects will deploy in 25 years. It would be far be tter to present costs for a range (high, medium and low) of CCS deployment scenario s and then explain the basis of these

scenarios.

o Page 43527. I also do not understand the ra tionale for assuming that a power plant would only capture half of its lifetime emissions. Why was that deemed to be an appropriate assumption to make?

o Page 43527. This page includes a reference to a research paper from my technical group as the basis for "we can use a long term average estimate of $3/tonCO2" for transportation costs. This research paper of ours does not speak to that specific monetary figure so I am not sure where that number comes from. There could be many instances where the co st of CO2 transport via a pipeline falls outside this $3/tonCO2 range.

o Page 43530. It is important to note that the determination as to whether this proposed rule will cost the public and or the private sectors more than $100 million in any given year is a function of the pace of CCS deployment which is something that will be driven by future climate policy. If there is no future national climate policy, then the cost of co mplying with this new rule should be close to $0. If there is a very tight / constraining climate policy, the cost could be significant. The USEPA is en couraged to model out a number of different climate policies and then a ssess what the incremental cost of complying with this rule is rather th an basing the cost on assumptions about there only being 22 pilot projects over th e next 25 years. Without doing this calculation, there is no way of knowing how robust the a ssertion is that the cost of complying with the proposed ru le will not exceed $100 million in any given year.

o Page 43527. The text here says that it is "unlikely that all coal plants would deploy CCS simultaneously." Not only is it "unlikely" it is simply impossible. There is no reason to hypothesize such a future deployment scenario and the computed results are meaningl ess for the purpose of public policy making. There is also no need to approach this particular calculation in this manner. My research group has completed a number of studies (as have other research groups) that could bound realistic CCS deployment rates. It is far

15better to use something within the re alm of the possible as a basis for informing / justifying this important rule making. See for example:

o MA Wise and JJ Dooley. 2008. "The Value of Post-Combustion Carbon Dioxide Capture and Storage Technol ogies in a World with Uncertain Greenhouse Gas

Emissions Constraints." In ternational Journal of Gr eenhouse Gas Control. In

press.

o Dooley JJ, RT Dahowski, and CL Da vidson. 2008. "Comparing Existing Pipeline

Networks with the Potential Scale of Futu re U.S. CO2 Pipeline Networks." In the Proceedings of the 9th International Conference on Greenhouse Gas Technologies. PNNL-SA-62187, Pacific Northwest Na tional Laboratory, Richland, WA.

o Wise MA, JJ Dooley, RT Dahowski, and CL Davidson (2007). "Modeling the impacts of climate policy on the deploym ent of carbon diox ide capture and geologic storage across electric power regions in the United States."

International Journal of Greenhouse Gas Control. Volume 1, Issue 2, April 2007, Pages 261-270. doi:10.1016/S1750-5836(07)00017-5

o Dooley, James, J.; Davidson, Casie L.; Wi se, Marshall A.; Dahowski, Robert T. "Accelerated Adoption of Carbon Dioxide Ca pture and Storage within the United States Electric Utility Industry: the Imp act of Stabilizing at 450 ppmv and 550 ppmv." In, ES Rubin, DW Keith and CF Gilboy (Eds.), Greenhouse Gas Control Technologies, Volume I (pp. 891-89 9). Elsevier Science, 2005.

Individual Response: In the cost analysis for the proposed rule, EPA used information from contacts in government and industry and its best professional judgment to develop the estimate of 22 baseline projects. The cost analysis also presented a sensitivity analysis that considered a 50-percent increase and a 50-percent decr ease in this estimated baseline.

The cost analysis for the proposed rule assumed that each pro forma saline injection site would operate for 20 years and that two sites would be developed to cover the typical 40-year operating life of each power plant. The current cost estimat e is based on one storage site operating for 40

years.

In updating the cost analysis baseline for the fi nal rule, EPA consulted with DOE on the current number of planned or actual deployments because GS is in a nascent stage and there has been fluctuation in the number of planned projects. EP A also used publicly available data, e.g., from the Carbon Sequestration Leadership Forum's web site, to estimate the number of projects. Based on the information provided by DOE, the updated cost analysis uses an initial baseline of 29 projects, including 13 in saline form ations and 16 at ER sites, as described in Chapter 3 of the Cost Analysis for the Final GS Rule. The final rule cost analysis also presents the alternative deployment scenarios of 50 percent mo re or 50 percent fewer projects.

The estimate of the costs for transporting CO2 has been updated from the previous $3 to $4.60 per ton CO2 based on the followi ng source: “Developing a Pipeli ne Infrastructure for CO2

16Capture and Storage: Issues and Challenges,” Feb. 2009, INGAA Foundation.

For additional information on the final costing ap proach, please see the final cost analysis and technology and cost document in the final rule docket.

Letter ID: 0156 Comment ID: 22629 Letter Lines: 365 to 380

Comment Code: 6220 3.2.2 Assumptions about the number of monitoring wells (seeking comment)

Comment: o Page 43528. The conclusion that "mon itoring requirements account for 60 percent of the incremental regulatory costs, of which 70 percent is incurred for the construction, operation, and maintenan ce of monitoring wells" is likely heavily influenced by the assumption that there would be three monitoring wells for each injector well. The assumption th at there are three monitoring wells per injector well is a significant cost dr iver. It is not clea r that this would hold true in a field with multiple inject or wells; for example a five spot injection pattern would require 15 monito ring wells, which could be excessive. For GS projects that have very large in jection fields with numerous injector

wells there is no reason to believe that this 3:1 ratio would hold true. USEPA should consider modeling out a number of different deployment scenarios to see

how robust this assertion is. This seems to be a worthwhile effort as this is the largest cost component caused by this Class VI rule a nd therefore this

estimated cost is one that could receive a good deal of atten tion. My sense is that adhering to this 3:1 ratio exaggera tes the cost of the proposed Class VI

rule.

Individual Response: EPA recognizes that the number of m onitoring wells associated with GS projects will be site-specific and vary based on many factors, including the local geologic characteristics, the presence of other injection wells, the size of the AoR, and volumes of CO2 injected. The proposed rule Cost Analysis descri bed the number of monitori ng wells as a ratio to the number of injection wells; EPA clarifies that the number of injection wells was based on the size of the AoR and the type of project. Therefor e, the number of monitori ng wells was indirectly based on the size of the AoR. Because ER projec t sites have injection wells that are more clustered than those in saline formations, the AoR and the number of monitoring wells were anticipated to be smaller at an ER project si te compared to a saline formation project. EPA retained this assumption regarding the density of injection wells fo r the final rule analysis, but it changed its assumption on the number of monitori ng wells at each site. For the final rule, the Agency assumes one monitoring well above the inj ection zone per two square miles of AoR; for monitoring wells into the injection zone, the Agency assumes one monitoring well per four square miles. EPA assumes monitoring wells into th e injection zone will also be used to sample above the injection zone. The number of monitoring wells assumed for each project type is presented in Exhibit 5.2 of the Cost Analysis.

Because the actual number of monitoring wells that will be necessary for a given project site is uncertain, EPA tested the sensitiv ity of overall cost estimates to the number of monitoring wells

17by applying a 25 percent decrease and increase in monitoring wells per project type to the original assumptions. This change results in a nnualized incremental rule costs approximately 16 percent less and 16 percent greate r than costs estimated for the primary analysis (as shown in Exhibit 5.26 of the Cost Analysis).

For additional information on EPA's final regula tory approach, includi ng testing and monitoring requirements, please see the final rule and preamble.

Letter ID: 0156 Comment ID: 22630 Letter Lines: 428 to 441

Comment Code: 3110 2.1.1 Proposed siting requirements (i.e., injection/confining zones, trapping mechanism)

Comment: Demonstrating Sufficient CO2 Storage Capacity

Page 43536. The draft Class VI rule states that the applican t is required to identify "An injection zone of sufficien t areal extent, thickness, porosity, and permeability to receive the total antic ipated volume of the carbon dioxide stream." This is a good requirement but it is incomplete. There needs to be some time element here. That is the pr oposed rule needs to address "total anticipated volume" over what period of tim e. There is no need to establish an arbitrary quantitative figure here (e.g., "over 40 years" ). Rather the calculation could be predicated on the e xpected lifetime of the facility, the duration of the injection permit, etc. It would be prudent to modify this sentence to explicitly communicate that th e USEPA was not consid ering "the total anticipated volume of the carbon dioxid e stream" for any given year of operations.

Individual Response: The Agency agrees with the commenter, in the final regulation, the owner or operator must demonstrate that the receiving formation (injection zone) is "sufficient... to receive the total anticipated volume of the CO2 stream" ( §146.83 (a)(2)). In addition, the

Director will also consider th e owner or operator's proposed Ao R and corrective action plan, in which the owner or operator must delineate, th rough modeling, the predicted extent of the CO2 plume over the duration of the project.

Letter ID: 0156 Comment ID: 22631 Letter Lines: 443 to 472

Comment Code: 1220 1.1.1.1 Terminology and definitions

Comment: Lack of Clarity throughout Draft Rule with respect to the "CO2 Stream"

Page 43493 and 43535. The draft Class VI rule has not adequately specified the critical concept of the "CO2 Stream." Th ere are many instances in the rule where critical decisions are made with respect to the "CO2 stream," but this term

itself is not well defined nor does it seem to be consistently used.

18o Page 43497. Under "Potential USDW Impacts" the text says that the "CO2 stream" may contain other impurities and lists as an example H2S.

o Page 43493. The Definition of "Geologic Sequestration" only speaks to CO2 being injected.

o Page 43496 contains a discussion about whether CO2 is a commodity or a pollutant. This issue of whether CO2 is a commodity or a pollutant is a red herring as far as this Class VI GS rule is concerned and EPA should be commended for saying that its ability to regulate CO2 injection under the SDWA is not contingent on determining whether it is a commodity or a pol lutant. However, the rule is never very clear about wh at an acceptable "CO2 stream" is.

o Pages 43503 and 43504. Are a bit clearer on wh at is and is not a "CO2 stream"

in the context of a Class VI well but it st ill is not clear what is allowed and

what is not.

o Page 43535. Defines the "carbon dioxide st ream" as CO2 from an anthropogenic source "plus incidental associated substa nces derived from the source materials and the capture process" as well as any tracers. This is more precise as it clearly would rule out th e intentional comingling of other gaseous waste products that were not derived from the primary anthropogenic CO2 point source. Yet it still hinges on the rather va gue concept of "incidental".

Individual Response: The final definition of carbon di oxide stream at §146.81(d) remains unchanged from the rule proposal and reads as fo llows: “Carbon dioxide that has been captured from an emission source (e.g., a power plant), plus incidental associated s ubstances derived from the source materials and the capture process, and a ny substances added to the stream to enable or improve the injection process. This subpart doe s not apply to any carbon dioxide stream that meets the definition of a hazardous waste under 40 CFR part 261.”

Based on its evaluation of all public comments and input on the proposed rule and the NODA and Request for Comment, EPA has made many revisions to the Cla ss VI GS rule. Please see the final rule and preamble for additional information.

