Air pollutant emissions from shale gas development and production

Transcription

1 Air pollutant emissions from shale gas development and production Allen L. Robinson Department of Mechanical Engineering Department Engineering and Public Policy Carnegie Mellon University Pittsburgh, PA

2 Air Pollution and Oil and Gas Criteria Pollutants Development O 3 (VOC + NOx + sunlight) NO 2 PM 2.5 Hazardous Air Pollutants / Air toxics Diesel particulate matter Formadehyde Benzene, toluene, ethylbenzene, xylenes Climate CH 4 Black carbon

3 Compressor stations Condensate Tanks Drill Rigs Frac pumps Drilling Fracing Completion Flaring Fugitives Pneumatics

4 Source NOx VOC PM Well development Drill Rigs Frac Pumps Truck Traffic Completion Venting Frac ponds Gas Production Compressor Stations Wellhead compressors Heaters and dehydrators Blowdown venting Condensate Tanks Fugitives Pneumatics Air Toxics Data Quality Medium Medium Medium Poor? Poor Medium Medium Medium Poor Poor Poor Poor = major source = minor source

5 Spatial Scales Site ~ 1 km Natural gas drill rigs in Hopewell Township, news.nationalgeographic.com

6 Widely distributed with significant aggregate emissions Field ~ s km Jonah WY Site ~ 1 km Natural gas drill rigs in Hopewell Township, news.nationalgeographic.com Regional ~ 100s to 1000s of km wilderness.org Marcellus Wells in PA as of Mar 2012

7 Very large chemical plant or refinery distributed over 1000s of sq miles?! Refinery Marcellus Wells in PA (data from PA DEP)

8 LIMITED DATA Poor spatial correlation between air monitoring networks and oil and gas development and production State and local air monitoring stations

9 Estimating air emissions in Marcellus region Actual region Inventory Domain (USGS, ) 9

10 Past and future Marcellus well development and gas production Wells drilled 5000 Projections Actual Considine, 2010; Considine et al. (, 2011); The Nature Conservancy, 2010; NETL, 2010; Annual Energy Outlook, EIA,

11 Development of Process Level Emisions Inventory Process-level inputs - Emission factors - Duty cycle - Source profiles - Load factor - Future controls Process-level estimates e.g. drill rigs or compressors Development Emissions Ton per well Production Emissions Ton per BCF Activity data Wells drilled/year Activity data Gas produced/year Temporal and spatial allocation Marcellus-level estimates Ton yr -1 Model-ready emissions 11

12 Accounting for Uncertainty Emission factors Load factors Horsepower Drilling time % on-time Emissions = EF i x LF x HP x time x %on-time Monte Carlo Cumulative distributions of NOx emissions to drill one well 12

13 Marcellus NOx emissions Fractile NOx Emissions, tpd (a) Total emissions Mean, 202 tons per day Mean, 71 tons per day NOx emissions, tons per day (c) Marcellus sources Others Compressor stations Wellhead compressors Trucks Fracing Drilling Fractile NOx emissions, tpd (b) Regional contribution Mean, 5% Mean, 17% 0.0 0% 10% 20% 30% 40% Contribution to regional NOx emissions (d) Regional context Industry Diesel Gasoline EGUs Other 95% CI Marcellus 13

14 Marcellus VOC emissions Marcellus Emissions Regional Contribution Fractile Fractile VOC emissions, tons per day 0.0 0% 5% 10% 15% 20% 25% 30% Contribution to regional VOC emissions Emissions, tons per day Marcellus Sources Transmission GasPlant Wellhead Condensate Compressors Completion Trucks Fracing Drilling Emissions, tons per day Marcellus in Context Marcellus Others Solvent Mobile

15 NOx + VOC + Sun = Ozone CAMx simulations of O 3 from Haynesville Shale Ozone (ppbv) max daily 8-hr ave Kemabll-Cook et al. Environ. Sci. Technol. 2010, 44,

16 Air Toxics Formaldehyde Emissions Fractile Mean, Mean, Formaldehyde, tons per day Fractile Mean, Mean, 0.0 0% 20% 40% 60% 80% % Regional Formaldehyde Emissions from Marcellus Natural gas powered compressor stations are major source. This is for primary emissions majority of formaldehyde in atmosphere is secondary.

17 Diesel particulate matter Fractile Mean, Mean, DPM, tons per day Fractile Mean, Mean, 0.0 0% 20% 40% 60% 80% % Regional DPM Emissions from Marcellus Diesel powered drill rigs, frac pumps and trucks

18 Some characteristics of oil and gas development Complex mix of small sources Widely distributed in space Poor coverage by routine network Aggregate emissions are significant in regional context: NOx and VOC ( regional O 3 ) Air toxic emission may create local problems Diesel PM and formaldehyde (local air toxics) More than just fracing Other important sources: drill rigs, compressor stations, completion venting

19 Acknowledgements Anirban Roy, Peter Adams NETL, PA DEP, WV DEP, NY DEC, MARAMA, GASP, EQT Heinz Endowment and DOE-NETL (funding)