Use of Photochemical Grid Models for NEPA:New Oil and Gas Wells**Ralph Morris ENVIRON International Corporation** **rmorris@environcorp.com EPA’s 9** **th Conference on Air Quality Modeling** **Non-Guideline Applications October 9, 2008** National Environmental Policy Act (NEPA)**Legislation enacted in 1969****Requires agencies to fully analyze and disclose imp acts of** **new projects****Guided by Council on Environmental Quality (CEQ)****Consultation with public and private parties****Disclosure provided through Environmental Assessmen ts (EAs)** **and Environmental Impact Statements (EISs)****Use**“Best Science”**available****Potential environmental impacts of Oil and Gas developments in the western states disclosed under** **NEPA****The FLM is responsible for preparing EISs/EAs for O &G** **development projects on federal land. The Bureau o f Land** **Management (BLM) has been most active in this area, although** **U.S. Forest Service, Tribes and other agencies are also are** **active in this area**NEPA Oil and Gas Example**Source: Wyoming Oil and Gas Conservation Commission****Wyoming natural gas production increasing****Efforts to increase domestic production of oil and gas** Background SWWY O&G**The development of an oil and gas production projec t on federal land** **usually involves the preparation of an EIS or EA un der NEPA that** **discloses the potential environment effects of the project** **EIS/EA includes air quality modeling to show projec t impacts on** **criteria pollutant concentrations, visibility, and deposition** Drill RigNatural Gas Processing Plant**Images from Wikipedia**Background: SWWY O&G AirQuality Assessments**Pre-History <1996: Qualitative****1996 – Moxa Arch: Set Many Precedents****1997 – 1 st** **Jonah & Pinedale Anticline EIS –** **Pinedale Anticline mitigates visibility impacts throu gh purchase of low NOx burner for** **Bridger coal-fired generating station****1997 – 1999 – SWWYTAF –** **Develop CALPUFF Database for SWWY****1999 Continental Divide & SUIT –** **First to Use CALPUFF for Cumulative Analysis****2000: FLAG guidance Issued****2004 – 2006 Jonah Infill EIS****2005 Ozone exceedances recorded in Pinedale area****2007 Pinedale Supplemental EIS –** **First to address ozone using PGM****2007-2008 – 4-Corners Interagency AQ Task Force Anal ysis** **2008 – 2009 Planned: Continental Divide-Creston EIS –** **Use PGM for air quality, visibility and deposition (No CALPUFF)** EIS Air Quality Modeling**Until recently, EIS AQ impact assessments used AERM OD for near** **field impacts and CALPUFF for far-field AQ and AQRV impacts.** **High ozone concentrations have been observed in sou thwest** **Wyoming****AERMOD/CALPUFF do not simulate ozone formation**8-Hour Ozone Measured at the Jonah Monitor inSouthwest Wyoming: February, 2005**0 10** **20 30** **40 50** **60 70** **80 90** **100 1 2 3 4 5 6 7 8 10 11 12 13 14 15 16 17 19 20 21 22 23 24 25 26 28** Day

8-Hour Ozone (ppb)Southwest Wyoming O&G Areas2006+ SWWY O&G Developments**2006 Moxa Arch and Hiawatha (MA&H) O&G Infill Proje cts** **– Use AERMOD for near-source AQ and CALPUFF for far-f** **ield AQ and AQRV** **2005-2006 ozone exceedances recorded in SWWY****2007 ozone analysis added to MA&H using PGM –** **Leverage off of WRAP 2002 PGM database****2007+ proposed Continental Divide-Creston O&G –** **First EIS to proposed using PGM for ozone and all f ar-field AQ and** **AQRV (still use AERMOD for near-source AQ)****2008 MA&H also adopt PGM approach for ozone and far -field** **AQ and AQRV –** **Need to redo ozone/AQ/AQRV analysis due to emission changes and** **lack of adequate cumulative inventory to address oz one** **– CD-C PGM and emissions database development availab** **le**Continental Divide-Creston EIS**Proposed natural gas project in southern Wyoming: 8,950 new wells** **First EIS to propose to use photochemical grid model to perform both ozone and AQ/AQRV** **impact analysis****Comprehensive emission inventory for oil and gas production sources in southwest Wyoming using** **field-specific information supplied by the producers** **2005 & 2006 36/12/4 MM5 meteorological modeling** 2006 Drill Rig Locations:5 County SWWY2006 Producing Wells:5 County SWWYMM5 Modeling Domains**3 nested grids****36 km grid is the RPO national grid** **12 km domain large enough to encompass** **CD-C 4 km domain as well as those of other** **O&G Basins****4 km domain focused on SWWY** **-3000 -2000 -1000 0 1000 2000 3000 -2000** **-1000 0** **1000 2000** **GIANT MM5 36km GIANT MM5 12km** **CD-C MM5 04km 2005 and 2006 Calendar Years** 