Letter ID: 0156 Comment ID: 22632 Letter Lines: 474 to 486

Comment Code: 1220 1.1.1.1 Terminology and definitions

Comment Code: 1614 1.3.1.2 Impurities in captured CO 2; purity standards for CO2

Comment: The issue of how pure the "CO2 stream" n eeds to be and whether trace or more significant quantities of other gases or liquids can be in jected into a Class VI

well is a critical issue th at will influence the overall economics of CCS and could impact the safety and efficacy of GS. Greater clarity on this issue (while still allowing for some site-s pecific flexibility) would help the

19business community better understand what the cost of using CCS will be. The USEPA is encouraged to continue trying to narrow the defin ition of the "CO2 stream" in subsequent versions of the draft rule. While this is a difficult

issue and there is no obvious "correct answer", USEPA is encouraged to continue research and dialogues with various stake holders to see if a narrower definition of what degree of co-injecti on is allowable for a Class VI well. It is possible that it could take many years maybe even decades to finalize this but it is important to begin pursuing it now.

Individual Response: EPA understands that many CO2 str eams may be relatively pure, and

research indicates that the estimated amounts of impurities in a CO2 stream are likely to be low. However, these estimates are based on limited in formation, and uncertainties remain about the expected concentrations of impurities from the va rious types of CO2 streams. The concentrations

of minor and trace elements in CO2 streams for GS projects are likely to vary by facility, coal composition, plant operating conditions, and pollution removal technologies.

The GS rule does not set generic purity standa rds for CO2 injectate streams (e.g., a percent CO2). Instead, the GS rule addresses the quality and quantity of impurities by requiring owners or operators to submit information on the sour ce of the CO2 and its physical and chemical properties. Specifically, the GS rule requires the owner or operator to subm it data about the site, including an analysis of the chemical and physical characteristics of the CO2 stream, as required at §146.82(a)(7)(iv), and information on the compatib ility of the CO2 stream with fluids in the injection zone and minerals in both the injection and the confini ng zones and the materials used to construct the well, per §146.82(c)(3). This info rmation can help the Director determine the potential for geochemical reactions between the injectate (CO2) and the host geologic formations, which could result in the plugging of pore spaces or the dissolution of formation

minerals.

Letter ID: 0156 Comment ID: 22633 Letter Lines: 488 to 517

Comment Code: 4344 2.4.4.2.2 Comments opposed to setting a minimum injection depth

Comment: No Minimum Injection Depth Specified

Page 43511. It is difficult to envision th at there will be widescale deployment

of CCS that would utilize formations that are shallow enough to favor injection of CO2 as a gas and not as supercritical fluid. It s eems that a better way to approach this from a regulatory standpoint would be to requ ire injection at depth that would call for injection as a supercritical fluid but to allow the Director to waive that requirement for cause and that the waiver would be contingent on the Class VI permitee satisfying additional requirements designed to ensure that the overarching goals of the SDWA and other environmental policies are fulfilled.

It seems odd and inconsistent to not speci fy a minimum depth when CO2 is being injected into a water bearing formation that is below the lower most USDW, but

20EPA is proposing that there would need to be "thousands of feet between the injection zone and [BOTH] the overlyi ng and underlying USDWs." (p. 43512). The overarching goal of the Class VI rule ma king is to protect USDWs and human health and welfare. If CO2 is buoyant a nd there are concerns about it migrating out of the target injectio n zone, it doesn’t seem consistent to specify a minimum depth in one relatively small s ubset of potential GS applications (injection of CO2 into a formation above the lowermost USDW) but not define a minimum depth for the vast majority of GS applications (injection of CO2 below the lower most USDW).

Lastly, perhaps "depth" is too narrow of a concept of what is being discussed here. "Deeper than any US DW and not in communicati on (i.e., not connected hydrodynamically or via faults or other in trusions) with any USDW" or "Deeper than any USDW and geochemically and geom echanically isolated under current and modeled co- and post-injection conditions w ith any USDW" seems much closer to the mark in terms of protecting what society wants protected.

Individual Response: EPA disagrees that it is appropriate to set a minimum injection depth for GS projects and the Agency believes that a determ ination of site-suitabili ty for GS (i.e., that

subsurface formations will receiv e and confine injected CO2) s hould be made on a site-specific basis. The GS rule, at §146.82, requires the owne r or operator to provide extensive site- and project-specific information to the Director to demonstrate that the site meets the minimum site criteria at §146.83, that the CO2 will be contai ned within the injection formation, and that USDWs will be protected from endangerment.

EPA acknowledges that there are limited circum stances where injectio n above the lowermost USDW can be performed in a manner that protec ts USDWs, as long as appropriate protections are in place. The final GS rule at §146.95 establis hes a process by which owners or operators can seek a waiver of the Class VI injection de pth requirements for in jection into non-USDW

formations above and/or between USDWs. The waiver approach requires the submission of extensive, site-specific information (in conjunc tion with the permit appl ication submission) to demonstrate that injection of CO2 into a non-US DW that is above or between USDWs can be done in a manner that is protective of USDWs. Th e requirements are designed to ensure that the owner or operator, the Director, and the Regional Administrator cons ider, on a site specific basis, the implications, benefits, and challenges associat ed with GS and ensuring water availability and USDW protection. For additional information on the waiver approach, please see the final rule and preamble, as well as EPA's responses to comments on the Notice of Data Availability and Request for Comment.

Letter ID: 0156 Comment ID: 22634 Letter Lines: 519 to 533

Comment Code: 5240 2.8.2.2 Post injection timeframe (seeking comment)

Comment: It is Appropriate to Utilize both a Fixed Time Frame and Performance Standard for Establishing the Period of Post Closure Monitoring

21Given humanity’s knowledge about GS deploye d at the scale of millions of tons per year for decades at a given injec tion field is quite slim, the USEPA’s proposal of a fixed time frame in conj unction with a performance standard appears to be an appropriate balance betw een discharging its responsibilities to protect human health and th e environment and not placing overly burdensome, unneeded requirements on prospective GS owner / operators (pp 43519-43520). The 50 year time frame will allow owners / ope rators to budget for post site closure

within the bounds of what is currently known. The performance standard is an assurance to the public that a site will not be released until it has reached a certain point of stability. Given where humanity is with GS, the USEPA should be commended for crafting this compromise and should retain this language in subsequent versions of th is draft Class VI rule.

Individual Response: EPA acknowledges the commenter’s support and has implemented a combination fixed timeframe and performance sta ndard approach for post-injection site care monitoring for Class VI wells in the final GS rule . The PISC requirements in the final GS rule, as specified in §146.93(b), incorporate a combinati on of a fixed timeframe and a performance standard approach. EPA believes that a default PISC timeframe of 50 years, with Director's discretion to shorten or lengthe n this timeframe, combined with a site-specific Director’s

discretion to create an alternative PISC time fr ame, ensures that USDW s are protected. The GS rule offers owners or operators flexibility rega rding the duration of the PISC timeframe by: (1) allowing the Director discretion to shorten or lengthen the PI SC timeframe during the PISC period based on site-specific data , pursuant to requirements at §146.93(b); or (2) affording the

Director discretion to allow a Class VI well owner or operator to demonstrate, based on substantial data during the permitting process, that an alternative PISC timeframe may be appropriate if it ensures non-e ndangerment of USDWs pursuan t to requirements at §146.93(c). EPA believes that a default post-injection site car e timeframe of 50 years, with flexibility to adjust the timeframe for a limited number of GS projects during the permitting process where

substantial data exists to demonstrate that an alternative timeframe would be protective of USDWs, or based on data collected during the PISC period, is appropriate to address the range of sites where GS is anticipated to occur, to ac commodate site-specific circumstances and various geologic conditions, and addre sses commenters’ concerns, wh ile ensuring USDW protection. Both approaches will utilize si te-specific data, and be based on pressure monitoring and USDW impacts.

Letter ID: 0156 Comment ID: 22635 Letter Lines: 535 to 542

Comment Code: 5300 2.8.3 Site closure activities (40 CFR 146.93)

Comment: Requirement to Document GS Sites and Pass that Information on to Future

Potential Users of the Land Above as well as any Subsurface Zones Is Appropriate Page 43541. It is appropriate for the USEPA to require that steps be taken to document the CO2 injection formation and to ensure that information is passed on into the future. The steps spelled out here are reasonable and not overly burdensome (e.g., survey plat and deed for land must include a notation that the

22deep subsurface was used for CO2 storage) . This language should be retained in subsequent versions of the Class VI rule.

Individual Response: The GS regulation at §146.93(g) requires the owner or ope rator to record a notation that the land has been used to sequester CO2 on the deed to the facility property at the

time of site closure.

Letter ID: 0156 Comment ID: 22636 Letter Lines: 544 to 592

Comment Code: 3420 2.2.2.1 Scope of the inventory pr ocess (e.g., reliance on publicly available information, depth of wells)

Comment Code: 4710 2.7.1 Proposed submissions required for permit applications (seeking comment)

Comment: All Wells and "All Known Wells" are not the Same Page 43507 and 43517. The proposed Class VI rule needs to be much mo re precise in its use of language in a couple of key areas. The rule requires an applicant for a Class VI permit to "identify all artificial pene trations." What exactly does this mean? Is it all known artificial penetrations (the rule speaks to the operator "review(ing) available information")? What is the test for what is a known well or available information (does it require detailed fi eld surveys or does one only need to do a quick search of a database of wells drilled in the area)? If on the other hand it means literally all human penetrati ons, then one must ask if this is technologically possible (e.g., are there te chnologies which would allow for the

identification of a small diameter non-st eel walled well that has no visible surface features)? Is there a danger in asking for something that can not actually be delivered? One can guess what was likely meant by "identify all artificial penetrations" in terms of draf ting this rule but it is not at all clear how this would be opperationalized at actual prospective GS sites.

More importantly on Page 43535 under "144.55 Corrective Action", the rule says that owners/operators need to identify the location of "all known wells" which

seems to be a lesser standa rd. In the actual text of the rule (page 43526), the applicant is told "Only information of public record is required to be included on this map." Given how many times the ru le and its preamble talk about old wells being a potential conduit for CO2 rel ease from the storage formation, this seems like an overly lax threshold. It w ould seem appropriate to require the applicant survey the actual site itself for artificial penetrations that might not be in the public record (the survey could include a number of different methods / tools). Further on in this sec tion, the applicant is asked to submit

a "tabulation of all wells within the area of review which penetrate the injection or confining zone s." Again, "all wells" and "a ll known wells" and how

much work does one need to do to determin e if they have tried to find "all the

wells" must be better articulated in the final rule. This same kind of language shows up on page 43537 within the discus sion of the Area of Review and

Corrective Action.

23Lastly, given the large am ounts of money involved in a commercial CO2 storage project, I would think that the electric production, oil and gas, or other large industrial company contemplating a large CCS -enabled facility would want (or be required) to go beyond simply collecting ex isting data as a way of decreasing risk and uncertainty. In this context, the proposed "requirement" for going beyond existing data could be imposed by en tities other than state or federal environmental regulators and could be im posed by shareholders, a public utility commission, or a firm’s own board of di rectors. In terms of abandoned wells, it seems likely that commercial firms would s ee it to be in their own best interest to do some kind of physical search / a ssessment of whether there are any known

or unknown wells within the area of review given the relatively minor cost associated with something like an aeria l magnetic survey versus the costs associated with loss of CO2 and any fines, the cost associated with any required post-leakage activities, or simply the cost of litigation and or loss of good will associated with such sloppy manageme nt of a critical, capital intensive pollution abatement facility.

Individual Response: EPA believes that, for the most part, data base and other public records searches will be sufficient to identify artificial penetrations in the AoR. This inventory and review process is similar to what is required of Class I and Class II inje ction well operators, that that the AoR and corrective action process for these well types has been successful.

