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.1 COMMENTS ON THE U.S. ENVIRONMENTAL PROTECTION AGENCY’S PROPOSED RULE FOR FEDERAL REQUIR EMENTS UNDER THE UNDERGROUND INJECTION CONTROL (UIC) PROG RAM FOR CARBON DIOXIDE (CO 2 ) GEOLOGIC SEQUESTRATION (GS) WELLS Docket ID No. EPA-HQ-OW-2008-0390

Introduction The Energy & Environmental Research Center (EERC) at the University of North Dakota directs

the Plains CO 2 Reduction (PCOR) Partnership, which is one of seven regional partnerships funded by the U.S. Department of Energy’s Re gional Carbon Sequestration Partnership Program and a broad range of project s ponsors. The PCOR Partnership is a diverse group of public and private sector stakeholders working together to better understand the technical and economic feasibility of capturing and storing CO 2 emissions from stationary sources of CO 2 in the central

interior of North America. Below, the PCOR Pa rtnership provides a general overview of topics to be considered when rules are developed; in addition, more detailed comments on specific sections of the proposed rules are provided.

General Overview Over the course of several decades, the enhanced oil recovery (EOR) industry has developed and successfully implemented operational prac tices to handle large volumes of CO 2 safely and effectively. Since the 1970s, millions of tons of CO 2 per year have been safely transported over thousands of miles of pipelines and injected into wells in a variety of geological settings throughout the world. The industry’s best practi ces can be extended into the field of CO 2 sequestration with almost seamless ease. Tools of exploration, surface CO 2 handling (including gas processing, compression, and transportation), well designs, injection practices, surveillance of emplaced CO 2 , and the science and experience to asse ss risks of site permanency are all directly applicable. For example, it is estim ated that over 8 tril lion cubic feet of CO 2 has been

stored in the Permian Basin. These volumes ar e indicative of an exis ting industry with an outstanding record of performance. This experi ence should not be discarded. Assurance of longterm storage is the key feature that needs to be demonstrated.

Just as in nature with deep-sourced, natural CO 2 , there are low-risk sites that will permanently entrap CO 2 , and there are places where it may mi grate, perhaps even to the surface.

CO 2 is a naturally occurring substance, and mo vement within the subsurface is very common. Rather than trying to fashion rules that protect against surf ace escape in all subsurface conditions, regulatory oversight needs to recogn ize the nearly ubiquitous presence of the molecule while identifying low-risk sites for entr apment and provide flexibility in regulation to

accommodate the attendant risk level.

In order to achieve statistically significan t reductions of greenhouse gas emissions, largescale carbon capture and storage (CCS) will have to be implemented at numerous sites. One of the greatest potential barriers to widespread deployment of se questration projects would be the specification of overly complex well design and monitoring of s ites. Experience shows that exotic well designs add little be nefit, while, on the other hand, judicious site selection adds2 greatly to the security of emplacement. For example, subsurface sequestration formations overlain by bedded salts provide optimal conditio ns for long-term storage. The focus of regulation should be performance criteria , not design criteria. As long as CO 2 sequestration sites can meet the standards required for permitting, injection of CO 2 for sequestration is, to a large extent, similar to EOR operations. In turn, requ irements for injection we lls accessing judiciously selected zones for sequestration should be more closely aligned with thos e of Class II standards than the more stringent Class I hazardous waste well standards. As currently proposed, the Class VI requirements are more reflective of Class I hazardous waste well standards.

It is important to be mindful that CO 2 , relative to other common and not-so-common injectates, is relatively innocuous . Increasing concentrations are easily detected in groundwater through simple monitoring of pH. Carbon diox ide in groundwater poses minimal acute or

chronic threat to human health or the environmen t, especially when compared to other materials

that have been classified as hazardous. As long as potential injection si tes are appropriately characterized and judiciously selected and in jection operations are designed and conducted according to longstanding engineering and regulatory standards, the leakage of CO 2 into underground sources of drinking water (USDW) is likely to be a preventable and infrequent

occurrence. In the rare event that CO 2 should leak into USDWs, it is also important to note that its primary effect on groundwater will be to fo rm a weak acid (carbonic acid) and lower pH, which can be relatively easily mitigated by a va riety of commonly used, simple remediation practices.

A final comment has to do with any rules or policies that might marginalize EOR as a sequestration tool. The PCOR Partne rship believes the early-captured CO 2 will be injected in large volumes and stored during existing and ne w commercial (i.e., EOR) operations. The only reference to the use of EOR sites for sequestra tion is contained in proposed rule § 146.83(c) which discusses repermitting existing wells as Class VI storage wells. The emission reduction potential and sequestration associated with EO R are immense, and revenues from the oil produced will offset the cost to the economy an d will, ultimately, acceler ate more widespread deployment of CCS technologies. With the growi ng energy concerns in the United States, the

contributions of CO 2 EOR in the advancement of CCS need to be embraced. This reality needs to be further embraced when one contemplates a st reamlined approach, such as “grandfathering” for Class II wells that may be useful fo r sequestration beyond the EOR project.

Detailed Comments

Page 43492. SUMMARY. Regarding the phrase “...help ensure consistency...”

Consistency does not necessarily mean that regulations are appropr iate or effective. Geology is notoriously heterogeneous and, therefore, by definition inconsistent. Striving for consistency across geologic syst ems is difficult at best. One need only to look at the history of injec tion regulation across different states to see a lack of consistency is appropriate and primarily due to heterogeneity a nd inconsistency with respect to regional geologic characteristics. Gu idelines must be flexible. Flexibility to

ensure the safe maximization of CO 2 storage must not be compromised by a desire to ensure consistency of rule s across all geologic settings.3 Page 43495. II. What Is EPA Proposing. “development of a key cl imate change mitigation technology”? Will these rules really support the “ development of a key climate change mitigation technology” ? Is it really within the purview of protecting USDW?

Page 43496. B. What Is EPA’s Authority und er the Safe Drinking Water Act (SDWA) to Regulate Injection of CO 2 ? Regarding the following quote from the document, referring to a key aspect of the Safe Drinking Water Act:

“Section 1421 (b)(3)(A) of the Act also pr ovides that EPA’s UIC regulations shall permit or provide for consider ation of varying, geologic, hy drological, or historical conditions in different States and in different areas within a State.”

It is important that this aspect of the SDWA is a guiding principle for the proposed regulations. Based on those words in the SDWA , flexibility is demanded by statute and must be built into any UIC regulations. Unfortunately, the regulations proposed for GS wells in this document are often anything but flexible, but rather ar e quite prescriptive

and inflexible.

Page 43498. The Weyburn Field is in Saskat chewan, Canada, not Alberta.

Page 43498. The example cited here (Crystal Geyser, Ut ah) is not associated with an “injection activity.” It is naturally occurring CO 2 that leaks via an improperly abandoned exploration well.

Page 43498. This page includes a very good and reas onable description of the relative inapplicability of the Lake Nyos inci dent as an analog for possible negative consequences of a large CO 2 leak from a geologic storage site.

Page 43498. Regarding the statement,

“the measures outlined in today’s propos ed rulemaking to prevent endangerment of

USDWs may also prevent migration of CO 2 to the subsurface.”

This statement is fine, as long as protecting leakage to the atmosphere does not lead to stricter measures than would be required to protect USDWs. For example, regulations should be driven by a desire to maintain a leakage rate below a certain percentage of the injected volume, unless that percentage can be demonstrated to adversely affect USDWs. Another way to state it is this: a 1% leakage rate may or may not adversely

affect USDWs; therefore, a 1% rate should not necessarily be unacceptable.

Page 43499. One would caution rule makers on putting t oo much faith into any one institution or any one method when studying potential im pacts. Should not such information be provided by various technical s ources? While the utility of models and laboratory data is recognized, their results s hould not supersede real-world experience, field-based data, and local knowledge.4 Page 43500. Regarding the statement,

“4-D seismic is a valuable tool for plume tracking” at Weyburn.

“ Is” is a strong word. Based on personal convers ations with those who have worked on Weyburn, it is suggested that “may be” is more accurate.

Page 43500. Regarding the basis of some of the rules related to modeling Much has happened in the world of modeling CO 2 injection and long-term storage since 2005. Many of the key messages from the workshop upon which some of the statements on this topic are based may be long out of date.

Page 43502. G. How Would This Proposal Affect Existing Injection Wells under the UIC Program?

The regulatory regime should readily accomm odate the adoption of Class II wells into any new category. Unfortunately, this entire se ction gives the impre ssion that storage is not occurring during EOR activities, which is not true. EOR provides partial storage capability until such time as the recove ry of hydrocarbons ceases and all production

activities are ended.

Page 43502. H. What Are the Target Geologic Formations for GS of CO 2 ?

This section grossly misrepresents the types of geologic formations th at are suitable for

CO 2 sequestration. It is irresponsible to disc redit the meaningful role that depleting and/or depleted oil and gas reser voirs can play in sequestering CO 2 . While the document gives credit to the vast amount of geologica l information that is known about oil and gas reservoirs, it then implies that this know ledge does not overcome all of the perceived technical challenges associated with using o il and gas reservoirs fo r geologic storage. The techniques that would be used to alleviate the concerns listed in this section are less onerous than the proposed requirements to pe rmit a Class VI injec tion well. Additionally, just as all deep saline formations may not be suitable for geologic storage, there may be oil and gas reservoirs that are not suitable as well. Prudent site selection should help determine suitable geologic settings, not broad statements declaring one geologic

formation better than the other.

CO 2 storage in coal seams is an area of ve ry active research. DOE Partnerships are conducting pilot-scale coal seam sequestration fi eld tests. Utilizing coal seams at shallow depths would require less compression (gas phase vs. supercritical CO 2 ), reduce drilling costs, may allow for greater concentrations of inert nitrogen (which could reduce capture costs), and be proximal to many minemout h operations. Ruling out such storage by administrative fiat is premature. The result s of ongoing research need to be considered prior to such proposed actions.5 Page 43503. H. Is Injected CO 2 Considered a Hazardous Waste under RCRA?

No. CO 2 should not be considered a hazardous waste under RCRA.

Page 43504. J. Is Injected CO 2 Considered a Hazardous Waste under CERCLA?

No. CO 2 should not be considered a hazardous waste under CERCLA.

Page 43505. 1. Proposed Geologic Siting Requirements

With regard to the need for data on all USDWs at a site:

Wording here suggests that maps and cross sections must be generated of all USDWs near the proposed injection well. Submitting maps and cross sections of all of the USDWs, not just the lowermost USDW, seems unnecessarily burdensome to the owner/operator. Such maps will require sign ificant additional work, and it is not clear how doing so will result in improved protec tion of USDWs since protective casing is already required from the surface all the way to the bottom of the lowermost USDW. Identifying and mapping the lowermost US DW should be sufficient to protect all overlying USDW zones.

There is also text in this section that can be interpreted as requiri ng the owner/operator to submit core, outcrop, seismic survey, cross se ctions, well logs, and other unspecified data. Some later passages on this subject suggest that they are not al l necessarily required, but rather are examples of types of data th at could be used to demonstrate and quantify various key characteristics of a formation. With respect to the need for various types of geological data, the document is at times vague, inconsistent and, occasionally, even contradictory. It is critical th at geologic heterogeneity and regional differences in data availability be acknowledged and state or regi onal directors be give n the flexibility to

make decisions based on data sets that re flect the geologic and re gional differences. For instance, seismic survey data are limited in coverage, are expensive to acquire, can be inconclusive with respect to interpretation, and should not be unive rsally required as a precondition for site consideration. The regul ations must be performance-based and reinforce the need to technically and efficien tly achieve specific goals, such as proving that an adequate and competent seal exists or that a target formation has sufficient injectivity. The regulations should not prescrib e precisely how such proof is obtained, but should only dictate that suffici ent proof be presented to th e director. The regulations should give the director a signi ficant degree of flexibility to determine whether the body of evidence presented by the owner/operator constitutes sufficient proof that USDWs will be protected. The regulations may include a list of useful data types, but EPA should clearly state that the list is one of available tools fro m which to choose the most applicable to a specific site, not a list of required applications a nd data that must be acquired and presented.

