Response to Comments

- OCS

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- R4015 Anadarko EGOM UNITED STATES ENVIRONMENTAL PROTECTION AGENCY REGION 4

Final Determination and Response to Comments for Outer Continental Shelf Air Permit OCS

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Anadarko Petroleum Corporation

On June 20, 2014, the Region 4 office of the United States Environmental Protection Agency (EPA) requested public comment on a draft Outer Continental Shelf (OCS) air permit for Anadarko Petroleum Corporation (Anadarko), 1201 Lake Robbins Drive, The Woodlands, Texas 77380. The permit will regulate air pollutant em issions from an exploratory drilling operation within the Eastern Gulf of Mexico (EGOM) of the OCS . The proposed project will mobilize the Transocean Discoverer Spirit and associated support vessels for the purpose of exploratory d rilling and well completion and does not include the establishment of any permanent production platforms . The operation will last no more than
two years and is expected to operate no more than 208 calendar days per year.

EPA prepared a preliminary determination and state ment of basis document that explains the derivation of the permit conditions. The preliminary determination and the draft permit are available on EPA Region 4’s website at: h ttp://www.epa.gov/region4/air/permits/ocspermits/ocspermits.html and regulations.gov (docket EPA

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- 0487 ). The permit incor porates applicable requirements from the federal Prevention of Significant Deterioration preconstruction and title V operating permit programs, New Source Performance Standards (NSPS), and National Emission Standards for Hazardous Air Pollutants (NESHAP), as required by the OCS Air Quality Regulations at 40 Code of Federal Regulations (CFR) part 55.

During the public comment period, which commenced on June 20, 2014, and ended on July 21, 2014, EPA only received comments from Anadarko. No request for a public hearing was received, and the hearing was canceled due to insufficient interest. The Response to Comments document s ummarizes the comments received, pro vides EPA’s response, and summarizes the changes made to the permit in response to comments recei ved. A copy of the comments is in the administrative record for the Anadarko EGOM permit and available at the website listed above.

After consideration of the expressed view of all interested persons, the pertinent federal statutes and regulations, and a dditional material relevant to the application and contained in the administrative record, EPA has made a final determination in accordance with title 40 CFR part 55 to issue an air permit to Anadarko for their proposed exploratory drilling operation. The final permit does not differ significantly from the draft permit offered for public comment.

.Response to Comments

- OCS

- EPA

- R4015 Anadarko EGOM

Summary of Comments R eceived from Anadarko Petroleum Corporation on Draft Outer Continental Shelf Air Permit OCS

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Followed by EPA R esponses:

Comme nt 1: Project De scription (Draft Permit page 2)

- Anadarko proposed that the description of the vessels associated with the Discoverer Spirit change from:

The proposed project will mobilize the Transocean Discoverer Spirit, up to two support vessels to transport personnel and supplies, and up to three support vessels for well completion.

t o
The proposed project will mobilize the Transocean Discoverer Spirit, and associated support vessels. The support vessel could consist of supply boats to transport personnel and supplies, and a combination of tug boats, a barge, and a stimulation vessel for well completion activities

. Response: The requested change is consistent with the application and the assumptions used in EPA’s review. EPA has added language to the Project Description of the final permit to more accurately describe the associated vessels

.

Comment 2: Table 3

- Support Vessels (Draft Permit page 4)

- Anadarko requested the footnote to Table 3 be updated to reflect the units listed in the table and th ose used during the project, f ro m:

a Specific crew, supply, and work boats available for use during the drilling project had not been identified at the time of application. The representative vessel is the worst

- case vessel in t he potential vessel fleet and used to calculate potential emissions

.

to

a Specific supply and anchor handling boats as well as well completion vessels available for use during the project had not been identified at the time of application. The representative vessel is the worst

- case vessel in the potential vessel fleet and used to calculate potential emissions.
Response: The requested change is consistent with the application and the assumptions used in EPA’s review. EPA has added language consistent to what Anadarko proposed to the Table 3 footnote of the final permit to accur ately reflect the vessels that will be used.

Comment 3: Sections 5.7.3 an d 5.7.4 (Draft Permit page 7)

- Anadarko proposed that these two conditions , related to permit expiration and renewal, be remo ved from the final permit. Anadarko applied for a 2

- year temporary source permit and believes that these conditions are not applicable

. Response: The EPA concurs with Anadarko that these conditions will not be used by a temporary

source , but retain ed these title V general conditions in the final permit for formatting and consistency purposes, as there is no practical need for them to be removed

. Comment 4: Section 6.5.4 (Draft Permit page 21)

– Anadarko has included the updated Global Warming Potential (GWP) Factor for CH 4 (25 and not 21) and for N 2 O (298 and not 310). These factors correlate to those used by Anadarko in their February 11, 2014 application.
Response: EPA concurs with the updated citation and has changed the table to reflect the GWP used in the application.Response to Comments

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- R4015 Anadarko EGOM

Comment 5 : Section 6.6.4 ( Draft Permit page 22)

- Anadarko noted that CO 2 was included in C onditions 6.6.4 and 6.6.6. Condition 6.6.4 requires Anadarko to stack test CO 2 emissions from the six main engines (DR

- GE

- 01 through DR

- GE

- 06) within 90 days of the start of drilling that the drilling

ve ssel operates under this permit

. Because the project is not subject to BACT for GHG, Anadarko was not expecting to source test for this pollutant and requests that CO 2 be removed from conditions 6.6.4 and 6.6.6.
Response: E PA acknowledges Anada rko’s comment and included the option to test for CO 2 or O 2 , consistent with condition 6.6.6, which indicates the fuel usage data may be used to calculate CO 2

. To clarify

, Condition 6.6.4 does not require co mpliance with BACT limits and only requires general stack testing. CO 2 can also be used as a reference pollutant for the measurement of other pollutants in lieu of O 2

. Comment 6: Section 6.7.1.1 (Draft Permit page 23)

- Anadarko requested the converted emission units for the following limits be changed as identified below from the emissions that are strick en through to the emissions listed in bold:

6.7.1.1.3 VOC BACT Limit: 0.08 lb/MMBtu ( 0.13 0.35 g/kW

- hr) on a rolling 24

- hour average basis.