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docket-customerservice@epa.govWinds at Jonah: 4 km GridObservedMM54 km**MM5 4km run shows good direction performance, but l ow** **wind speed bias for peak wind speeds****Improvement over 4 km CALMET runs using 12 km MM5 data** **NORTH SOUTH** **WEST EAST** **5% 10%** **15% 20%** **25% W** **I N** **D S** **P E** **E D** **( K** **n o** **t s** **) >** **= 2** **2 1** **7 -** **2 1** **1 1** **- 1** **7 7** **- 1** **1 4** **- 7** **1 -** **4 C** **a l** **m s** **: 5** **. 7** **7 %** CALMET4 km36/12/4 km CD-C PGM DomainsCD-C 12/4 km PGM Domain**Impact assessment will focus on ozone everywhere** **and AQ/AQRV impacts at Class I and sensitive Class II** **areas –** **AERMOD still used for near source impacts** **12/4 km domains defined so that the inputs developed for** **the CD-C project can be used for other EISs** **– Moxa Arch** **– Hiawatha** **– Other?** **Consistency among EIS assessments** **Using best science available**PGM Configuration**MM5 36/12/4 km meteorology (2005 & 2006)****CB05 gas-phase and RADM aqueous-phase chemical mechanisms and ISORROPIA aerosol** **thermodynamics****Boundary conditions on 36 km grid from global chemistry model** **How to simulate winter high ozone events in SWWY?** **– Clear Skies** **– Snow on ground** **– Strong surface inversion** **– High VOC and NOx concentrations** SWWY EIS Modeling Challenges**Monitoring network not as dense as is typical for urban areas** **– How to use EPA-guidance projection** **approach using relative modeling results?** **– How to perform model evaluation?** **How to obtain project-specific and cumulative impacts?** **– Use ozone and PM source** **apportionment to obtain incremental contributions** **How to address ozone given that current measurements violate new** **(75 ppb) ozone NAAQS? –** **Need Projects that reduce emissions (existing decline plus controls on new** **wells) –** **Ozone source apportionment to assess Project’s contribution to** **ozone exceedances**PGMs in NEPA-Related Studies**Comprehensive Air-quality Model with extensions** **(CAMx; www.camx.com** **) for SWWY and Four** **Corners region****Community Multiscale Air Quality (CMAQ) model for** **Uinta Basin Air Quality Study** **(www.cmasceneter.org)**Conclusions**Recent advances allows for the more routine use of PGMs for NEPA** **EIS/EA air quality assessments –** **Represents best science –** **Advances in PGM modeling features Two-way grid nesting** **Flexi-nesting Plume-in-Grid** **Ozone and PM source apportionment –** **Advances in database availability and expertise RPO databases (e.g., WRAP)** **– Advances in computing** **Doubling computing speed every 18 months –** **Advances in PGM software MM5/WRF meteorological; SMOKE/CONCEPT emissions; post-pr** **ocessing tools****Current NEPA-related studies demonstrate utility of PGMs** **– BLM Moxa Arch and Hiawatha EISs in SWWY** **– Uinta Basin Air Quality Study (UBAQS) Utah** **– Four Corners Air Quality Task Force NM/CO** **– BLM/WDEQ Continental Divide Creston EIS SWWY** Acknowledgements**We acknowledge the assistance of numerous groups to make the use of PGMs routine for** **EISs/EAs –** **Bureau of Land Management (BLM) –** **U.S. Environmental Protection Agency (EPA) –** **Wyoming Department of Environmental Quality (WDEQ) –** **Colorado Department of Health and Environment (CDPHE)** **– New Mexico Environmental Department (NMED)** **– BP and other Operators** **– Sage Environmental Consulting** **– SWCA Environmental Consultants**