Following is a series of comments with regard to the quote on page 43505:6 “...require owners or operators to submit geoc hemical data on (a) the injection zone, (b) the confining zones, (c) containment zone s above the confining zones in which any potentially migrating CO 2 could be trapped, (d) all USDW s, and (e) any other geologic zone or formation that is important to the proposed monitoring program.”

The EPA should recognize that it is essentially saying that the entire rock column from the injection zone to the surface must be geochemically characterized. Such characterization goes far above and beyond th at which is necessary to protect the USDWs. It is essentially forcing owners/ope rators to pay for pot entially unnecessary

research activities. For instance, in th e Williston Basin, a vast majority of the hydrocarbon production is historically from Pa leozoic formations. One result of this is

that there is a wealth of readily available data on the natu re of Paleozoic formations in the

Williston Basin. Likewise, the Cenozoic formati ons are fairly well characterized because of the presence of coal and potable aquifers. However, the Mesozoic formations that lie between those two groups are re latively poorly understood. This is because ther e is little

economic incentive to characteri ze most of the Mesozoic rocks beyond the fact that they are dominated by low permeability shales and evaporites. There are 15 named rock units

in the Mesozoic section of the Williston Basi n. The regulations as proposed indicate that they must all be geochemically characterize d. To geochemically characterize all of these Mesozoic units as part of a GS project in which the primary sinks and seals are in the deeper Paleozoic would be very expensive and of dubious value to anyone. Once again, there must be flexibility and discretionary pow ers given to directors with respect to what formations must be geochemically characterized . Indeed, this concept of flexibility must apply for all types of characterization that ar e considered necessary to prove that a GS well application can be approved.

Page 43507. Regarding the use of proprietary models:

The use of proprietary models absolutely should be allowable. In many cases, such software packages are the only reliable mode ls that can be applied with any real

confidence in their results. That being said, the use of such models should not be required because, in some cases, especially those wh ere adequate data exist, nonproprietary models can serve the purpose in a more cost-effective manner.

Page 43507. Corrective Action. Regarding the use of specific cements in GS wells:

The document states that the EPA proposal does not prescribe the specific cements to be used to plug abandoned wells, but in the next paragraph states th at corrosion-resistant cements would be required. This is contra dictory. EPA must cl arify this issue.

Pages 43509 to 43510. Well Component Degradation. Regarding cements:

It is frustrating that the EPA discounts real-w orld, field-based data in favor of laboratorygenerated data and models. In this case, it describes laboratory work that had somewhat contradictory results and acknowledge that “... field studies show clear evidence of

reactions between CO 2 and well cement, but do not show such severe corrosion.” EPA7 then goes on to mention two instances of fi eld-based research that show only limited

effects of CO 2 on cements. But as they historically have been known to do (EPA rulings on air quality issues in sout hwestern North Dakota being just one example), EPA chooses to ignore the real-world data and make d ecisions based on the di re results of tests conducted on small samples under laboratory co nditions that can be applied only to a very narrow set of subsurface conditions, if at all. The result of this is that the proposal can be interpreted to require the use of re latively new and expens ive corrosion-resistant

cements rather than cements that have alre ady been used successfully at large-scale CO 2 injection sites, in some cases for decades. One potential unintended consequence of this requirement is that the mechanical integrit y of these new cements under deeper reservoir pressure and temperature condi tions may not be completely understood, especially over time. Again, flexibility should be allowed with respect to the selection of cements.

Page 43512. Injection Depth in Relation to USDWs.

The requirement to be below the lowest USDW is not needed and should be evaluated on a site-specific basis. Furthermore, minimum depths should not be required. Again, this should be site-specific.

Page 43515. Regarding monitoring wells in the Area of Review (AoR).

Text in this section implies that monitoring we lls in the injection zone within the AoR are desirable, which could be interpreted by some as being required. The first comment with respect to this issue is that it is important to note that monitoring we lls that penetrate the plume have potential to serve as a leakage pathway and, therefore, their use should be minimized. Secondly, one of the reasons given for the placing of monitoring wells in the AoR is that studying the inter actions between brine and CO 2 may allow for the determination of whether precip itation and/or dissolution of minerals is occurring. It is important to note that such interactions are cu rrently not well understood and are the topic of great debate and c ontroversy within th e published literature. There is no consensus in the technical community as to how such data evaluated in the context of a single site, as site-specific permitting and monitoring must be, can be applied to ensuring the protection of USDWs at that site. While such data would surely be interesting and possibly useful from a scientific standpoint when taken in the context of many sites, it is not clear how it could be applie d to prove or disprove that USDWs at a given location are being protected or are in danger of contamin ation. This requirement comes across as a regulatory-mandated means of gath ering data for researchers, an activity that is outside the scope of USDW protection a nd should not be forcibly paid for by owners/operators of

GS wells.

Page 43515 to 43516. Regarding monitoring.

In general, this section is overly prescriptive with respect to the se lection and application of monitoring techniques. One of the things that is lost in this discussion is that if the geometry of the trapping structure is we ll understood and the overl ying seal has been demonstrated to be competent and thick, then plume monitoring should be relatively8 straightforward and less complicated. Consider , for example, injection into a thoroughly characterized high-relief stru cture, such as an anticline or pinnacle reef encased in impermeable anhydrite. Migration of the CO 2 would be minimal, and plume stabilization would be relatively rapid. A few carefully instrumented and placed monitoring wells, some above the seal and others just outsid e and below the structure, would be enough to ensure the plume does not leak through the seal or slip beneath the spill point at the

bottom of the structure. With this in mi nd, it can be reasonably argued that seismic surveys (which may or may not provide usef ul insight regarding the plume, depending on the lithology) would not offer any additional da ta that would further ensure the protection

of USDWs. If there is no significant structural element to the trap, then plume stabilization could very well take many decad es, and in such a case, a more robust and comprehensive suite of monitoring tools may have to be applied. Many examples of both types of sites, and many more that fall in between, have been identified throughout the United States, and it is because of this variety that it is critical that UIC regulations for GS allow flexibility in choosing plume- tracking methods. The EPA acknowledges the need for flexibility in a paragraph in the middle of page 43516, but many of the requirements laid out in the docum ent do not reflect that need.

Page 43519. Combination of Fixed Time Frame and Performance Standard (monitoring).

The EPA is proposing a postinjection monitoring period of 50 years, with the director having some discretion to either shorten or lengthen that time period. Based on the proposed text, 50 years is the default time pe riod for postinjection monitoring until data on pressure, fluid movement, mineralizati on, and/or dissoluti on reactions support a determination that the plume has stabilized and does not pose a risk to USDWs. Referring to this as the “default” time period and requiri ng the acquisition of de scribed data sets to modify the time period for monitoring i ndicate that a significant amount of

characterization effort would have to be conducted during th e postinjection period, perhaps over several years, to get such a change. The EPA acknowledges that modeling

results indicate that CO 2 plume stabilization likely occurs on the time frame of 10 to 100 years after injection stops. One example of a GS site where plume stabilization could very well take 50 years or more is a site wh ere there is no significant structural trapping element to the reservoir. A plume at such a location may behave in a less predictable manner and expand or migrate a significant distance before it stabilizes. However, CO 2 injected into a thoroughly confined high-re lief structure (e.g., pinnacle reef, carbonate mound, anticline, etc.) would lik ely stabilize relatively quick ly. Barring a seismic event that breaches the seal, the movement of such a plume would be nil because it would literally have nowhere to go. In those cases, requiring the continued collection of several types of data for several years in order to prove what was probably obvious years before injection ceased would serve no real purpose other than to satis fy an arbitrary regulation.

The nature of structural characteristics at each site under consider ation for GS will be identified almost immediately, defined in detail during the earliest stages of site evaluation, and the understanding of their geomet ry will likely be further refined over the course of monitoring during the in jection phase of the project. It is also important to keep in mind that the injection phase of GS projec ts, and the monitoring th at goes with them,

will, in most cases, be conducted for decad es. Over those years, knowledge of the9 reservoir system will increase, and by the time the injection phase comes to an end, there will be ample data to make informed decisi ons regarding an appropriate postinjection monitoring period. All of this leads to a logical conclusion that the establishment of postinjection monitoring periods should be site-specific and flexible. The 50-year site monitoring statement appears to have no rati onal basis and might effectively eliminate commercial activity.

In summary, the proposed default monitoring time frame should be eliminated and replaced with a solely performance-based stan dard that reflects the specifics of a project and the knowledge of that project gained th rough the procedures a nd processes that are already required. The proposed rule gives th e program director discretion to extend or shorten the postinjection site care period based on project-speci fic considerations; therefore, it seems unnecessary to, by rule , establish a lengthy default period.

Page 43520. Proposed Financial Responsibi lity and Long-Term Care Requirements

The requirements for financia l assurance may discourage co mmercialization of CCS. As currently proposed, the rules would place great er financial assurance requirements on Class VI wells than are currently placed on Class I hazardous waste wells. The more rigorous requirement may result in a need less negative public perception of CCS. The chemical and physical properties of carbon diox ide injected for storage purposes are not uniquely distinctive to garner such attention under the UIC Program.

Furthermore, in order for CCS projects to come to fruition, financial assurance obligations need to be cons istently and reasonably achieva ble. If not, considerable

uncertainties will be introduced into the ec onomics and finances of proposed projects. The currently proposed rule assumes reliable co st estimates will be av ailable at the time of permitting for a broad range of long-term activities lasting more than 50 years into the future. EPA should carefully consider th e implications of the proposed financial assurance provisions so as to not discourage CCS activities.

Pages 43525 to 43526. Regarding cost of compliance.

EPA compares the costs associat ed with standard Class I we lls and the proposed Class VI wells and estimates that the proposed rules w ould increase the costs of complying with UIC regulations by 46%. The EPA also states that it they “believe[s] the proposed rule will not impede CO 2 GS from happening....” First, a 46% increase in costs is significant. Second, to profess that such a large increase in costs will not impede the implementation of GS projects seems rather naïve.

Page 43535. § 146.5 Classification of injection wells.

Class VI wells should not be limited to injections beneath the lowermost formation containing a USDW. This is t oo restrictive in some areas. For instance, consider as an example the Lower Cretaceous Dakota Group in the North Dakota portion of the Williston Basin. On the eastern margin of the Williston Basin in North Dakota, the water within the10 Dakota Group contains total dissolved solid (TDS) concentrations well below 10,000 parts per million (ppm), and the formation theref ore qualifies as a USDW. However, hundreds

of miles to the west and southwest, near the center and southwestern flanks of the Williston Basin, the Dakota Group has TDS concentra tions well above 10,000 ppm, and it is used extensively as an injection di sposal zone for oil field produc ed waters. The demonstrated injectivity of the Dakota Group and its unsuitab ility as a potential US DW in western North Dakota make it an attractive target for indus tries seeking to geologically store large

volumes of CO 2 . A strict, literal interpretation of the proposed rule could unreasonably preclude the Dakota Group from being consider ed as a potential target zone for CO 2 storage. It is likely that si milar examples of this scenar io could be found in many other sedimentary basins.

