### 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.

### September 29,2009

Water Docket

Environmental Protection Agency

Mailcode: 2822T

1300 Pennsylvania Avenue NW

Washington, DC 20460

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



### Electronically Delivered: Via: www.regulations.gov

To Whom It May Concern:

Company Introduction and Frame of Reference for Comments



### Global Energy, Inc. (Global) appreciates the opportunity to comment on the Notice of

Data Availability (NODA) in the Subject Docket, as issued in 74FR44802, on August 31,

2009, regarding Federal Requirements under the Underground Injection Control (UIC)

Program for Carbon Dioxide (C02) Geologic Sequestration (GS) Wells.

As we noted in our December 2008 comments on the Proposed Rule, Global is actively

developing gasification based energy production projects, with particular focus on the

production of Synthetic Natural Gas (SNG), Fischer-Tropsch (F-T) liquids, Hydrogen, as

well as electric power generation via Integrated Gasification Combined Cycle (IGCC)

technology. Gasification technology can effectively capture carbon dioxide (C0 2 ) during

manufacture of energy products such as Synthetic Natural Gas (SNG) or

Fischer- Tropsch liquid fuels. Gasification related technologies can also adjust the

synthetic gas fuel composition (i.e. lower the carbon monoxide and increase the

hydrogen content) to enable combustion emissions comparable or superior to natural

gas. Importantly, Global is committed to carbon capture and sequestration (GGS), and

believe it can be done cost effectively. As also noted in our earlier submittal, our Lima

Energy project is planning Geologic Sequestration (GS) in the 

### Mt. Simon Sandstone,

which lies directly beneath western Ohio and several adjacent states.



### We appreciate the recent NODA and the opportunity to comment on it here. Global

Energy appreciates the analysis and development work provided to USEPA by the

National Laboratories, and EPA's willingness to "be adaptive" and incorporate beneficial

results into the rule making. We encourage USEPA to proceed with the rule making,

and feel it is important that the rule is structured in an adaptable manner in order to

accommodate knowledge and experience over time.

Global offers specific comments below, relative to different aspects of the NODA:

Clob,ll [w}r9V inc Suite 2,10(\ 312 \'1"lnu[ S(r8el CiI1Ginnnti, Oil 4;)2(1) ty:;!\

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### 1. We concur that the NODA provides helpful and informative new information and

that USEPA should proceed with finalizing the rule.



### 2. We believe that "Far Field" pressure is important to understand, but need not be a

concern with proper and effective injection site characterization, which in this case

would consider pressure effects more remote from the injection site. A practical

approach should be able to monitor plume pressure migration and alter the

operation if appropriate. This is an area where more experience is needed and the

rule should be written to foster gaining this experience.

3. We do not support the view of other com menter's that more rigorous attention to

RCRA and CERCLA are necessary or appropriate. The rule already prohibits

injection of the regulated wastes, as well as injection stream characterization that

will demonstrate that these characteristics are avoided. This is a C02 injection rule

not a waste management rule. Regular update of the stream qualities is

reasonable, without making the process overly burdened.

As we noted in our earlier comments, if the requirements are too onerous GS of

C02 will not occur as desired.

4. We strongly support the proposed "adaptive approach" to this rule, and that USEPA

should have flexibility to implement changes that result from experience gained

over time.

5. Our evaluations of the geology in Ohio and preliminary modeling of the Mt. Simon

Sandstone ("the Mt. Simon") in the vicinity of Lima in Allen County, reinforces US

Department of Energy knowledge of this deep saline aquifer, and their view that it is

generally ideal of GS. One USDOE Regional Carbon Sequestration Partnership

intended to utilize the Mt. Simon at a location less than forty miles from our project

in Lima, Ohio. For reasons unrelated to the suitability of the site, the project is

understood to be on hold. Our results are also supported by the Ohio Geologic

Survey, whose periodic newsletter, attached here, addressed the subject in 

### 2007.

6. We support the requirement for project design with a "robust monitoring plan" that is

capable of corroborating modeling with actual performance. This should include

assessment of dissolution or dissociation and effects on the mobilization of trace

elements.

7. We note that a LBNL study, referenced in the NODA, made an assumption in a

release scenario that "leakage into a shallow aquifer would occur at a constant rate

over a 

### 100 year period". Constant rate leakage is not logical, especially over such

a long time period -7 

### pressures (driving force) will decline, and mineralization will

occur, to list two factors against constant rate leakage. The assumption is not even

valid as a "worst case scenario".3



### 8. While the LBNL work is appreciated, USEPA should view it as a "generalization"

and still allow "local studies in local conditions". Specifically, assessment of

leakage risk needs to be in context of local conditions.

9. We appreciate the modeling LBNL conducted of a hypothetical sedimentary basin

with several projects injecting high aggregate and cumulative quantities of C02

annually over an extended period. The results, though hypothetical, argue in favor

of case-specific consideration of: (a) large volume injections; and (b) defendable

close proximity between injection points. That is local conditions may

accommodate higher than normal injection rates and closer proximity to other

injection activity.

Specifically, the rule should be finalized with language that allows consideration of

injection projects that, based on modeling, that show the injection horizon to have

characteristics favorable to high-volume injection and/or relatively close proximity

injection sites. Injection pressure effects, plume migration rate, and avoidance of

fracture pressure would be some of the considerations.



### 10. As noted earlier, we support consideration of the potential effects of "far field"

pressure build up in siting criteria to ensure the integrity of the injection horizon

remote from the injection location. The rule should allow case specific

determination of appropriate injection quantities and conditions.



### 11. The rule should provide for data collection and reporting to facilitate EPA

knowledge accumulation and its "adaptive" rule management.



### 12. We support USDW protection, and argue for a practical rule and implementation to

facilitate actual deployment of GS (Le. the process needs to be practical or it will

not evolve timely).

13. We strongly concur with the observation that "treating high-salinity" waters (i.e.

those in excess of USDW protectiveness threshold) will be generally less costly

than obtaining water rights.

14. We support the view of some States that GS should be allowed where site-specific

demonstration is made that USDW will be protected**~** 

### even though depth criteria

may not be in conformity with the basic rule requirement for injection below the

lower most aquifer. A straightforward "waiver" process may serve in these cases.