EPA is developing guidance on AoR and corrective action for GS sites. The guidance describes EPA's recommended approaches for the data to be considered in an initial AoR delineation, how to apply computational m odeling to delineate the AoR, perfor ming corrective action at GS sites, and, when appropriate, completing AoR reevalua tions. The guidance will be available on EPA's web site, at http://water.epa.gov/type/g roundwater/uic/wells _sequestration.cfm.

EPA agrees with commenters that, for most GS sites, relying on database and other public records searches (i.e., of "know n" artificial penetrations) wi ll be sufficient to meet the requirements at §146.84(c)(2). However, the Agency recognizes that there may be situations where additional surveys or resear ch to locate wells may be appropriate. For example, there may be cases where the Director may determine th at ground or airborne surveys for wells are appropriate, e.g., if there is reas on to believe, based on knowledge of the site or of available data, that the incompleteness of information on know n wells could compromise USDW protection from endangerment. In order to preserve the Di rector's discretion to require an operator to supplement a records search, EPA did not make the suggested change. EPA encourages owners or operators to expand their sear ches, as the commenter suggests. EPA adds that all corrective action must be performed pursuant to the a pproved AoR and corrective action plan, which

affords the Director the discre tion to require any additional information needed (including information that is not publically available) to ensure that all necessary corrective action is performed.

24Letter ID: 0156 Comment ID: 22637 Letter Lines: 594 to 600

Comment Code: 4710 2.7.1 Proposed submissions required for permit applications (seeking comment)

Comment: In this same section (page 43526), the appl icant is asked to submit information on "the presence and depth of seismic s ources" but this falls under a heading that is limited to the "proposed storage site and overlying fo rmations." So if a proposed GS site sat 10 cm, 10m or 10km north of any aspect of the New Madrid Fault, that would not be noted in the application. Limiting the scope of data

collection to the boundaries of the project site might not be appropriate for data related to "the presence and depth of seismic sources"

Individual Response: EPA believes that consideration of local and regional seismicity is important and this type of review is relevant to every project. The site characterization provisions in the GS rule, including a review of the loca l and regional geology, and detailed review of any known or potential seismically activ e terrain in the vicinity of a proposed GS site, are necessary to minimize the potential for induced seismic events or the reactivation of faults, which are a known potential risk associated w ith underground injection and are addressed in all aspects of the UIC regulations.

Letter ID: 0156 Comment ID: 22638 Letter Lines: 602 to 626

Comment Code: 5430 2.9.1 Comments on proposed financia l responsibility requirements (40 CFR 146.85)

Comment: It Should Be a Requirement to Periodical ly Revaluate Funds Set Aside for Well Plugging and Post-Injection Site Care Pa ge 43520. The USEPA should mandate that owners / operators periodically update the cost estimate for well plugging, post-injection site care, ec t. Given how long GS projec ts are likely to last,

there is no reason to believe that the amount of money se t aside at the start of the project even if it were invested in something that kept up with inflation would necessarily be sufficient to cover these costs. The US DOE Energy

Information Administration in its Annual Energy Outlook: 2007 ( http://www.eia.doe.gov/oiaf/aeo/otheran alysis/cecei.html) documented how drilling and other associated costs have escalated at a rate that is far above the core inflation rate for the economy as a whole. On page 43522, the draft rule says "Trying to determine the cost for post injection site care, possible 30 to 50 years in the future, could be difficult." Yes, it is difficult to understand what anything would cost 50 year s in the future. However, one can figure out what it would cost to do th ose things now and then one could periodically reassess those costs. That is quite straightforward and the

USDOE’s EIA maintains a Oil and Gas Leas e Equipment and Operating Costs Index which could easily be used to true up these costs as needed to account for inflation (see http://www.eia.doe.gov/pub/oil_gas/natural _gas/data_publications/cost_indices_eq

25uipment_production/current/coststudy.html ). The Oil and Gas Journal also publishes indices of construc tion costs which could be used to true up these costs over the life time of a GS project . Again, there are many reasons to

mandate that these costs be revised periodically and if need be the corresponding financial assurance m echanisms should be revalued.

Individual Response: EPA agrees that it is important to periodically update cost estimates that support financial responsibility determinations, which is why the final GS rule, at §146.85(c) requires the owner or operator to provide annua l updates to the cost es timate to account for any amendments to the AoR and corrective action plan, the injection well pl ugging plan, the PISC and site closure plan, and the emergency and reme dial response plan. EPA adds that the Director can also require the owner or ope rator to provide an adjustment of the cost estimate if the Director determines that the original demonstr ation is no longer adequate, as specified at §146.85(e). The owner or operator must also update the cost estimate for inflation annually under §146.85(c)(2). See the final rule and preamble for fu rther discussion of EPA's final approach to financial responsibility.

EPA will include DOE's EIA Oil and Gas Lease E quipment and Operating Costs and the Oil and

Gas Journal as sources of information in the discussion on estimating costs in its guidance on financial responsibility.

Letter ID: 0156 Comment ID: 22639 Letter Lines: 628 to 639

Comment Code: 4110 2.4.1.1 Injection pressure limitations

Comment: 90% of the Injection Zone or the Capr ock’s Fracture Pressure Page 43510 under "Proposed Injection Well Operating Requi rements." Citing the IOGCC report and the expert opinion of permit writers is not the most rigorous basis for asserting that injection pressure can no t exceed 90% of fracture pressure for all GS applications. Perhaps in a Notice of Data Availability (NODA) for this rule, USEPA could ask for data or studies that would help establish a firmer basis for this threshold. This is an important criteria as it directly impacts how much CO2 can be put down a given we ll and therefore how many wells will be needed to handle the anthropogenic CO2 fr om a given facility. The number of injector wells is a key determinant of the cost of CO2 storage. On page 43538, this same language is found in the pr oposed rule text (i.e., not in the preamble).

Individual Response: EPA believes that the injection pressure limits in the final GS rule are appropriate and necessary to protects USDWs from endangerment. The injection pressure limit for each GS project will be ba sed on site-specific conditions, a nd be informed by data on the injection zone. During injection, the pressure in th e injection zone must not exceed 90 percent of the fracture pressure of the injection zone, as specified at §146.88(a). The fracture pressure (and, therefore, the injection pressure) are based on site-specific geologic and geomechanical data collected during the site characterization process required at §146.82. Tests are available and have been used by injection well operators, e.g., Cl ass I operators, to measure fracture pressure.

26Examples include the step-rate test, in-situ stre ss tests, and a combinati on of a long spaced sonic log with laboratory measurement of the mechan ical properties of cores. To meet the GS requirements, the permitting authority would set the injection pressure limit at 90 percent of this

value.

The Director will also review geologic, hydrogeologic, and geomechanical information submitted by the owner or operator in setting pe rmit conditions. If, based on this information, a lower pressure limitation is appropriate, the Director has the authority to set a lower limit in the operating permit. EPA clarifies that fracturing of the confining zone dur ing injection and/or stimulation is also prohibited at §146.88(a).

EPA published a Notice of Data Availability and Request for Comment on August 31, 2009 (74 FR 44802) that described research underway at several pilot projects and LBNL and sought comment on any other research associated with potential environmental risks and risk management approaches for GS. EPA received a variety of comments and data in response, but none of the comments or information provided by commenters provided scie ntific rationale to support changing the injection pressure limitation.

Letter ID: 0156 Comment ID: 22640 Letter Lines: 641 to 651

Comment Code: 4120 2.4.1.2 Allowing hydraulic fracturing during GS (seeking comment)

Comment: More importantly did the USEPA intend to ti e this 90% pressure threshold to the fracture pressure of the "injection zone " or the fracture pressure of the "primary caprock / seal above the injection zone"? If a GS project was injecting at the bottom of a 500 meter thic k interval of a sa ndstone, is there any harm in allowing for some amount of deformation to areas near the injection point in the target formation? In ma ny areas, the caprocks are stronger than the injection zones based on the rock types, degree of cementation etc. In such cases, it may be good to have a mechanism where you can stimulate the injection zone more aggressively to increase permeability / injectivity. Fracturing of the injection zones may be critical in improving injection performance and even in making some of the marginal inj ectivity sites into viable sites.

Individual Response: EPA clarifies that the injection pressu re must not exceed 90 percent of the fracture pressure of the injection zone. The fina l rule retains this provision at §146.88(a). EPA believes that the 90 percent requirement, whic h was suggested by state representatives whom EPA consulted when writing the regulation, is a satis factory margin of safety for well operation.

EPA recognizes that there may be well completions which require intermittent treatments that include stimulation to improve wellbore injectiv ity. Stimulation of the injection zone during a well workover will be permissi ble, if approved by the Direct or (operators seeking to use stimulation must submit the proposed stimulation pr ogram as part of the permit application under §146.82(a)(9) where injection pressure limits will be set). EPA has also added a requirement that owners or operators notify the Director in advance of any planned stimulation activities, as specified at §146.91(d). During inje ction, the injection pressure must not exceed 90 percent of

27the fracture pressure, as specified in §146.88(a). EPA clarifies that th e injection pressure limit at §146.88(a) applies only to the period of injection, not well stimulation.

Letter ID: 0156 Comment ID: 22641 Letter Lines: 653 to 660

Comment Code: 4460 2.4.4.4.1 Comments in favor of allowing aquifer exemptions in certain

circumstances

Comment: It Is Appropriate to Require Class II Fiel ds to be Recertified before Conversion to Class VI Fields Page 43512. It is appropriate for th e USEPA to require a new aquifer exemption for a formerly Class II injection field if there is a desire

to use that field for GS. EPA should retain this requirement in the final rule. Just because a formation was deemed appropriate for Class II activities, does not guarantee that it is suitable for GS and therefore EPA is right to ask for more fact finding and potentially remediati on of artificial penetrations before allowing the formation to be exempted and used for GS.

Individual Response: EPA recognizes that there are lim ited circumstances where aquifer exemptions for GS may be warranted, and the final GS rule allows for the expansion of the areal extent of existing aquifer exemptions for Cl ass II EOR/EGR wells tran sitioning to Class VI injection for GS pursuant to requirements at §§146.4 and 144.7(d). Class VI owners or operators granted expansions of existing Class II EOR/EGR a quifer exemptions for GS projects must meet all of the tailored requirements for GS wells in the final GS rule.

EPA agrees that Class II EOR/EG R owners or operators should reapply for exemptions before transforming to Class VI status. If an owner or operator applies for a Class VI permit to inject CO2 into a previously exempted aquifer (non-USDW) that is located above and/or between USDWs, the permit applicant must also apply for a waiver of the injec tion depth requirements pursuant to §146.95 to ensure that if a waiver is granted, USDWs above and below the injection zone are protected from endangerment.

EPA clarifies that the final rule precludes the issuance of new aquifer exemptions for Class VI GS wells; that is, aquifer exemptions will only be granted for projects that are transitioning from

Class II EOR/EGR wells to Class VI.

EPA adds that any Class II well ow ner or operator seeking to inj ect CO2 for the purpose of GS would need to have their well re-permitted as Cl ass VI. The final Class VI regulations require that any owner or operator injecting CO2 for th e primary purpose of long term storage obtain a Class VI permit with some special consideration fo r the fact that they are transitioning from a well not originally designed to meet Class VI requirements. The Director has the authority to determine at what point a Class VI permit is re quired for those projects that are transitioning from the primary purpose of EOR to long term storage of CO2. The fina l regulation provides a

set of technical factors for the Director to ev aluate in making this determination, at §144.19. EPA believes that this approach provides sufficient pr otection of USDWs when there is an increased risk to USDWs as compared to traditional Cla ss II operations while allowing for site-specific flexibility. See the preamble and final rule for additional information on EPA's approach

28transitioning of Class II wells for GS.

