DRAFT

EPA Completeness C omments on Anadarko Petroleum Corporation , OCS Air Permit Application for Drilling and Exploration Activities i n the Eastern Gulf of Mexico dated December 2012

Regulatory Applicability

1. Section 4 of the application contains the Regulatory Applicability Analysis for all emission units onboard the Discoverer Spirit

, and emission units on board the support vessels that will contribute to the stationary sources aspects of the vessel while atta ched to the OCS source. The applicability of the New Source Performance Standards (NSPS) and the National Emission Standards for Hazardous Air Pollutants ( NESHAPS) is dependent on the model year of the emission source s . The application does not provide the model year of all emission sources subject to the regulatory applicability analysis. The application should provide the model year of all regulated emission sources in order to support the analysis . For the th ird party emission sources, the model years a nd compliance certificates will be required to confirm compliance once the specific engines have been determined.

Best Available Control Technology Analysis (BACT)

2. The BACT analyses for diesel engines in section 5 of the application identified Replacement of Older Engines with Newer Engines and EPA Tier 2 Standards as available control technologies. The Replacement of Older Engines with Newer Engines should identify the cleanest engines that are currently available; this may be EPA Tier 2, EPA T ier 3 compliant engines, or another cleaner engine. The BACT analyses for the diesel engines, (specifically DR

- GE

- 07, DR

- GE

- 08, DR

- AC

- 01, DR

- AC

- 02, third party engines, and SV

- PE

- 01 through SV

- PE

- 08), should identify what the cleanest engines are for each applicable unit, and use the cleanest available engine for any applicable cost analyses.

a. The NO x , CO, PM/PM 1 0 /PM 2.5 , and VOC BACT analyses for the Emergency Diesel Engine are provided in Sections 5.1.2, 5.2.2, 5.3.2, 5.5.2 of the application, respectively . Step 2 eliminated Replacement of Older Engines with Newer Engines as a feasible control technology because this would be cost prohibitive. However, the application does not contain a cost analysis for replacing the existing Emergency Diesel Generator wit h a newer engine. For this control technology to be considered technically infeasible, the application should provide a cost analysis in Step 4 of the BACT analyses to determine if replacing the air compressor engines with new cleaner engines is cost prohi bitive.b. The NO x , CO, PM/PM 1 0 /PM 2.5 , and VOC BACT analyses for the Air Compressor Engines are provided in sections 5.1.3, 5.2.3, 5.3.3 and 5.5.3 of the application, respectively. Step 1 of the BACT analyses identified Replacement of Older Engines with Newe r Engines as a technically feasible control technology. In step 2 of the BACT analyses, this option eliminates the control technology as technically infeasible because it would be extremely cost prohibitive. For this technology to be considered technically infeasible the application should provide a cost analysis in Step 4 of the BACT analyses to determine if replacing the air compressor engines with Tier 2 compliant engines is cost prohibitive.

3. The application has identified Painting Operations as a sour ce of PM/PM 10 /PM 2.5 and V OC emissions and included BACT analyses for both of these pollutants in sections 5.3.13 and 5.5.14, respectively. These analyses propose best management practices as BACT for both pollutants , which include s down spraying of paint a nd use of a shroud or barrier around the a rea being painted. However, t he description of the emission sourc e, on page 31 of the application, explains that the airless spray transfer efficiency also affect s emissio ns. The application states that the potent ial

- to

- emit ( PTE ) ca lculations were done assuming a 50% transfer efficiency, but Anadarko is proposing to use a 30% transfer efficiency, which would result in higher emissions from the painting operation. The vendor information provided in the application does not contain the transfer efficiency expecte d for the proposed airless spra yer . Please provide documentation for the transfer efficiency of the proposed model s prayer and provide revised PM/PM 10 /PM 2.5 and VOC BAC T analyses consistent with the top

- down approach to evaluate the various transfer efficiencies.

Emission Calculations

1. The emission calculation description in section three, and throughout the application, states that the associated support vessels (i.e., supply and anchor handling boats) and equipment (e.g., engines) are unknown so a representative supply boat ( HOS Coral ), handling boat ( Kirt Chouest ), and third party equipment were used to develop representative emissions. This language is also used to describe the third party engines on the drillship. The EPA recommends using worst

- case rather than representative emission s for all emission units to allow the use of any available support vessel or equipment without the possible need for an additional impact assessment or further emission limit ations

.
2. It is unclear how the total worst

- case well complet ion emissions were calculated.

a. Each well completion scenario uses b oth the emission units listed in Table 1 on page 4 of Appendix B and emission units on the drillship and support vessels . For example

, each of the four well completion scenarios will use the Main Engines, listed as DR

- ME

- 01 through DR

- ME

- 06, (it is assumed that these engines are the same as the drillship engines listed in the first part of the emission calculations, DR

- GE

- 01 thro ugh DR

- GE

- 06). Yet, this results in a discontinuity. The total emissions from each well completion scenar io, listed at the bottom of T able 1 on page 4 , do not result from a summation of the emission units listed on this page.The application indicates that the additional units will be used during a given well completion scenario, but t he information provided does not clearly show how many hours the se emission units will operate. Please provide additional information that details how the totals for the worst

- case well completion scenarios were calculated.

b. The PTE for the project was calculated by summing the emissions from the worst

case support vessel and the emissions from the drillship. However, the emissions from the worst

- case well completion scenario, provided in Table 1 of Appendix B, lists these emissions as higher for all pollutants except for CO when compared to the emissions from the worst

- case support vessel. As mentioned above, the well completion scenarios will use engines onboard the drillship and support vessel

, and it is unclear if these totals have already been accounted for in the worst

- case well completion totals. It is not clear if the emissions generated from units used solely for the well completion activities are mutually exclusive fro m the supply boats, and should therefore be added to the PTE and not omitted. Additional information is needed to demonstrate why the worst

- case emission units used solely for the well completion scenario have not been incorporated in the PTE.