There should NOT be a blanket prohibition of injection above or between USDWs.

Well completion technology and characterization of injection horizon and fluid

interaction is a sufficiently developed state of the art to promote EPA's "adaptive

rule making".

Global**[!~erpv** Inc. Suits ?:lOO**:11~'** V\I,1Inlll Slm"L C !IlGiIHlati OH ,1 :';20;' US1\

Tel' ;)1:,;**(l~'1,nO(1** <> Fa):, b 1 J b./l**S~l4/**4



### 15. We strongly support the EPA view that different well classes warrant different

treatment, and that EPA approval criteria should therefore differ. C02 at injection

pressures will greatly differ from other fluids regardless of well class. In EPA's

phrase, "site-suitability" for GS is what needs to be determined.

16. For pragmatic reasons, with respect to deployment of GS at least, State Discretion

and Delegation should be maximized; as well as the cooperative relationships with

external expertise, whether State or not, that USEPA has already established.

Again, we appreciate the opportunity to provide these comments and look forward to

well-founded regulations that provide a pragmatic, cost effective and expeditious path

forward in the management of carbon dioxide via the utilization of Class VI wells.

Respectfully Submitted,

Dwight N. Lockwood, PE, QEP

Group Vice President



### P:

Email: 513.621.0077

dnlockwood@globalenergyinc.com

Attachment: Ohio Geologic Survey Quarterly Newsletter, 2007 Issue 2

Ci(,i)dl [nuIUY inc. SUits ::'300 W<llnul Sti**e~)l C:ni~lI1n()!1**  Of 145:0:02, USA

TC'I 'in U:'1UU!f • f Sl:Hi!15'Qi

# Geologic sequestration of carbon

dioxide in Ohio

By Larry 

### Wickstrom

Much research on carbon dioxide sequestration is taking place worldwide, yet many people

do not understand what sequestration is and

why so much effort is going into researching it.

Carbon dioxide (C0

2 ) naturally occurs in the

air we breathe and within the earth's crust. We

also use it in fire extinguishers and dry ice and

as the source of bubbles in soda pop. So, why

are we trying to get rid of such a common and

useful gas?

Carbon dioxide is one of many gases known

to cause an elevated warming of the earth

through the greenhouse effect. Known greenhouse gases (GHGs) include carbon dioxide,

methane, nitrous oxides, and hydrofluorocarbons. Carbon dioxide comprises nearly 80%

of the GHGs emitted into the atmosphere by

humans. Many people feel that human contributions of GHGs into the atmosphere may be

having a significant impact on global climate

change. Thus, research is taking place on ways

to reduce the amount of GHGs that society emits

into the atmosphere.

Infrared radiation is emitted from the earth's surface. Some

passes through the atmosphere and some is absorbed and

re-emitted in all directions by greenhouse gas molecules,

which warms the earth.

Greenhouse gases in

the earth's atmosphere

trap some solar

radiation.

warm the earth. The United States emits more CO 2 than any

other country in the world. Total world anthropogenic (human-made) CO 2 emissions for 2002

are estimated to have been 24.405 million metric tons. In 2005, the U.S. Energy Information

Administration reported that the United States

emitted 5,746 million metric tons of carbon

dioxide. During the same year, Western Europe

was the second-largest producer of CO 2 emissions at 3,585 million metric tons, and China

was the third-largest producer at 3,176 million

metric tons (it is projected that China will emit

more CO

2 than the United States within the next

several years). Within the United States, Ohio

is the fourth-largest producer of CO 2 emissions

behind California, Texas, and Pennsylvania,

respectively.

It is estimated that in 2003, Ohio emitted

265.5 million metric tons of CO 2 into the atmosphere. This amount is distributed between

electric power generation, transportation, industry, and commercial and residential output.

The primary sources of anthropogenic CO

2 are

activities that involve burning hydrocarbons.

Other activities, such as the manufacture of iron

and steel. cement, and fertilizers, also contribute

significantly to Ohio's carbon footprint (a carbon

footprint is the total amount of carbon dioxide

directly or indirectly caused by a specific activity. entity, or product life cycle). The two largest

sources of Ohio's CO

2 from hydrocarbons are

electric power generation and transportation.

Nearly 90% of Ohio's electricity comes from

coal-burning power plants, and coal-burning

power plants are the single largest emitter of CO 2

in Ohio.

To be sustainable in the long-term, our

SOciety must develop more fuel-efficient vehicles

and, ultimately, an alternative energy source for

transportation. For near-term planning, large

industrial point-sources of CO 2

, such as coalburning power plants, provide the best and most

cost-efficient opportunity to capture and sequester CO 2 before it is emitted into the atmosphere.

continued on page 32 • ohio Geology • 2007, No.2



# .......................................................



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Larry Wickstrom,

Division Chief and State Geologist

Recently, stakeholders in many natural

resources issues have placed much emphasis

on the term sustainable development, which was

defined by the 1987 Brundtland Commission

as "meeting the needs of the present without

compromising the ability of future generations

to meet their own needs." I think the popularity

of this concept is long past due and I hope the

momentum of sustainable development continues in its wise application.

The Division of Geological Survey investigates many aspects of Ohio's geology that are

relevant to sustainable development in the state.

Geology is the ground we live on; the rocks and

minerals we use to produce building materials and energy; the geologic hazards (such as

landslides and earthquakes) that threaten us; and

so much more. How our society uses natural resources and interacts with our geology (building

roads or shopping malls, for example) affects the

sustainability of such developments. By striving

for sustainable development, we are recognizing

that we cannot control what nature gives us any

more than we can control earth processes like

erosion or the rising and falling of water levels.

We can only control how we use our natural resources for short- and long-term development.