Page 43536. § 146.82 Required Class VI permit information.

There are numerous requirements for inform ation on formations overlying the proposed storage site. Requirements shoul d be flexible and site-specifi c. The required information should be limited to relevant primary and/or secondary seals and be used to document the vulnerability or lack thereof of any USDWs in the area.

Page 43536. § 146.82 Required Class VI permit information.

The requirement of baseline geochemical da ta on subsurface formations should be flexible and site-specific. Th e required information should be limited to relevant primary and/or secondary seals and be used to documen t the vulnerability or lack thereof of any

USDWs in the area.

Page 43536. § 146.82 Required Class VI permit information.

Well-plugging requirements can change thr oughout the life of a well. Therefore, requiring a well-plugging plan with the permit application is excessive and unnecessary.

Page 43536. § 146.83 Minimum criteria for siting.

Requiring the injection z one to have the ability to receive the “ total anticipated volume of

the carbon dioxide stream” seems unreasonable. Linking CO 2 source potential with CO 2 injection potential is not recommended, and flex ibility is required. For example, if the stream is coming from a power generating f acility, it can be difficult to estimate the longevity of the plant given changes in tec hnology that may allow for increased energy output. Multiple storage sites may be requi red for one source, or conversely, multiple sources may utilize a single storage site.11 Page 43538. § 146.86 Injection well construction requirements.

Requiring surface casing to extend below the base of the lowermost USDW precludes potential sequestration zones.

Page 43538. § 146.87 Logging, sampling, and testing prior to injection well operation.

“... the owner or operator must run appropriate logs, surveys and test s to determine or verify the depth, thickness, porosity, perme ability, and lithology of, and the salinity of any formation fluids in, all re levant geologic formations.” Relevant geologic formations

needs to be defined.

Page 43538. § 146.87 Logging, sampling, and testing prior to injection well operation.

The coring requirements are too burdensome if applicable cores are already available in the vicinity of the project.

Page 43538. § 146.87 Logging, sampling, and testing prior to injection well operation.

Given the complexity of scheduling various se rvice companies and activities at a project location requiring a schedule of all logging and testing 30 days prior to the first test and submission of any changes to the schedule 30 da ys prior to the next scheduled test are pointless and oftentimes impractical.

Comments with regard to operating requirem ents, testing and monitoring, plugging, postinjection site care and site closure.

Many comments that could be direct ed at the specific requirements were addressed previously in this document. Therefore, they will not be repeated here.Letter ID: 0220

Commenter: Edward Steadman Organization: The Energy and Envir onmental Research Center at th e University of North Dakota

Letter ID: 0220 Comment ID: 21573 Letter Lines: 53 to 77

Comment Code: 1250 1.1.1.4 Flexibility is needed (p erformance-based standards)

Comment: Just as in nature with deep-sourced, natu ral CO2, there are low-risk sites that will permanently entrap CO2, and there are places where it may migrate, perhaps even to the surface. CO2 is a naturally o ccurring substance, and movement within the subsurface is very common. Rather than trying to fashion ru les that protect against surface escape in all subsurface conditions, regulatory oversight needs to recognize the nearly ubiquitous pres ence of the molecule while identifying low-risk sites for entrapment and pr ovide flexibility in regulation to

accommodate the attendant risk level.

In order to achieve statistically si gnificant reductions of greenhouse gas emissions, large-scale carbon capture a nd storage (CCS) will have to be implemented at numerous sites. One of the greatest potenti al barriers to widespread deployment of sequestration pr ojects would be the specification of overly complex well design and monitoring of sites. Experience s hows that exotic well designs add little benefit, while , on the other hand, judicious site selection adds greatly to the security of emplacement. For example, subsurface sequestration formations overlain by bedded salts provide optimal conditions for long-term storage. The focus of regulati on should be performance criteria, not design criteria. As long as CO2 sequest ration sites can meet the standards required for permitting, injection of CO2 for sequestration is, to a large extent, similar to EOR operations. In tu rn, requirements for injection wells accessing judiciously selected zones for se questration should be more closely aligned with those of Class II standard s than the more stringent Class I hazardous waste well standards. As currently proposed, the Class VI requirements

are more reflective of Class I hazardous waste well standards.

Individual Response: The Agency believes that the Class VI requirements balance site-specific flexibility with USDW protection. Rather than setting performance or technology-based standards for GS projects, EPA is adopting a flex ible approach, where operators of GS projects would develop and implement site-specific plans for delineating the AoR, testing and monitoring the site, performing corrective actio n, and post-injection site care . EPA believes that the plans— which would be reviewed and approved by the Director and periodical ly updated throughout the life of the project—promote an ongoing dialogue between the operato r and the Director that will encourage use of the most appropriate t echnologies for a particular project.

EPA clarifies that the Class VI GS requirements are designed to ensure that, where deployed, GS

1is conducted in a manner that protects USDWs fr om endangerment. Encouraging investment in CCS projects and facilitating deployment are outside the scope of the GS rulemaking.

Letter ID: 0220 Comment ID: 21574 Letter Lines: 79 to 92

Comment Code: 1480 1.2.2.2.2 CO2 is not a pollutant

Comment Code: 1680 1.3.8 Don't overstate ris k, don't stigmatize CO2

Comment: It is important to be mindful that CO 2, relative to other common and not-socommon injectates, is relatively innocuous . Increasing concentr ations are easily detected in groundwater through simple m onitoring of pH. Carbon dioxide in groundwater poses minimal acute or chroni c threat to human health or the environment, especially when compared to other materials that have been classified as hazardous. As long as potent ial injection sites are appropriately characterized and judiciously selected and injection operations are designed and conducted according to longstanding engine ering and regulatory standards, the leakage of CO2 into underground sources of drinking water (USDW) is likely to be a preventable and infrequent occurrence. In the rare ev ent that CO2 should leak into USDWs, it is also important to not e that its primary e ffect on groundwater will be to form a weak acid (carboni c acid) and lower pH, which can be relatively easily mitigated by a variety of commonly used, simple remediation practices.

Individual Response: In response to the comment that CO2 is relatively innocuous and that the primary effect of a leak to gr oundwater will be to form a weak acid and lower pH, EPA clarifies that the mission of the UIC Program is to pr otect USDWs from injection activity that may endanger USDWs. Reduction in pH may also lead to mobilization of contaminants (e.g., arsenic, lead, and organic compounds), which can degrad e water quality. In addition, the migration of formation fluids containing mobilized contaminants could cause endangerment of USDWs (Birkholzer et al., 2008a).

EPA believes that the creation of a new inject ion well class (VI) under th e existing UIC Program is necessary to enable deployment of GS as a climate change mitigation technology in a manner that protects USDWs from endangerment. EPA ag rees that the UIC Program, under the authority of the SDWA, provides a strong fr amework for regulating injection of CO2 for GS and adds that the GS regulation tailors the UIC requirements to address the unique i ssues associated with large-scale GS including large injection volumes, the relative buoya ncy of CO2, its corrosivity in the presence of water, the potential presence of impurities in captured CO2, and its mobility within subsurface geologic formations.

EPA disagrees that the GS regulation overstates the risk of CO2 injec tion. EPA recognizes that injecting large volumes of CO2 for GS poses uni que challenges that, if not properly managed, could endanger drinking water sources and have other adverse impacts. However, with proper site selection, the final, tailored, Class VI requirements address the large volumes of CO2 injected, its buoyancy, potential corr osivity in the presence of wate r, and potential impurities in the CO2 stream. In addition, EPA expects the tailored permitting, siting, construction, operation,

2monitoring, and post-injection site care requirements in the GS rule to prevent leakage from injection formations and protect USDWs.

EPA adds that the requirements of the GS rule ar e tailored to the nature of the CO2 itself and risks associated with the injec tion of CO2, and do not address th e status of CO2 as either a pollutant, commodity, or waste.

Letter ID: 0220 Comment ID: 21575 Letter Lines: 94 to 104

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: A final comment has to do with any rules or policies that might marginalize EOR as a sequestration tool. The PCOR Partne rship believes the early-captured CO2 will be injected in large volumes and stor ed during existing and new commercial (i.e., EOR) operations. The only refere nce to the use of EOR sites for sequestration is contained in proposed rule § 146.83(c) which discusses repermitting existing wells as Class VI storage wells. The emission reduction potential and sequestration associated with EOR are immense, and revenues from the oil produced will offset the cost to the economy and will, ultimately, accelerate more widespread deployment of CCS technologies. With the growing energy concerns in the United States, th e contributions of CO2 EOR in the

advancement of CCS need to be embrace d. This reality needs to be further

Individual Response: EPA recognizes that the oil and gas industry has decades of experience injecting CO2 for the purpose of ER, and that site s used for ER may be suitable for GS and may be among the first GS sites. However, EPA believes that injection for the primary purpose of long term storage is sufficiently different fr om Class II ER operations and warrants tailored requirements. For example, the vo lume of CO2 anticipated to be injected in Class VI wells is significantly greater than for Class II wells. Reser voir pressure conditions will also be different, with Class VI injection opera tions involving large volumes of CO2 and likely having higher pressures within their storage forma tions than Class II ER projects.

EPA clarifies that the purpose of the GS rule is to ensu re protection of USDWs from endangerment and not to promote or incentivize GS deployment. However, the Agency believes that establishing a regulatory framework for the future development and deployment of CCS technology can provide the regulato ry and jurisdictional certainty needed to foster development and deployment of CCS while ensuring USDW protection.

Letter ID: 0220 Comment ID: 21576 Letter Lines: 104 to 106

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

Comment: advancement of CCS need to be embrace d. This reality needs to be further embraced when one contemplates a streamlined approach, such as "grandfathering"

3for Class II wells that may be useful fo r sequestration beyond the EOR project.

Individual Response: EPA agrees that many Class II well s are designed and constructed to withstand exposure to CO2. The final GS rule provi des for the construction of these wells to be grandfathered per §146.81(c), provid ed the owner or operator can demonstrate to the Director that the wells were engineered and constructed to meet th e requirements at §146.86(a) and ensure protection of USDWs, in lieu of requirements at §146.86(b) and §146.87(a).

EPA adds that promotion of CCS is not within the scope of the GS ru lemaking. The purpose of the rulemaking is to ensure that, where GS is deployed, it is conducted in a manner that protects USDWs from endangerment.

Letter ID: 0220 Comment ID: 21577 Letter Lines: 108 to 120

Comment Code: 1250 1.1.1.4 Flexibility is needed (p erformance-based standards)

Comment: Detailed Comments

Page 43492. SUMMARY. Regarding the phras e "...help ensure consistency..."

Consistency does not necessarily mean th at regulations are appropriate or effective. Geology is notoriously heter ogeneous and, therefore, by definition inconsistent. Striving for c onsistency across geologic sy stems is difficult at best. One need only to look at the hi story of injection regulation across different states to see a lack of consistency is appropriate and primarily due to heterogeneity and inconsistency with respect to regional geologic characteristics. Guidelines must be flexible. Flexibility to ensure the safe maximization of CO2 storage must not be compromised by a desire to ensure consistency of rules across all geologic settings.

Individual Response: EPA agrees that permitting decisions for GS wells should be based on site-specific factors. The GS ru le requires owners or operators to submit, and Directors to consider, extensive site-specific data, specified at §146.82, to demons trate that a site is suitable for GS. Additionally, many of the permit require ments for GS wells are established through individualized site-specific pl ans for AoR and corrective actio n, testing and monitoring, and injection well plugging and post-injection site care and site closure. EPA adds that the final GS rule includes a balance of speci fic criteria to be met by the owner or operator and areas of

Directorial discretion and consider ations for how that discretion would be exercised. The Agency believes this balance allows for GS projects to be designed and permitted to address the unique, site-specific aspects of each project, while prov iding consistency in permitting across the U.S.