For additional information on aquifer exemptions for Class VI wells, please see the final rule and preamble, as well as EPA's responses to comments on the Notice of Da ta Availability and Request for Comment.

Letter ID: 0156 Comment ID: 22642 Letter Lines: 662 to 679

Comment Code: 3120 2.1.2 Need to identify additional confining and containment zones (seeking comment)

Comment: Allowing the Director the Discretion to Ask for Additional Fact Finding on Supplemental Confining Layers Page 43505-43506. EPA specifically asks for comments on allowing the Direct or to require that additi onal confining zones be identified for certain projects. Assuming th at the Director uses this authority to require more fact finding for cause (i.e., it is not a capricious request),

then it seems as if USEPA has struck an appropriate balance here and should retain this flexibility in the final rule. Given the capital cost of something like an IGCC+CCS, it does not seem unreasonabl e to ask that cores be taken from a second or third overlying caprock if ther e is some reason to want to ensure

that there are additional containment systems beyond the caprock immediately above the target injection zone. While the USEPA might receive comments saying that this is potentially a significan t unknown cost that could delay CCS deployment, the cost of this additional fact finding is likely denominated in the millions of dollars or less while the rest of the complete end-to-end CCS facility could be worth tens of billions of dollars. Again assuming that this flexibility is only used when needed and for cause, it seems to be an appropriate and cost effec tive tool for ensuring the ove rall goals of the Class VI program are fulfilled.

Individual Response: EPA acknowledges the commenter's s upport and agrees that, in some situations, the presence of add itional confining and containment zones above the primary (i.e., lowermost) confining zone can improve US DW protection from endangerment. The final regulation retains the requirement at §146.83(b) whic h affords the Director discretion to require owners or operators to identify a nd characterize additional zones.

Letter ID: 0156 Comment ID: 22643 Letter Lines: 681 to 714

Comment Code: 1210 1.1.1 Comments about the proposed rule

Comment: Dialogue between the Regulated and Regulat or Isn’t Obvious Th e draft Class VI rule and especially the preamble assert numerous times that a key to ensuring the safety and efficacy of geologic seque stration is a well functioning dialogue between the regulated entity and the re gulatory agency. There are at least

three intertwined concerns I have with th e way the current draft Class VI rule

29is written that if left unresolved woul d hamper a robust, meaningful dialogue between the regulated entity and the regul ator has been created by this rule.

1) The concept that there is "working" relationship between the permitee and the permit-granting agency doesn’t really come through here. This seems like a very arms length relationship.

2) The draft rule never establishes that the process of moving from initial site selection to permitting, to operations to re newal of permits to closure is an iterative one between the operator and the EPA or state permit writer (acting as stewards of the public’s we lfare) as new data are ge nerated and incorporated into the site management plan. That is, the rule could do a mu ch better job of explaining that the permittee and the regul ator should be lear ning a great deal about how a particular geostorage field is operating in practice and that this knowledge will be factored into how the field is regulated in the future (including decisions ab out post closure).

3) Data is collected but it is not clear how it is used by the regulator nor is

it clear who has access to this data. In particular, there appears to be only two instances (one at the ve ry earliest stages of site selection and the other before site closure) where the public is invited to learn a nd comment on a GS project.

Given that humanity is in the early days /decades of CCS deployment, it seems to me that much could be learned by having closer and more fre quent communication between the regulator and owner/operator of a GS project, and allowing for some

dissemination of the massive amount of data generated by these projects. A more transparent and meaningful dialogue between these two pa rties would also help with stakeholder acceptance of CCS.

Individual Response: EPA agrees that communication and coordination between owners or operators and permitting authorities are important. The GS rule incorporates a flexible approach, where operators of GS projects develop and im plement site-specific plans for delineating the AoR, performing corrective action, testing and monitoring, and post-injection site care. EPA believes that the plans—which will be reviewed and approved by the Director and periodically updated throughout the life of the project—promote an ongoing dialogue between the operator

and the Director that will enc ourage use of the most appropriat e technologies for a particular project and that GS projects are permitted si ted, constructed, operated, and closed in a manner

that avoids releases of CO2 into USDWs.

EPA is developing a number of technical guid ances and implementation materials to assist owners or operators and Directors in the permitti ng process. These guidances will address how to perform many of the activities necessary for applying for a pe rmit, including developing all required plans and conducting site characterizations that meet the requirements of §146.82. The guidances will be available on EPA’s website at http://water.epa.gov/type/groundwater /uic/wells_seque stration.cfm

30Letter ID: 0156 Comment ID: 22644 Letter Lines: 716 to 728

Comment Code: 4720 2.7.2 Operational record keeping and reporting

Comment: Much Data Is Collected; But how is it used and who has access to the data?

o Page 43514 includes a requirement that m echanical integrity be demonstrated annually, but it does not say what is done with this information or what it is used for. How long is this data retained?

o Page 43514 includes a requirement that ow ners / operators report semi-annually on the injection pressure, flow rate, temp erature, volume and annular pressure

and on MIT test results. What is the da ta collection method and who will have access to these data? Is it an open we bsite like the Toxic Report Inventory (TRI) where any citizen could view this information, or is it a single hard copy report locked in a state or regional EPA of fice that can only be seen via a FOIA request by members of the public or other stakeholders?

Individual Response: EPA has clarified the recordkeeping requirements in the final GS rule, which includes requirements that well plugging re ports, as required at §146.92(d), post-injection site care data, as required at §146.93(f), and site closure report s, as required at §146.93(h), be kept for ten years after site closure. See the final rule and preamble for further discussion on EPA's final approach to post-injection site care.

EPA will use the data to verify that the well and the site are behaving as predicted and within permitted guidelines to ensure that USDWs are protected from endangerment. In addition, the data may be used as evidence of a violation of a permit requirement that may result in an enforcement action under SDWA. The Agency clar ifies that owners or operators may claim

confidential business informati on under existing UIC regulations at §144.5. These requirements are applicable to all well classes.

Letter ID: 0156 Comment ID: 22645 Letter Lines: 730 to 735

Comment Code: 4740 2.7.4 Electronic reporting (seeking comment)

Comment: o Page 43514. EPA asks for "comments on the requirements for monitoring" but it is not clear that there are any requireme nts articulated here. The USEPA should require that data on the areal extent of the CO2 plume a nd the pressure front as well as any other relevant data from MMV be reported to EPA on an annual / semiannual basis. USEPA still must come to some consensus on how these data will be collected, who will have access to them, ect.

Individual Response: EPA clarifies that the monitoring re quirements for Class VI well owners or operators are presented in the final rule at §146.90. EPA is retaining the requirement at §146.91(a) for semi-annual reportin g of monitoring and operationa l data, including data on

31monitoring and tracking the CO2 plume and pre ssure front. For additional information about monitoring requirements and reporting requireme nts see the preamble to the final rule.

EPA is developing guidance for states that describes the recordkeeping, reporting, and additional data management needs associated with Cl ass VI activities and provides recommended guidelines on the types of data to be collected for tracking Class VI proj ects, reporting to EPA for compliance tracking, and transfer of data to EPA's GS data system. The recordkeeping and reporting guidance will be avai lable on EPA's web site, at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Letter ID: 0156 Comment ID: 22646 Letter Lines: 737 to 744

Comment Code: 4740 2.7.4 Electronic reporting (seeking comment)

Comment: o Page 43514 under "Monitoring CO2 Movement and Reservoir Pressure", USEPA states that the owner/operator must co mpare the results of monitoring to baseline data but the text of the propos ed rule does not re quire that this information be shared with the USEPA or state permitting agency. Isn’t this critically important information on how GS is working at a site? Isn’t that information needed by USEPA to understand wh ether the Class VI rule is effective in protecting USDWs and the other goal s of the SDWA? There should be a requirement that this data and comp arison be shared w ith regulators.

Individual Response: EPA expects that CO2 plume and pressure front tracking data will be reviewed as part of the AoR reevaluation and plan update process. The final GS rule, at §§146.84(c), 146.90(j), and 146.94(d), requires owners or operators to revi ew and update the AoR and corrective action plan, th e testing and monitoring plan, a nd the emergency and remedial response plan throughout the life of the project. Own ers or operators must review each plan and identify necessary amendments to the plan or de monstrate to the Director that no amendment is needed. These reviews must be performed with in one year of an AoR reevaluation, following any significant changes to the facility (e.g., the addition of monitoring or injection wells), or when required by the Director. In no case can reviews occur less often than once every five years. Furthermore, §146.90(b) requires that the owner or operator continuously monitor injection pressure, rate and volume; the pressu re on the annulus between the tubing and the long string casing; and the annul us fluid volume added.

EPA believes that by requiring periodic reeval uations of the AoR, as required at §146.84(e), along with any revisions to the required plan s that may be required based on the AoR reevaluation or other data collected during we ll operations, will promote an ongoing relationship between the permitting authority and the owne r or operator, including discussion of all monitoring results.

Letter ID: 0156 Comment ID: 22647 Letter Lines: 746 to 748

Comment Code: 4720 2.7.2 Operational record keeping and reporting

32Comment: o Page 43517 contains a requirement to repor t various data on the performance of GS on a semi-annual basis, but again it is not clear how these data will be used, retained, or who has access to them.

Individual Response: EPA has clarified the recordkeeping requirements in the final GS rule, which includes requirements that well plugging re ports, as required at §146.92(d), post-injection site care data, as required at §146.93(f), and site closure report s, as required at §146.93(h), be kept for ten years after site closure. See the final rule and preamble for further discussion on EPA's final approach to post-injection site care.

EPA will use the data to verify that the well and the site are behaving as predicted and within permitted guidelines to ensure that USDWs are protected from endangerment. In addition, the data may be used as evidence of a permit violatio n that would result into an enforcement action. The Agency clarifies that owne rs or operators may claim conf idential business information under existing UIC regulations at §144.5. These requiremen ts are applicable to all well classes.

Letter ID: 0156 Comment ID: 22648 Letter Lines: 750 to 753

Comment Code: 4000 2.4 Proposed Injection Well Operat ing Requirements (40 CFR 146.88)

Comment: o Page 43538. Owners and operators of Class VI wells are required to install and use continuous recording devices to m onitor a number of critical performance

variables. The rule does not specify how long these data are to be retained and

who has access to them.

Individual Response: The GS regulation at §146.91(f) requires injection well operators to retain monitoring records for ten years af ter the data is collected. The Director has the authority to request this data.

Letter ID: 0156 Comment ID: 22649 Letter Lines: 755 to 764

Comment Code: 1210 1.1.1 Comments about the proposed rule

Comment: Who has access to reports on an ongoing GS project?

o Page 43517. It is asserted that the requirement for "monitoring, testing, AOR, and corrective action" plans will help establish "an ongoing dialogue between the operator and the permitting aut hority." This reviewer just doesn’t see this "dialogue" in this rule. There is no discussion of how these plans are

used and therefore this looks like a very distant and at arms length process. I am 100% in support of there being an ongoing dialogue between the operator and the regulator and I believe that these a dditional plans are a wise requirement

for Class VI GS wells.

33Individual Response: EPA believes that the plans site-spe cific plans for delineating the AoR, performing corrective action, testing and monitoring, and post-injection site care —which will be reviewed and approved by the Director and pe riodically updated thr oughout the life of the project—promote an ongoing dialogue between the ope rator and the Director that will encourage use of the most appropriate technologies for a particular project and that GS projects are permitted sited, constructed, operated, and closed in a manner that avoids releases of CO2 into

USDWs.