Each of us uses a large amount of energy

and mineral resources every day. To meet our

own demands, we must operate sand, gravel,

and limestone quarries; mines; and oil and gas

wells. To obtain sustainable development, we

must practice conservation methods on an

individual and national level. The United

States, and Ohio in particular, have

some of the highest environmental

standards and regulations in the

world. When we deny development

of extractive industries locally, we

are often transferring the burden

of producing the commodities

that we use to somebody who will

develop the resources using environmental standards that are lower

than our own. By displacing this

responsibility, we make environmental

problems worse and increase commodity prices for ourselves, especially when

the commodities have to be transported from

remote locations to our own localities. The Five pIs-Proper Planning Prevents

Poor Performance. We've all heard this saying

before, but, until recently, few of our communities actually took into account their natural

resources management when planning for development (even though communities are built

and maintained using natural resources). Here's

a scenario that has happened over and over again across the nation: A local zoning commission allows developers to build wherever they

want; for example, next to an existing quarry. In

this situation, rock material from the quarry is

used to build houses and roads in the development, and then the quarry cannot be expanded

because of the dense housing development

around it. Soon, all of the "neighbors" complain about the dust and noise from the quarry

and start efforts to shut it down. Inevitably, the

quarry operator is portrayed as the source of

the problem when in reality the lack of planning from developers and community leaders

began the problem. This is just one example of

how our society needs to take control of our development in a sustainable manner. Thankfully, some local and regional commissions are

now conSidering our natural resources when

planning. It is short-sighted to develop over our

best sand and gravel deposits and our access to

the best groundwater just as it is short-sighted

to build in landslide prone areas.

The work products of the Ohio Geological

Survey are an integral part of long-range planning for sustainable development, which helps

prevent future conflicts, shortages, and myriad

other problems. Our mapping shows where the

best sand and gravel, aggregate, and coal deposits exist and helps identify and delineate lake

coastal erosion and other geohazards, as well as groundwater resources.

While on the topic of sustainable development, readers should know that the Division of

Geological Survey has been very involved for

several years in characterizing the geology of

the state for geologic sequestration of carbon

dioxide, which is released during many natural

and human-caused processes, such as when coal

is burned for electric power generation. The lead

article in this month's Ohio Geology attempts

to explain a little more about carbon dioxide

sequestration and how it affects our state.

www.ohiodnr.com/geosurvey/

# ·

..................................................... . Ohio Geology • 2007, No.2· 3

continued from page 1

Methane Nitrous

9.5% oxide

5.8%

Percentage breakdown of greenhouse gases (excluding

water vapor) that humans emit into the atmosphere.

(Data source: < http://www.climatetechnology.gov »

What is CO 2 Sequestration?

Carbon dioxide sequestration, simply put,

is capturing and securely storing carbon dioxide from the atmosphere and/or human-made

sources before it is released into the upper atmosphere. There is a natural carbon cycle in which

earth processes consume carbon (e.g., photosynthesis; weathering of silicate rocks) as well as

produce carbon dioxide (e.g., volcanoes; oxidation of plant life). Most of the C02 released into

the atmosphere is from these natural processes.

Anthropogenic CO 2 emissions account for only

3 to 4 % of the world's carbon output, but many

scientists feel that this amount is enough to

cause global climate change.

We can use natural processes to sequester

C02 from the atmosphere and mitigate anthropogenic CO 2

. Through agriculture, development,

mining, and other activities, humans have removed a significant amount of carbon from our

soil systems. Terrestrial sequestration methods

such as no-till farming seek to replenish this lost

carbon by capturing carbon from the atmosphere via photosynthesis and locking it into

the soil. However, there is a limit to how much

carbon the soil can hold, so terrestrial sequestration cannot mitigate the effects of all anthropogenic CO 2

. Geological sequestration involves injecting

C02 into appropriate rock units in the deep subsurface (generally greater than 2,500 feet deep)

where it is securely stored, or trapped. Once it is

trapped in the subsurface, it will slowly combine with the native fluids found in the rocks

and react with the minerals and organic matter

in the geologic formation to form (precipitate)

stable compounds/minerals, primarily calcium, iron, and magnesium carbonates. Mapping of

geologic sequestration capacities by the Division

of Geological Survey and other resource professionals has shown hundreds of years of storage

capability in Ohio. The wide-scale deployment

of geologic and terrestrial sequestration technologies appears to be key in facilitating sustained

and significant reductions in CO 2 emissions.

The primary attraction of geologic sequestration for public planners and resource professionals is the potential for direct and long-term storage of C02 emissions in close proximity to large

CO 2 sources (such as ethanol or power plants).

However, to achieve this objective, the potential

capacity of any geologic reservoir needs to be

verified by detailed regional assessments, as well

as site-specific investigations to allow decisionsmakers to fully understand the characteristics of

the geologic sequestration system. The Division

of Geological Survey has been working on both

regional and site-specific projects over the past

seven years.

Natural geologic reservoirs have held oil,

natural gas, water, and even CO 2 for millions of

years with minimal to no leakage. These same

systems are thought to offer both near-term

opportunities and longer-term possibilities

for future management of anthropogenic CO 2

. Some industries use these natural reservoirs

for storage of industrial wastes (hazardous and

industrial waste injection wells) and the disposal

of oilfield brines (brine injection wells). Natural

gas is also stored in geologic reservoirs for later

withdrawal during peak (winter) usage periods to

lessen the demand on the interstate pipeline system. Additionally, the injection of C02 in oil field

reservoirs to stimulate additional oil production

(enhanced oil recovery [EOR)) has been taking

place since the early 1 970s and is a growing

methodology in the petroleum industry. Thus,

substantial experience with geologic injection

operations already exists.

mt = million tons

Ohio's anthropogenic C02 emissions by sector (2003).

(Data source: U.S. Energy Information Agency)

www.ohiodnr.com/geosurvey/4 • Ohio Geology • 2007, No.2



# .......................................................

What are Ohio's primary potential

geologic reservoirs for CO 2 ?

There are several types of geologic reservoir

systems that are being investigated for potential

CO 2 sequestration. In Ohio, two types have the

largest near-term capacity for storage and use.

These are deep saline formations and oil and

gas fields.

Deep saline formations are natural saltwaterbearing intervals of porous and permeable rocks

that occur beneath the level of potable groundwater. Currently, a number of saline formations

in Ohio are used for waste-fluid disposal; thus, a

long history of technological and regulatory factors exists that could be applied to CO 2 injectionl

storage. Saline formations are widespread, close

to many large CO 2 sources, and are thought to

have large pore volumes available for potential injection. In order to maintain the injected

CO 2 in liquid form, the injection zone must be

approximately 2,500 feet or greater in depth.