As described above, encouraging investment in CCS projects and fac ilitating deployment are outside the scope of the GS rulemaking.

4Letter ID: 0220 Comment ID: 21584 Letter Lines: 122 to 125

Comment Code: 1400 1.2 Comments on EPA's Authority to Regulate Injection of CO2

Comment: Page 43495. II. What Is EPA Proposing. "development of a key climate change mitigation technology"? Will these rules re ally support the "development of a key climate change mitigation technology"? Is it really within the purview of protecting USDW?

Individual Response: EPA is finalizing federal mini mum requirements for geologic sequestration under the SDWA’s UIC program. EPA believes that GS is a key climate change mitigation technology that is part of a portfolio of options that could be deployed to reduce CO2

emissions. The SDWA mandates EPA to establ ish federal minimum requirements for state programs in order to prevent underground inject ion that endangers USDWs. See 42 U.S.C. §300h et. seq. Under the SDWA, the underground inje ction of any "fluid" is subject to the requirements of the UIC program. "Fluid" is de fined under 40 CFR 144.3 as any material or substance which flows or moves, whether in a semisolid, liquid, sludge, gas or other form or state, and includes liquids, gases, and semisolids (i.e., slurries) injected into the subsurface. CO2 injected for the purpose of GS is subject to the SDWA.

EPA clarifies that the scope of this GS regulat ion is limited to injection of CO2, and that all requirements in the GS rule are design ed to protect 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.

Letter ID: 0220 Comment ID: 21585 Letter Lines: 127 to 140

Comment Code: 1250 1.1.1.4 Flexibility is needed (p erformance-based standards)

Comment: Page 43496. B. What Is EPA’s Authority under the Safe Drinking Water Act (SDWA) to Regulate Injection of CO2?Regarding the following quote from the document, referring to a key aspect of the Safe Drinking Water Act:

5"Section 1421 (b)(3)(A) of the Act also provides that EPA’s UIC regulations shall permit or provide for consideration of varying, geologic, hydrological, or

historical conditions in di fferent States and in di fferent areas within a

State."

It is important that this aspect of the SDWA is a guiding principle for the proposed regulations. Based on those words in the SDWA, flexibility is demanded by statute and must be built into any UIC regulations. Unfortunately, the regulations proposed for GS wells in this document are often anything but flexible, but rather are quite prescriptive and inflexible.

Individual Response: As described above, EPA believes that the Class VI requirements balance site-specific flexibility with USDW protection. The final GS rule a ffords flexibility to owners or operators. Many of the permit requirements will be established through site-specific plans developed by the owner or operato r and approved by the Director.

Letter ID: 0220 Comment ID: 21586 Letter Lines: 142 to 142

Comment Code: 1240 1.1.1.3 Suggested changes/ed its to rule language

Comment: Page 43498. The Weyburn Field is in Sask atchewan, Canada, not Alberta.

Individual Response: EPA acknowledges the comment and agrees.

Letter ID: 0220 Comment ID: 21587 Letter Lines: 144 to 146

Comment Code: 1230 1.1.1.2 General comments on the regulatory text

Comment: Page 43498. The example cited here (Crystal Geyser, Utah) is not associated with an "injection activity." It is naturall y occurring CO2 that leaks via an improperly abandoned exploration well.

Individual Response: EPA agrees with the commenter that the Crystal Geyser site is not associated with injection. However, this inci dent demonstrates that abandoned or improperly plugged boreholes can serve as conduits for migrati on of fluids to USDWs. It is for this reason that the final rule includes requi rements related to performing 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.

Letter ID: 0220 Comment ID: 21588 Letter Lines: 148 to 150

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

Comment: Page 43498. This page includes a very good and reasonable description of the

6relative inapplicability of the Lake Nyos incident as an analog for possible negative consequences of a large CO2 leak from a geologic storage site.

Individual Response: EPA acknowledges the comment.

Letter ID: 0220 Comment ID: 21589 Letter Lines: 152 to 162

Comment Code: 1670 1.3.7 Other/miscellaneous risks

Comment Code: 5280 2.8.2.4 USDW non-endangerment demonstrations

Comment: Page 43498. Regarding the statement, "the measures outlined in today’s proposed rulemaking to prevent endangerment of USDWs may also prevent migration of CO2 to

the subsurface."

This statement is fine, as long as protec ting leakage to the atmosphere does not

lead to stricter measures than would be required to protect USDWs. For example, regulations should be driven by a desire to maintain a leakage rate below a certain percentage of the injected volume, unless th at percentage can be demonstrated to adversely affect USDWs. Another way to state it is this: a 1% leakage rate may or may not adversely affect USDWs; ther efore, a 1% rate should not necessarily be unacceptable.

Individual Response: EPA clarifies that all requirements in the GS rule are for the purpose of preventing endangerment to USDWs, and that the tailored permitting, siting, construction, operation, monitoring, and post-injection site care requirements in the GS rule are intended to prevent leakage from injection fo rmations and protect USDWs.

EPA acknowledges that there are po tential risks associated with GS. The purpose of the Class VI requirements is to minimize and mitigate pot ential/identified risks through proper site characterization, well constructi on, operation, monitoring, post-inje ction site care, and site closure and to ensure protection of USDWs. Th e Agency clarifies that , under SDWA, EPA does not have the authority to dire ctly regulate air emissions vi a CO2 leakage to the surface. However, the GS rule requires that CO2 injected for GS remain confined in the injection zone. Leakage outside of the injection zone as define d in a Class VI permit, which may be evidenced by leakage to the surface, would be a perm it violation if a USDW is endangered.

Letter ID: 0220 Comment ID: 21590 Letter Lines: 164 to 168

Comment Code: 1810 1.4.1 Research on identify ing risks to USDWs

Comment Code: 3300 2.2.1 Delineating the AoR/M odeling CO2 movement

Comment: Page 43499. One would caution rule makers on putting too much faith into any one institution or any one method when studyi ng potential impacts. Should not such information be provided by various tec hnical sources? While the utility of models and laboratory data is recognize d, their results shou ld not supersede

7real-world experience, field-ba sed data, and local knowledge.

Individual Response: EPA considered a wide range of in formation from laboratory, modeling, and field research as it developed the requirements for GS wells. In addition to laboratory studies and modeling research that provide relevant info rmation on GS, the Agency is also involved in collecting and analyzing GS project data and permit informati on from a variety of sources. Most notably, EPA has evaluated UIC permits and reviewed operational data and information associated with the seven regional carbon se questration partnerships funded by the U.S. Department of Energy and coordinated thr ough the National Energy Technology Laboratory (NETL), and several international projects. In additi on to the information cited in the preamble to the proposed rule, EPA published a Notice of Data Availability and Request for Comment (NODA) on August 31, 2009 (74 FR 44802), in which the Agency described the preliminary results of research at three DOE partnership site s: the Escatawpa, Mississippi project; the Aneth Field project in Paradox Basi n, Southeast Utah; and the Pu mp Canyon Site, New Mexico.

Regarding the suggestion that EPA give more we ight to field data a nd experientia l knowledge,

EPA notes that it continues to track ongoing field and laboratory rese arch into all aspects of GS. For example, EPA is tracking the operations and technical developments of more than three dozen small- and large-scale GS injection proj ects in the US and abroad. Also, since field experience and well construction, injection, and monitoring information relevant to GS comes from operations that inject acid gas or inject CO2 for ER, the Agency has conducted evaluations regarding these commercial field operations and continues to track GS-relevant developments in these commercial operations.

The Agency will continue to track GS proj ect developments and evaluate new and ongoing research and information to ensure USDW prot ection. EPA is using an adaptive approach to regulating GS under the UIC Program. Even after finalization of the GS regulation, the Agency plans to collect and review da ta every six years on GS proj ects to determine whether the appropriate amount and types of information a nd appropriate documentation are being collected,

and to determine if modifications to the fina lized requirements are ap propriate or necessary.

EPA agrees that AoR modeling should be base d on actual data collected on the site, including detailed geologic data collected to characteri ze the injection zone, c onfining zone and any additional zones, as required at 146.84(c)(1)(i). The Agency believe s that the integration of site specific information into a predictive multiphase computational model will ensure the best possible AoR delineation. EPA also recognizes that modeling technology will continue to improve, and encourages and expects owners or operators to use the best available multiphase computational models to determine the AoR. Re liance on improved models will likely increase the accuracy and quality of the AoR characteri zation, resulting in increased protection of USDWs from endangerment.

Letter ID: 0220 Comment ID: 21591 Letter Lines: 170 to 173

Comment Code: 1240 1.1.1.3 Suggested changes/ed its to rule language

Comment: Page 43500. Regarding the statement, "4-D seismic is a valuable tool for plume

8tracking" at Weyburn. "Is" is a strong word. Based on personal conversations with those who have worked on Weyburn, it is suggested that "may be" is more

accurate.

Individual Response: EPA acknowledges the comment; this paragraph is not included in the preamble to the final rule.

Letter ID: 0220 Comment ID: 21592 Letter Lines: 175 to 178

Comment Code: 1810 1.4.1 Research on identify ing risks to USDWs

Comment Code: 3300 2.2.1 Delineating the AoR/M odeling CO2 movement

Comment: Page 43500. Regarding the basis of some of the rules related to modeling Much has happened in the world of modeling CO2 injection and long-term storage since 2005. Many of the key messages from the workshop upon which some of the statements on this topic are ba sed may be long out of date.

Individual Response: EPA continues to review new a nd ongoing modeling studies, including

those conducted at national research laboratories, such as Lawrence Berkeley National

Laboratories as well as data from the DOE Partne rship GS pilot projects where some of the most current models are being developed and/or use d. EPA published a Notice of Data Availability and Request for Comment on August 31, 2009 (74 FR 44802), in which the Agency described two recent modeling studies by the Lawrence Be rkeley National Laboratory on the potential effects of CO2 injection on USDW s and human health in the even t that a GS project is not properly sited, operated, or manage d. These studies are in the ru lemaking docket and on LBNL's website at http://esd.lbl.gov/GCS/projects/CO2 /index_CO2.html. Additionally, EPA continues to fund research on ground water that will integrate experimental and modeling efforts with the objective of evaluating the potenti al consequences of CO2 leaks from GS operations into ground

water resources.

EPA is using an adaptive approach to re gulating GS under the UIC Program. Even after finalization of the GS regulation, EPA plans to collect and review data every six years on GS projects to determine whether the appropriate amount and types of information and appropriate documentation are being collected, and to determ ine if modifications to the requirements are appropriate or necessary.

As described above, EPA recognizes that modeling technology will continue to improve, and encourages and expects owners or operators to use the best av ailable multiphase computational models to determine the AoR. Reliance on improve d models will likely increase the accuracy and quality of the AoR characterization, resu lting in increased pr otection of USDWs from endangerment.

Letter ID: 0220 Comment ID: 21593 Letter Lines: 180 to 187

Comment Code: 2046 1.5.2.3 Continuing to classify CO2 in jection for EOR/EGR as Class II/

9dividing line between Class II and Class VI (seeking comment)

Comment: Page 43502. G. How Would This Proposal Affect Existing Injection Wells under the UIC Program?

The regulatory regime should readily accomm odate the adoption of Class II wells into any new category. Unfortunately, this entire section gi ves the impression that storage is not occurring during EO R activities, which is not true. EOR provides partial storage capability un til such time as the recovery of hydrocarbons ceases and all production activities are ended.