EPA is developing a number of technical guid ances and implementation materials to assist owners or operators and Direct ors, including a guidance that de scribes recommended approaches for developing, reviewing, and updating the GS projec t plans. The guidances will be available on EPA’s website at http://water.epa.gov/type /groundwater/uic/wells _sequestration.cfm.

Letter ID: 0156 Comment ID: 22650 Letter Lines: 766 to 775

Comment Code: 4730 2.7.3 Reporting associated with closur e and post-injection site care

Comment Code: 5280 2.8.2.4 USDW non-endangerment demonstrations

Comment: o Page 43517. Records retention of only 3 years after site closure. That seems incredibly short. Also it is not clear how this requirement to hold on to these data for three years after site closure is consistent with the owner operators requirement to discharge its respons ibilities under the pos t closure period including establishi ng that non-endangerment continue s to be the cas e. Wouldn’t access to baseline and data collected during the period of principal operations be needed to report out these findings dur ing the period of post closure. This short record retention period also se ems to undercut assertion of a open continuous dialogue being a center piece of how USEPA and any states that have Class VI primacy will ensure public safety.

Individual Response: EPA has changed the recordkeeping re quirement in the final rule to require that owners or operators retain records collected dur ing the post-injection site care period for at least 10 years following site closure. EPA believes that the requireme nts that the owner or operator retain for ten years following site closure, records collected during the post-injection site care period at §146.93(f) and §146.93(h) are appropriate to ensure that data are available to support non-endangerment demonstrations and to a ddress any concerns that may arise following

site closure. This data will also support EPA's review of projec t data as part of the adaptive rulemaking approach.

Letter ID: 0156 Comment ID: 22651 Letter Lines: 777 to 785

Comment Code: 4740 2.7.4 Electronic reporting (seeking comment)

Comment: o Page 43517. USEPA asks for comments on electronic reporting. Yes, electronic reporting should be mandatory. USEPA also needs to find a way to ensure that electronic reports are eventually consolid ated at a national level. Having the

34reports be submitted to a state but not having the reporting go any further will frustrate efforts to improve our knowledge about how CCS works in practice and

it will frustrate efforts to cost effectiv ely include GS in to the structure of a national climate policy. Page 43529. The USEPA should consider whether a requirement of being granted primacy for Class VI wells would be a requirement

to share data collected at the state or Tribal area with the federal USEPA. EPA

Individual Response: EPA retains the requirement that owners or operators submit data electronically to an EPA data system. EPA belie ves that it is prudent to provide assistance by developing a central framework for the electronic sy stem that will be used by States to gather and track owner or operator data. This will enable owners or operators to submit data without having to wait for a State to develop a system. It will also provide for standardized submissions across the country and enable States to fo cus resources on reviewing and approving permit applications rather than building or upgrad ing separate, independent databases for GS information. EPA believes that electronic formatting is the most appropriate format for submitting Class VI project information to the Director, and that many GS well owners or operators will have the capability to report el ectronically. In additi on to minimizing redundancy and streamlining reporting for GS projects, EPA in tends to use the data collected to support its

evaluation associated with the adaptive process.

EPA is developing guidance for states that describes the record keeping, reporting, and additional data management needs associated with GS activities and provides recommended guidelines on the types of data to be collected for tracking GS projects, reporting to EPA for compliance tracking, and transfer of data to EPA's GS data system. The recordkeeping and reporting guidance will be avai lable on EPA's web site, at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Letter ID: 0156 Comment ID: 22652 Letter Lines: 787 to 809

Comment Code: 5500 2.1 Comments on Involving the Public in Permitting Decisions

Comment: Stakeholder Input and the Period icity of this Involvement

o Page 43520. The draft rule states "Duri ng this 50 year period, the owner or operator would be required to submit peri odic reports." What’s the periodicity of these reports? A layperson would likely see this as a more meaningful step to regulate GS if the periodicity wa s annually as opposed to once every 15 years. I do not intend to imply that annual reporting is the appropriate periodicity but by not specifyi ng the interval the value of this as a regulatory tool or a means of building public trust in nascent GS technol ogies is largely gutted.

o Page 43520. The draft rule seems to impl y that the draft site closure plan would be made publically available. That is fine and appropria te, but the rule

does not address what data will be made publically available wh en the GS project is being planned or during its operational phase. I do not see how the USEPA

35can be silent on this point.

o Pages 43522-43523 contain an ex plicit discussion of public involvement in GS projects. This passage says that a su mmary of this pre-construction public involvement activity would become part of the public record. So the rule says that something at the very earliest stages of a GS project a nd something at the very end are public documents, but it is not clear what da ta during the 30-50 year operational life of the proj ect are publically available.

Individual Response: EPA clarifies that the final GS rule does not specify a frequency for monitoring or reporting during the post-injection period. However, the post-injection site care and site closure plan submitted as part of th e permit application must specify monitoring and reporting frequencies (See §146.93(a) (2)), and the Director must approve the plan. Additionally, the owner or operator must conti nue monitoring as specified in the post-injection site care and site closure plan for 50 years following the cessa tion of injection, unless demonstrated otherwise

or for the duration of the alternative time frame approved by the Di rector pursuant to requirements in §146.93(c).

In addition to the public process during the permitting phase, EPA expects that permitting

authorities will maintain an administrative record for the project, which at the discretion of the permitting authority might be available online and at the authority's office. This record should consist of the application materials and draft and final permits, along with public comments received on the draft permit as required under 40 CFR Part 124. Please no te all state programs for purposes of Class VI wells must be at least as stringent as the federal minimum requirements under the UIC program, which includes pe rmitting requirements under 40 CFR 145.11. EPA anticipates that permitting authorities will main tain monitoring and operational data submitted by owners and operators; the public could request this information from the permitting authority. Where EPA is the permitting authority, such data could be requested by the public under the

Freedom of Information Act. EPA will also en courage an ongoing rela tionship between the permitting authority and the owner or operator, e. g., at the time of periodic reevaluation of the AoR and corrective action plan required at §146.84(e), as well as when any revisions are made to the testing and monitoring plan and financial responsibility de monstrations based on the AoR

reevaluation.

EPA notes that administrative procedure laws va ry by state. States wi ll describe their public participation activities in their primacy applicatio ns and must be at leas t as stringent as those provided under Parts 145 and 146.

EPA recognizes that the AoR reev aluation process may generate significant levels of public interest. EPA added text to §144.39(a)(5) that pe rmit modifications woul d be required if the

Director determines that a modification is nece ssary based on an AoR reevaluation, amendments to any of the project plans, or a review of th e testing and monitoring results. This would invoke the public notification procedures of 40 CF R Part 124. EPA clarifies that minor permit

modifications under 40 CFR 144.41 do not require public notification.

36Letter ID: 0156 Comment ID: 22653 Letter Lines: 811 to 817

Comment Code: 5700 2.12 Comments on the proposed durati on of Class VI permits (seeking comment)

Comment: Page 43523. EPA explicitly asserts that because it (or a state that has primacy) has such a rigorous on-going dialogue with owners/operato rs that it is prudent to issue injection permits "for th e life of the GS project including the post-injection site care period." This very conseque ntial decision hinges upon whether or not there truly is an ongoi ng dialogue that is substantive and happens with enough frequency to allow probl ems to be detected and remediated quickly. I am not sure that I see th is dialogue as bei ng that robust.

Individual Response: EPA agrees with the commenters rega rding the importance of continuous interaction between permitting authorities and owners and operators during the life of a GS project. In response, EPA has built periodic plan reevaluations by the Director and owners and operators into the GS regulation . The final ru le under §144.36(a) require s that the Director review each Class VI permit at least every 5 years to determin e whether it should be modified, revoked and reissued, terminated or a minor modification made as provided in §§144.39, 144.40,

or 144.41. The Director’s review will be info rmed by the owners’ or operators’ iterative reevaluation of the project. Sp ecifically, the final rule includes a requirement that the AoR be reevaluated at least every five y ears, and also requires owners or operators to review and update the AoR and corrective action plan, the testing and monitoring plan, and the emergency and remedial response plan throughout the life of the project (146.84(e), 146.90(j), and 146.94(d)). Owners or operators must review each plan and identify necessary amendments or demonstrate

to the Director that no amendment is needed. In no case can reviews occur less often than once every five years. EPA believes that this process will promote rigorous on-going dialogue between owners and operators and the permitting au thority to ensure protection of USDWs from endangerment.

EPA believes that the iterative process of develo ping and executing the va rious plans required of GS well operators is tailored to the unique aspect s of GS and is preferab le to a periodic permit reapplication. The iterative proc ess and subsequent plan reeval uations ensure that time and resources are committed to the most critical aspects of the permit in preventing endangerment to

USDWs..

The Agency plans to collect and review data on GS projects every six years 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 appr opriate or necessary.

Letter ID: 0156 Comment ID: 22654 Letter Lines: 819 to 825

Comment Code: 4700 2.7 Proposed Recordkeeping and Reporting Requirements (40 CFR 146.91)

Comment Code: 5500 2.1 Comments on Involving the Public in Permitting Decisions

37Comment: Page 43528. The proposed Class VI rule stat es "The information gathered as a result of this proposed rule" allows th e Agency to verify throughout the life of the injection project that UIC protec tive requirements are in place and that USDWs are protected. At the end of the day, this is indeed the figure of merit. Does this rule allow for sufficient exchange of information between the owners/operators of GS projects and re gulators and stakehol ders (?). This

reviewer is not convinced that this metric is sati sfied by the proposed rule.

Individual Response: EPA agrees that interaction betw een the owner or operator and the Director is an important part of ensuring that GS projects are ope rated in a manner that protects USDWs from endangerment. EPA believes that the site-specific GS project plans which will be reviewed and approved by the Director and pe riodically updated thr oughout the life of the project—promote an ongoing dialogue between the ope rator and the Director that will encourage use of the most appropriate tec hnologies for a particular project.

EPA encourages (but does not require) operators and permitting agencies to begin involving the public by providing information as early in the GS project development process as possible. Involving the public in the permitting process is an important aspect of both UIC Program requirements and EPA's overall mission. The public will also have the opportunity to submit written comments and, in many cases, attend hear ings on proposed GS projects during formal public comment periods. Although permit application information will not be made available as it is submitted, permitting authorities must follow the public participation requirements for UIC permits specified in 40 CFR Part 124 which require that owners or operators publish a public

notice that includes information about where interested parties can obtain copies of the draft permit and application in addition to requesting a public hearing.

Furthermore, the Agency recognizes that the ini tial phases of site evalua tion and site selection may begin in advance of permit application s ubmission. The public may become aware of these activities and begin to have questions or conc erns about the pending project. For this reason, outreach and education—which are outside of, but complementary to, the public notification process—can help clarify project details and a void public misperceptions about the nature and safety of GS projects. This may also benef it the owner or operator by improving local acceptance of the site. EPA also notes that should change s to these plans require a permit modification under §144.39, the public must be notified according to the public comment procedures under 40 CFR

124.

In addition, EPA is evaluating op tions for a centralized data system through which the public could have access to public information on a GS project. EPA will also provide access to any required plan to the public upon request. Providi ng the public with info rmation throughout the GS project will help clear up and avoid public misper ceptions about the nature and safety of GS.