Impervious confining rock

C02 displaces methane

from deep unmineable

coal seams

Impervious confining rock

CO 2 displaces trapped

oil and gas

Impervious confining rock

Depleted oil and gas

reservoirs store CO 2

Impervious confining rock

Deep saline reservoirs

store C02 Maintaining the C02 in a liquid phase is desirable because it can more readily mix and go into

solution with a native formation's brine and, as a

liquid, it takes up less volume than when it is in

gaseous form. One ton of CO 2 at surface temperature and pressure (in its gaseous phase) occupies almost 18,000 cubic feet. The same amount

of C02 injected to a depth of approximately

2,500 feet will occupy only 50 cubic feet. The

2,500-foot minimum sequestration depth also

helps insure that there is an adequate interval

of rocks (confining layers) above tFte potential

injection zones to serve as a geologic seal.

In these types of reservoirs, C02 is injected

under pressure down a specially constructed

wen into the reservoir where it displaces and

mixes with saline water and fins the pore spaces

between the mineral grains of the rocks in the

reservoir. The CO

2 is trapped within the rock

matrix. Depth, permeability, injectivity, reservoir

pressure, reservoir integrity, and water chemistry

are some of the variables that control the sequesGeneralized block diagram illustrating CO

2 from an industrial source being injected in deep

saline formations for storage and

for use in enhanced oil recovery

(EOR).

Sand and gravel

Limestone

www.ohiodnr.com/geo5urvey/

# ·

..................................................... . Ohio Geology • 2007, No.2' 5

tration potential of deep saline formations. In

addition to the properties of the injection zone or

reservoir, characterization of the overlying seal

units (confining layers) is necessary. The injected

CO

2 has a lower specific gravity than natural

formation fluids, thus it is more buoyant and will

rise to the top of the porous zones. Cap rock units

must be relatively impermeable and sufficiently

thick to arrest any appreciable vertical movement of the CO

2 within the sequestration interval,

thereby trapping it in the deep subsurface.

Oil and gas fields represent geologic traps

(structural or stratigraphic) that contain hydrocarbons within a reservoir with a known cap or

seal. In depleted or abandoned petroleum fields,

CO 2 sequestration would take place by injecting

CO

2 into the reservoir to fill the pore volume left

by the extraction of oil or natural gas resources.

The injected C02 would be trapped by the same

limits as the original hydrocarbon for secure

storage in the reservoir. Volume, permeability,

injectivity, pressure, reservoir integrity. water

chemistry. the nature of the cap rock or reservoir seal, and the history of production are some

of the variables that control the sequestration

potential of depleted oil and gas fields. This may

be an attractive sequestration option in some

parts of Ohio because large areas of the state

have a long history of oil and gas recovery (to

view an Ohio oil and gas fields map online, go to

< www.ohiodnr.com/Portals/1 O/pdf/pgO 1. pdf>

. However, much caution must be exercised when

investigating this potential because of the large

number of old, undocumented wells abandoned

within some areas of the state. These wells could

provide pathways for the CO

2 to leak upward.

In active oil fields, it has been demonstrated

in other parts of the country that CO

2 can be

used for enhanced oil recovery (EOR). In this

process, some of the oil that remains in reservoirs after primary production is recovered by

injecting CO

2 that 1) repressurizes the reservoir

and displaces and drives the remaining oil to a

recovery well, and 2) directly mixes and chemically interacts with the remaining oil to make

it more mobile, allowing more oil to be pushed

to the producing wells (miscible flooding). Approximately 70 oil fields worldwide (most of

these in the western US) currently inject C02 for

EOR, and over 1 billion barrels of additional oil

have been produced, which demonstrates the

effectiveness of this value-added sequestration

option. The Division of Geological Survey maintains the oil and gas field maps of Ohio and performs research to characterize the reservoirs for

more efficient production of oil and gas and for

possible use of them as CO 2 containers. The Division of Geological Survey is currently attempting

to form partnerships and the funding necessary

to investigate the effectiveness of using specific

Ohio reservoirs for C02 EOR.

A third type of geologic reservoir, deep, unmineable coal beds. may have (limited) potential

for storing CO

2 in Ohio. Carbon dioxide injected

into unmineable coal beds would not only occupy

pore space but bond, or adsorb, onto the carbon

in the coal. Because of this adsorption. miscibility would not be a concern like in oil and gas

reservoirs and saline formations, and C02 injection (and resulting enhanced recovery of coalbed

methane) could occur at shallower depths than in

depleted oil reservoirs or saline formations.

Coal beds often contain large amounts of

methane within the pore space of the coal as

well as adsorbed onto the coal itself. The adsorption rate for CO 2 in coals is approximately twice

that of methane; thus. injected CO

2 displaces

methane and allows for potentially enhanced

gas recovery while sequestering CO 2

.

Is Ohio well suited for geologic

CO 2 sequestration?

The Division of Geological Survey has been

analyzing data from tens of thousands of wells

and producing dozens of maps of favorable Ohio

sequestration reservoirs and cap rocks as part of

a multi-state partnership, the Midwest Regional

Carbon Sequestration Partnership (MRCSP).

Some of the resultant maps and data can be

viewed as an interactive map available on the

Division's website < www.dnr.state.oh.us/

website/geosurvey/MRCSPGEO/disclaimer.htm> ;

you may also want to visit the MRCSP website

< www.mrcsp.org> for more information about

the partnership and CO

2 sequestration in general. The Division of Geological Survey will soon

release a publication about the regional mapping and capacities estimate for the state and the

Midwest region.

The partnership's initial assessments of

Ohio's deep C02 storage capacity indicate that

Ohio can potentially sequester approximately

45 billion tons of CO

2 • This represents about 350

years of Ohio's current output of CO

2 from stationary point sources. However. that capacity is

not equally distributed around the state-some

geologic areas have high storage potential while

other areas have little to no potential. This is

very important information to help the public

and large CO

2 -producing industries plan for

future CO

2 sequestration sites and/or pipelines

that distribute CO 2 from point-source iocations

to appropriate storage sites.

www.ohiodnr.com/geosurvey/6 • Ohio Geology • 2007, No.2

Drill rig on location at the Ohio

Geological Survey C02 No. I carbon

sequestration research well in Tuscarawas County, Ohio.