Individual Response: EPA recognizes that the oil and gas industry has decades of experience injecting CO2 for the purpose of ER, and that site s used for ER may be suitable for GS and may be among the first GS sites. Furthermore, EPA recognizes that some CO2 is sequestered when injecting CO2 for purposes of EOR. However, the Agency believes that the nature and risks of CO2 injection for the primary purpose of long term storage poses different risks than injection for the primary purpose of EOR, and therefore has developed new Cla ss VI regulations to address these unique risks. For example, the volu me of CO2 anticipated to be injected for long term storage is significantly greater than for EO R operations. Reservoir pre ssure conditions will also be different, with Class VI injection opera tions involving large vo lumes of CO2 and likely having higher pressures within their storage formations th an Class II EOR projects.

Letter ID: 0220 Comment ID: 21594 Letter Lines: 189 to 204

Comment Code: 2143 1.6.2.1 Comments in favor of inject ion into depleted reservoirs

Comment: Page 43502. H. What Are the Target Geol ogic Formations for GS of CO2?

This section grossly misrepresents the t ypes of geologic form ations that are suitable for CO2 sequestration. It is irres ponsible to discredi t the meaningful role that depleting and/or depleted oil and gas reservoi rs can play in sequestering CO2. While the document gi ves credit to the vast amount of geological information that is known about oil and gas reserv oirs, it then implies that this knowledge does not overc ome all of the perc eived technical challenges associated with using oil and gas reservoirs for geologic storage. The techniques that would be used to alleviate the concerns listed in this section are less onerous than the propos ed requirements to permit a Class VI injection well. Additionally, just as al l deep saline formations may not be suitable for geologic storage, there may be oil and gas reservoi rs that are not

suitable as well. Prudent si te selection should help determine suitable geologic settings, not broad statemen ts declaring one geologic formation better than the

other.

Individual Response: EPA agrees that depleted oil and gas fields are promising formations for GS. However, EPA also believes that large-sc ale GS presents unique technical challenges, including large injection volumes, the relative buo yancy of CO2, its corrosivity in the presence

10of water, the potential presence of impurities in captured CO2, and its mobility within subsurface geologic formations. For this reason, EPA has finaliz ed the tailored requirements in the GS rule. The final GS rule does not preclude injection into any formation type, including oil and gas reservoirs, provided owners or operators can dem onstrate that GS can be performed in a manner that protects USDWs from endangerment and th at the Class VI siting, well construction and operation, monitoring and testing, an d post-injection site care and site closure requirements are

met.

EPA further clarifies that the GS rule is not intended to promote a preference for GS in any particular formation type, to addr ess use of resources, or to reduce costs associated with GS into

various formations. The focus of the GS rule is to ensure that, where GS is deployed, it is conducted in a manner that prot ects USDWs from endangerment.

Letter ID: 0220 Comment ID: 21595 Letter Lines: 206 to 213

Comment Code: 2163 1.6.3.1 Comments in favor of injection into unmineable coal seams

Comment: CO2 storage in coal seams is an area of very active research. DOE Partnerships are conducting pilot-scale coal seam seque stration field tests. Utilizing coal seams at shallow depths would require less compression (gas phase vs. supercritical CO2), reduce drilling costs, may allow for greater concentrations of inert nitrogen (which could reduce capture costs), and be proximal to many minemouth operations. Ruling out such storage by administrative fiat is premature. The results of ongoing research ne ed to be considered prior to such proposed actions.

Individual Response: The final GS rule does not preclude in jection into unmineable coal seams (or any formation type) provided ow ners or operators can demonstrate that GS can be performed in a manner that protects USDWs from endangerment as required under the GS final rulemaking. The Agency anticipates that in the near-term, mo st GS in unmineable coal seams will continue to be experimental. Such projects may be permitte d as Class V experiment al technology wells if they are of an experimental nature (i.e., to test GS technologies and collect data). EPA will continue to review data on early GS projects , including those in unmineable coal seams, to determine whether the appropriate amount and types of information and documentation are required and being collected. EPA plans, every si x years, to collect a nd review data on GS projects to determine whether the appropriate amount and types of information and appropriate documentation are being collected, and to determ ine if modifications to the requirements are appropriate or necessary.

EPA recognizes that GS in unmineable coal seam s has been the subject of less research than saline formations or depleted oi l and gas reservoirs. However, EPA has examined select field projects involving injection into unmineable co al seams, including the Pump Canyon Site, near Archuleta, New Mexico. In the Notice of Data Availability and Reque st for Comment, EPA described research at the Pump Canyon site where the Southwes t Partnership is studying CO2 injection into deep, unmineable coal seams and pe rforming a "seal analysis" of the ability of the

11Kirtland Formation to act as a barrier to the m ovement of CO2 or othe r reservoir fluids. EPA continues to follow this projec t, recently completed projects, and ongoing GS projects injecting

into unmineable coal seams. Other coal seam in jection projects are underway through the RCSPs in the Illinois Basin, Black Warrior Basin, and Central Appalachian Basin.

Letter ID: 0220 Comment ID: 21608 Letter Lines: 215 to 217

Comment Code: 1630 1.3.3 RCRA/hazardous waste i ssues (seeking comment)

Comment: Page 43503. H. Is Injected CO2 Considered a Hazardous Waste under RCRA?

No. CO2 should not be considered a hazardous waste under RCRA.

Individual Response: EPA received many comments regardi ng the applicability of the RCRA regulations and statute to CO2 st reams that are geologically seque stered under the final Class VI UIC well requirements. As a result, EPA has deci ded to initiate a sepa rate proposed rulemaking specifically to examine the issue of RCRA appl icability to CO2 streams being geologically sequestered, including the possible option of a conditional exemption from the RCRA requirements for CO2 GS in Class VI wells. EPA will consider these comments as part of its development of that proposal. The Agency will consider issues pa rticular to RCRA in the context of that separate rulemaking, and recommends that the commenter read that proposed rule when it is published. The Agency notes that comment ers who wish to submit comments on the RCRA proposal will need to do so during the comment pe riod for that rule. Finall y, EPA also notes that the final GS rule, which adds ne w regulations for Class VI wells under the Safe Drinking Water Act (SDWA), is not making any ch anges to the RCRA regulations.

Letter ID: 0220 Comment ID: 21609 Letter Lines: 219 to 221

Comment Code: 1640 1.3.4 CERCLA issues (seeking comment)

Comment: Page 43504. J. Is Injected CO2 Consider ed a Hazardous Waste under CERCLA?

No. CO2 should not be considered a hazardous waste under CERCLA.

Individual Response: CO2 itself is not listed as a hazardous substance under CERCLA however, the CO2 stream may contain a listed hazardous substance (such as mercury) or may

mobilize substances in the subsurface that could react with ground water to produce listed hazardous substances (such as sulf uric acid). Whether such subs tances may result in CERCLA liability from a sequestration f acility depends entirely on the composition of the specific CO2

stream and the environmental media in which it is stored (e.g., soil or ground water). CERCLA exempts from liability, under CERCLA section 107, 42 U.S.C. 9607, certain “federally permitted releases” (FPR) as defined in CERCLA, 42 U.S. C. 9601(10). Class VI permits will need to be carefully structured to ensure that they prevent potential releases from the well which are outside the scope of the Class VI permit.

12EPA is promulgating this rule under SDWA. To the extent that commenter is seeking interpretations of CERCLA and its related provisi ons, such interpretations are outside the scope of this rulemaking.

EPA clarifies that, while the Administrator re serves the right to promulgate regulations designating additional substances as hazardous under §102 of CERCLA, EPA intends to avoid any potential overlap of SDWA and CERCLA authority through its comprehensive Class VI requirements.

Letter ID: 0220 Comment ID: 21610 Letter Lines: 223 to 234

Comment Code: 3140 2.1.4 Comments that the proposed ge ologic data requirements are too stringent

Comment: Page 43505. 1. Proposed Geologic Siting Requirements

With regard to the need for data on all USDWs at a site:

Wording here suggests that maps and cro ss sections must be generated of all USDWs near the proposed injection well. Submitting maps and cross sections of all of the USDWs, not just the lowermost USDW, seems unnecessari ly burdensome to the owner/operator. Such maps will requi re significant additional work, and it is not clear how doing so will result in improved protection of USDWs since protective casing is already required from the surface al l the way to the bottom of the lowermost USDW. Identifying and ma pping the lowermost USDW should be sufficient to protect all overlying USDW zones.

Individual Response: EPA believes that identifying a nd mapping all surrounding USDWs near an injection well, as specified at §146.82(a)(5), is necessary to ensure protection of all USDWs from endangerment. The purpose of the UIC require ments (including those fo r Class VI wells) is to ensure the protection of USDWs from e ndangerment, which are defined based on total dissolved solids (TDS) content, no t their location or depth (§144.3).

EPA adds that knowing the number, location and depth of USDWs near an injection well will generate baseline regional information, suppor t development of an effective testing and monitoring plan, and enhance owne r or operator and Director unde rstanding of the site. This requirement is common to all injection well classes.

Letter ID: 0220 Comment ID: 21611 Letter Lines: 236 to 260

Comment Code: 1250 1.1.1.4 Flexibility is needed (p erformance-based standards)

Comment Code: 3100 2.1 Proposed Geologic Siting Requirements (40 CFR 146.83)

13Comment: There is also text in this section th at can be interpreted as requiring the owner/operator to submit core, outcrop, seismic survey, cross sections, well logs, and other unspecified data. Some la ter passages on this subject suggest that they are not all necessarily require d, but rather are exam ples of types of

data that could be used to demonstrate and quantify various ke y characteristics of a formation. With respect to the need for various types of geological data, the document is at times vague, inconsistent and, occasionally, even contradictory. It is critical that ge ologic heterogeneity and regional differences in data availability be ack nowledged and state or regional directors be given the flexibility to make decisions based on data sets that reflect the geologic and regional differen ces. For instance, seismic survey data are limited in coverage, are expensive to acquire, can be inconclusive with respect to interpretation, and should not be univers ally required as a precondition for site consideration. The regulations must be performance-based and reinforce the need to technically and efficiently achiev e specific goals, such as proving that an adequate and competent seal exists or that a target formation has sufficient injectivity. The regulations should not pr escribe precisely how such proof is obtained, but should only dictate that su fficient proof be presented to the director. The regulations should give th e director a significant degree of flexibility to determine whether th e body of evidence presented by the owner/operator constitutes sufficient proof that USDWs will be protected. The regulations may include a list of useful data types, but EPA should clearly

state that the list is one of available tools from which to choose the most applicable to a specific site, not a list of required applicatio ns and data that must be acquired and presented.

Individual Response: EPA disagrees that any of these pr otective requirements are unnecessary. EPA believes that requiring appropr iate site characterization by the owner or operator (under §146.82) and providing an appropriate degree of flexibility to the Director to evaluate sitespecific geologic data will afford the greatest protection of USDWs from endangerment. EPA believes that it is important for the Director to ha ve as much site-specific information as possible in order to make an informed decision to permit injection for GS at a specific site. The GS regulation allows flexibility where appropria te. Certain requirements (e.g., the need to characterize additional confining layers) are at the Director's discre tion (§146.83(b)), based on his or her understanding of a particular site.

Additionally, EPA disagrees that c onsideration of local and regiona l seismicity is not important. The site characterization provisions in the GS ru le, including a review of the local and regional geology, and detailed review of any known or potenti al seismically active te rrain in the vicinity of a proposed GS site are necessary to minimize the potential for induced seismic events or the reactivation of faults, which ar e a known potential risk associ ated with injection and are addressed in all aspects of the UIC regulations.