Letter ID: 0156 Comment ID: 22655 Letter Lines: 829 to 850

Comment Code: 1210 1.1.1 Comments about the proposed rule

38Comment: - Page 43497. To the extent that EPA w ill revise this preamble language, please consider ending the section on "Potential USDW Impacts" with a new sentence that reaffirms that the purpose of this proposed rule is to put in place regulations, best practices, enforcement mechanisms , etc. to ensure that all of the previously mentioned bad things that c ould go wrong with a CO2 storage project do not take place. This reviewer thinks th at given the negative tone of much of the material in this section it is appr opriate for the USEPA to reinforce the point that the purpose of this rule is to ensure that CO2 storage is done safely thus significantly reducing if not eliminating the extent to which any of these things actually happen.

- Page 43495 under "Why is Geologic Seque stration Under Consid eration". Please change sentence which says in part "he cap ture and storage of CO2 would enable

the continued use of coal in a manner th at" The first deployments of CCS are not going to be at coal fired electric power plants. There is no reason for this rule to be overly focused on coal based CCS applications and is not appropriate for this Class VI UIC rule since it is bounded by the SDWA which

means that the source of CO2 is not a cri tical aspect of this rule. Focusing on coal can also bring in a lot of ancillary (although important) issues surrounding the use of coal like mining practices that do not need to be

discussed within the boundari es of a proposed Class VI UIC rule. CCS is more than just coal.

Individual Response: EPA clarifies that the intent of the Class VI GS requirements are designed to ensure that, where deployed, GS is conduc ted in a manner that protects USDWs from endangerment. Please see the final rule and preamble for additional information on EPA's final approach.

Letter ID: 0156 Comment ID: 22656 Letter Lines: 852 to 858

Comment Code: 1320 1.1.3 General comments about GS

Comment: - Page 43498. Second paragraph on that page . "However, some CO2 releases from injection activities have been documented." Crystal Geyser is not an "injection activity" as that term is used in the context of this Class VI rule. The text in that paragraph makes it clear that th e CO2 which erupts from Crystal Geyser is from "improper well plugging." It is technically inaccurate, misleading and prejudicial to start off this paragrap h by saying "some CO2 releases from injection activities ha ve been documented."

Individual Response: EPA agrees that the Crystal Geyser si te is not associat ed with injection. However, this incident demonstrates that aba ndoned or improperly plugg ed boreholes can serve as conduits for migration of fluids to USDWs. It is for this reason that the final rule includes requirements related to performi ng corrective action on all deficient wells within the AoR at §146.84, and proper injection well construc tion that meets the goals of §146.86.

39Letter ID: 0156 Comment ID: 22657 Letter Lines: 860 to 863

Comment Code: 1655 1.3.5.1 Concerns about Lake Nyos a nd Mammoth Mountain-type events

Comment: - Page 43498. The USEPA is to be commended for the passage here on Lake Nyos and Lake Monoun and in particular for th e forcefulness with which the draft

Class VI rule makes it clear that these ar e not analogous to CO2 injected into a deep geologic formation.

Individual Response: EPA acknowledges the comment.

Letter ID: 0156 Comment ID: 22658 Letter Lines: 865 to 877

Comment Code: 1620 1.3.2 Induced seismicity

Comment: - Page 43498, section on "Seismic Events." The first sentence in this section is clearly speaking to the potential for CO2 injection to cause seismic activity in the future when commercial deployme nt of CCS becomes more common place. However, the second sentence and the subse quent discussion of induced seismicity at the Rocky Mountain Arsenal are not rela ted to CO2 injection. To be clear, it was not CO2 that was being injected into deep geologic formations beneath the Rocky Mountain Arsenal. If this section of the preamble is retained in future versions of this proposed rule, this sec tion must be rewritten to make it clear

that the technical literatu re suggests that poorly managed CO2 injection could in the future induce small scale seismic activity. And then if there is a need to discuss previous instances where inj ection of fluids that were not CO2 triggered seismic activity the language n eeds to be clear a nd explicit so the reader understands that these are not pa st instances of poor CO2 injection.

Individual Response: EPA clarifies that the seismic episodes at the Rocky Mountain Arsenal, which occurred in the 1960s—before the original UIC regulations were developed—were due to poor site characterization and well operation, including high, unmonitored injection pressures (73 FR 43498). While EPA acknowledges that the volumes of CO2 injected at GS sites will likely be larger than the volumes of waste wa ter injected at the Rocky Mountain Arsenal, injection volume is not the sole factor that de termines induced seismicity. Induced seismicity also depends on other geologic variables such as pre-existing faults, porosity, and permeability (Sminchak & Gupta, 2003). With proper site ch aracterization (i.e., pursuant to §146.82), these variables can often be quantified prior to inje ction (Sminchak and Gupta, 2003) and used to identify sites capable of safely sustaining prolon ged injection of large volumes with low risk. As long as a site is well-characterized and mon itored, and the injection volume and rate remain within permitted limits set forth by the Director, the injection of large volumes of fluid should not increase the risk of seismic activity.

EPA does not believe that limiting GS to "stable ar eas" will provide certainty that seismic events will not occur. The Agency acknowledges that some regions of the country are at risk for

40infrequent, damage-causing seismic events even if such events have not been recorded in the recent historical record (i.e., in the past seve ral hundred years). For this reason, EPA requires seismic risk to be evaluated on a site-specific basi s, through an analysis of seismic history and an evaluation of known or suspected faults in th e AoR, geomechanical information on fractures, stress, ductility, rock strength, and in situ fluid pressures within the confining zone as specified in §146.82(a)(3). In addition, if an adverse event, such as a well failure or evidence of fluid movement were to occur, the monitoring requ irements at §146.90 and emergency and remedial response requirements as specified in §146.94 provide addi tional protection.

Letter ID: 0156 Comment ID: 22659 Letter Lines: 879 to 895

Comment Code: 2140 1.6.2 Depleted oil and gas reservoirs

Comment: - Page 43503. While it is a widely held be lief that much more is known about depleted oil and gas (DOG) fields within the US as opposed to DSFs, it is not at ll clear if this is true or significant in terms of the proposed Class VI rule or in terms of the decision making proce ss a private firm would use to decide

whether to utilize DOG or DSF fields in a commercial CO2 storage project. To

the extent that there is more known about DOG fields, much of this data is proprietary and is in the hands of oil companies and oil field service companies. For more than a decade memb ers of the CCS community have been seeking access to this presumed treasur e trove of geologic data to build a national CO2 storage reservoir data base w ith this presumably high quality data. But the data have not been released, lik ely due to legitimate private sector concerns over protecting valuable proprieta ry information or perhaps this wealth of easily exploitable high quality data do not exist at these firms. So if the data exist but are not available, it seems immaterial to assert here that a significant cost savings could be had by exploiting DOG fields. This has not been proven in practice and I believe it might not ever be proven out in practice.

Individual Response: EPA clarifies that the statement presumed that owners or operators planning GS in depleted oil and ga s fields would be the same part ies that delineated the field for the purpose of oil and gas explor ation and would have already co llected much of the necessary data in the course of explorati on and therefore would realize a co st savings as a result of that previous work.

Letter ID: 0156 Comment ID: 22660 Letter Lines: 897 to 908

Comment Code: 3864 2.3.3.2 Use of corrosion-resistant cements (seeking comment)

Comment: - Page 43509, last full paragraph on that page. The text here seems to imply that the cement used for CO2 storage wells will be eaten away by "acid" in one week. This is one example of a number of places in the rule where "perhaps inadvertently in the editing process" it seems as if text was deleted that

41would have helped a reader understand that "we are now discu ssing a scientific study that has some bearing on the topic at hand but isn’t exactly like GS" and "now are switching to an explicit discussion of what the USEPA will require of owners and operators of GS projects." If this text is retained in subsequent

interations of the Class VI rule it woul d be good to explain why this study is germane to regulating GS in the United States and whether the same thing is expected to happen in practice. If ceme nts in wells are going to fail in a week, then there isn’t much point in promulgating this rule.

Individual Response: EPA clarifies that the Duguid et al. (2004) study referenced in the preamble to the proposed rule was only one of many studies it considered when developing the construction requirements for Class VI wells. The laboratory studies of Duguid et al. (2004, 2005) found rapid degradation of cement under conditions of flowi ng (replenishing) CO2- saturated brines. Other more recent laboratory st udies (Barlet-Gouedard et al., 2006; Kutchko et al., 2007) found cement alteration, but no significant degradation (loss of integrity) in experiments that subjected the cement to st atic (non-replenishing) volumes of CO2. The SACROC well materials sampled and studied also likely were not exposed to flowing (replenishing) acidic brines (Carey et al., 2007). Cement alteration and corrosion were found to occur at differing rates in the various studies re searched. The two studies with the most cement alteration were Duguid et al. ( 2004) (presumably due to exposure to the CO2-brine flux) and Barlet-Gouedard et al., (2006) (perhaps due to the higher experimental temperatures), but EPA notes that other important factor s such as pressure, contact with CO2-saturated brine, and time between cement curing and cont act with CO2 may have an impact on the rate of cement

corrosion.

Letter ID: 0156 Comment ID: 22661 Letter Lines: 910 to 918

Comment Code: 4200 2.4.2 Down-hole shut-off valves in GS wells (seeking comment)

Comment: - Page 43511. The USEPA does a good job of explaining why the cost of requiring

down hole shut off valves should not be seen as being overly burdensome for potential operators of GS sites. While th e logic and data pres ented here seem convincing and make the point, it seems that a cost/benefit calculation might be a secondary issue. If the USEPA believes that these down hole shut off valves are needed to discharge its responsi bilities under the SDWA (i.e., protect USDWs) then that should be the primar y reason. The USEPA should not need to defend requirements needed to carry out its responsibilities under the SDWA with cost/benefit analyses.

Individual Response: After evaluating the risks and benefi ts of down-hole shut-off systems and considering additional research, EPA will not re quire automatic down-hole shut-off devices for onshore Class VI wells since it is not necessary in all cases to ensure protection of USDWs from endangerment. Instead, the final rule, at §146.88(e)(2 ), requires that owne rs or operators of

onshore Class VI wells install automatic surface shut-off devices. The rule affords Director's

discretion to mandate automatic down-hole shut -off devices in onshore situations that may warrant their use. However, the Agency believ es that offshore Class VI wells present unique

42construction and operational conditi ons, including isolation from shorelines and the need to construct wells through the water column and the subsurface, which may delay response time in

the event of well difficulties. Th e rule requires, at §146.88(e)(3), that owners or operators of

offshore wells within State territorial waters install automatic down-hole shut-off systems. EPA believes that these requirements at §146.88(e) ensure that proper precautions are taken to prevent subsurface fluid movement and ensure protection of USDWs.

EPA clarifies that the decision not to require the use of down-hole shut-off systems for all

onshore wells was not based on the co st of such systems, but the effect such systems would have on well operation and whether it was necessary to protect USDWs from endangerment in all

cases.

Letter ID: 0156 Comment ID: 22662 Letter Lines: 920 to 926

Comment Code: 4490 2.4.5 Use of tracers and potential im pact on human health or ecosystems (seeking comment)

Comment: - Page 43513. EPA should not require th at tracers be used in all GS applications across the very heterogeneous set of deep geologic formations that could be used to store CO2 in the USA. The USEPA (and in particular the Office of Air and Radiation) might want to cons ider doing full life-cycle analyses of the manufacture, storage, use and potential leakage of tracers to help better inform the technical community about the co st / benefits of us ing this one class of MMV technologies.