1/

...... /" • 

# Revised 

# karst map



# available 

# .......................................................

In addition, we still have much to learn about the rate at which reservoirs will

accept C02 and how pressure buildup from neighboring injection operations might

interact with one another. This information is vital in determining how many wells

would be needed and the spacing intervals between them, which determine the

level of compression needed, pipeline lengths, and the overall distribution of operations. Therefore, the Division of Geological Survey continues to develop more

detailed data, maps, and models related to CO

2 sequestration. Working with the

Ohio Air Quality Development Authority, Battelle Memorial Institute, and the U.S.

Department of Energy, we recently completed drilling a deep test well < www.

ohiodnr.com/Home/ogcim/ogcim/C02/tabid/17870IDefault.aspx > in Tuscarawas

County. We are now performing detailed analyses on its rock materials and data

and will issue a report on this important project in early 2008. We also continue to

gather and analyze data from existing and new deep wells.

Through geologic sequestration research, the Division of Geological Survey

has gained close partnerships with dozens of companies and trade associations,

including the U.S. Department of Energy, Battelle Memorial Institute, the Ohio

Coal Development Office, the Ohio State University, Western Michigan University,

the Interstate Oil and Gas Compact Commission (IOGCC), and the state geological surveys of Indiana, Illinois, Kansas, Kentucky, Maryland, Michigan, Pennsylvania, and West Virginia. Through these efforts and partnerships, the Division of

Geological Survey has assumed a regional leadership role in carbon sequestration

and is nationally recognized for this role. The knowledge gained and the contacts

maintained through this work have helped prepare Ohio for future greenhouse gas

registries and regulations and for companies that plan to build clean fuel and power

plants in our state.

Further Reading

The Brundtland Commission, 1987, Our Common Future: Oxford, Oxford University Press,

400 p. The full text of the Brundtland Report, hosted by the Swiss Federal Office for Spatial

Development ARE, can be downloaded as a scanned copy of the UN General Assembly

document A1421427-a 16 MB pdf file at < http://www.are.admin.ch/themen/nachhaltig/

00266100540100542Iindex.html?lang 

### = en > .

''Z > 'i

• The 2007 release of Known and**ProQabl~** .... Karst in Ohio, originally released in.1999 and

revised in 2002, includes new /drift**thickness'.{~** .. and karst data-including 57 newly documented

sinkhole/s**andcaves~giving** map ,users a more

comprehensive product to use when identifying karsfareas. The map depicts areas 

### of kndwn

and probable karst terrain, where dissolution

processesin carbonate rocks (limestQne ,and

. dolomite) and gypsum have pr()dw;:e4;.net,Works.

of<;onduits below the**~lJrfctCe** and siflkholesand')

caves at the surfaqe. Environm.ental anqsoCietal'\t

concerns 'related to karst**inc~t.1de** groundwater: .'

contam.ination and unlfxpectedcbnstruction

costs and delays.

. . Known and Probable KarsUn Ohio can be'

purchased from theOhio**Geological;~urv:y** for'

. S15. Please see ordering information on page 8.

>**WWW~.9hi9dnr** .• com/ge(;su.r.veYI

•

# ·

..................................................... . Ohio Geology • 2007, No.2· 1



## Book review 

# of Roadside Geology of Ohio

Roadside Geology oj Ohio is University of Toledo Geology Professor Dr. Mark

Camp's second book in Mountain Press's

Roadside Geology series. The series'

six-by-nine-inch paperback format and

vision-friendly text and graphics make the

book easy to use while traveling. Instead

of chapters in a book or a map in an atlas,

this book features 25 driving routes, such as

"1-71: Columbus to Cincinnati." Each route

has an overview map, usually with several

geologic or historic features labeled on it,

and a few pages describing the geology along the

route. Camp expands on his book's introductory

review of geology by including a discussion on

the geology, bedrock formations, and Ice Age deposits and features in four Ohio regions. He also

describes significant geologic and historic events

specific to each region. In addition to the route maps and text, there

are numerous sidebar features on points of

geologic, historic, and economic interest that are

either quickly accessible or visible from many of

the routes. This well-illustrated book has numerous historic and present-day black and white

photographs highlighting Ohio's geology and

how it played a role in the state's development.

The book also includes a glossary, a list of additional reading material, and a thorough index.

This book will be a valuable asset to anyone

living in or visiting Ohio who wants to make

traveling through the state both entertaining and

educational.

-Doug Shrake

Roadside Geology oj Ohio can be purchased

from the Ohio Geological Survey for $24. Please

see ordering information on page 8.



# Revised Ohio earthquake map available

Earthquake Epicenters in Ohio and Adjacent Areas was originally developed in 2002

to document the magnitude and spatial

distribution of earthquakes with epicenters

in Ohio and surrounding areas. More than

30 earthquakes in the Ohio region have occurred since 2002 and are included on the

new 2007 map, which allows map users

to easily gain information about the most

recent earthquakes, as well as earthquakes

dating back to 1776: earthquake event time,

location, depth, magnitude, felt-area size

and information source. This dataset allows

users to determine which portions of the

state are historically more susceptible to

earthquakes and to apply this knowledge to

varied applications, including earthquake

insurance rate determinations, construction

strength determinations for bridges and buildings, and research on deep-earth structures such as

hidden faults.

The new map shows a concentration of earthquake epicenters in two areas of the state:

western Ohio in the vicinity of Shelby County, and along the Lake Erie coast in Lake County at

Painesville. While it might seem like earthquakes are occurring more frequently in recent years,

the Ohio Seismic Network attributes this perceived change to improved technology and communication among people who experience the earthquakes.

Earthquake Epicenters in Ohio and Adjacent Areas can be purchased from the Ohio Geological

Survey for 

### S 1 O. Please see ordering information on page 8.

www.ohiodnr.com/geo5urvey/8 • Ohio Geology • 2007, No.2



# .......................................................

Survey staff changes

Comings:

• Mike P. Angle-Geology Program Supervisor,

Geologic Mapping and Industrial Minerals

Group

• Christopher P. Gordon (promoted)-Geologist

2, Energy Resources Group

• Katy H. Pan-Publications Editor, Technology

Transfer Group

Goings:

• Paul M. Harbulak-Geographic Information

Management Systems Specialist 2, Lake

Erie Geology Group

• Christiana A. Tickle-Publications Editor,

Technology Transfer Group



# Ordering information

To order any of the Survey's publications

or maps, contact the Geologic Records Center,

2045 Morse Road, Bldg. C-l, Columbus, Ohio

43229-6693; telephone: 614-265-6576; fax:

614-447-1918; email: geo.survey@dnr.state.

oh.us. In-state sales tax rates are based upon

the county where the map is shipped. Handling

charges apply to all mailed orders (please call for

rates). Visa and MasterCard are accepted

. 