Letter ID: 0220 Comment ID: 21612 Letter Lines: 262 to 290

14Comment Code: 1250 1.1.1.4 Flexibility is needed (p erformance-based standards)

Comment Code: 3140 2.1.4 Comments that the proposed ge ologic data requirements are too stringent

Comment: Following is a series of comments with regard to the quote on page 43505: "...require owners or operators to submit geochemical data on (a) the injection zone, (b) the confining zone s, (c) containment zones above the confining zones in which any potentially migrating CO2 c ould be trapped, (d) all USDWs, and (e) any other geologic zone or formation that is important to the proposed monitoring program."

The EPA should recognize that it is esse ntially saying that the entire rock column from the injection zone to the surface must be geochemically

characterized. Such charact erization goes far above a nd beyond that which is

necessary to protect the USDWs. It is essentially forcing owners/operators to pay for potentially unnecessary research activities. For instance, in the Williston Basin, a vast majority of the hydrocarbon production is historically

from Paleozoic formations. One result of this is that there is a wealth of readily available data on the nature of Paleozoic formations in the Williston Basin. Likewise, the Cenozoic formations are fairly well char acterized because of the presence of coal and potable aquife rs. However, the Mesozoic formations that lie between those two groups are relatively poorly understood. This is

because there is little economic incentive to characterize most of the Mesozoic rocks beyond the fact that they are domi nated by low permeability shales and evaporites. There are 15 named rock un its in the Mesozoic section of the Williston Basin. The regulations as proposed indicate that they must all be geochemically characterized. To geochemica lly characterize all of these Mesozoic units as part of a GS project in which the primary sinks and seals are in the deeper Paleozoic would be very expensive and of dubious value to anyone. Once again, there must be flexibility and di scretionary powers given to directors with respect to what formations must be geochemically characterized. Indeed, this concept of flexibility must apply for all types of characterization that are considered necessary to prove that a GS well application can be approved.

Individual Response: The Agency believes that the re quirement at §146.82(a)(6) to submit baseline geochemical data on subsurface geologic formations, including all USDWs in the AoR is appropriate and protective of USDWs. EPA believes that this data will support monitoring plan development, inform injectate fate a nd transport model development (e.g., by providing appropriate input parameters), a nd provide information needed to respond to any unexpected and unpermitted leaks outside of the injection zone. Th e baseline geochemical information will allow the owner or operator and permitting authority to evaluate monitoring data and identify any changes in subsurface geochemistry that may indicate fluid movement.

The rule requires geochemical analysis of, at a minimum, the injection zone, confining zone, and all USDWs (§146.82(a)(6)). These geochemical tests ar e necessary to ensure the adequacy of the confining system and to serve as a baseline for future monitoring. The Director has the discretion

15to require geochemical analysis of additional s ubsurface zones if in the Director's opinion they are necessary for the protection of USDWs from endangerment.

EPA agrees that site characterizati on should be site-specific, particul arly in light of the variety of geologic settings in which GS may be employe d. EPA believes that, while there is a large amount of required information, the owner or operat or is given flexibility in determining what methods are used to demonstrate the suitability of a potential site. EPA envisions an ongoing dialogue between the Director and the owner or operator during the permitting process (as well as throughout the operation of the site).

Letter ID: 0220 Comment ID: 21613 Letter Lines: 292 to 297

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

Comment: Page 43507. Regarding the use of proprieta ry models: The use of proprietary models absolutely should be allowable. In many cases, such software packages are the only reliable models that can be app lied with any real confidence in their results. That being said, the use of such models should not be required because, in some cases, especially those where ade quate data exist, non proprietary models can serve the purpose in a more cost-effective manner.

Individual Response: EPA agrees with commenters that av ailable proprietary models may meet the complex needs for calculating the AoRs of GS sites. EPA will allow, but not require, the use of proprietary models in meeting the requireme nts for the GS regulation, as long as GS well operators using a proprietary m odel clearly disclose, to the Di rector's satisfaction, the code assumptions, relevant equations, and scientific basis. EPA adds that its Confidential Business Information requirements at 40 CFR 144.5 will apply to the use of proprietary models.

Letter ID: 0220 Comment ID: 21622 Letter Lines: 299 to 324

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

Comment: Page 43507. Corrective Action. Regarding th e use of specific cements in GS

wells: The document states that the EPA proposal does not prescribe the specific cements to be used to plug abandoned we lls, but in the next paragraph states

that corrosion-resistant cements would be required. This is contradictory. EPA must clarify this issue.

Pages 43509 to 43510. Well Component De gradation. Regarding cements:

It is frustrating that the EPA discounts real-world, field-base d data in favor of laboratory-generated data and models. In this case, it describes laboratory work that had somewhat contradictory results and acknowledge that "... field

studies show clear evidence of reactions between CO2 and well cement, but do not

16show such severe corrosion." EPA then goes on to mention two instances of fieldbased research that show only limited eff ects of CO2 on cements. But as they historically have been known to do (E PA rulings on air quality issues in southwestern North Dakota being just one example), EPA chooses to ignore the

real-world data and make decisions based on the dire results of tests conducted on small samples under laboratory conditions th at can be applied only to a very narrow set of subsurface conditions, if at a ll. The result of this is that the proposal can be interpreted to require th e use of relatively new and expensive

corrosion-resistant cements rather than cem ents that have already been used successfully at large-scale CO2 injection sites, in some cases for decades. One potential unintended consequence of this requirement is that the mechanical integrity of these new cements under deeper reservoir pressure and temperature conditions may not be completely unders tood, especially over time. Again, flexibility should be allowed with resp ect to the selection of cements.

Individual Response: Regarding corrective action requirements, EPA clarifies that all corrective action performed under §146.84(d) must be appropriate to the GS site to ensure that the well

does not allow CO2 or other flui ds to move into or endange r USDWs. EPA is developing guidance on AoR and corrective action at GS Class VI sites to assist owners or operators and Directors in evaluating requi rements and proposed AoR and corrective action plans under §146.84. This guidance will be available on EPA’s website at http://water.epa.gov/type/groundwat er/uic/wells_se questration.cfm.

Regarding cementing requirements, EPA disagrees that the potential corrosion of well materials and cements when exposed to CO2 in the presence of water or other fluids is overstated. While some studies of cement performance have shown encouraging results, other information gathered through stakeholder workshops, research, and field data provide evidence of chemical alteration and suggest a potential for degradation to occur and potentially endanger USDWs.

EPA clarifies that the requireme nt at §146.86(b)(5) is that cement and cement additives must be compatible with the CO2 stream and formation fluids and of sufficient quality and quantity to maintain integrity over the design life of the GS project. EPA believes that the use of acidresistant cements is one of several protectiv e measures for meeting that Class VI well construction requirement, along with the requir ements for surface casing and long-string casing and well tubulars that are compatible with the CO2 and formation fluids. See the discussion of Class VI well construction requirements in the preamble to the final GS rule for additional

information.

EPA clarifies that it has reviewed both laboratory and field-based research (Barlet-Gouedard et al., 2006; Kutchko et al., 2007, Carey et al., 200 7, and Crow et al., 2008) that have shown Portland cement alteration (carbon ation) when the cement is e xposed to CO2. While research indicates that cement alteration occurs, the alte ration appears not to significantly reduce the integrity or performance of the cement. Ho wever, under conditions simulating flowing CO2- saturated brine, loss of structur al integrity (more significant degr adation) of cement was found in laboratory studies (Duguid et al . 2005), although it is uncertain wh ether wells in GS operations would be exposed to flowing CO2-saturated brin e. The field-based studies that identified

17alteration reflect the results of relatively few samp les from a very small nu mber of wells, and the well material samples may have been exposed primarily to dry CO2. Cement degradation andcorrosion are a possibility, so the cement and cement additives used may need to be acidresistant to meet the requirement that they are compatible with the CO2 stream, formation fluids, and the anticipated inje ction zone conditions.

Although the laboratory and field studies suggest that corrosion problems may not be severe, such problems cannot be conclusively ruled out, a nd the amount of available data on this topic is still limited. Laboratory explorati on of cement alteration and degr adation is an ongoing research area, and field-based studies are very few. There also does not appear to be a clear consensus on the corrosion risks for the steel components of injection wells. Given the anticipated long lifespan of Class VI wells and the difficulties that would be associated with a corrosion-related well failure, EPA believes that the construction requireme nts at §146.86 are justified.

The Agency plans to, every six years, collect and review data on GS projects to determine whether the appropriate amount and types of information and appropriate documentation are being collected, and to determine if modificatio ns to the requirements are appropriate or

necessary.

Letter ID: 0220 Comment ID: 21623 Letter Lines: 326 to 329

Comment Code: 4324 2.4.4.1.2 Comments opposed to requiring injection below the lowermost

USDW

Comment: Page 43512. Injection Depth in Relation to USDWs.

The requirement to be below the lowest USDW is not needed and should be evaluated on a site-specific basis. Furt hermore, minimum depths should not be

Individual Response: EPA acknowledges that there are lim ited circumstances where injection above the lowermost USDW can be performe d in a manner that protects USDWs from endangerment, as long as appropriate protections are in place. The final GS rule at §146.95 establishes a process by which owne rs or operators can seek a waiv er of the Class VI injection depth requirements for inject ion into non-USDW formations above and/or between USDWs.

Such determinations would be ma de on a site-specific basis.

Letter ID: 0220 Comment ID: 21624 Letter Lines: 329 to 330

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

Comment: evaluated on a site-specific basis. Furt hermore, minimum depths should not be required. Again, this should be site-specific.

Individual Response: EPA agrees that it is not appropriate to set a mi nimum injection depth for GS projects and the Agency believes that a determ ination of site-suitabili ty for GS (i.e., that

18subsurface 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: 0220 Comment ID: 21625 Letter Lines: 332 to 353

Comment Code: 4610 2.6.1 Testing and monitoring plan requirement (seeking comment)

Comment Code: 4660 2.6.6 Geochemical monitoring

Comment: Page 43515. Regarding monitoring wells in the Area of Review (AoR).

Text in this section implies that monito ring wells in the injection zone within the AoR are desirable, which could be inte rpreted by some as being required. The first comment with respect to this issue is that it is important to note that monitoring wells that penetr ate the plume have potential to serve as a leakage pathway and, therefore, their use shou ld be minimized. Secondly, one of the reasons given for the placing of monito ring wells in the AoR is that studying

the interactions between brine and CO2 may allow for the determination of whether precipitation and/or dissoluti on of minerals is occurring. It is important to note that such interactions ar e currently not we ll understood and are the topic of great debate and contr oversy within the pub lished literature.

There is no consensus in the technical comm unity as to how such data evaluated in the context of a single site, as site-specific permitting and monitoring must be, can be applied to ensuri ng the protection of USDWs at that site. While such data would surely be interesting and possibly useful from a scientific standpoint when taken in the context of ma ny sites, it is not cl ear how it could be applied to prove or disprove that USDWs at a given location are being protected or are in danger of contamina tion. This requirement comes across as a regulatory-mandated means of ga thering data for researchers, an activity that is outside the scope of USDW protection a nd should not be forcibly paid for by

19owners/operators of GS wells.

Individual Response: EPA disagrees that the monitoring requirements in the GS rule do not provide site-specific benefits for protection of USDWs or that monitoring is for the benefit of

scientific research onl y. EPA believes that geochemical mon itoring, when compared to baseline data, can provide direct evidence that USDWs may be endangered.