6.7.1.1.4 PM BACT Limit: 0.1 lb/MMBtu ( 0.15 0.43 g/kW

- hr) on a rolling 24

- hour average basis.

6.7.1.1.5 PM10/ PM2.5 BACT Limit: 0.06 lb/MMBtu ( 0.09 0.24 g/kW

- hr) on a rolling 24

- hour average basis.
Response: The requested change is consistent with the application and the assumptions used in EPA’s review. The g/kW

- hr emission limits were provided only for consistency with the NO x and CO g/kW

- hr limits

. EPA has corrected these values in the permit using the appropriate specific brake horse power for converting the emission limit units from lb/MMBtu to g/kW

- hr

. This revision does not represent a change in the mass emission limits, only a change in the calculation used to convert the emission limits to g/kW

- hr units

. Comment 7: Section 6.7.1.2.3 (Draft Permit page 23)

- Condition 6.7.1.2.3 identifies the main engine as part 40 CFR 94.8 compliant. However, these engines are only IMO compliant. Anadarko has recommended the removal of “ (40 CFR 94.8)(or better) ” from the condition.
Response: The emission standards in 40 CFR 94.8 mirror those found in the IMO standard for engines of this size and model year, but the EPA understands that these engines are only IMO compliant. T he requested change is consistent wit h the application and the as sumptions used in EPA’s review. The EPA has revised the permit to remove the “ (40 CFR 94.8) (or better) ” language.
Comment 8: Section 6.7.6.1.2 (Draft Permit page 29)

- Condition 6.7.6.1.2 identifies the fast rescue craft engin e as an EPA Tier 2 non road engine (40 CFR 89) . However, this engine is an EPA marine Tier 2 engine. Anadarko has recomme nded the condition be updated to state : an engine certified to EPA marine Tier 2 engine (40 CFR 94)

. Response: Anadarko’s December 2012 application identified this unit as subject to 40 CFR 89

. However, EPA concurs that the applicable standard should be referenced in the permit and has revised the permit to include the correct reference and tier standard for the fast recue craft engine

.Response to Comments

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Comment 9 : Section 6.7.11.1.1 (page 32)

- The identified condition requires third party engines to be equipped with turbocharger, aftercooler, and high injection pressure. Anadarko notes that the application assumed the use of large engines that r epresented the “worst

- case” emissions scenario. These engines, with rating s of 600 hp or higher

, generally include these specific technologies to meet the applicable Tier 2 emissions standards. Smaller, lower horse power engines, however, may not include these specific technologies. Anadarko will ensure that all third party engines meet EPA Tier 2 or higher non road tier ratings

, as specified in condition 6.7.11.1.2, and requests that condition 6.7.11.1.1 be removed

. Response: The December 2012 and May 2013 application s listed these engines as equipped with low NO x engine (LNE) design which is identified (in the December 2012 application BACT analysis) as including turbo

- charger s with after coolers and high injection pressure

. EPA appreciates the clarification that th ese engines represent a worst

- case scenario and concurs that the permit should allow for the use of engines that will still meet Tier 2 or better standards and are not equipped with the technologies

. The intention of these conditions i s to require Anadarko to meet the EPA Tier 2 limit, whether or not the engines may have add

- on control technologies. The EPA has revised the permit to replace the requirements of condition 6.7.11.1.1 with the requirements of 6.7.11.1.2.

Comments 10 and 11 : Sections 6.7.11.5 (Draft Permit page 32) and Section 6.7.11.6 (Draft Permit page 33)

- These conditions require that total hours per year be calculated for all engines specified in the conditions , i.e. combined . Anadarko calculated their emissions based on hours per year per engine and proposed the word combined be changed to each.
Response: The requested change is consistent with the application and EPA’s intent

. T he permit was revised to require that the emissions be calculated for “each” engine

. Comme nt 12 and 13: Section 6.7.15.2 and Section 6. 7.15.3.3 (Draft Permit page 35)

- Anadarko requested the permit be revised to require a record of the amount of gas flared through the boom, as opposed to the yearly hourly usage. Anadarko has a mechanism to monitor and measure the amount of gas flared through the boom flare.
Response: The requested change is consistent with the application and repre sents a more reliable emission compliance methodology. These conditions have been updated to include the proposed language and clarifying language.
Comment 14 Section 6.10.1 and Section 6.10.1.1 (Draf t Permit page 41)

- These conditions list units AB

- DT

- 0 1 through AB

- DT

- 19 as condensate tanks, but the application has them listed as diesel storage tanks. These conditions should include the correct description.
Response: The EPA concurs with the request and has revised the permit to include the description, as included in the permit application

.