APPENDIX E SATURN (UNITS 1 & 2) AIR TDR

Transcription

1 APPENDIX E SATURN (UNITS 1 & 2) AIR TDR

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3 Technical Data Report for Saturn Compressor Station (Units 1&2) Air Quality Prepared for: NOVA Gas Transmission Ltd. Calgary, Alberta Prepared by: Stantec Consulting Ltd. Calgary, Alberta

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5 Table of Contents EXECUTIVE SUMMARY... V ABBREVIATIONS... VII 1.0 INTRODUCTION TDR OBJECTIVES SUBSTANCES OF INTEREST NITROGEN DIOXIDE RESPIRABLE PARTICULATE MATTER CARBON MONOXIDE AMBIENT AIR QUALITY OBJECTIVES AND STANDARDS REGIONAL SETTING ASSESSMENT AREA TOPOGRAPHY CLIMATE Temperature Precipitation Humidity Winds BASELINE AIR QUALITY Oxides of Nitrogen and Nitrogen Dioxide Respirable Particulate Matter Carbon Monoxide SUMMARY MODELLING METHODOLOGY AERMOD DISPERSION MODEL DISPERSION METEOROLOGY RECEPTOR GRIDS AND TERRAIN BUILDING DOWNWASH EFFECTS NOX TO NO2 CONVERSION EXISTING INDUSTRIAL SOURCES AND BACKGROUND AIR QUALITY MODELLING SCENARIOS EMISSION RATES Compressor Station Air Emission Sources Regional Air Emission Sources DISPERSION MODELLING RESULTS BASELINE CASE PROJECT ONLY CASE APPLICATION CASE i

6 6.0 GREENHOUSE GASES EMISSIONS OF GHGS PROPOSED PROJECT SENSITIVITIES TO CLIMATE CHANGE SUMMARY AND CONCLUSIONS REFERENCES INTERNET SOURCES LIST OF TABLES Table 2-1 Provincial and National Ambient Air Quality Objectives and Standards Table 3-1 Geographic Coordinates of Stations Used in the Climate Analysis Table 3-2 Seasonal and Mean Daily Temperatures Wonowon and Fort St. John CCNS Table 3-3 Rainfall, Snowfall, and Total Precipitation at the Fort St. John CCNS Table 3-4 Historical Monthly Mean Relative Humidity at the Fort St. John Airport CCNS Table 3-5 Summary Statistics for WRF-Derived Wind Data Table 3-6 Continuous Ambient Air Quality Monitoring Stations Used in the Baseline Air Quality Analysis Table 3-7 Data Periods for Continuous Ambient Air Quality Monitoring Stations Used in the Baseline Air Quality Analysis Table 3-8 Summary of Continuous Ambient Air Quality Monitoring Data at Stations Used in the Baseline Air Quality Analysis Table 4-1 Buildings and Structures Considered in Dispersion Modelling (Saturn 1&2 Compressor Station) Table 4-2 Stack and Emission Parameters Applied in Dispersion Modelling for Compressor Station Sources Table 4-3 Summary of Emission Sources Included in Dispersion Modelling at Shell Gas Processing Facility Table 5-1 Maximum Predicted Ground-level Concentrations Associated with the Baseline Case Table 5-2 Maximum Predicted Ground Level Concentrations for NO2, CO and PM2.5 for the Project Only Case Table 5-3 Maximum Predicted Ground Level Concentrations for NO2, CO and PM2.5 for the Application Case Table 6-1 Greenhouse Gas Emissions from Compressor Station Operations Table 6-2 Greenhouse Gas Emissions: Canada and British Columbia ii

7 LIST OF APPENDICES APPENDIX A REPORT FIGURES... A.1 APPENDIX B CLIMATE AND METEOROLOGY OF THE ASSESSMENT AREA... B.1 B.1 Introduction... B.1 B.2 Climate and Meteorology... B.2 B.2.1 Ambient Temperature... B.2 B.2.2 Wind... B.3 B.2.3 Atmospheric Stability... B.5 B.2.4 Mixing Height... B.7 APPENDIX C DISPERSION MODELLING ISOPLETH MAPS... C.1 iii

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9 Executive Summary Stantec Consulting Ltd. (Stantec) was contracted by NOVA Gas Transmission Ltd. (NGTL), a wholly owned subsidiary of TransCanada PipeLines Limited (TransCanada), to conduct an air quality assessment to support the regulatory application for the North Montney Project (the Project). The majority of the air emissions related to the operation of the Project will result from the operation of the compressor stations. The air emission sources in these facilities comprise compressor turbines, boilers and generators. This technical data report (TDR) describes a dispersion assessment conducted as part of additional written evidence (AWE) for the NGTL s.52 Application to the National Energy Board (NEB). The initial November 2013 Project filing included an air quality assessment of Aitken Creek and Saturn compressor stations. The following TDR describes an air quality re-assessment of the Saturn compressor station location to include an additional compressor turbine (Saturn unit 2). An associated TDR has also been prepared for Groundbirch compressor station. The following cases are therefore considered in the current TDR: Baseline Case: includes emissions from the nearby facilities alone Project Case: includes emissions from the operation of the proposed Saturn 1&2 compressor station Application Case: includes emissions from the Baseline Case and the Project Case In each case, the maximum concentrations of NO2, PM2.5 and CO, including representative background concentrations, are predicted to fall below the applicable ambient air quality objectives. Annual greenhouse gas (GHG) emissions from operation of the proposed units, expressed as carbon dioxide equivalent (CO 2 eq) emissions, represent 0.04% of the Canadian total emissions for 2011, and 0.46% of the British Columbia total emissions for The 2011 emissions data represent the most recent, reviewed data available at the time of this assessment. Mitigation and adaptive management measures will be designed into the proposed compressor units where economically reasonable, to further reduce potential effects on air quality. v

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11 Abbreviations % percent C degrees Celsius µg/m 3 microgram per cubic metre µm micrometre or micron AAQO Ambient Air Quality Objective AERMAP terrain pre-processor for AERMOD AERMET meteorological data pre-processor for AERMOD AERMOD plume dispersion model m asl above sea level BC British Columbia BC HLS British Columbia Ministry of Healthy Living and Sport BC MOE British Columbia Ministry of Environment CASA Clean Air Strategic Alliance CCME Canadian Council of Ministers of Environment CCNS Canadian Climate Normal Station CEA Agency Canadian Environmental Assessment Agency CH4 methane cm centimetre CO carbon monoxide CO2 carbon dioxide CO2 eq carbon dioxide equivalents CWS Canada-Wide Standard U.S. EPA Environmental Protection Agency GHG greenhouse gas g/s grams per second H2S hydrogen sulphide K degrees Kelvin km kilometre km/h kilometres per hour LST Local Standard Time m. metres me metres east mm millimetres MM5 Mesoscale Model v5 vii

12 MMIF mn MOE m/s N N/A NAAQO NAD NCAR NEB NGTL N2O NO NO2 NOX PM10 PM2.5 SO2 TDR TSP t/y UTM WRAP WRF Mesoscale Model Interface Program metres north Ministry of Environment meter per second north not applicable National Ambient Air Quality Objectives North American Datum National Centre for Atmospheric Research National Energy Board NOVA Gas Transmission Ltd. nitrous oxide nitric oxide nitrogen dioxide nitrogen oxides inhalable particulate matter respirable particulate matter sulphur dioxide technical data report total suspended particulates tonnes per year Universal Transverse Mercator Western Regional Air Partnership Weather Research and Forecasting viii

13 Introduction 1.0 Introduction Stantec Consulting Ltd. (Stantec) was contracted by NOVA Gas Transmission Ltd. (NGTL), a wholly owned subsidiary of TransCanada PipeLines Limited (TransCanada), to conduct an air quality assessment to support the regulatory application for the North Montney Project (the Project). The majority of the air emissions related to the operation of the Project will result from the operation of the compressor stations. The air emission sources in these facilities comprise compressor turbines, boilers and generators. This technical data report (TDR) describes a dispersion assessment conducted in support of additional written evidence (AWE) for the NGTL s.52 Application to the National Energy Board (NEB). The initial application included an air quality assessment of Aitken Creek and Saturn 1 compressor stations. The following TDR describes an air quality re-assessment of the Saturn compressor station location to include an additional compressor turbine (Saturn unit 2). An associated TDR is also being prepared for the Ground birch compressor station. There are no permanent residences within 2 km of the Saturn 1&2 compressor station. The nearest resident is located approximately 9.5 km north northeast of the site. To evaluate the air quality effects associated with emissions from Saturn 1&2, ground-level concentrations were predicted through mathematical dispersion modelling. Dispersion modelling was conducted in accordance with the Guidelines for Dispersion Modelling in British Columbia (BC) (BC MOE 2008) and predicted ground-level concentrations were compared to the relevant ambient air quality criteria to assess compliance. Saturn (units 1&2) compressor station emissions during normal operating conditions were modelled and other sources of air emissions in the region were also considered. The secondary focus of this TDR concerns the emissions of greenhouse gases (GHGs), which are assessed consistent with Canadian Environmental Assessment Agency (CEA Agency 2003) guidance. A description of existing climatic and air quality conditions near the Saturn (units 1&2) compressor station is also included. 1.1 TDR OBJECTIVES The purpose of this TDR is to describe the methodologies and technical details related to the air quality assessment for the Saturn (units 1&2) compressor station. Information has been generated from existing literature and technical data sources, engineering estimates and computer dispersion modelling. 1.1