3. From Table 1 and Table 3 of Appendix B it is unclear how the emissions for the Main Propulsion Generator Engines (DR

- GE

- 01 through DR

- GE

- 06) were calculated. The detailed emission calculations for DR

- GE

- 01 through DR

- GE

- 06 are provided in this section. However, in T able 1 underneath the rows for the Main Propulsion Generator Engines there is a row titled, “Main Engines Worst

- Case Operating Emissions (Maximum 325 bbls/day of fuel used for all main engines).” The application does not provide information how the numbers in this row were calculated. The emissions in this additional row are more than the emissions from a single engine, but less than the emissions from two engines. This row of emissions was used to provide the total drillship emissions used for the PTE, and not a summation of the six engines. Therefore, it appears that Anadarko will only operate one Main Propulsion Generator Engine at a time. Please provide additional calculations for the row titled “Main Engines Worst

- Case Operating Emissions (Maximum 325 b bls/day of fuel used for all main engines),” and please explain why these emissions are representative of worst

- case operation.

4. The emission calculation tables for the Main Propulsion Electrical Generator Engines notes that the data used for the CO emis sions factor is based on data from Wärtsilä LNE engine specifications for operating at 50% load, and “The more conservative factor is chosen between the stack test (December 2010) and Vendor Provided Data,” footnote 1 found in Appendix B. However, based on a review of the Stack Test Report, found in Appendix H, the highest emission rates occur not at 50% load, but at an approximate load of 20%. Emissio n limits will be established with emissions presented in the permit application . The application should ver ify that the main engines will be able to meet the emissions at 50% load

.Modeled Operational Scenarios

Temporary Source Exemption

– The content of the application assumes the project will qualify as a temporary emission source (i.e., project duration less than 2 years), and therefore will be exempted from the ambient impacts assessment as provided in 40 CFR 52.21(i)(3). The followi ng comments are associated with this exemption.

5. The provided PSD Class I area modeling is not, as indicated in the application, to demonstrate compliance with the PSD Class I increments, NAAQS, and AQRV but to demonstrate compliance with the exemption req uirement of no project impacts to any PSD Class I area.

6. For a source to qualify as a temp orary emission source it must meet several requirements

, including that the source must demonstrate that its emissions will not impact any Class I

area , and that no ar ea where an a p plicable increment is known to be violated 40 CFR 52.21(i)(3 )( i)

. The application does not address the requirement that the project will have no impacts in any area with known violations of the PSD increments.

Project Drilling and Support Ves sels

– The following comments are associated with the project emission sources used in the impact assessment.

7. Section 2.1 of the Class I Area Air Quality Dispersion Modeling Analysis Report (Appendix D) indicates worst

- case support vessels emissions were modeled. This section states the hourly, daily, and annual emissions were estimated for the worst

- case boats t o conservatively account for the worst

- case emissions from the support vessels potentially available to support operations of the drillship. However, the description provided earlier in the application describes these sources as representative. This appar ent discrepancy should be clarified.

In addition, the equivalence determination provided in section 3.1 of the application addresses the emission calculations procedures, but not the reason the selected engine and/or support vessel provide the worst

- case emissions from those available. Please provide additional supporting information.

The following comments are associated with the input parameters used in the ambient impact modeling.

8. The Appendix D modeling report indicates the support vessels were model ed while docked at the drillship, as well as when within 25 miles en route to and from the drillship, and that all emissions were modeled as emitted from the single drillship stack. It is unclear which method was used; the modeling procedure used for the support vessel emissions should be clarified.

9. The Q/D analysis indicates emission sources operating intermittently or seasonally were adjusted to account for year round operation. This adjustment does not appear appropriate given the Federal Land Manager ’s guidance states that the Q value used in this assessment should be the sum of maximum 24

- hour emissions of all visibilityimpairing pollutants annualized in tons per year. The adjustment procedure and its

appropriateness should be explained.

Requests for Clarification

1. Table 1

- 2 on page 3 of the application lists the project’s PTE. The PTE for PM 10 is listed at 33.60 tons per year. However, “Table 1

- Annual Emissions Summary (tons/year)” found on page 4 of Appendix A, lists the total emissions for PM 10 from the drilling operating scenario as 23.03 tons per year. Please clarify this discrepancy and provide the correct PTE for PM 10
.

2. The NO x , CO, PM/PM 10 /PM 2.5 and VOC BACT analyses for the drillship third party engines selected LNE design as BACT, sections 5.1.8, 5.2.8, 5.3.8, 5.5.8, respectively. These BACT analyses have ranked LNE design in Step 3; however, Step 1 of the BACT analyses did not identify LNE desi gn as an applicable control technology. Please correct this inconsistency in the application and verify that LNE design is part of BACT control for NO x , CO, PM/PM 10 /PM 2.5 , and VOC from the third party engines.

3. Table 2

- 2 of in the Representation of Modele d Sources section, on page 2

- 4, gives the stack parameters used in the modeling analysis. These parameters were based on the stack test report found in Appendix H which lists temperatures in Kelvin. However, the temperature provide in Table 2

- 2 appears to be in degrees Fahrenheit (Rankin) rather than Kelvin.