EPA believes that monitoring using wells in the in jection zone (i.e., that penetrate the confining zone) can be safely performed if the wells are co nstructed to prevent flow between the injection zone and USDWs or other layers above the conf ining zone. Such construction technologies exist and have been used in the oil and gas industry for years. EPA believes that the benefits of monitoring in the injection formation outweigh th e manageable risk of those monitoring wells serving as conduits for fluid movement. EPA a dds that owners or operators may consider performing additional pressure monitoring in wells that are above the confining zone (e.g., in the same wells used to perform ground water qualit y monitoring required at §146.90(d)) to provide additional verification that no pr essure changes are occurring above the conf ining zone due to CO2 leakage. Monitoring also identifies n eeded remedial actions, provides inputs for AoR reevaluation modeling, and targets additiona l geochemical and surface monitoring needs. Knowledge of the location of the CO2 plume and the associated pressure front will assure the public that GS projects are proceeding according to plan, provide sufficient information to the owner or operator and Director, or allow for a ppropriate actions to addr ess any indication that USDWs may be endangered.

EPA acknowledges that, at certain sites, there ma y be a need for more or different monitoring schemes (which may include monitoring in the conf ining zone), and adds that it is important to balance the need for adequate monitoring that ensures USDW protection from endangermentagainst too many artificial penetrations which could serve as conduits for fluid migration. Sitespecific testing and monitoring pl ans must describe the proposed monitoring regime, which must be approved by the Director.

Letter ID: 0220 Comment ID: 21626 Letter Lines: 355 to 378

Comment Code: 4600 2.6 Proposed Plume and Pressure Front Monitoring Requirements (40 CFR 146.90)

Comment: Page 43515 to 43516. Regarding monitoring. In general, this section is overly prescriptive with respect to the sele ction and application of monitoring techniques. One of the things that is lo st in this discussion is that if the geometry of the trapping structure is well understood and the overlying seal has been demonstrated to be competent and thick, then plume monitoring should be relatively straightforward and less co mplicated. Consider, for example, injection into a thoroughly characterized high-relief st ructure, such as an anticline or pinnacle reef encased in im permeable anhydrite. Migration of the CO2 would be minimal, and plume stabili zation would be relativ ely rapid. A few carefully instrumented and placed monito ring wells, some above the seal and others just outside and below the structur e, would be enough to ensure the plume

20does not leak through the seal or slip be neath the spill point at the bottom of the structure. With this in mind, it ca n be reasonably argued that seismic surveys (which may or may not provide useful insight regarding the plume, depending on the lithology) would not o ffer any additional data that would further ensure the protection of USDWs. If there is no signif icant structural element to the trap, then plume stabiliza tion could very well take many decades, and in such a case, a more robust and co mprehensive suite of monitoring tools may have to be applied. Many examples of both types of sites, and many more that fall in between, have been identified throughout the United States, and it is because of this variety that it is crit ical that UIC regulations for GS allow flexibility in choosing pl ume-tracking methods. The EP A acknowledges the need for flexibility in a paragraph in th e middle of page 43516, but many of the requirements laid out in the docum ent do not reflect that need.

Individual Response: EPA agrees that flexibility is impor tant in developing and implementing a monitoring plan that is appropria tely tailored for a specific GS site, and believes that the final regulation provides for flexibility in: 1) methodologi es used to collect thes e data, 2) the spatial

resolution at which the data should be collecte d, and 3) how often the data should be collected. The number and placement of monitoring wells will be based on site-specific information such as the calculated AoR, injection rate and volume, site geology, base line data, and the presence of artificial penetrations within the AoR. In so me instances, there may be a limited number of options for complying with EPA's minimum requirements. For example, monitoring for geochemical changes will require use of monito ring wells and collection of groundwater samples for chemical analysis. Many options currently exis t for complying with other requirements, such as tracking the position of the plume and pr essure front within the injection zone.

Flexibility is also provided re garding how to monitor for the sp ecific data required by the final rule. The testing and monitoring plan is develope d by the owner or operato r in consultation with the Director and is designed to ensure that a detailed, Director-approved document describing how monitoring will be conducted during the lifetime of the project exists. 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 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.

With specific regard to plume tracking and pressu re monitoring, EPA maintains that they are key components of monitoring at GS sites. A ri gorous plume tracking and pressure monitoring scheme, such as one that meets the requireme nts at §146.90(g), is imperative for ensuring that the CO2 plume is contained w ithin the injection zone.

21The final rule at §146.90(g) requir es owners or operators to pe rform monitoring to track the extent of the CO2 plume and pressure front. The owner or operator must use direct methods to monitor for pressure changes in the injection zone. Indirect met hods (e.g., seismic, electrical, gravity, or electromagnetic surveys and/or down- hole CO2 detection tools) are required unless the Director determines, based on site-specific geology that such methods are not appropriate

Pressure monitoring in the injection zone is nece ssary to track the develo pment and movement of the pressure front and CO2 plume. When combin ed with information on temperature, pressure data provide an indication of the phase (e.g., gas, supercritical) and distri bution of the injected CO2 (73 FR 43515). Monitoring can also identify n eeded remedial actions, provide inputs for AoR reevaluation modeling, evaluate predictions of plume movement, and target additional geochemical and surface monitoring needs.

Letter ID: 0220 Comment ID: 21627 Letter Lines: 380 to 424

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

Comment: Page 43519. Combination of Fixed Time Frame and Performance Standard (monitoring). The EPA is proposing a pos tinjection monitoring period of 50 years, with the director having some disc retion to either shor ten or lengthen that time period. Based on the proposed text, 50 years is the default time period for postinjection monitoring until data on pressure, fluid movement, mineralization, and/or dissolution reactions support a determin ation that the plume has stabilized and does not pose a risk to USDWs. Referring to this as the "default" time period and requiring the acq uisition of described data sets to modify the time period for monitoring i ndicate that a significant amount of

characterization effort would have to be conducted during the postinjection period, perhaps over several years, to ge t such a change. The EPA acknowledges that modeling results indicate that CO2 pl ume stabilization likely occurs on the time frame of 10 to 100 years after injection stops. One example of a GS site where plume stabilization could very well take 50 years or more is a site where there is no significant struct ural trapping element to th e reservoir. A plume at such a location may behave in a less pred ictable manner and expand or migrate a significant distance before it stabiliz es. However, CO2 injected into a thoroughly confined high-reli ef structure (e.g., pinnacle reef, carbonate mound, anticline, etc.) would likely stabilize relatively quickly. Barring a seismic event that breaches the seal, the movement of such a plume would be nil because it would literally have nowhere to go. In those cases, requiring the continued collection of several types of data for se veral years in order to prove what was probably obvious years before injection ceas ed would serve no real purpose other than to satisfy an arbitrary regula tion. The nature of structural

characteristics at each site under cons ideration for GS will be identified almost immediately, defined in detail during the earliest stages of site evaluation, and the understanding of their geometry will likely be further refined over the course of monitoring dur ing the injection phase of the project.

22It is also important to keep in mind th at the injection phase of GS projects, and the monitoring that goes with them, will, in most cases, be conducted for decades. Over those years, knowledge of th e reservoir system will increase, and by the time the injection phase comes to an end, there will be ample data to make informed decisions regarding an appropriate postinjection monitoring period. All of this leads to a logical conclusion that the establishment of postinjection monitoring peri ods should be site-specifi c and flexible. The 50- year site monitoring statement appears to have no rational basis and might effectively eliminate commercial activity.

In summary, the proposed default monitoring time frame should be eliminated and replaced with a solely performance-based standard that reflects the specifics of a project and the knowledge of that proj ect gained through the procedures and processes that are alread y required. The proposed rule gives the program

director discretion to extend or shorte n the postinjection si te care period based on project-specific considerations; therefore, it seems unnecessary to, by rule, establish a lengt hy default period.

Individual Response: EPA agrees that there will be circumst ances where it can be demonstrated in less than 50 years that the plume and pressure front no longer pose a risk of endangerment to USDWs. For this reason, the final GS rule offers owners or operators flexibility regarding the duration of the PISC timeframe by: (1) allowing the Director discretion to shorten or lengthen the PISC timeframe during the post-injection 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, during the permitting process based on substantial data, that an alternative PISC timeframe may be appropria te if it ensures non- endangerment of USDWs pursuant to requirements at §146.93(c).

EPA believes however, that to ensure USDW protection from enda ngerment, a default timeframe for post-injection site care will be necessary in al l but a limited number of cases. This default 50 year post-injection site care ti meframe represents a reasonable and protective monitoring period based on a review of research studies, industr y reports, and existing environmental programs, and evaluation of public comments.

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: 0220 Comment ID: 21628 Letter Lines: 426 to 440

Comment Code: 5400 2.9 Proposed Financial Respons ibility and Long-Term Care

23Requirements

Comment: Page 43520. Proposed Financial Responsibility and Long-Term Care Requirements The requirements for financ ial assurance may discourag e commercialization of CCS. As currently proposed, the rules woul d place greater fina ncial assurance requirements on Class VI wells than are currently placed on Class I hazardous waste wells. The more rigorous requiremen t may result in a needless negative public perception of CCS. The chemical and physical properties of carbon dioxide injected for storage purposes are not uniquely distinctive to garner such attention under the UIC Program. Furthermor e, in order for CCS projects to come to fruition, financial assurance obligati ons need to be consistently and reasonably achievable. If not, considerab le uncertainties wi ll be introduced into the economics and finances of propos ed projects. The currently proposed

rule assumes reliable cost estimates will be available at the time of permitting for a broad range of long-term activities lasting more than 50 years into the future. EPA should carefully consider the implications of the proposed financial assurance provisions so as to not discourage CCS activities.

Individual Response: The goal of financial responsibility is to ensure that resources are available to prevent endangerment of US DWs from improper plugging, remediation, and management of wells in the event that the owne r or operator experiences financial difficulties. EPA believes that assuring financ ial responsibility for corrective action on wells in the AoR, injection well plugging, PISC and si te closure, and emergency and remedial response at GS sites is an important component of ensuring that USDWs are protected. See the final rule and preamble for further discussion of EPA's fi nal approach to financial responsibility.

EPA disagrees that the requirements on financial responsibility are overly stringent. The goal of financial responsibility is to ensure that resour ces are available to prevent the endangerment of USDWs from improper plugging, remediation, and ma nagement of wells in the event that the owner or operator experiences financial difficulti es. EPA disagrees that the requirements equate GS wells with Class I hazardous waste wells; rath er, the financial responsi bility requirements for GS wells are tailored to the unique nature of the long term GS of CO2. EPA does not agree that the financial assurance requirements will result in negative public perceptions of GS. EPA believes that the public will be reassured that an y necessary activities will be covered despite the owner’s or operator’s financial difficulties.

EPA adds that the purpose of the GS rule is not to encourage the use of GS; rather, the purpose of the GS rule is to ensure that, where GS is deployed, it is conducted in a manner that protects USDWs from endangerment.

Letter ID: 0220 Comment ID: 21629 Letter Lines: 442 to 448

Comment Code: 6100 3.1 Comments on the cost estimates

Comment: Pages 43525 to 43526. Regarding cost of co mpliance. EPA compares the costs

associated with standard Class I wells and the proposed Class VI wells and

24estimates that the proposed rules would in crease the costs of complying with UIC regulations by 46%. The EPA also states that it they "believe[s] the proposed rule will not impede CO2 GS from happeni ng...." First, a 46% increase in costs is significant. Second, to pr ofess that such a large incr ease in costs will not impede the implementation of GS projects seems rather naïve.