14 Introduction This TDR presents the following key information: A listing of substances of interest in the air quality assessment A discussion of the assessment area, its climate, and air quality baseline conditions A summary of air quality dispersion modelling methods, modelling scenarios and emission estimates A summary of air quality dispersion modelling results, and An assessment of greenhouse gases (GHGs) consistent with CEA Agency (2003) guidance. 1.2

15 Substances of Interest 2.0 Substances of Interest For this assessment, nitrogen dioxide (NO2), fine particulate matter (PM2.5) and carbon monoxide (CO) were selected as the key substances of interest with respect to air emissions from the compressor station. The majority of the compressor station sources emit these substances, which are common by-products of combustion. Emissions of sulphur dioxide (SO2) and hydrogen sulphide (H2S) were not included in the scope of the air quality assessment as the gas to fuel the turbines will be sweet natural fuel gas. 2.1 NITROGEN DIOXIDE Nitrogen dioxide is an orange to reddish gas that is corrosive and irritating. Most NO2 in the atmosphere is formed by the oxidation of nitric oxide (NO), which is emitted by combustion processes, particularly those at high temperature and pressure, such as internal combustion engines. External combustion processes such as fired equipment (e.g., heaters, boilers) are also sources of oxides of nitrogen (NOX). The levels of NO and NO2, and the ratio of the two gases, together with the presence of hydrocarbons and sunlight are the most important factors in the formation of ground-level ozone and other oxidants. Further oxidation, and subsequent combination with water in the atmosphere forms nitric acid, a component of acid rain. NOX is produced in most combustion processes and are almost entirely made up of NO and NO2. Nitrogen dioxide is a respiratory irritant, while NO is relatively inert (CDC, 2013). As such, ambient air quality objectives exist for NO2 and not for NO or NOX. 2.2 RESPIRABLE PARTICULATE MATTER Particulate matter is classified by particle size. Particle size determines the velocity with which gravitational settling occurs and the ease with which the particles penetrate the human respiratory tract. Generally, large particles settle out very close to the source while very fine particles extend further from the source and penetrate deep into the respiratory tract. Total suspended particulates (TSP) encompass all size ranges from about 100 μm to the submicrometre range. Inhalable particulate matter (PM10) consists of small particles with diameters less than 10 μm. Respirable particulate matter (PM2.5) consists of very small particles with diameters less than 2.5 μm. The emphasis of regional air quality related to particulate matter has shifted in recent years from an emphasis on TSP to the smaller particles (particularly PM2.5) as a result of concerns related to potential effects on human health (EPA, 2013). As a result, this assessment of particulate emissions is limited to PM

16 Substances of Interest 2.3 CARBON MONOXIDE Carbon monoxide is a colourless, odourless gas. A product of combustion, its sources include fossil fuel combustion (e.g., motor vehicles) and natural sources (e.g., forest fires). 2.4 AMBIENT AIR QUALITY OBJECTIVES AND STANDARDS Air quality is assessed by comparing predicted ground-level concentrations to applicable objectives and standards developed by regulatory agencies. The BC and Canadian (National) Ambient Air Quality Objectives (AAQO) are shown in Table 2-1. The BC AAQO are denoted as Levels A, B and C (BC HLS 2009). The National Ambient Air Quality Objectives (NAAQO) are denoted as Desirable and Acceptable (Health Canada 2006). The BC and Canadian AAQO for some substances are very similar. The BC AAQO are defined as follows: Level A is set as the objective for new and proposed discharges and, within the limits of best practicable technology, to existing discharges by planned staged improvements for these operations. Level B is set as the intermediate objective for all existing discharges to meet within a period of time specified by the Director (BC MOE), and as an immediate objective for existing discharges which may be increasing in quantity or altered in quality as a result of process expansion or modification. Level C is set as the immediate objective for all existing chemical and petroleum industries to reach within a minimum technically feasible period of time. The NAAQO are defined as follows: The Maximum Desirable Level is the long-term goal for Air Quality and provides a basis for anti-degradation policy for unpolluted parts of the country, and for the continuing development of control technology. The Maximum Acceptable Level is intended to provide adequate protection against effects on soil, water, vegetation, materials, animals, visibility, personal comfort and wellbeing. In 2009, BC adopted AAQO for respirable particulate matter (PM2.5) which are 25 µg/m 3 for a 24-hour averaging period (as a 98 th percentile value over one year) and 8 µg/m 3 for the annual averaging period (BC HLS 2009). In May of 2013, the Government of Canada published Canadian Ambient Air Quality Standards (CAAQS) for PM2.5, These standards are to be achieved by 2015 and 2020, with the 2020 standards to be reviewed again in The CAAQS metric for PM2.5 is 28 µg/m 3, averaged over 24-hours, and 10 µg/m 3, averaged over a year. The 24-hour metric is calculated based on a 2.4

17 Substances of Interest three year average of the annual 98 th percentile of the daily 24-hour average concentrations. The annual value is calculated based on a three year average of the annual average concentrations (Government of Canada 2013). Table 2-1 describes the relationship of the provincial and federal air quality standards for this project. It should be noted that at a location where predicted concentrations exceed an objective or standard, there needs be a receptor (e.g., resident population, sensitive ecosystem) capable of being affected by that substance for a potential effect to occur. Table 2-1 Provincial and National Ambient Air Quality Objectives and Standards Substance (Units) Averaging Period Provincial (BC) AAQO a Level Aa Level Ba Level Ca CAAQS National (Canada) Maximum Desirable NAAQOc Maximum Acceptable NO2 (µg/m 3 ) 1 hour hour 200 Annual PM2.5 (µg/m 3 ) 24 hour 25 a 28 b Annual 8 a 10 b CO (µg/m 3 ) 1 hour 14,300 28,000 35,000 15,000 35,000 8 hour 5,500 11,000 14,300 6,000 15,000 NOTES: a BC Ministry of Healthy Living and Sport, Air Quality Objectives and Standards The PM hour average is based on 98 th percentile value for one year. b Canadian Ambient Air Quality Standards (CAAQS) for PM2.5. These objectives are referenced to the 98 th percentile 24-h concentration, averaged over three consecutive years, for the 24-hour time period, and for the annual time period it is referenced to the annual average concentrations averaged over three years (Government of Canada 2013). c National Ambient Air Quality Objectives, or NAAQO (Health Canada 2006). No applicable Objective or Standard in this Jurisdiction 2.5

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19 Regional Setting 3.0 Regional Setting 3.1 ASSESSMENT AREA The proposed Saturn 1&2 compressor station is located 30 km southwest of Fort St. John, BC at 55º 59' "N and 121º 06' 39.49"W (UTM Zone 10: m N; m E). Assessment area boundaries were established to focus the scope of the assessment to a 25 km by 25 km area centered on the compressor station. The assessment area is sized to capture all values of interest; in this case all predicted concentrations greater than 10% of the applicable ambient air quality objective (see Section 2.4). 3.2 TOPOGRAPHY Topography within the 25 km by 25 km air quality assessment area is shown in Figure A-1 (Appendix A). The proposed Saturn 1&2 compressor site is located at a base elevation of approximately 692 m above sea level (asl). 3.3 CLIMATE Climate elements influence the transport and dispersion of air emissions from the proposed units, and must be considered as part of the compressor station environmental effects assessment. Specifically, wind speed, wind direction, and atmospheric turbulence exert major influences on the dispersion of air emissions. The following climate baseline considers measurable parameters at the nearest representative regional climate stations in the vicinity of the proposed Project. The measurable parameters of the regional climatic environment that have been characterized are temperature, precipitation, relative humidity, and winds. Historical climate data are available from the Canadian Climate Normal Stations (CCNS) for the 30-year period of 1971 to 2000 (Environment Canada 2013). Table 3-1 summarizes the monitoring stations, which were used in the regional climate summary discussed throughout this section, and includes the station locations in geographic coordinates and site elevations. The Fort St. John CCNS station is the closest CCNS station to Saturn 1&2, located approximately 35 km to the northeast. To supplement these surface data, wind speed and direction data were extracted from the 4 km grid resolution one year Weather Research and Forecasting (WRF) model data from January 1, 2010 to December 31, 2010, surrounding Saturn 1&2. 3.7