# Re

... release Of popular

local geology book

With help from their supporters, including the Ohio Geological Survey, the Kentucky

Geological Survey recently released the second

edition of University of Cincinnati (UC) Geology

Professor Emeritus Paul E. Potter's Exploring

the Geology oj the Cincinnati/Northern Kentucky

Region. Potter's 128-page report-style paperback

is popular with amateur and professional geologists, historians, teachers, and planners because

it carefully balances technical information about

the area with many illustrations, sidebars, and

interesting photographs. Potter says about half

of the 87 illustrations in the book have been updated for the new version. The text also reflects

new information about subsurface geology and

how it affects people at the surface.

Sections of the book are dedicated to today's

geological issues, such as land movements, how

geology affects groundwater levels, and use of

geographic information systems (GIS). However,

the immediate and local relevance of geology is

present throughout the history sections of the

book as well.

Potter's publication is unique in that it focuses on a primarily urban area. It is timely because

it reflects the significant population growth of

the Cincinnati area in recent years. When the

book was first released in 1996, the area's population was 1.7 million. Today it is 2 million.

Exploring the Geology oj the**CincinnatilNorth~**

ern Kentucky Region can be purchased from

the Ohio Geological Survey for $15. Please see

ordering information at left.



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Ted Strickland, Governor

Sean 0 Logan, Director

Larry Wickstrom, State Geologist & Chief

OhiO Department of Natural Resources

DiViSion of Geological Survey

2045 Morse Road, Bldg C-1

Columbus, OhiO 43229-6693

614-265-6576

geo survey@dnrstate all us

www ohlodnr com/geosurvey/

OhiO Geology IS a free publication To become a

subscnber please contact the DIVISion of Geological

Slirvey at tile above address, phone number, or email

Back Issues can be found on the DIVISIOn'S webSite

Compilers Mac SWinford, Greg Schumacher,

and Mark Wolfe

Editor Katy Pan

Layout!Deslgn Lisa Van Doren

An Equal Opportunity Employer-M/F/H

Pnnted on recycled paper PRSRTSTD

U.S. Postage

PAID

Columbus, OH

Permit No. 5767

Administration/State Geo\o9lst GeoJo9ic Mapping and Energy Resourcfui Group Lake Erfe Geology Group Techoolo9yTransfer Group Geologic Records Center

614·265·6988**In~"strial** Minerals Group 614,265·6602**614·~65·6597** 419·626·4296 614·265·6591**614·~65·6576** Or 614·265·6585Letter ID: 0332

Commenter: Dwight N. Lockwood

Organization: Global Energy, Inc.

Letter ID: 0332 Comment ID: 28187 Letter Lines: 53 to 64

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

Comment: We appreciate the recent NODA and the opportunity to comment on it here. Global

Energy appreciates the analysis and development work provided to USEPA by the

National Laboratories, and EPA’s willingness to "be adaptive" and incorporate

beneficial results into the rule making. We encourage USEPA to proceed with the

rule making, and feel it is important that the rule is structured in an

adaptable manner in order to accommodate knowledge and experience over time.

Global offers specific comments below, relative to different aspects of the

NODA:

1. We concur that the NODA provides helpful and informative new information and

that USEPA should proceed with finalizing the rule.

Individual Response: EPA is finalizing the rule and intends to follow an adaptive approach to the GS

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

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

Letter ID: 0332 Comment ID: 28188 Letter Lines: 66 to 71

Comment Code: 2220 2.2.2. Basin

‐ Scale Hydrologic Impacts of CO2 Storage (seeking comment)

Comment: 2. We believe that "Far Field" pressure is important to understand, but need not

be a concern with proper and effective injection site characterization, which in

this case would consider pressure effects more remote from the injection site. A

practical approach should be able to monitor plume pressure migration and alter

the operation if appropriate. This is an area where more experience is needed

and the rule should be written to foster gaining this experience.

Individual Response: EPA agrees that proper site characterization, together with predictive modeling

and far

‐ field pressure monitoring are important components of siting and managing GS projects. Thefinal GS rule requires a detailed site

‐ specific evaluation of local geologic conditions (§146.82) and

modeling to delineate the AoR based on the detailed geologic data collected during the site

characterization process (§146.84). Monitoring of the plume and the pressure front are required

throughout the operational phase (§146.90). One goal of the siting and AoR delineation process is to

identify the potential for pressure changes that may cause unacceptable fluid movement, even if they

occur far from the injection well. If such pressure increases were predicted at levels that could

potentially endanger USDWs, a GS site would not be permitted. If far field pressures were to increase

above predicted levels, pressure management schemes via brine extraction from the storage reservoir

may be an appropriate remedial action; however prevention of such impacts is the focus of the GS rule.

For additional information regarding EPA’s requirements for AoR delineation and monitoring for GS

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

Letter ID: 0332 Comment ID: 28189 Letter Lines: 73 to 81

Comment Code: 1100 1.1 Comments on the Comprehensive Approach

Comment: 3. We do not support the view of other commenter’s that more rigorous attention

to RCRA and CERCLA are necessary or appropriate. The rule already prohibits

injection of the regulated wastes, as well as injection stream characterization

that will demonstrate that these characteristics are avoided. This is a CO2

injection rule not a waste management rule. Regular update of the stream

qualities is reasonable, without making the process overly burdened.

As we noted in our earlier comments, if the requirements are too onerous GS of

CO2 will not occur as desired.

