Fort Worth Shale Gas Air Quality Study. Mike Pring, Eastern Research Group, Inc. May 29, 2013

Transcription

1 Fort Worth Shale Gas Air Quality Study Mike Pring, Eastern Research Group, Inc. May 29, 2013

2 Fort Worth Shale Gas Study Urban Drilling Citizen Concerns City formed Air Quality Committee (AQC) AQC developed Scope of Work City of Fort Worth staff implemented project with ERG 2

3 Fort Worth Shale Gas Study How much air pollution is being released by natural gas exploration in Fort Worth? How do releases from these sites affect off-site air pollution levels? Are the city s required setbacks for these sites adequate to protect public health? 3

4 Fort Worth Shale Gas Wells 4

5 Urban Drilling 5

6 Urban Drilling 6

7 Hydraulic Fracturing 7

8 Hydraulic Fracturing 8

9 Fort Worth Shale Gas Study Fort Worth Shale Gas Air Quality Study Ambient Air Monitoring Source Testing Air Dispersion Modeling Public Health Evaluation 9

10 Ambient Air Monitoring Measure pollutant concentrations in ambient air downwind from natural gas activities 10

11 Ambient Air Monitoring High Level Activity Sites Background Site Pre-production Sites Mobile Sources Site Fence Line Sites 11

12 Ambient Air Monitoring Sampled every 3 days for 2 months Over 140 different pollutants Benzene Toluene Ethylbenzene Xylene High Level Activity Sites 11 additional air pollutants Formaldehyde Acetaldehyde Fence Line Sites Methane 12

13 Ambient Air Monitoring 169 ambient air samples from 8 locations collected and analyzed 15,000 ambient air data points generated Toxic pollutants such as benzene and formaldehyde were detected in the ambient air Methane, ethane, propane, and butane were the pollutants found at highest concentrations 13

14 Ambient Air Monitoring Benzene Averages By Site (ppbv) 14

15 Source Testing Objective: Characterize emissions from natural gas production sources Survey drill sites, fracturing sites, well pads, and compressor stations Survey various stages of well development Measure emissions with: Infrared Camera Toxic Vapor Analyzer HiFlow Sampler Summa Canister 15

16 Source Testing 16

17 Source Testing Perform an infrared (IR) Camera emissions survey of all equipment (Larger Leaks) Obtain concentration measurements with the toxic vapor analyzer (TVA) of all emission points identified by the IR Camera 17

18 Source Testing Collect emission rate data with a HiFlow Sampler for each IR detected emission point 18

19 Source Testing Collect a canister sample for each detected emission point Document all sample collection data (e.g., site characteristic data, emissions data, weather, etc.) 19

20 Source Testing Average Annual VOC Emissions from Well Pad Average Tons/Year

21 Source Testing Tank Thief Hatch Pneumatic Valve Controller Tank Relief Device Gas Regulators 21

22 Air Dispersion Modeling Emissions Fate and Transport Downwind Impacts 22

23 Air Dispersion Modeling Scenario 1 Typical Well Pad 23

24 Air Dispersion Modeling Scenario 4 Compressor Station 24

25 Air Dispersion Modeling 25

26 Public Health Evaluation Screening was used to focus on pollutants of greatest interest from a health perspective Applied to monitoring and modeling results Pollutants of greatest interest Chemical Screening 26

27 Public Health Evaluation Serious health effects Less serious health effects Exposure levels No health effects Health-based screening levels published by various agencies 27

28 Monitoring Data Evaluation ~140 pollutants 8 monitoring stations More than 15,000 data points 24-hour average concentrations Highly sensitive monitoring methods Health-based screening level Monitoring detection limit Air concentrations 28

29 Monitoring Data Evaluation 24-hour average concentrations All below short-term health-based screening levels Overall-average concentrations All below long-term health-based screening levels No health hazard associated with continued exposure to measured levels 29

30 Modeling Data Evaluation Scenario 1 No estimated air quality impacts above screening levels Scenario 2 Estimated concentrations above screening levels for acrolein, benzene, and formaldehyde, but only in highly localized areas Scenarios 3 and 4 Estimated concentrations above screening levels for acrolein and formaldehyde extend beyond property boundaries and beyond setback distances 30

31 Modeling Data Evaluation 31

32 Public Health Findings Monitoring and modeling data indicate that setback distances are adequate For overwhelming majority of sites, no pollutants were found to exceed screening levels beyond setback distances For sites with multiple, large engines, estimated acrolein and formaldehyde concentrations exceed protective screening levels, but do not reach levels expected to cause adverse health effects 32

33 How much air pollution is being released by natural gas exploration in Fort Worth? Average Well Pad 32 (tons/yr) methane 0.7 (tons/yr) VOC 0.3 (tons/yr) HAP Average Compressor Station 69 (tons/yr) methane 17 (tons/yr) VOC 10 (tons/yr) HAP City-Wide 19,030 (tons/yr) methane 929 (tons/yr) VOC 505 (tons/yr) HAP 33

34 How do releases from these sites affect offsite air pollution levels? The key pollutants from a public health perspective are: Benzene Formaldehyde Acrolein No health hazard associated with continued exposure to measured levels Ambient Air Monitoring concentrations below both short term and long term screening levels 34

35 Are the city s required setbacks for these sites adequate to protect public health? Required setbacks are adequate for most sites Modeled concentrations did not reach levels expected to be associated with adverse health effects Ambient Air Monitoring concentrations below both short term and long term screening levels Large, line compressor engines may emit acrolein and formaldehyde at concentrations greater than protective health-based screening levels 35

36 Recommendations Encourage the use of air pollution control strategies Catalytic oxidizers on large compressor engines Electric-driven compressor engines Low bleed or no bleed pneumatic valve controls Vapor recovery units on storage tanks Conduct additional research evaluating acrolein and formaldehyde emissions Continue ambient air monitoring 36

37 Recommendations Implement enhanced inspection and maintenance of equipment 37

38 Project Website 38