20 Regional Setting Table 3-1 Geographic Coordinates of Stations Used in the Climate Analysis Station Type Station Name Latitude Longitude CCNS WRF Fort St. John (Climate ID ) Saturn 1&2 Compressor Station Elevation (m asl) Location (UTM NAD83) mn me Zone 56 14' N 'W ' N 'W NOTE: CCNS = Canadian Climate Normal Station (Environment Canada 2013) WRF = Weather Research and Forecasting Model Temperature A summary of the historical seasonal and mean air temperatures at the Fort St. John CCNS is provided in Table 3-2. Based on the available data, seasonal mean daily temperature ranges from C in winter to 14.7 C in summer. A more detailed breakdown of the monthly mean temperatures at the Fort St. John CCNS is shown in Figure A-2 (Appendix A). Also shown are extreme maximum and minimum temperatures. The historical extreme temperatures at the Fort St. John station from C to 33.6 C. Table 3-2 Seasonal and Mean Daily Temperatures Wonowon and Fort St. John CCNS Station Name Mean Daily Temperature ( C) Winter a Spring a Summer a Autumn a Annual Fort St. John CCNS NOTE: a Winter Months: December, January, February; Spring Months: March, April, May; Summer Months: June, July, August; Autumn Months: September, October, November SOURCE: Environment Canada Precipitation Monthly mean and maximum daily rainfall, snowfall, and total precipitation as observed at the Fort St. John CCNS are presented in Table 3-3. Figures A-3 (Appendix A) are graphical representations of historical mean daily rainfall, snowfall, and total precipitation by month. 3.8

21 Regional Setting Table 3-3 Rainfall, Snowfall, and Total Precipitation at the Fort St. John CCNS Parameter Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual Rainfall (mm) Mean Monthly Max Daily Snowfall (cm) Mean Monthly Max Daily Total Precipitation (mm) Mean Monthly Max Daily SOURCE: Environment Canada 2013 Table 3-3 shows a summary of precipitation at the Fort St. John CCNS. The June to August period (summer) is typically the wettest season during the year. The historical maximum daily rainfall (80.3 mm) was recorded in the month of June. The months with the most snowfall are typically November to March. The maximum historical daily snowfall (47.8 cm) was recorded during the month of May. The months with maximum snow depth are typically during late winter and early spring, with the maximum historical daily snow depth (112 cm) recorded during the month of March. Annual precipitation is mm, with the maximum (83.2 mm) occurring during the month of July Humidity Relative humidity is the ratio of the amount of water vapour actually contained in the air compared to the maximum amount of water vapour required for saturation at air temperature. It is therefore the ratio (usually expressed as percent) of the air s water vapour content to its capacity. Table 3-4 shows the associated mean relative humidity at the Fort St. John Airport CCNS for each month at 15:00 local standard time (LST). Relative humidity values at 15:00 LST range from 40.6% to 71.8%. Relative humidity is temperature dependent. It often reaches its maximum in the predawn when air temperatures are typically at a minimum, and reaches its minimum when air temperatures are at a maximum in the early to mid-afternoon. 3.9

22 Regional Setting Table 3-4 Historical Monthly Mean Relative Humidity at the Fort St. John Airport CCNS Month Average Relative Humidity (%) 15:00 LST January 69.1 February 63.8 March 55.0 April 42.6 May 40.6 June 47.3 July 51.3 August 52.7 September 53.6 October 56.9 November 71.8 December 71.6 SOURCE: Environment Canada 2013 (Internet Site) Winds Data obtained from the Weather Research and Forecasting (WRF) model database for a 1-year period (January 1, 2010 to December 31, 2010) were analyzed to characterize wind patterns. An extraction utility provided by the United States Environmental Protection Agency (U.S. EPA) Mesoscale Model Interface (MMIF) program was used to extract surface and upper air files from the 4 km grid resolution WRF model output so it could be used in AERMET. Table 3-5 shows a summary of wind statistics at the proposed Saturn 1&2 compressor station location, including the maximum and average recorded wind speeds. Also presented is the frequency of recorded calms (defined as winds with speeds of less than 0.5 m/s). The mean and maximum wind speeds for the one year-period are also shown at the proposed compressor station site. Wind roses are a graphic means of presenting wind speed and direction frequency data. The length of the radial barbs gives the total percent frequency of winds from the indicated direction, while coloured portions of the barbs indicate the frequency of associated wind speed categories. Figure B-2 (Appendix B) presents the frequency distributions of hourly average wind speed and the wind roses depicting annual wind speed and direction frequency distributions based on data extracted from WRF data between the period of January 1, 2010 and December 31, 2010 at the proposed compressor station location. 3.10

23 Regional Setting The winds at the proposed Saturn 1&2 compressor station site are predominantly from the west, west southwest and southwest directions. Wind speeds average 3.65 m/s (13.1 km/h). The maximum hourly wind speed is 15.9 m/s (57.2 km/h). For 60.5% of the time, wind speeds were less than 4.0 m/s. Calm winds (less than 0.5 m/s) occur about 1.4% of the time. Table 3-5 Summary Statistics for WRF-Derived Wind Data Parameter WRF Data for the Proposed Saturn 1&2 Compressor Station Location Station Location UTM NAD83 me Start Date End Date UTM NAD83 mn Elevation (m asl) Jan Dec-2010 Total Hours No. (% available) 8760 (100%) Calm Hrs (Wind Speeds < 0.5 m/s) No. (%) 125 (1.4%) Maximum Wind Speed m/s (km/h) 15.9 (57.2) Average Wind Speed m/s (km/h) 3.65 (13.1) 3.4 BASELINE AIR QUALITY Characterizing future air quality involves knowledge of both existing ambient air quality and compressor station emissions, and how they disperse in the environment. The ambient air quality baseline summary considers measurable substances of interest at the nearest most representative continuous monitoring stations in the proximity of the compressor station. An analysis was completed of ambient air quality monitoring data collected at nearby stations. No one station measures all substances of interest, and therefore a suite of data from a variety of stations must be examined. Data were obtained from the Alberta Clean Air Strategic Alliance (CASA) website. This assessment for baseline ambient air quality focuses on substances of interest relative to compressor station emissions, including: Oxides of Nitrogen (NOX) and Nitrogen dioxide (NO2) Respirable particulate matter (PM2.5) Carbon monoxide (CO) A summary of the available station locations and substances monitored are provided in Table 3-6. Available data periods for each station are given in Table 3-7 by substance. The Henry Pirker station is closest, located 170 km southeast of the proposed Saturn 1&2 compressor station, that continuously measures CO concentrations and it is considered representative of the area due to its rural location. The Beaverlodge continuous monitoring station is located 140 km southeast of the proposed Saturn 1&2 compressor station. It was used to assess baseline ambient concentrations for NOX, NO2 and PM

24 Regional Setting A summary of the statistical data analysis performed on the continuous ambient air quality monitoring data is provided in Table 3-8. The results for each substance are discussed in the following sections Oxides of Nitrogen and Nitrogen Dioxide As shown in Table 3-8, the maximum one-hour, 24-hour, and annual average NOX concentrations for Beaverlodge were 188, 89, and 10 µg/m 3, respectively. There are no regulatory criteria for ground-level NOX concentrations. Similarly, in Table 3-8, the mean one-hour average NO2 concentration for Beaverlodge was 8 µg/m 3 and maximum one-hour, 24-hour concentrations were 94 and 64 µg/m 3, respectively. These values are much less than the National AAQO for one-hour, 24-hour and annual average NO2 concentrations (400 µg/m 3, 200 µg/m 3, and 100 µg/m 3, respectively. The observed NO2 concentrations at this site indicate little potential for adverse effects Respirable Particulate Matter Inhalable particulate matter (PM2.5) is monitored continuously at the Beaverlodge air quality monitoring station. As shown in Table 3-8, the mean one-hour average PM2.5 concentration at the Beaverlodge monitoring station was 6.54 µg/m 3 and the maximum one-hour concentration was 322 µg/m 3. The 24-hour average PM2.5 concentration recorded at Beaverlodge monitoring station, based on annual 98 th percentile averaged over 3 years, was 21.6 µg/m 3. This value is less than the 30 µg/m 3 CWS and the 25 µg/m 3 AAQO for 24-hour average PM2.5 concentrations. The average 24-hour PM2.5 concentration (6.52 µg/m 3 ) is also lower. 3.12