Individual Response: EPA clarifies that the GS rule addresses costs associated with sequestration only, i.e., not captu re or transportation. Sequestrati on costs are expected to be a small component of total CCS project costs. Increasing this small component of the total CCS costs by 48 percent (i.e., based on final GS Rule costs) amounts to approximately a 2 percent increase in total CCS project costs.

EPA clarifies that the GS regula tion does not promote or encourage the use of GS; rather it is designed to ensure consistency in permitting underground injection of CO2 at GS operations across the United States and pr ovide requirements to prevent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions.

Letter ID: 0220 Comment ID: 21630 Letter Lines: 450 to 466

Comment Code: 4324 2.4.4.1.2 Comments opposed to requiring injection below the lowermost

USDW

Comment: Page 43535. § 146.5 Classification of injection wells. Class VI wells should not be limited to injections beneath the lowe rmost formation containing a USDW. This

is too restrictive in some areas. For inst ance, consider as an example the Lower Cretaceous Dakota Group in the North Dakot a portion of the Williston Basin. On the eastern margin of the Williston Basin in North Dakota, the water within the Dakota Group contains total dissolved solid (TDS) concentrations well below 10,000 parts per million (ppm), and the forma tion therefore qualif ies as a USDW. However, hundreds of miles to the west and southwest, near the center and southwestern flanks of the Williston Basin, the Dakota Group has TDS concentrations well above 10,000 ppm, and it is used extensively as an injection disposal zone for oil field produced waters . The demonstrated injectivity of the Dakota Group and its unsuitability as a pot ential USDW in western North Dakota make it an attractive target for industrie s seeking to geologically store large volumes of CO2. A strict, literal interpretation of the proposed rule could unreasonably preclude the Dakota Group from being considered as a potential target zone for CO2 storage. It is likely that similar examples of this scenario could be found in many othe r sedimentary basins.

Individual Response: EPA acknowledges that there are lim ited circumstances where injection above the lowermost USDW can be performe d in a manner that protects USDWs from endangerment, as long as appropriate protections are in place. The final GS rule at §146.95 establishes a process by which owne rs or operators can seek a waiv er of the Class VI injection depth requirements for injecti on into non-USDW formations above and/or between USDWs. It establishes: 1) requirements spec ifying information that owners or operators must submit, and

25Directors must consider, in consultation with PW SS Directors; 2) procedures for public notice of a waiver application and for Director-Regiona l Administrator communicat ion; 3) the waiver issuance process; and, 4) additiona l requirements that apply to owne rs or operators of Class VI wells granted a waiver of the in jection depth requirements to en sure USDW protection above and below the injection zone.

EPA believes that these requirements will ensure USDW protection while providing flexibility to UIC program Directors and owne rs or operators who undertak e CO2 injection for GS. The Agency believes this approach: 1) responds to co ncerns about local and re gional geologic storage capacity limitations imposed by th e proposed injection depth require ments; 2) allows for a more site-specific assessment of injection depth for GS projects; 3) accommodates injection into different formation types; 4) a llows for injection of CO2 for GS into non-USDWs above and/or between USDWs when appropriate and where it can be demonstrated that USDWs will be protected; and 5) responds to concerns about the use of aqui fer exemptions for GS. Finally, EPA’s approach to addressing injection depth va riability through a waiver process responds to concerns about future drinking wa ter resource availability and the need to ensure that high quality water remains available in sufficient qua ntities to supply drinking water needs. For additional information on the waiver approach, pleas e 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: 0220 Comment ID: 21631 Letter Lines: 468 to 472

Comment Code: 3140 2.1.4 Comments that the proposed ge ologic data requirements are too stringent

Comment Code: 3150 2.1.5 Comments on required permit information (40 CFR 146.82)

Comment: Page 43536. § 146.82 Required Class VI permit information. There are numerous requirements for information on formations overlying the proposed storage site. Requirements should be flexible and site -specific. The required information should be limited to relevant primary and/ or secondary seals and be used to document the vulnerability or lack th ereof of any USDWs in the area.

Individual Response: EPA agrees that site characterization should be site-specific, particularly in light of the variety of geologic settings in which GS may be employed. EPA believes that, while there is a large amount of required informati on, the owner or operator is given flexibility in determining what methods are used to demons trate the suitability of a potential site. EPA envisions an ongoing dialogue be tween the Director and the owner or operator during the permitting process (as well as throug hout the operation of the site).

Letter ID: 0220 Comment ID: 21632 Letter Lines: 474 to 482

Comment Code: 3150 2.1.5 Comments on required permit information (40 CFR 146.82)

Comment: Page 43536. § 146.82 Required Class VI permit information. The requirement of baseline geochemical data on subsurface fo rmations should be flexible and site26specific. The required information should be limited to relevant primary and/or secondary seals and be used to document th e vulnerability or lack thereof of any

USDWs in the area.

Page 43536. § 146.82 Required Class VI pe rmit information. Well-plugging requirements can change throughout the life of a well. Therefore, requiring a well-plugging plan with the permit app lication is excessive and unnecessary.

Individual Response: The Agency believes that the re quirement at §146.82(a)(6) to submit baseline geochemical data on subsurface geologic formations, including all USDWs in the AoR is appropriate and protective of USDWs. EPA believes that this data will support monitoring plan development, inform injectate fate a nd transport model development (e.g., by providing appropriate input parameters), a nd provide information needed to respond to any unexpected and unpermitted leaks outside of the injection zone. Th e baseline geochemical information will allow the owner or operator and permitting authority to evaluate monitoring data and identify any changes in subsurface geochemistry that may indicate fluid movement.

The rule requires geochemical analysis of, at a minimum, the injection zone, confining zone, and all USDWs (§146.82(a)(6)). These geochemical tests ar e necessary to ensure the adequacy of the confining system and to serve as a baseline for future monitoring. The Director has the discretion to require geochemical analysis of additional s ubsurface zones if in the Director's opinion they are necessary for the protection of USDWs from endangerment.

Letter ID: 0220 Comment ID: 21633 Letter Lines: 484 to 492

Comment Code: 3100 2.1 Proposed Geologic Siting Requirements (40 CFR 146.83)

Comment: Page 43536. § 146.83 Minimum criteria for siti ng. Requiring the injection zone to have the ability to receive the "total antici pated volume of the carbon

dioxide stream" seems unreasonable. Linking CO2 source potential with CO2 injection potential is not recommended, and flexibility is required. For example, if the stream is coming from a power generating facility, it can be difficult to estimate the longevity of th e plant given changes in technology that may allow for increased energy out put. Multiple storage sites may be required for one source, or conversely, mu ltiple sources may utilize a single storage site.

Individual Response: The Agency disagrees with the commenter that there should not be an absolute requirement that the injection zone be capable of receiving the total anticipated volume of CO2. The GS rule is designed to ensure that th e total volume of CO2 anticipated to be injected can be safely stored within the target injecti on zone. This evaluation is based on site-specific characteristics including the local geology (e .g., data on formation thickness, porosity, and permeability and the presence of confining zones) . The GS injection requirements, under SDWA authority, ensure protection of USDWs from endangerment through assessment of the suitability of an injection zone (§146.83), appropriate site characterization (§146.82), and area of review

27evaluation (§146.84) among other requirements.

The Agency believes that this comment may be based on an assumption that Class VI injection

wells will be co-located with CO2 producing facilities. While this may, in some cases, be an accurate assumption, the specifications, design, a nd purpose of the CO2 source/facility are not addressed by the Class VI GS requirements.

The productivity of the CO2 source (e.g., power plant, industrial facility, etc.) is not the driver of site suitability. Rather, the acceptability of a candi date site is determined, in part, by the amount of CO2 it can receive without allowing pressures in the injection formation to build up to levels that may fracture the confining zone or cause unacceptable fluid movement. If a CO2 source produces more than a formation can hold, then on ce the capacity of the receiving formation is reached, any additional CO2 produced would have to be injected elsewhere.

Letter ID: 0220 Comment ID: 21634 Letter Lines: 494 to 496

Comment Code: 3824 2.3.1.2 Cementing of long-string casing (seeking comment)

Comment: Page 43538. § 146.86 Injection well constructi on requirements. Requiring surface casing to extend below the base of th e lowermost USDW precludes potential sequestration zones.

Individual Response: EPA disagrees that the surface casing requirements in the GS rule preclude injection below deep USDWs. EPA re cognizes concerns rega rding construction of

Class VI wells where the lowermost USDW is ve ry deep. To further address comments on deep injection wells, the final GS rule at §146.95 includes requireme nts for owners or operators that seek a waiver of the injection depth requireme nts. Owners or operators of wells operating under injection depth waivers must comply with addi tional construction require ments to ensure that wells used to inject above or between USDWs ar e protective. See the di scussion of the waiver approach in the preamble to the fina l GS rule for additional information.

EPA stresses that protection of USDWs from en dangerment, regardless of their depth or the number of USDWs in an area, is the primary mission and mandate of the UIC program and the purpose of all requirements for injection wells. A ny injection activity must be demonstrated to not endanger USDWs, regardless of their depth, and if such non-endangerment cannot be shown, the activity will not be allowed unde r UIC requirements or the SDWA.

Letter ID: 0220 Comment ID: 21635 Letter Lines: 498 to 512

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

Comment: Page 43538. § 146.87 Logging, sampling, and te sting prior to injection well operation. "...the owner or operator must run appropriate lo gs, surveys and tests to determine or verify the depth, thickness, porosity, permeability, and

2829 lithology of, and the salinity of any forma tion fluids in, all relevant geologic formations." Relevant geologic fo rmations needs to be defined.

Page 43538. § 146.87 Logging, sampling, and te sting prior to injection well operation. The coring requirements are too bu rdensome if appli cable cores are already available in the vi cinity of the project.

Page 43538. § 146.87 Logging, sampling, and te sting prior to injection well operation. Given the complexity of sche duling various service companies and activities at a project location requiring a schedule of all l ogging and testing 30 days prior to the first test and submi ssion of any changes to the schedule 30 days prior to the next scheduled test ar e pointless and oftentimes impractical.

Individual Response: Regarding clarification of the term "relevant geologic formations," EPA expects that during the permit application pro cess, the owner or operator and the permitting authority will work together to determine which formations should be studied, based on the sitespecific circumstances.

EPA disagrees that the requirements for logs, surv eys and tests are excessive. All logs, surveys, and tests listed at §146.87(a) ar e necessary to verify information about the injection and confining zones and ensure th at the well is being drilled and cased as approved and has mechanical integrity. Reliance on existing lithol ogic and geologic information may not provide adequate details for site-specific well design and geologic knowledge to support protection of USDWs from endangerment. EPA not es that the Director has th e discretion at §146.87(a)(5) to approve alternative methods that provide equivale nt or better information, and the Director may accept information on cores of the injection and c onfining zones from nearby wells if the owner or operator can demonstrate that such cores are representative of conditions at the well in question and core retrieval is not pos sible, as specified at §146.87(b).

EPA disagrees that the 30-day notification requirement is unreasonable. Acknowledging the developing nature of CO2 GS, EP A believes that involvement by the permitting authority in each project will provide much n eeded field data for assurance of USDW protection from endangerment and will help update and refine the permitting process. Adequate timing of

notification will ensure the Direct or's ability to be involved.

EPA is developing guidance on monitoring and tes ting that will describe recommended tests and procedures to assist owners/operators and Di rectors in evaluating the requirements for preoperational logging and testing under §146.87. This guidance will be available on EPA’s website at http://water.epa.gov /type/groundwater/uic/wells_sequestration.cfm.