Individual Response: EPA acknowledges that GS falls within the broader context of CCS and the need for

regulatory clarity to ensure that USDWs are protected from endangerment. In developing 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 States Geological Survey; Bureau of Ocean Energy

Management, Regulation, and Enforcement, formerly the Minerals Management Service; Bureau of

Land Management). The Agency continues to evaluate 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 Comprehensive Environmental Response, Compensation, and Liability Act; and the

Marine Protection, Research 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 entitled "How Does This

Rulemaking Relate to Other Federal Authorities and GS and CCS Activities?" in the preamble to the final

GS rule.Regarding RCRA, the final GS rule requires owners or operators to characterize their CO2 stream as part

of their permit application process to determine whether the injectate is a RCRA hazardous waste. If the

CO2 stream is determined to be a hazardous waste, injection may only occur in a Class I hazardous

waste injection well. Additionally, EPA clarifies that a determination as to whether the presence of

hazardous substances in CO2 results in CERCLA liability from a sequestration facility 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). For additional information, see the preamble to the final rule and the responses to

comments on the proposed GS rule.

Letter ID: 0332 Comment ID: 28190 Letter Lines: 83 to 85

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

Comment: 4. We strongly support the proposed "adaptive approach" to this rule, and that

USEPA should have flexibility to implement changes that result from experience

gained over time.

Individual Response: EPA is finalizing the rule and intends to follow an adaptive approach to the GS

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

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

Letter ID: 0332 Comment ID: 28192 Letter Lines: 97 to 100

Comment Code: 2120 2.1.2. SWP (Aneth Field, UT)

Comment Code: 5450 5.9. Comments on the Proposed Monitoring Requirements (146.90)

Comment: 6. We support the requirement for project design with a "robust monitoring plan"

that is capable of corroborating modeling with actual performance. This should

include assessment of dissolution or dissociation and effects on the

mobilization of trace elements.

Individual Response: EPA agrees that GS project design requires a robust monitoring plan. An essential

part of that monitoring plan must be obtaining data to validate computational model performance. The

GS rule includes requirements at 146.90(d) for ground water monitoring for geochemical changes, which

can be used to detect mobilization of metals and dissolution of CO2 in subsurface brine. See the

response to comments document for the proposed rule for additional information on EPA’s final

approach to monitoring for GS projects.Letter ID: 0332 Comment ID: 28193 Letter Lines: 102 to 112

Comment Code: 2210 2.2.1. Groundwater Quality and Mobilization of Trace Elements (seeking

comment)

Comment: 7. We note that a LBNL study, referenced in the NODA, made an assumption in a

release scenario that "leakage into a shallow aquifer would occur at a constant

rate over a 100 year period". Constant rate leakage is not logical, especially

over such a long time period

‐ > pressures (driving force) will decline, and

mineralization will occur, to list two factors against constant rate leakage.

The assumption is not even valid as a "worst case scenario".

8. While the LBNL work is appreciated, USEPA should view it as a

"generalization" and still allow "local studies in local conditions".

Specifically, assessment of leakage risk needs to be in context of local

conditions.

Individual Response: EPA agrees that the LBNL study is a generalization with the objective to better

understand, in a global sense, the vulnerability of representative and relevant aquifer types in the case

of CO2 intrusion, in order to provide sound scientific information as a basis for further studies on

groundwater quality concerns. The study was not meant to be site specific; rather the authors suggest

the work should be followed by site

‐ specific investigations, such as in situ experiments with associated

modeling. Furthermore, the LBNL study focused on the potential consequences of CO2 leakage into

USDWs, without assessment of the probability for leakage. It is understood (and mentioned in the

NODA) that the risk of CO2 leaking from deep storage is low for properly managed GS projects.

However, the potential conse¬quences of unlikely leakage events need to be understood and predictive

capabilities need to be developed as a basis for risk and vulnerability assessment.

As to the leakage case chosen for the LBNL modeling study, EPA notes that even a comprehensive

sensitivity study cannot encompass all possible aquifer conditions and release scenarios. The 100

‐ year

time period selected in the LBNL study is reasonable, assuming that the leak remains undetected. The

time period was chosen to be able to evaluate both the short

‐ term and the long

‐ term geochemical

consequences of leakage.

EPA agrees over

‐ pressures necessary to inject CO2 into a storage reservoir will decline following

cessation of injection, which may reduce the risk of leakage in certain cases. However, buoyancy forces

causing upward migration of CO2 through geologic formations will remain for hundreds if not thousands

of years following injection, long after over

‐ pressures due to injection have dissipated in the injection

zone. Furthermore, sequestration of CO2 by the aqueous phase and by precipitation of carbonates is

very slow in relation to the 100

‐ year time period specified. Finally, the specified leakage rate is very

small compared to the expected volume of CO2 in geologic storage reservoirs, i.e., only about 2.4 tonnes

CO2/yr.EPA clarifies that site

‐ specific data are necessary to understand the potential geochemical reactions at a

GS site. For this reason, all GS project owner or operators must submit detailed, site

‐ specific information

about a proposed GS site, including information on the porosity, permeability, mineralogy, and

geochemistry of the targeted injection and confining zones as well as all USDWs within the Area of

Review. Operators must also present information on the compatibility of the CO2 stream with fluids in

the injection zone and minerals in the injection and confining zones (§146.82(c)(3)). The data can help

the Director determine the potential for geochemical reactions between the injectate (CO2) and the

host geologic formations. For additional information on EPA’s approach to site characterization for Class

VI GS wells, see the responses to comments on the proposed rule in the rulemaking docket.

Letter ID: 0332 Comment ID: 28194 Letter Lines: 114 to 132

Comment Code: 2220 2.2.2. Basin

‐ Scale Hydrologic Impacts of CO2 Storage (seeking comment)

Comment: 9. We appreciate the modeling LBNL conducted of a hypothetical sedimentary basin

with several projects injecting high aggregate and cumulative quantities of CO2

annually over an extended period. The results, though hypothetical, argue in

favor of case

‐ specific consideration of: (a) large volume injections; and (b)

defendable close proximity between injection points. That is local conditions

may accommodate higher than normal injection rates and closer proximity to other

injection activity.

Specifically, the rule should be finalized with language that allows

consideration of injection projects that, based on modeling, that show the

injection horizon to have characteristics favorable to high

‐ volume injection

and/or relatively close proximity injection sites. Injection pressure effects,

plume migration rate, and avoidance of fracture pressure would be some of the

considerations.

10. As noted earlier, we support consideration of the potential effects of "far

field" pressure build up in siting criteria to ensure the integrity of the

injection horizon remote from the injection location. The rule should allow case

specific determination of appropriate injection quantities and conditions.