25 Regional Setting Table 3-6 Continuous Ambient Air Quality Monitoring Stations Used in the Baseline Air Quality Analysis Station Name Latitude Longitude Elevation (m asl) Location (UTM NAD83) Substances Monitored me mn Zone NOX NO2 PM2.5 CO Beaverlodge 55 12'N 'W x x x Henry Pirker 55 06'N 'W x SOURCE: CASA 2009 Table 3-7 Data Periods for Continuous Ambient Air Quality Monitoring Stations Used in the Baseline Air Quality Analysis Station Name Beaverlodge January 1, 2008 June 30, 2013 Monitoring Data Period NOX NO2 PM2.5 CO SO2 January 1, 2008 June 30, 2013 January 1, 2008 June 30, 2013 Henry Pirker N/A N/A N/A January 1, 2008 June 30, 2013 NOTE: N/A = Not applicable N/A N/A N/A 3.13

26 Regional Setting Table 3-8 Summary of Continuous Ambient Air Quality Monitoring Data at Stations Used in the Baseline Air Quality Analysis Substance NOX (µg/m 3 ) NO2 (µg/m 3 ) PM2.5 (µg/m 3 ) CO (µg/m 3 ) Parameter AAQO (Table 2-1) Beaverlodge Henry Pirker One-hour Maximum N/A 188 N/A One-hour 99 th Percentile N/A 67 N/A One-hour 98 th Percentile N/A 51 N/A Mean One-hour Average N/A 9.1 N/A 24-hour Maximum N/A 89 N/A 24-hour Average N/A 9.2 N/A Annual Average N/A 9.9 N/A One-hour Maximum N/A One-hour 99 th Percentile N/A 44.2 N/A One-hour 98 th Percentile N/A 37.2 N/A Mean One-hour Average N/A 7.5 N/A 24-hour Maximum N/A 24-hour Average N/A 7.5 N/A Annual Average N/A One-hour Maximum N/A 322 N/A One-hour 99 th Percentile N/A 29 N/A Mean One-hour Average N/A 6.54 N/A 24-hour Maximum N/A 84.8 N/A 24-hour 98 th Percentile a N/A 24-hour Average N/A 6.52 N/A Annual Average N/A One-hour Maximum 14,300 N/A 3161 One-hour 99 th Percentile N/A N/A 882 One-hour 98 th Percentile N/A N/A 699 Mean One-hour Average N/A N/A hour Maximum 5,500 N/A 1,407 8-hour Average N/A N/A 249 NOTES: N/A = not applicable. Values in bold identify ambient concentrations applied in this assessment a BC Ministry of Healthy Living and Sport, Air Quality Objectives and Standards The PM hour average is based on 98 th percentile value for one year. 3.14

27 Regional Setting Carbon Monoxide As shown in Table 3-8, the mean one-hour average CO concentration for Henry Pirker was 249 µg/m 3. The maximum, 99 th, and 98 th percentile one-hour average concentrations were 882 and 699 µg/m 3, respectively. These values are much less than the BC HLS (2009) Level A AAQO for one-hour average CO concentrations (14,300 µg/m 3 ). At the Henry Pirker monitoring station, the maximum 8-hour average CO concentration was 1,407 µg/m 3. This value is lower than the 5,500 µg/m 3 BC HLS (2009) Level A AAQO for 8-hour average CO concentration. 3.5 SUMMARY Baseline air quality in the region is influenced primarily by regional industrial air emission sources and traffic near the site. All monitored concentrations of NO2, PM2.5 and CO have been below the applicable regulatory criteria for ambient air quality. In addition to anthropogenic sources, forest fires can cause elevation of PM2.5 levels during such occurrences for considerable distances, but are not known to have contributed to any readings described here. 3.15

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29 Modelling Methodology 4.0 Modelling Methodology 4.1 AERMOD DISPERSION MODEL For this assessment, the AERMOD plume dispersion model was applied to evaluate the effect of the compressor station emissions from continuous emission sources. AERMOD is a steady-state plume dispersion model developed by the United States Environmental Protection Agency (US EPA 2004a, 2004b). The model is designed to estimate near-field (less than 50 km) ground-level concentrations from most types of industrial emission sources. The AERMOD modelling system consists of three programs: the plume dispersion model (AERMOD), a meteorological pre-processor (AERMET), and a terrain pre-processor (AERMAP). Version (December 2012) was used in this assessment. The AERMOD dispersion model is recommended for refined air quality assessments in the BC Model Guidelines (BC MOE 2008). 4.2 DISPERSION METEOROLOGY Meteorology influences the manner in which air emissions from industrial and natural sources disperse into the atmosphere, and affect air quality. Atmospheric dispersion of emissions is governed by wind speed and the turbulence that exists in the mixed layer of air in contact with the ground. Turbulence levels depend on thermal effects (e.g., vertical temperature stratification) and mechanical effects caused by topography, surface roughness and wind speed. The height of the mixing layer determines the vertical extent to which emissions are able to diffuse. For this assessment, WRF meso-meteorological data for the year 2010 were used in the dispersion modelling. Historically, the MM5 meteorological model has been the standard used. However, MM5 has been officially phased out by the National Center for Atmospheric Research (NCAR). NCAR announced on October 31, 2008 that technical support for the MM5 model has been discontinued and strongly encouraged users to move to the new NCAR supported WRF model. The WRF model provides better algorithms, handling of topography, and programming compared to MM5. It also includes new features and options developed by the Mesoscale & Microscale Meteorology Division at NCAR. A recently published U.S. Western Regional Air Partnership (WRAP) report has demonstrated that WRF outperforms MM5 in overall model accuracy (US WRAP 2012). The AERMOD meteorological preprocessor AERMET was used to process the meteorological dataset used in dispersion modelling (US EPA 2004b). AERMET is used to estimate two stability parameters, friction velocity and Monin-Obukhov length, to characterize the amount of turbulence in the atmosphere. The friction velocity is a measure of mechanical effects alone, such as wind shear at ground-level. The Monin-Obukhov length indicates the relative strengths of mechanical and buoyancy effects on atmospheric turbulence. AERMOD can account for turbulence from both wind shear and from buoyancy effects due to solar heating during the day and radiation cooling at night. To properly account for these effects, AERMET requires three 4.17

30 Modelling Methodology land use parameters: albedo, Bowen ratio, and surface roughness. Albedo is the fraction of total incident solar radiation reflected by a particular surface without absorption. Bowen ratio is defined as the ratio of the sensible heat flux to the latent heat flux and can be an indicator of surface moisture conditions. Surface roughness is a length scale that characterizes the roughness of the earth s surface. Bowen ratio can vary significantly over the course of the day; however, it usually remains fairly constant during mid-day. For this assessment, site-specific values for albedo, Bowen ratio, and surface roughness were selected based on land use within 3 km of the compressor station recommended by the BC Model Guidelines (BC MOE 2008). These values are shown in Table B-1 (Appendix B). 4.3 RECEPTOR GRIDS AND TERRAIN Predictions of ground-level concentrations were made for locations on and outside the property boundary for the Saturn 1&2 compressor station, according to the BC Model Guidelines (BC MOE 2008), using a series of nested Cartesian grids with increasing receptor density and proximity to the compressor stations. The receptor grids and their corresponding spacing are shown in Figure A-4 (Appendix A). They are as follows: 20 m receptor spacing along the plant property boundary 1 50 m spacing within 500 m of source 250 m spacing within 2 km of source 500 m spacing within 5 km of source 1,000 m spacing beyond 5 km of source 1 as defined in Section 6.3 of the Guidelines (BC MOE 2008)) Terrain elevations were applied to all receptors used in dispersion modelling based on the Global Digital Elevation Data (1.5 arc sec resolution). 4.4 BUILDING DOWNWASH EFFECTS Buildings or other solid structures can affect the flow of air near a source and may induce building downwash effects (e.g., eddies on the downwind side), which have the potential to reduce plume rise and affect dispersion. For dispersion modelling purposes, building downwash effects were considered for all point sources as proposed for the Saturn 1&2 compressor station. The buildings and structures that were considered in dispersion modelling are summarized in Table 4-1 and illustrated in Figures A-9 and A-10 (Appendix A). 4.18