Individual Response: EPA agrees that tracer use is not ap propriate in all situations. For this reason, EPA does not require the use of tracers at all GS sites; however, the Director has discretion to require their use if he/she determines that th e use of tracers could improve monitoring of the site and enhance USDW prot ection from endangerment. The rule will also allow their use if proposed by the owner or operator and approved by the Director.

Letter ID: 0156 Comment ID: 22663 Letter Lines: 928 to 938

Comment Code: 4655 2.6.5.1 Plume tracking techniques/ geophysical methods (seeking comment)

Comment: - Page 43515. It strikes this reviewer as odd to cite only one study (Burton et al, 2007) to support the statement that "current monitoring technologies are more than adequate for monitoring pressure in a GS project." It is not clear if by including this in the preamble to the draft rule whether EPA shares this

assessment or not. This seems like an aw fully broad and sweeping statement. Consider rewording. Consider being explicit as to whether EPA shares this view or if part of any NODA associated with th is rule making should try to collect information that goes beyond this one study to confirm or refute this assertion that pressure monitoring technologies whic h exist today are su fficient to meet

43any GS need in any kind of formation anyw here and at any time across all regions

of the USA.

Individual Response: EPA clarifies that the GS rule, at §146.90(g), requires owne rs or operators to perform monitoring to track the extent of the CO2 plume a nd pressure front. The owner or operator must use direct methods to monitor for pressure changes in the injection zone. Indirect methods (e.g., seismic, electrical, gravity, or electromagnetic surveys and/or down-hole CO2 detection tools) are required un less the Director determines, ba sed on site-specific geology that such methods are not appropriate. EPA recognizes that monitoring technologies will evolve and improve over time, and for these reasons, the Agency is using an adaptive approach to regulate GS injection. The Agency plans, every six years, to collect and review data on GS projects to determine whether the appropriate amount a nd types of information and appropriate documentation are being collected, and to determ ine if modifications to the requirements are appropriate or necessary.

Letter ID: 0156 Comment ID: 22664 Letter Lines: 940 to 957

Comment Code: 4655 2.6.5.1 Plume tracking techniques/ geophysical methods (seeking comment)

Comment: - Page 43516. It is not clear if the USEP A is asserting that using "seismic crosswell methods" are "costly and time cons uming" or if that is a finding of the GEO-SEQ (2004) report mentioned at the start of this para graph. If it is the latter then it is important to clea rly attribute that statement to the authors of the GEO-SEQ report. Otherwise, it appears that the USEPA is calling into question the cost effectiveness and ut ility of a technique that has yet to be robustly tested with respect to GS. That would seem to be a premature assumption based only on the results of the GEO-SEQ project, since crosswell seismic could be a preferred option for so me sites where alternative options are impractical or economically infeasible. This section contains a number of implicit references to cost/b enefit calculations for monitoring t echnologies. If

the USEPA believes that these techni ques are needed to discharge its responsibilities under the SDWA, then that should be stated and these techniques should be required. The text could say something about encouraging technological progress in the hopes of co ming up with less costly but equally effective monitoring technologies, but it do es not seem appropriate to try and justify some actions by alluding to cost benefit analyses as the basis for decision making.

Individual Response: EPA does not believe that prescribing specific technologies to be used in all cases for GS would be appropriate given the variability in sites. Rather, EPA is developing guidance on testing and monitoring to assist owners or operators and Directors in evaluating requirements under §146.90, including proposed monitoring plans. The guidance describes available technologies and reco mmended approaches for implem enting a testing and monitoring plan, including pre-operational geophysical logging and testin g of injection wells, MITs, injection well testing during ope ration, groundwater quali ty monitoring, tracking the CO2 plume

44and pressure front, and soil gas and surface ai r monitoring which may be required by the UIC Director for specific GS projects. The guidance can be found on EPA’s website at http://water.epa.gov/type/groundwat er/uic/wells_se questration.cfm.

EPA clarifies that cost-benef it analyses are not required to be done under the SDWA to determine the most appropriate monitoring tech nologies, location, or frequency. Instead, the Agency believes that the flexibility afforded the owner or operator at §146.90 to develop a testing and monitoring plan tailored to site-specific characteristics is appropriate for GS. EPA estimated the costs of monitoring GS sites as part of the GS rulemaking effort, and estimates that the Class VI requirements will result in additiona l costs. The cost analysis for the final GS rulemaking (which is available in the docket) shows an approximate in crease of 30 percent in comparison to Class I wells.

Letter ID: 0156 Comment ID: 22665 Letter Lines: 959 to 969

Comment Code: 1360 1.1.3.4 Effectiveness of trapping mechanisms

Comment Code: 5280 2.8.2.4 USDW non-endangerment demonstrations

Comment: - Page 43519. Consider explic itly referencing the work laid out by Benson to support the statement that physical and geochemical trapping mechanisms will help to improve the integrity of storag e as time moves forward. This is a critically important "but widely misunde rstood" point about how GS will work in practice. It would be good to includ e at least one citation to technical work to back up this point.

o OTC 19244. Multi-Phase Flow and Trapping of CO2 in Saline Aquifers. Sally M. Benson, SPE, Stanford University. Copyri ght 2008, Offshore Technology Conference This paper was prepared for presen tation at the 2008 Offshore Technology Conference held in Houston, Texas, U.S.A., 5-8 May 2008.

Individual Response: EPA added the Benson study to the final rule preamble (and has made it available in the rulemaking docket).

Letter ID: 0156 Comment ID: 22666 Letter Lines: 971 to 988

Comment Code: 5434 2.9.1.2 Need for additional instruments (seeking comment)

Comment: - Page 43521. The text here briefly me ntions on going analysis of "pay-in periods for trust funds" in the context of financial assurance. I do not understand the statement here that says "E PA is considering a guidance approach that would recommend a pay in period of three years for GS projects." "Three years" seems completely arbitrary. What w ould be the basis for the fee paid in those three years? Would it be a charge of $1/tonCO2 or $50/tonCO2? There is no way to understand the utility of a thr ee year pay-in period without knowing

much more about what costs this fund was supposed to cover, how the fee would be

45assessed, at what level would the fee be set, etc We have recently completed an analysis that sheds light on a number of issues specifically related to trust funds applied to GS and I believe it is potentially relevant to the USEPA’s ongoing evaluation of these issues. Please s ee [SEE PDF TO VIEW THIS DOCUMENT]:

o Dooley JJ, C Trabucchi, and L Patton. 2008. "Tipping Fees Can't Save us from the Tipping Point: The Need to Create Rati onal Approaches to Risk Management that Motivate Geologic CO2 Storage Best Practices." To be published in the Proceedings of the 9th International Conference on Greenhouse Gas Technologies. October 2008. PNWD-SA-8349, Pacific Northw est National Laboratory, Richland, WA.

Individual Response: EPA acknowledges that there may be several possible approaches to setting pay-in periods for trust funds. The three ye ar pay-in period considered for comment in the proposal is not arbitrary because it is a time frame consistent with other similar programs in the Agency. The final rule requires th at the Director approve the use and length of pay-in periods. EPA is developing guidance (a vailable on EPA's website at http://water.epa.gov/type/groundwat er/uic/wells_sequest ration.cfm) that describes the types of financial instruments that owners or operato rs can use to meet financial responsibility requirements for GS wells. Specifically, the guida nce will discuss pay-in periods and provide guidance for Directors to use in determining an appropriate pay-in period so that the financial benefits to the owner or opera tor of a longer pay-in period ar e balanced with the increased financial risk to the public. EPA adds that ow ners or operators may choose from a variety of

financial instruments to meet thei r financial responsibility needs.

Letter ID: 0156 Comment ID: 22667 Letter Lines: 990 to 1000

Comment Code: 7300 4.3 Regulatory Flexibility Act

Comment: o Page 43530. The draft rule correctly stat es "Sequestering CO2 via injection wells is a voluntary action that would only be undertaken by an entity if it were in its interest compared to other alternatives it may have." This point is worth repeating a number of times in this proposed rule. In particular, this might be worth repeating in discussions of what is required for Class VI wells and the cost of meeting these requiremen ts. At times, it seems as if the USEPA is apologizing for requiring compliance with measures designed to protect USDWs. The USEPA should ask for the public and other stakeholders to perform a thorough and rigorous review of any proposed re quirements but there is no need to apologize. As the draft Class VI rule ma kes clear, no one is being required to use GS. That is important to remember and likely bears repeating.

Individual Response: EPA acknowledges this comment. The GS rule does not require any facilities to sequester CO2. The purpose of the GS regulation is to ensu re that, where deployed, GS is conducted in a manner that protects USDW s from endangerment. EPA discussed this in the preamble to the proposed rule (73 FR 43492), a nd further clarified this fact in the final rule preamble and the Cost Analysis, which is av ailable in the docket for the rulemaking.

46Letter ID: 0156 Comment ID: 22668 Letter Lines: 1002 to 1003

Comment Code: 4650 2.6.5 CO2 plume and pressure fr ont tracking (seeking comment)

Comment: o What if any are the co nstruction requirements and mechanical integrity requirements for monitoring wells?

Individual Response: Construction specifications for monito ring wells must be described in the testing and monitoring plan subm itted with the permit applicati on. EPA is developing guidance

on well construction that will include recommen dations for monitoring well construction. The guidance will be available on EPA’s website at http://water.epa.gov/type/groundw ater/uic/wells_seque stration.cfm. EPA is also developing guidance on testing and monitoring to assist owners or operators and Directors in evaluating requirements under §146.90, includi ng proposed monitoring plans. The guidance describes available technologies and reco mmended approaches for implem enting a testing and monitoring plan, including pre-operational geophysical logging and testin g of injection wells, MITs, injection well testing during ope ration, groundwater quali ty monitoring, tracking the CO2 plume and pressure front, and soil gas and surface ai r monitoring which may be required by the UIC Director for specific GS projects. The guidance can be found on EPA’s website at http://water.epa.gov/type/groundwat er/uic/wells_sequestration.cfm. In addition, in January 2009, DOE published a best practices manual entitled "Monitoring, Verificat ion, and Accounting of CO2 Stored in Deep Geologic Formations" (DOE/NETL-311/081508); this manual is included in

the docket for the final GS rule.

Letter ID: 0156 Comment ID: 22669 Letter Lines: 1005 to 1018

Comment Code: 7700 4.7 Executive Order 13045: Child ren's Health Protection

Comment: o Page 43531. The USEPA invites the public to identify peer reviewed studies

that assess the effects on infants and t oddlers who are exposed to drinking water that has been degraded "by geologi c sequestration of ca rbon dioxide." The wording here seems to assume a number of key steps that I am not sure one can assert given where humanity is in terms of the commercial deployment of GS. This request for information would be better if it requested information on studies that speak to the impact of drinking contaminated wa ter by infants and toddlers caused by processes that could result from a poorly functioning GS project at some point in the future. I do not see how there can be existing studies that show negative impacts on children from drinking water contaminated by a malfunctioning GS project. It is worth comp aring the language here with the far more balanced and accurate language on page 43532 where the USEPA forcefully asserts that the proposed rule will not have a disproportionate impact on minority and low-income populations.

Individual Response: EPA is funding research related to the potential for USDW contamination associated with GS projects. In addition, the Agen cy is tracking external research that focuses on

47potential exceedances of drinking water standards, which were developed by EPA and take into account impacts on children's health.