Individual Response: The LBNL modeling study of the hypothetical basin was not meant to provide

arguments in favor of large

‐ volume projects and close proximity between sites. Rather, LBNL started

with the assumption that in order to have GS make a contribution to climate change mitigation, large

volumes of CO2 may have to be injected and individual projects may have to be in proximity to each

other. The example study cited assumes that one third of the current annual emissions from largestationary sources in the hypothetical sedimentary basin are being captured and stored.

EPA agrees with the commenter that the determination of appropriate injection quantities and

conditions is important, and the GS rule requires that the AoR delineation account for the types of site

‐

specific circumstances the commenter describes. The rule requires that the owners or operators of GS

wells delineate the AoR for GS sites using computational fluid flow models appropriate to the site

‐

specific conditions and injection regime (§146.84). These site

‐ specific conditions include the injectivity

and storage capacity to allow the appropriate volume of injection for the particular formation without

initiating or propagating fractures in the confining zone(s) and creating risk to any ground water

resources due to any effects of hydraulic perturbations. For additional information regarding EPA’s

requirements for AoR delineation for GS projects, see the responses to comments on the proposed rule

in the rulemaking docket.

Letter ID: 0332 Comment ID: 28195 Letter Lines: 134 to 139

Comment Code: 5700 5.14. Comments on Other Aspects of the Proposed Rule

Comment: 11. The rule should provide for data collection and reporting to facilitate EPA

knowledge accumulation and its "adaptive" rule management.

12. We support USDW protection, and argue for a practical rule and

implementation to facilitate actual deployment of GS (i.e. the process needs to

be practical or it will not evolve timely).

Individual Response: The final rule is based on the most recent GS

‐ related data, information, and

scientific research available. EPA intends to continue to collect data on GS and to incorporate such data

as it implements its adaptive approach to GS rulemaking. EPA plans to, every six years, collect and

review data on GS projects to determine whether the appropriate amount and types of information and

appropriate documentation are being collected, and to determine if modifications to the requirements

are appropriate or necessary.

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

to comments on the proposed rule in the rulemaking docket.

Letter ID: 0332 Comment ID: 28196 Letter Lines: 141 to 143

Comment Code: 3000 3. Injection Depth for GS Projects

Comment: 13. We strongly concur with the observation that "treating high

‐ salinity" waters(i.e. those in excess of USDW protectiveness threshold) will be generally less

costly than obtaining water rights.

Individual Response: EPA acknowledges the concerns regarding water availability and interest in current

and future water resources and recognizes that advances in technology are making high TDS aquifers

more attractive as potential future water sources. EPA clarifies that the primary purpose of the GS rule is

the protection of USDWs from endangerment and the purpose of the permitting, siting, construction,

operation, monitoring, post

‐ injection site care, financial responsibility, and site closure requirements for

Class VI injection wells is to further this goal.

Letter ID: 0332 Comment ID: 28197 Letter Lines: 145 to 154

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

Comment: 14. We support the view of some States that GS should be allowed where site

‐

specific demonstration is made that USDW will be protected

‐ > even though depth

criteria may not be in conformity with the basic rule requirement for injection

below the lower most aquifer. A straightforward "waiver" process may serve in

these cases. There should NOT be a blanket prohibition of injection above or

between USDWs.

Well completion technology and characterization of injection horizon and fluid

interaction is a sufficiently developed state of the art to promote EPA’s

"adaptive rule making."

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

‐

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

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

‐ USDW

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

EPA agrees that a flexible, site

‐ specific approach to waiver determinations (and all Class VI permitting

decisions) is appropriate. Site

‐ specific demonstrations of injection zone integrity along with proper well

construction, operation, monitoring, and post closure site care are the best way to ensure USDW safety

while allowing flexibility for GS above or between USDWs. EPA believes that the additional requirements

that apply to owners or operators of Class VI wells granted a waiver of the injection depth requirements

will provide additional considerations for the owner or operator and Director when permitting such

wells to ensure protection of all USDWs. EPA adds that all determinations regarding the appropriateness

of a waiver will be made by the Director based on site

‐ specific information. Additionally, the final GS rule

does not categorically preclude or prohibit injection into any type of formation.The Agency believes this approach: 1) responds to concerns about local and regional geologic storage

capacity limitations imposed by the proposed injection depth requirements; 2) allows for a more site

‐

specific assessment of injection depth for GS projects; 3) accommodates injection into different

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

‐ USDWs above and/or between USDWs

when appropriate and where it can be demonstrated that USDWs will be protected; and 5) responds to

concerns about the use of aquifer exemptions for GS. Finally, EPA's approach to addressing injection

depth variability through a waiver process responds to concerns about future drinking water resource

availability and the need to ensure that high quality water remains available in sufficient quantities to

supply drinking water needs.

Letter ID: 0332 Comment ID: 28198 Letter Lines: 156 to 160

Comment Code: 3100 3.1. Comments on Concerns About Injection Depth for Class VI Wells

Comment: 15. We strongly support the EPA view that different well classes warrant

different treatment, and that EPA approval criteria should therefore differ. CO2

at injection pressures will greatly differ from other fluids regardless of well

class. In EPA’s phrase, "site

‐ suitability" for GS is what needs to be

determined.

Individual Response: EPA agrees that site and project specific factors are important in determining the

applicability of GS in a specific formation. The final GS rule includes flexibility for the Director to consider

site

‐ specific geology and proposed operational conditions when making permitting decisions. EPA

believes that proper siting, well construction, operation, monitoring, and post

‐ injection site care are key

to determining site suitability for GS and ensuring USDW protection from endangerment.

Letter ID: 0332 Comment ID: 28199 Letter Lines: 162 to 165

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

Comment: 16. For pragmatic reasons, with respect to deployment of GS at least, State

Discretion and Delegation should be maximized; as well as the cooperative

relationships with external expertise, whether State or not, that USEPA has

already established.

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

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

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

this process available to Class VI wells under their jurisdiction. Although some commenters asked EPA torequire that waivers be applied nationally, the Agency believes that the decision about whether a waiver

program is appropriate in a specific State, Tribe, or Territory should be made by each program. This

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

for waivers based on regional or state

‐ specific conditions, such as the predominant geologic settings

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

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

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

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

protective.