31 Modelling Methodology Table 4-1 Buildings and Structures Considered in Dispersion Modelling (Saturn 1&2 Compressor Station) Building ID Description Length (m) Width (m) 1 Compressor Building # Compressor Building # Height (m) 3 PPU #1 Generator Skid PPU #2 Generator Skid Mechanical Skid # Mechanical Skid # Mechanical Skid # Mechanical Skid # Electrical Skid Personnel Skid Heated Storage Building SOURCE: NGTL NOX TO NO2 CONVERSION Ambient air quality objectives exist for NO2 rather than total NOX. Therefore it is important to estimate the portion of AERMOD predicted NOX concentrations in the form of NO2. The BC Model Guidelines (BC MOE 2008) recommends reporting the results as NOX (100% conversion), if the maximum NOX concentrations are less than the ambient objectives for NOX. For this assessment all NO2 will be reported as NOX (100% conversion). 4.6 EXISTING INDUSTRIAL SOURCES AND BACKGROUND AIR QUALITY Existing industrial emission sources within a 5 km radius of the Saturn 1&2 compressor station were considered for inclusion in dispersion modelling, as recommended in the BC Model Guidelines (BC MOE 2008). A Shell gas processing facility (Shell 3-28 Saturn Gas processing Plant) is currently under construction 4 km to the southeast of the proposed Saturn 1&2 compressor station, and was included in modeling of the baseline case. The location of this facility is shown on Figure A-4 (Appendix A). To account for the other potential air emission sources (natural and human-caused) inside and outside of the 25 km x 25 km assessment area that have not been included in the dispersion modelling assessment, representative background (or reference) ambient air quality concentrations for each of the substances of interest are required. The background ambient air quality is generally established based on an analysis of regional ambient air quality monitoring data. For a summary of the background concentrations used for this assessment, see Table 3-8. (Section 3.4: Baseline Air Quality). 4.19

32 Modelling Methodology 4.7 MODELLING SCENARIOS Three dispersion modelling scenarios were investigated for each proposed compressor station and included: 1. Baseline Case includes the emissions from the Shell Gas Plant, and representative background ambient concentrations from regional monitoring stations. 2. Project Only Case includes the emissions from the operation of Saturn 1&2 (compressor turbines, boilers and generators). 3. Application Case includes the emissions from both the Baseline Case and the Project Only Case. 4.8 EMISSION RATES Air emissions associated with the operation of Saturn 1&2 were provided by NGTL. These operational sources include two compressor turbines, four boilers and one generator. Emission estimates were based upon a similar facility (RWDI 2011). Air emissions associated with the Shell Gas Plant were obtained from the operators and were included in the dispersion modelling as a baseline source Compressor Station Air Emission Sources The proposed equipment included at Saturn 1&2 are presented in Table 4-2. The mass emission rates and source exit conditions were provided by NGTL. The locations of these sources and the layout of facility buildings are provided in Figures A-9 and A-10 (Appendix A) Regional Air Emission Sources Air emissions from the Shell Gas Facility were included in the dispersion modeling for Saturn 1&2. Air emission source information and emissions rates (NOX, PM2.5 and CO) for The Shell Gas Processing Facility were provided by Shell. Table 4-3 lists the emission sources (shown in Figure A-5 (Appendix A)) and various stack parameters. 4.20

33 Modelling Methodology Table 4-2 Stack and Emission Parameters Applied in Dispersion Modelling for Compressor Station Sources Source Description Compressor Turbine 1 Compressor Turbine 1 Boiler 2 Boiler 2 Boiler 2 Boiler 2 Generator 3 Source type Point Point Point Point Point Point Point Location (UTM Zone 10) Base elevation (m asl) m E m N Stack height (m) Stack dia. (m) Exit velocity (m/s) Exit temp. (K) Approximate Power Rating (kw) Maximum Emission Rates (g/s) 15,000 15, NOX PM CO NOTES: 1 Solar Titan 130 NG Turbine & Solar C65 XP 2 Superhot AAE CAT G3406TA SOURCE: NGTL 2013; RWDI

34 Modelling Methodology Table 4-3 Summary of Emission Sources Included in Dispersion Modelling at Shell Gas Processing Facility Source Description Generator #1 (1.0 MW) Generator #2 (1.5 MW) Medium Heater #1 Medium Heater #2 Solar Titan 130 Solar Titan 130 LP/HP Flare Source type Point Point Point Point Point Point Point Location (UTM Zone 10) me mn Base elevation (m asl) Stack height (m) Stack diameter (m) Exit velocity (m/s) * Exit temperature (K) * NOX CO PM NOTE: * Pseudo Flare Parameters SOURCE: Shell Canada,

35 Dispersion Modelling Results 5.0 Dispersion Modelling Results To determine the potential effects on local ambient air quality associated with existing regional and proposed air emissions from Saturn 1&2, dispersion modelling was conducted for NOX, PM2.5 and CO for all three modelling scenarios. The maximum predicted concentrations from these modelling scenarios were compared to the relevant Ambient Air Quality Objectives (AAQO) to assess the compressor station effect on air quality. The results of the assessment are presented within the following sections. Maximum predicted concentrations of CO were well below the applicable AAQO for all periods considered. The results for CO are tabulated for each case but not discussed further. Instead, this assessment focuses on predicted concentrations of NO2 and PM2.5. The predicted NO2 concentrations are based on 100 % conversion of NO to NO2 (see Section 4.5). Isopleth maps of maximum predicted ground-level NO2 concentrations for all three cases for each compressor station and all relevant averaging intervals are provided in Appendix C. To account for the potential effects of all emission sources located inside and outside of each assessment area that have not been included in the dispersion modelling assessment, an ambient background value (as outlined in Section 3.4) was added to the tabulated predicted concentrations. 5.1 BASELINE CASE The Baseline Case modelling scenarios include emissions from existing regional sources within the assessment area. A summary of the maximum predicted ground-level concentrations associated with emissions from the Baseline Case, including the ambient background, is presented in Table 5-1. The maximum predicted one-hour, 24-hour and annual average ground-level NO2 concentrations associated with the Baseline Case are equal to 194, 63.1 and 5.75 µg/m 3 respectively. Including the ambient background NO2 concentrations, these maximums are equal to 231, 70.6 and 13.8 µg/m 3 respectively. Isopleths of maximum predicted ground-level NO2 concentrations for the Baseline Case are shown in Figures C-1 to C-3 (Appendix C). The maximum predicted 24-hour and annual average ground-level PM2.5 concentrations for the Baseline Case are 9.93 and µg/m 3, respectively. Including the ambient background concentration, these maximums are equal to 16.5 and 7.15 µg/m 3, respectively. These are less than the BC PM2.5 Objectives of 25 and 8 µg/m

36 Dispersion Modelling Results Table 5-1 Maximum Predicted Ground-level Concentrations Associated with the Baseline Case Substance Averaging Period a Maximum Predicted Ground-level Concentration (µg/m 3 ) b Ambient Background Concentration (µg/m 3 ) Maximum Predicted Ground-level Concentration Including Ambient Background (µg/m 3 ) AAQO c (µg/m 3 ) NO2 d 1-hour hour Annual PM hour Annual CO 1-hour ,300 8-hour ,500 NOTES: a Only averaging periods with BC AAQO NAAQO, or CWS are shown. b All predicted concentrations represent the 1 st highest values. c The most stringent of the BC AAQO, NAAQO and CWS is used. d Assumes 100% conversion of NOX to NO2 5.2 PROJECT ONLY CASE The Project Case modelling scenarios include emissions solely from the operation of the proposed compressor stations (as outlined in Section 4.8.1). A summary of the maximum predicted ground-level concentrations associated with emissions from the Project Only Case for Saturn 1&2 are presented in Table 5-2. These tables also present the maximum predicted concentrations including ambient background. The maximum predicted one-hour, 24-hour and annual average ground-level NO2 concentrations are 70.5, 52.4 and 8.65 µg/m 3, respectively. Including the ambient background NO2 concentrations, these maximums are equal to 108, 59.9 and 16.7 µg/m 3, respectively. There are no predicted exceedances of the NAAQO (400, 200, and 100 µg/m 3, respectively) for NO2. Isopleths of maximum predicted ground-level NO2 concentrations for the Project Only Case for both proposed compressor stations are shown in Figures C-4 to C-6 (Appendix C). The maximum predicted 24-hour and annual average ground-level PM2.5 concentrations for the Project Only Case are 1.29 and µg/m 3, respectively. Including the ambient background concentration, these maxima are equal to 7.81 and 6.85 µg/m 3, respectively. These are less than the BC PM2.5 Objectives of 25 and 8 µg/m