In the August 31, 2009, Notice of Data Availabi lity (NODA) and Request for Comment (74 FR 44802), EPA published the results of a study in which Lawrence Berkeley National Laboratory (LBNL) evaluated the potential for GS to cause changes in ground water quality as a result of CO2 leakage and subsequent mobilization of trace elements such as arsenic, barium, cadmium, mercury, lead, antimony, selenium, zinc, and uranium (Birkholzer et al., 2008a). LBNL

estimated the amount of trace elements from na tive mineral species that could potentially be mobilized by the intrusion of CO 2 and the potential ground water con centrations that could result to determine the potential for drinking water standards to be exceeded. EPA has also examined potential methods for conducting treatment of wa ter affected by a CO2 leak; this study is presented in the final rulemaking docket.

EPA continues to fund research in this area. In December 2009, EPA's Office of Research and Development (ORD) awarded a Science to Achieve Results (STAR) grant to Clemson University to investigate the potential for GS to affect USDWs. This research will involve laboratory experiments and modeling simulations to invest igate the fate of dissolved CO2 in underground geologic formations and to determine possible ri sks associated with the dissolution of CO2 in underground aquifers. This STAR Grant is among six such grants awarded to major universities and institutions focusing on: "Integrated De sign, Modeling and Monitoring of Geologic Sequestration of Anthropogenic Carbon Dioxide to Safeguard Sources of Drinking Water."

EPA clarifies that the purpose of the GS rule is to protec t USDWs from endangerment through permitting, siting, construction, operation, injection, a nd post-injection site care and site closure requirements that are tailored to address the unique nature of GS. The Class VI requirements, therefore, minimize health risk s to all populations, including ch ildren. The "Risk and Occurrence Document for the Geologic Sequestration Rule making," available in the rulemaking docket, presents a broad discussion of risks to human h ealth and the environment associated with GS, including those addressed under SDWA authority and those environmental and human health impacts that are beyond the scope of the SDWA.

As part of its adaptive rulemaking approac h, EPA plans to collect and review available

information such as the research described abov e and data every six year s on early GS projects, including impacts to USDWs and dr inking water quality that may aff ect the health of children, to determine whether the appropriate amount and t ypes of information and documentation are being collected, and to determine if modifications to the requirements are a ppropriate or necessary.

Letter ID: 0156 Comment ID: 22670 Letter Lines: 1020 to 1025

Comment Code: 5220 2.8.2.1 Post-injection monitoring activities

Comment: o Page 43540 under "Post-injection site care and site clos ure." The USEPA should ask for a seismic image or other data that depicts the current extent and placement of the CO2 plume. The current language asks for "the predicted

48position." If the EPA would like modeling of the predic ted position for some purpose that is fine but there is no reason not to ask for data that shows where the plume really is.

Individual Response: EPA clarifies that the purpose of the requirement that the PISC and site closure plan include a prediction of the magnit ude of the pressure di fferential between preinjection and during post-injec tion at §146.93(a)(2)(i) is to suppor t planning of the amount of monitoring that is necessary during PISC and planning the length of th e PISC timeframe. EPA anticipates that this information will be provided by the computational modeling performed for

the AoR delineation.

EPA is developing guidance to assist owners or operators in evaluating well plugging, postinjection site care, and site closure requirements of §146.92 and §146.93. Additionally, the guidance will assist Directors in evaluating propo sed well plugging plans a nd post-injection site care and site closure plans under §146.92 a nd §146.93. The guidance describes recommended approaches for how an owner or operator coul d plug injection and m onitoring wells; perform post-injection monitoring; dem onstrate non-endangerment; and perf orm site closure activities. The guidance will be available at http://www.epa.gov/safewater/ wells_sequestration.html.

Letter ID: 0156 Comment ID: 22671 Letter Lines: 1029 to 1033

Comment Code: 1220 1.1.1.1 Terminology and definitions

Comment: - Page 43493, in the "Definitions." Consideration should be given to breaking

the definition of EOR/EGR into two diffe rent short paragraphs. The physical processes as well as economic drivers i nvolved in EOR and EGR are not strictly

similar and it is not clear that these should be lumped together in something like a federal regulation.

Individual Response: EPA disagrees with the suggested edit . The final definition of enhanced oil or gas recovery (EOR/EGR) remains unchanged. The Agency clarifies that the final Class VI GS rule does not require owners or operators to use GS technologies, no r does it impact business as usual for Class II owners or operators that are injecting CO2 to enhance production of oil or gas. Additionally, EPA clarifies that the intent of the Class VI GS rule is not to address the use of CO2 for EOR or EGR. Rather, the purpose of the Cl ass VI GS regulation is to ensure that, where deployed, GS is conducted in a manner that protects USDWs from endangerment.

Based on its evaluation of all public comments and input on the proposed rule and the NODA and Request for Comment, EPA has made many revisions to the Cla ss VI GS rule. Please see the final rule and preamble for additional information.

Letter ID: 0156 Comment ID: 22672 Letter Lines: 1035 to 1043

Comment Code: 1320 1.1.3 General comments about GS

49Comment: - Page 43495, third column, under "II What is EPA Proposing?" I believe the IPCC Special Report on Carbon Dioxide Capture and Storage (IPCC SR on CCS) and/or more recent peer reviewed papers can shed light on the timeframes under which primary and secondary trapping mech anism begin to operate. Adding some quantification to this poin t would likely help stake holders better understand and be more familiar with CO2 storage. Consider adding something like "Some of these trapping mechanisms begin as soon as the CO2 is inject ed into the host

formation while others take hundred to thous ands of years to run their course."

I believe one could cite the IPCC SR on CCS to substantiate that point.

Individual Response: EPA agrees that the IPCC study me ntioned is informative. The IPCC report is cited extensivel y in the preambles to the proposed and final rules, and is also available in the rulemaking docket.

Letter ID: 0156 Comment ID: 22673 Letter Lines: 1045 to 1050

Comment Code: 1612 1.3.1.1 Leaching and mobilization of cont aminants; reactions in injection

zone

Comment: - Page 43497 under "What are the risks associated with CO2 GS?" I do not see any reason to include the modifier "likely" in the first sentence of "Potential USDW Impacts." Under what set of circumst ances would CO2 injected into a waterbearing deep geologic formation not come into contact with formation waters? Delete "likely" from this sentence. It does not help readers understand CCS or how EPA will regulate CO2 storage.

Individual Response: EPA acknowledges that there are pote ntial risks associated with GS, including the potential that CO2 injection for GS may result in leaching of subsurface materials that could mobilize contaminants or compromi se pore space, and ther efore injectivity. The purpose of the Class VI requirements is to minimize and mitigate potential/identified risks through proper site characterization, well cons truction, operation, monitoring, post-injection site care, and site closure. To ensure USDW protect ion and mitigate risks, the GS regulation requires the owner or operator of a Cla ss VI well to submit data about the site (during the site characterization process), including information on the porosity, permeability, mineralogy, and geochemistry of the injection and confining zones, along with information on the compatibility of the CO2 stream with fluids in the injecti on zone and minerals in both the injection and confining zones as specified in §146.82. This data can help identify potential geochemical reactions that may occur between the inject ed CO2 and the host geologic formation. Identification of potential reactions prior to inj ection would address concerns that formation of carbonic acid could dissolve potential limestone creating karst features.

During injection operations, opera tors must extensivel y monitor ground water quality to provide early detection of any unacceptable movement of fluids or impurities in the subsurface as specified in §146.90. Operators must develop and follow an emergency and remedial response plan to address any adverse effects associated with the GS operation, including contamination as

50specified in §146.94, and provide financial responsib ility to address contamination as specified in §146.85.

Letter ID: 0156 Comment ID: 22674 Letter Lines: 1052 to 1074

Comment Code: 1200 1.1 General comments about the rulemaking

Comment: - Page 43497 under what are the "Potential USDW Impacts." Please consider adding at the very end of this section a senten ce that reaffirms for the reader that the fundamental purpose of the proposed Cla ss VI rule is to make sure that the bad things above enumerated do not occur.

- Page 43502, third sentence under "How W ould this Proposal Affect Existing Injection Wells Under the UIC Program?" Pl ease consider being specific as to what kind of "production" is being discu ssed here. From the context of this sentence it would seem to be "producti on of oil" or perh aps "production of hydrocarbons" but it would not seem to c over "production of brackish waters for the purpose of desalination to provide potable water." The phrase "any production seems overly vauge.

- Page 43505 within the discussion of CO 2 storage in coal seams. It is

incorrect to state that "the process of CO2 adsorption to the coal has not been proven." This is well established. I th ink what USEPA intended to say was something like "the commercial applicat ion of coal-based CO2 storage has not been proven." The fundamental principle of CO2 adsorbing on the coal surface is established. Whether this is going to work in situ and at commercial scale has not been established / proven. Please consider rewording.

- Page 43516. "Simulations discussed in the manual confirm seismic and - What

- manual"? It is not clear what is being discussed here.

Individual Response: In response to the comment regarding production, EPA clarifies that this discussion refers to Class II wells, which are associ ated with the recovery of oil and or gas. The purpose of the discussion is to distinguish injection (which is regulated under the UIC regulations) from produc tion (which is not).

In response to the comment regarding CO2 adsorp tion to the coal, EPA clarifies that GS in

unmineable coal seams has been th e subject of less research than saline formations or depleted oil and gas reservoirs. EPA acknowledges that site -suitability for GS is dependent on a number of factors and that many formation types may be suitable for GS. The final GS rule does not preclude injection into unmineable coal seam s (or any formation type) provided owners or operators can demonstrate that GS can be pe rformed in a manner that protects USDWs from endangerment. The Agency anticipates that in the near-term, most GS in unmineable coal seams will continue to be experimental. Such projects may be permitted as Class V experimental technology wells if they are of an experimental nature (i.e., to test GS technologies and collect data).

51The "manual" referenced on page 43516 is th e GEO-SEQ Best Practic es Manual. Geologic Carbon Dioxide Sequestration: Si te Evaluation to Implementati on. Lawrence Berkeley National Laboratory. Paper LBNL-56623. The GEO-SEQ Be st Practices Manual is available at: http://www.netl.doe.gov/technol ogies/carbon_seq/refshelf/GEO -SEQ_BestPract_Rev1-1.pdf.

Please see the remainder of EPA's responses to th is comment for further details. For additional information on EPA's final regulatory approach, pl ease see the final rule and preamble as well as the rulemaking docket.

Letter ID: 0156 Comment ID: 22675 Letter Lines: 1076 to 1086

Comment Code: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87)

Comment: - Page 43538. Does the USEPA (or states th at have primacy for Class VI wells) really want to take physical possession of cores from prospective GS sites? The rule currently states "The owner or op erator must take and submit to the

Director whole cores or si dewall cores of the injec tion zone and confining system and formation fluid samples from the injection zone(s)." I understand the requirement that the Class VI permit a pplicant needs to take cores and needs to perform tests upon them but wouldn’t it be more meaningful for the "Director" to receive a written summary of thos e tests and a description of the methodologies used in the testing of the cores than to litera lly take physical possession of the cores themselves? The US EPA should consider rewording this

passage.

Individual Response: EPA clarifies that it is not the Agency's intent that physical cores be submitted to the Director. In the final GS rule, EPA has revised the first sentence of §146.87(b) to read as follows: "The owner or operator mu st take whole cores or sidewall cores of the injection zone and confining system and formati on fluid samples from the injection zone(s), and must submit to the Director a detailed report pr epared by a log analyst that includes: well log analyses (including well logs), core analyses, and formation fluid sample information...."

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