Response to Comments -OCS-EPA-R4015 Anadarko EGOM

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY REGION 4

Final Determination and Response to Comments

for Outer Continental Shelf Air Permit OCS-EPA-R4015

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 emissions 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 drilling 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 statement 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: http://www.epa.gov/region4/air/permits/ocspermits/ocspermits.html and 

regulations.gov (docket EPA- EPA-R04-OAR-2014-0487). The permit incorporates 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 summarizes the 

comments received, provides EPA’s response, and summarizes the changes made to the permit in 

response to comments received. 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 additional 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 Received from Anadarko Petroleum Corporation on 

Draft Outer Continental Shelf Air Permit OCS-EPA-R4015

Followed by EPA Responses:

Comment 1: Project Description (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.

to 

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 those used during the project, from:

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 the 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 accurately reflect the vessels that will be used.

Comment 3: Sections 5.7.3 and 5.7.4 (Draft Permit page 7) - Anadarko proposed that these two 

conditions, related to permit expiration and renewal, be removed 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 retained 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 CH4 (25 and not 21) and for N2O (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 -OCS-EPA-R4015 Anadarko EGOM

Comment 5: Section 6.6.4 (Draft Permit page 22) - Anadarko noted that CO2 was included in 

Conditions 6.6.4 and 6.6.6. Condition 6.6.4 requires Anadarko to stack test CO2 emissions from the six 

main engines (DR-GE-01 through DR-GE-06) within 90 days of the start of drilling that the drilling 

vessel 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 CO2 be removed from conditions 6.6.4 

and 6.6.6.

Response: EPA acknowledges Anadarko’s comment and included the option to test for CO2 or O2, 

consistent with condition 6.6.6, which indicates the fuel usage data may be used to calculate CO2. To 

clarify, Condition 6.6.4 does not require compliance with BACT limits and only requires general stack 

testing. CO2 can also be used as a reference pollutant for the measurement of other pollutants in lieu of 

O2.

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 stricken 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 NOx 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. The 

requested change is consistent with the application and the assumptions 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 engine as an EPA Tier 2 non road engine (40 CFR 89). However, this engine is an EPA marine 

Tier 2 engine. Anadarko has recommended 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 -OCS-EPA-R4015 Anadarko EGOM

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 represented the “worst-case” emissions scenario. These engines, 

with ratings 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 applications listed these engines as equipped with low 

NOx engine (LNE) design which is identified (in the December 2012 application BACT analysis) as 

including turbo-chargers with after coolers and high injection pressure. EPA appreciates the clarification 

that these 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 is 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. The permit was 

revised to require that the emissions be calculated for “each” engine.

Comment 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 represents 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 (Draft Permit page 41) - These conditions list units 

AB-DT-01 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.