37 Dispersion Modelling Results Table 5-2 Maximum Predicted Ground Level Concentrations for NO2, CO and PM2.5 for the Project Only Case Substance Averaging Period a Maximum Predicted Ground-level Concentration (µg/m 3 ) b Ambient Background Concentration (µg/m 3 ) Maximum Predicted Ground-level Concentration Including Ambient Background (µg/m 3 ) AAQO c (µg/m 3 ) NO2 d 1-hour hour Annual PM hour e Annual CO 1-hour ,300 8-hour ,500 NOTES: a Only averaging periods with BC AAQO NAAQO, or CWS are shown. b All predicted concentrations represent the 1 st highest values. c The most stringent of the BC AAQO, NAAQO and CWS is used. d Assumes 100% conversion of NOx to NO2 5.3 APPLICATION CASE The Application Case modelling scenario includes emissions from the proposed Saturn 1&2 compressor station in combination with regional background emission sources (Section 4.8). A summary of the maximum predicted ground-level concentrations associated with emissions from the Application Case are presented in Table 5-3. The table also presents the maximum predicted concentrations including ambient background. The maximum predicted one-hour, 24-hour, and annual average ground-level NO2 concentrations associated with the Application Case are 231, 70.6 and 16.7 µg/m 3, respectively. These are lower than the AAQO of 400, 200, and 100 µg/m 3, respectively. Isopleths of maximum predicted ground-level NO2 concentrations for the Application Case are shown in Figures C-7 to C-9 (Appendix C). The maximum predicted 24-hour and annual average ground-level PM2.5 concentrations for the Application Case are 16.5 and 7.15 µg/m 3, respectively. These are less than the BC PM2.5 Objectives of 25 and 8 µg/m 3, respectively. 5.25

38 Dispersion Modelling Results Table 5-3 Maximum Predicted Ground Level Concentrations for NO2, CO and PM2.5 for the Application Case Substance Averaging Period a Maximum Predicted Ground-level Concentration (µg/m 3 ) b Ambient Background Concentration (µg/m 3 ) Maximum Predicted Ground-level Concentration Including Ambient Background (µg/m 3 ) AAQO c (µg/m 3 ) NO2 d 1-hour hour Annual PM hour e Annual CO 1-hour ,300 8-hour ,500 NOTES: a Only averaging periods with BC AAQO NAAQO, or CWS are shown. b All predicted concentrations represent the 1 st highest values. c The most stringent of the BC AAQO, NAAQO and CWS is used. d Assumes 100% conversion of NOX to NO2 5.26

39 Greenhouse Gases 6.0 Greenhouse Gases The compressor station operation will result in the release of substances that, owing to their physical and chemical properties, are classed as greenhouse gases (GHGs). These include carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). Total GHG emissions are normally reported as CO2-equivalents (CO2e), whereby emissions of each of the specific greenhouse gases are multiplied by their global warming potential (GWP). The global warming potential of CO2 is 1; CH4 is 21, and N2O is 310. The carbon dioxide equivalent factor is CO2e = (CO2 mass x 1.0) + (CH4 mass x 21) + (N2O mass x 310) As combustion processes predominate CO2 constitutes the majority of GHG emissions for a natural gas compression facility. Canadian Environmental Assessment Agency (CEA Agency 2003) guidance requires that the quantities of GHG emissions be established for each phase of a project and that the proponent estimate the marginal contribution of the project emissions to the provincial and national emission totals. The operation of the proposed compressor stations will result in the majority of emissions. Additional GHG emissions include fugitive emissions from the piping infrastructure and venting from pipeline launching and receiving facilities during maintenance activities. Emissions from the installation of the compressor stations, and the commissioning phases, are very minor and are not quantified. 6.1 EMISSIONS OF GHGS Emissions of GHGs associated with the operation of the proposed Saturn 1&2 compressor station are provided in Table 6-1. The National and BC total GHG emissions are presented in Table 6-2. Compressor station operations represent 0.02% of Canadian GHG emissions totals for 2011, and 0.23 % of the BC total emissions for The 2011 emissions data represents the most recent, reviewed data available at the time of this assessment. 6.27

40 Greenhouse Gases Table 6-1 Greenhouse Gas Emissions from Compressor Station Operations Equipment Emission Quantity (tonnes per year) CO2 N2O CH4 CO2e Compressor Turbines 122, ,000 Boilers 3, ,950 Generator ,180 Total Emissions from Compressor Station Equipment 127, ,000 Fugitive Emissions a ,310 Total Compressor Station Emissions 128, ,000 SOURCE: NGTL 2013; RWDI 2011 a Fugitive emissions include venting from routine operations at the compressor station Table 6-2 Greenhouse Gas Emissions: Canada and British Columbia Year Estimated Total Greenhouse Gas Emissions Canadian Total (tonnes CO2-equivalent/year) BC Total (tonnes CO2-equivalent/year) ,000,000 59,100, ,000,000 59,900, ,000,000 49,400,000 SOURCES: Environment Canada PROPOSED PROJECT SENSITIVITIES TO CLIMATE CHANGE The conclusions of the proposed Project sensitivities to climate change (See section 6.2, Appendix I of the ESA ) are not materially affected by the Project refinements as described and assessed in this TDR. 6.28

41 Summary and Conclusions 7.0 Summary and Conclusions Stantec conducted an air quality assessment of the proposed Saturn 1&2 compressor station as additional Written Evidence (AWE) in support of the s.52 Application to the NEB by NOVA Gas Transmission Ltd. The air quality effects (ground-level concentrations) associated with emissions from the proposed compressor station were predicted using the AERMOD plume dispersion model. Emissions of greenhouse gases from the proposed units are also assessed consistent with Canadian Environmental Assessment Agency (CEA Agency 2003). Three cases were considered for the compressor station. The first includes emissions from nearby existing facilities (the Baseline Case). The second includes emissions from the operation of the proposed compressor station (the Project Case). The third includes the emissions from the Baseline Case plus the Project Case (the Application Case). In all three cases the maximum predicted concentrations of NO2, PM2.5 and CO plus the representative background concentrations are below the applicable ambient air quality objectives. The modelling shows that the operation of the proposed Saturn 1&2 compressor station contributes a small increment (2.95 µg/m 3 ) to existing NO2 concentrations on an annual average basis, at the location of the maxima (Baseline Case = µg/m 3 ; Application Case is 16.7 µg/m 3 ). In terms of the compressor station greenhouse gas emissions, annual carbon dioxide equivalent emissions are 0.02% of the Canadian total emissions for 2011, and 0.23% of the BC total emissions for

42 Summary and Conclusions Respectfully submitted, STANTEC CONSULTING LTD. Original signed by: Brian Bylhouwer, MRM Air Quality Scientist Reviewed by: Original signed by: John Walker, PhD Senior Associate Original signed by: Peter D. Reid, MA Principal

43 References 8.0 References BC HLS (British Columbia Ministry of Healthy Living and Sport) Air Quality Objectives and Standards, Revised April British Columbia Ministry of Healthy Living and Sport. April BC MOE (British Columbia Ministry of Environment) Guidelines for Air Quality Dispersion Modelling in British Columbia. British Columbia Ministry of Environment, March CEA Agency (Canadian Environmental Assessment Agency) Incorporating Climate Change Considerations in Environmental Assessment: General Guidance for Practitioners. Federal-Provincial-Territorial Committee on Climate Change and Environmental Assessment. Canadian Environmental Assessment Agency, November, Available at: Environment Canada National Inventory Report ( ): Greenhouse Gas Sources and Sinks in Canada Government of Canada Canada Gazette, Part 1, Vol. 147, No.21, Canadian Ambient Air Quality Standards (CAAQS) for PM2.5 and Ozone. RWDI Hidden Lake North and Moody Creek Compressor Stations: Final Report Updated Air Quality and Greenhouse Gas Assessment. NGTL (NOVA Gas Transmission Ltd.) Communication, Compressor Station Plot Plans & Source Emissions Data. U.S. EPA (United States Environmental Protection Agency) A Brief Description of the AERMOD. United States Environmental Protection Agency, Office of Air Quality Planning and Standards, Emissions, Monitoring, and Analysis Division, Research Triangle Park, North Carolina. U.S. EPA. 2004a. User s Guide for the AERMOD Terrain Preprocessor (AERMAP). Office of Air Quality Planning and Standards, Emissions, Monitoring, and Analysis Division, Research Triangle Park, North Carolina. EPA-454/B October U.S. EPA. 2004b. User s Guide for the AERMOD meteorological Preprocessor (AERMET). Office of Air Quality Planning and Standards, Emissions, Monitoring, and Analysis Division, Research Triangle Park, North Carolina. EPA-454/B November U.S. EPA. 2004c. User s Guide for the AMS/EPA Regulatory model - AERMOD. Office of Air Quality Planning and Standards, Emissions, Monitoring, and Analysis Division, Research Triangle Park, North Carolina. EPA-454/B September

44 References U.S. EPA Addendum User s Guide for the AMS/EPA Regulatory model - AERMOD. Office of Air Quality Planning and Standards, Emissions, Monitoring, and Analysis Division, Research Triangle Park, North Carolina. December U.S. WRAP, 2012 West-wide Jump Start Air Quality Modeling Study (WestJumpAQMS) WRF Application/Evaluation prepared by ENVIRON International Corporation, Alpine Geophysics, LLC and the University of North Carolina (February 29, 2012). United States (U.S.) Western Regional Air Partnership (WRAP). 8.1 INTERNET SOURCES BC MOE Online Air Quality Data. Available at: Clean Air Strategic Alliance (CASA) Data Warehouse: Data Reports. Available at: Environment Canada National Climate Data and Information Archive: Canadian Climate Normals or Averages Available at: Health Canada National Ambient Air Quality Objectives (NAAQOs). Available at: Health Canada Regulations Related to Health and Air Quality. Available at: National Aeronautics and Space Administration (NASA) Shuttle Radar Topography mission: The mission to map the World. Available at: US EPA AP42, Fifth Edition, Compilation of Air Pollutant Emission Factors, Volume 1: Stationary Point and Area Sources. Section 1.4: Natural Gas Combustion. Available at: US EPA AP42, Fifth Edition, Compilation of Air Pollutant Emission Factors, Volume 1: Stationary Point and Area Sources. Section 3.1 Stationary Gas Turbines and Section 3.2: Natural Gas-fired Reciprocating Engines. Available at:

45 Appendix A Report Figures

46

47 Proposed Saturn 1&2 Compressor Station Shell Gas Processing Facility Elevation (m) Terrain Elevations within the Project Area (Saturn 1&2 Compressor Station) PROJECTION DATUM DATE UTM NAD 83 - ZONE 10 March 5, 2014 DRAWN BY CHECKED BY FIGURE NO. BRB RP Fig. A-1

48 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month of Year Daily Average Temperature ( C) Daily Maximum ( C) Daily Minimum ( C) Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month of Year Extreme Maximum ( C) Extreme Minimum ( C) Historical Mean Daily and Extreme Temperatures Surrounding the Proposed Saturn 1&2 Compressor Station PROJECTION DATUM DATE UTM NAD 83 - ZONE 10 March 5, 2014 DRAWN BY CHECKED BY FIGURE NO. BRB RP Fig. A-2

49 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Rainfall (mm) Precipitation (mm) Historical mean Monthly Rainfall, Snowfall, and Total Precipitation Surrounding the Proposed Saturn 1&2 Compressor Station Snowfall (cm) PROJECTION DATUM DATE UTM NAD 83 - ZONE 10 March 5, 2013 DRAWN BY CHECKED BY FIGURE NO. BRB RP Fig. A-3

50 Proposed Saturn 1&2 Compressor Station Shell Gas Processing Facility Elevation (m) Legend Receptor Terrain Elevations And Receptor Grid for Saturn 1&2 Compressor Station PROJECTION UTM DATUM NAD 83 - ZONE 10 DATE March 5, 2014 DRAWN BY BRB CHECKED BY --- FIGURE NO. Fig. A-4

51 Boiler Generator Generator Skid Compressor Turbine Compressor Building Mechanical Skid Personnel Skid Control Skid Heated Storage Building Proposed Saturn 1&2 Compressor Station Shell Saturn Gas Plant Switchgear Compressor Power Turbine Generation Electrical Fuel Gas Communication Shop Office Generator Heater VRU Genset Mechanical Inlet Separator Liquids metering Compressor Refrigeration Recycle Compression Sales Gas HP/LP Flare Legend Building Emission Source Property Boundary Simplified Plot Plan and Project and Regional Air Emission Sources PROJECTION UTM DATUM NAD 83 - ZONE 10 DATE March 5, 2014 DRAWN BY CHECKED BY FIGURE NO. BRB --- Fig. A-5

52

53 Appendix B Appendix B Climate and Meteorology of the Assessment Area

54

55 Appendix B Climate and Meteorology of the Assessment Area Appendix B Climate and Meteorology of the Assessment Area B.1 INTRODUCTION Stantec has analyzed the meteorological data that were used in the dispersion modelling for the North Montney Project at Saturn Units 1& 2. One year of meteorological model data from January 1, 2010 to December 31, 2010 were used in the dispersion modelling. The selection of a one-year period is consistent with the Guidelines for Air Quality Dispersion Modelling in British Columbia (BC MOE 2009) that requires data for a one-year period when using data from a prognostic model. The AERMOD meteorological pre-processor, AERMET, was used to process the meteorological dataset used in dispersion modelling. AERMET is designed to accept data from any for the following sources: (1) standard hourly Environment Canada Weather data from the most representative site; (2) morning soundings of winds, temperature, and dew point from the nearest Environment Canada upper air station; and, (3) on-site wind, temperature, turbulence, pressure, and radiation measurements (if available). As there are no hourly surface meteorological stations and nearby upper air stations in the assessment area, one year Weather Research and Forecasting (WRF) model data from January 1, 2010 to December 31, 2010 was used. The National Centers for Environmental Prediction (NCEP) 32 km resolution North American Regional Reanalysis (NARR) gridded analysis data were used as input to the Version 3 of WRF model to produce a one-year (2010) meteorological data on a 4 km grid resolution using the Stantec high performance computing cluster. EPA Mesoscale Model Interface Program (MMIF) program was used to extract AERMET readable input surface and upper air files from the 4 km grid resolution WRF model output. AERMET is used to estimate two stability parameters, friction velocity and Monin-Obukhov length, to characterize the amount of turbulence in the atmosphere. The friction velocity is a measure of mechanical effects alone, such as wind shear at ground-level. The Monin-Obukhov length indicates the relative strengths of mechanical and buoyancy effects on atmospheric turbulence. Thus, AERMOD can account for turbulence both from wind shear and from buoyancy effects due to solar heating during the day and radiational cooling at night. To properly account for these effects, AERMET requires three land use parameters: albedo, Bowen ratio, and surface roughness. Albedo is defined as the fraction of total incident solar radiation reflected by a particular surface without absorption. Bowen ratio is an indicator of surface moisture conditions and can be defined as the ratio of the sensible heat flux to the latent heat flux. Surface roughness is a length scale that characterizes the roughness of the earth s surface. For this assessment, site-specific values for albedo, Bowen ratio, and surface roughness were selected based on land use surrounding the facility and Guidelines for Air Quality Dispersion Modelling in BC (BC MOE, 2008). Considering the surface characteristics surrounding the compressor station, one wind direction sector (0 to 360) was used in AERMET stage 3 run. B.1

56 Appendix B Average values for deciduous and coniferous forest type surface parameters were selected and are presented in Table B-1. The values of each parameter were varied as a function of month of year to account for the changes surface characteristics of the growing seasons and snow cover. Table B-1 Surface Parameters Applied in AERMET Processing Month Surface Roughness (m) Albedo Bowen Ratio January February March April May June July August September October November December The meteorological data used to run AERMOD (as output from AERMET) can be summarized in terms of its major parameters: ambient temperature, wind speed and direction, atmospheric stability, and mixing height. The following sections discuss these parameters and present the results of analyses performed on the meteorological dataset. The three major components of the meteorological data that were analyzed are ambient temperature, winds and atmospheric stability. The following sections discuss these components and present the results of analyses performed on the meteorological dataset. B.2 CLIMATE AND METEOROLOGY B.2.1 Ambient Temperature Average and median surface temperatures extracted from the WRF model data for January 1, 2010 to December 31, 2010 are provided in Table B-2. Average surface temperatures for winter, spring, summer, and autumn were equal to -9.4, 1.4, 12.5, and 2.4 respectively for the Saturn 1&2 assessment area. Extreme minimum and maximum temperatures for the one-year period for the Saturn 1&2 assessment area were and 24.1, respectively. B.2

57 Appendix B Climate and Meteorology of the Assessment Area Table B-2 Average and Median Surface Temperatures for the Region of the Saturn 1&2 Compressor Site Based on WRF Model Data from January 1, 2010 to December 31, 2010 Season a Average Air Temperature ( C) Median Winter Spring Summer Autumn NOTE: a B.2.2 Winter: December, January, and February. Spring: March, April, and May. Summer: June, July, and August. Autumn: September, October and November Wind Figure B-1 shows the frequency distributions of hourly average wind speed based on the WRF model data from January 1, 2010 to December 31, 2010 for the proposed Saturn 1&2 compressor site. For 60.5% of the time, wind speeds were less than 4.0 m/s. Wind roses are an efficient and convenient means of presenting wind data. The length of the radial barbs gives the total percent frequency of winds from the indicated direction, while portions of the barbs of different widths indicate the frequency of associated wind speed categories. Figure B-2 presents the annual wind rose for the proposed Saturn 1&2 compressor site. Winds from the west southwest, southwest and west were the most dominant and prevailing winds for the area. B.3

58 Appendix B 45 Wind Class Frequency Distribution % Calms >= 10.0 Wind Class (m/s) Figure B-1 Frequency Distribution of Hourly Average Wind Speed for the proposed Saturn 1&2 Compressor Site Based on WRF Model Data from January 1, 2010 to December 31, 2010 B.4

59 Appendix B Climate and Meteorology of the Assessment Area NORTH 20% 16% 12% 8% WEST 4% EA ST WIND SPEED (m/s) SOUTH >= Calms: 1.43% Figure B-2 Annual Wind Rose of Hourly Average Wind Speed and Direction for the proposed Saturn 1&2 Compressor Station Site Based on WRF Model Data from January 1, 2010 to December 31, 2010 B.2.3 Atmospheric Stability Atmospheric turbulence near the earth s surface is a function of atmospheric stability, which is governed by thermal and mechanical influences. The atmosphere can be broadly described as being stable, neutral, or unstable. During night-time hours, the earth s surface emits thermal radiation and cools. Air in contact with the ground thus becomes cooler and denser than the air aloft. This phenomenon is referred to as a ground-based temperature inversion. Vertical motions of the atmosphere are suppressed and the atmosphere is described as stable. This contrasts with daytime situations when the sun heats the ground. Air in contact with the ground becomes warmer and less dense than the air aloft. Vertical motions of the atmosphere are enhanced and the atmosphere is said to be unstable. When a balance exists between incoming and outgoing B.5

60 Appendix B radiation, there is no net heating or cooling of the air in contact with the ground and vertical motions of the atmosphere are neither enhanced nor suppressed. Such an atmosphere is described as neutral and exists during overcast skies or in transition from unstable to stable conditions. Mechanical mixing may also create neutral atmospheres generated by strong winds. Figure B-3 presents the frequency distribution of atmospheric stability with time of day for meteorological data applied in dispersion modelling for the Saturn 1&2 compressor site. Generally, highly and moderately unstable conditions are dominant from early morning (approximately 9:00) to early evening (approximately 16:00) while neutral and stable conditions occur most often during night-time. Stability Distribution with Time of Day Frequency (%) 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Hour Highly Convective Mod. Convective Neutral Stable Figure B-3 Frequency Distribution of Atmospheric Stability with Time of Day at the Proposed Saturn 1&2 Compressor Site from January 1, 2010 to December 31, 2010 B.6

61 Appendix B Climate and Meteorology of the Assessment Area B.2.4 Mixing Height Strong solar heating or strong winds can create a two-layered atmosphere. The lower layer is well mixed and characterized by either neutral or unstable conditions; the upper layer is characterized by stable conditions (elevated temperature inversion). Vertical motions in the upper layer are damped, which effectively prevents the transfer of air between the two layers. The depth of this lower atmospheric boundary layer is defined as the mixing height. Thus, emissions injected into the mixing layer may become trapped if they do not have enough buoyancy or momentum to penetrate the elevated stable layer. This leads to the classical trapping situation that is often associated with poor air quality. Mechanical interactions result in mixing of air by roughness at the surface of the earth. Surface roughness can be due to topography, forests, or buildings. Heights of the mechanically mixed layer are location dependent and proportional to wind speed. Atmospheric thermal interactions are caused by the effects of solar radiation. During the day, unstable conditions are created by radiation from the sun. This creates warmer, less dense air that rises, while cooler, more dense air from above sinks to ground level. As air rises, it expands and cools. Upward motion ceases at the height where rising air reaches the same temperature as surrounding air. This height is called the convective mixing height. It is dependent on the intensity of solar radiation and vertical temperature characteristics of the air mass. Mixing heights vary from several tens of metres to several thousands of metres, depending on the intensity of solar radiation reaching the earth s surface and wind speed. Mixing heights are much greater during the spring and summer than the winter. Maximum mixing heights usually occur during late-afternoon hours when the effects of solar heating are greatest, while minimum heights occur at night. B.7

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63 Appendix C Dispersion Modelling Isopleths

64

65 Proposed Saturn 1&2 Compressor Station Shell Gas Processing Facility Legend 3 Maximum Predicted One-hour Ground Level NO2 Concentrations (mg/m3) for the Baseline Case One-hour NO2 AAQO = 400 mg/m3 PROJECTION DATUM DATE UTM NAD 83 - ZONE 10 March 5, 2014 DRAWN BY BRB CHECKED BY FIGURE NO. JIW Fig. C-1

66 Proposed Saturn 1&2 Compressor Station Shell Gas Processing Facility Legend 3 Maximum Predicted 24-hour Ground Level NO2 Concentrations (mg/m3) for the Baseline Case 24-hour NO2 AAQO = 200 mg/m3 PROJECTION DATUM DATE UTM NAD 83 - ZONE 10 March 5, 2014 DRAWN BY BRB CHECKED BY FIGURE NO. JIW Fig. C-2

67 Proposed Saturn 1&2 Compressor Station Shell Gas Processing Facility Legend 3 Maximum Predicted Annual Ground Level NO2 Concentrations (mg/m3) for the Baseline Case Annual NO2 AAQO = 100 mg/m3 PROJECTION DATUM DATE UTM NAD 83 - ZONE 10 March 5, 2014 DRAWN BY BRB CHECKED BY FIGURE NO. JIW Fig. C-3

68 Proposed Saturn 1&2 Compressor Station Shell Gas Processing Facility Legend 3 Maximum Predicted One-hour Ground Level NO2 Concentrations (mg/m3) for the Project Case One-hour NO2 AAQO = 400 mg/m3 PROJECTION DATUM DATE UTM NAD 83 - ZONE 10 March 5, 2014 DRAWN BY BRB CHECKED BY FIGURE NO. JIW Fig. C-4

69 Proposed Saturn 1&2 Compressor Station Shell Gas Processing Facility Legend 3 Maximum Predicted 24-hour Ground Level NO2 Concentrations (mg/m3) for the Project Case 24-hour NO2 AAQO = 200 mg/m3 PROJECTION DATUM DATE UTM NAD 83 - ZONE 10 March 5, 2014 DRAWN BY BRB CHECKED BY FIGURE NO. JIW Fig. C-5

70 Proposed Saturn 1&2 0.2 Station Compressor Shell Gas Processing Facility Legend 3 Maximum Predicted Annual Ground Level NO2 Concentrations (mg/m3) for the Project Case Annual NO2 AAQO = 100 mg/m3 PROJECTION DATUM DATE UTM NAD 83 - ZONE 10 March 5, 2014 DRAWN BY BRB CHECKED BY FIGURE NO. JIW Fig. C-6

71 Proposed Saturn 1&2 Compressor Station Shell Gas Processing Facility Legend 3 Maximum Predicted One-hour Ground Level NO2 Concentrations (mg/m3) for the Application Case One-hour NO2 AAQO = 400 mg/m3 PROJECTION DATUM DATE UTM NAD 83 - ZONE 10 March 5, 2014 DRAWN BY BRB CHECKED BY FIGURE NO. JIW Fig. C-7

72 Proposed Saturn 1&2 Compressor Station Shell Gas Processing Facility Legend 3 Maximum Predicted 24-hour Ground Level NO2 Concentrations (mg/m3) for the Application Case 24-hour NO2 AAQO = 200 mg/m3 PROJECTION DATUM DATE UTM NAD 83 - ZONE 10 March 5, 2014 DRAWN BY BRB CHECKED BY FIGURE NO. JIW Fig. C-8

73 Proposed Saturn 1&2 Compressor Station Shell Gas Processing Facility Legend 3 Maximum Predicted Annual Ground Level NO2 Concentrations (mg/m3) for the Application Case Annual NO2 AAQO = 100 mg/m3 PROJECTION DATUM DATE UTM NAD 83 - ZONE 10 March 5, 2014 DRAWN BY BRB CHECKED BY FIGURE NO. JIW Fig. C-9