AIR QUALITY ASSESSMENT FOR THE PROPOSED HALTON HILLS GENERATING STATION

Transcription

1 DRAFT SUPPORTING DOCUMENT 1 AIR QUALITY ASSESSMENT FOR THE PROPOSED HALTON HILLS GENERATING STATION Prepared For: Prepared By: SENES Consultants Limited September 2006

2 SUPPORTING DOCUMENT 1 AIR QUALITY ASSESSMENT FOR THE PROPOSED HALTON HILLS GENERATING STATION DRAFT Prepared for: Prepared by: SENES Consultants Limited 121 Granton Drive, Unit 12 Richmond Hill, Ontario L4B 3N4 September 2006

3 ARTIST S RENDITION OF HALTON HILLS GENERATING STATION Final Rendering in progress.

4 EXECUTIVE SUMMARY TransCanada Energy Ltd. (TCE) will plan, develop, own, and operate the proposed Halton Hills Generating Station (HHGS). The proposed HHGS is a 680 Megawatt (MW) natural gas fuelled, combined cycle facility that will be located on undeveloped, industrial lands in the 401 industrial corridor in the Town of Halton Hills on a site located between Highway 401 and Steeles Avenue west of 6 th Line. The HHGS is being developed in response to the Ontario Power Authority s (OPA) planned procurement for new generation in the Greater Toronto Area West of Toronto Request for Proposals No.: 2006-GTA-West-Trafalger-RFP-2006 Issued: April 28, The proposed HHGS will generate power using state-of-the-art combustion turbine technology. The proposed HHGS is a natural gas fuelled 2 x 1 combined cycle power plant capable of generating a nominal 680 MW of electricity. The nominal 680 MW is derived from two 190 MW gas turbine generator sets, two heat recovery steam generators (HRSGs), and one 300 MW steam turbine generator (STG). The steam leaving the STG exhaust is condensed using an Air Cooled Condenser (ACC). The equipment will be monitored and controlled from a central control room, and will be designed to meet all applicable municipal, provincial, and national standards. The proposed HHGS is subject to an environmental screening as defined under the Ontario Ministry of the Environment s Guide to Environmental Assessment Requirements for Electricity Projects (March 2001). This Air Quality Assessment is being undertaken as part of the environmental screening process. The principal contaminant released during operation of the two 190 MW natural gas fuelled combustion turbine generator sets, the auxiliary boiler, and the standby diesel generator is nitrogen oxides (NO x ). Minor contaminants are particulate matter (PM), sulphur dioxide (SO 2 ) and carbon monoxide (CO). Operation of this equipment will also release trace quantities of volatile organic compounds (VOCs) and polycyclic aromatic hydrocarbons (PAHs). As with the combustion of any fossil fuel, there are atmospheric releases of greenhouse gases, predominately carbon dioxide (CO 2 ). The enhanced thermal efficiency of the combined cycle produces lower atmospheric emissions on a MW of power produced basis. The proposed gas turbines will be using dry low NO x (DLN) combustion technology, which reduces the formation of N 2 O. Conservative emission estimates of the above mentioned contaminants were based on information supplied by the equipment manufacturers or recognized emission factors for different operating scenarios. The various operational scenarios were assessed to determine the worst-case emission scenarios (maximum emission rates) for both short term (1 hour) and long term (24 hour, annual) operational conditions. Air dispersion modelling using a government DRAFT September 2006 ES-1 Halton Hills Generating Station

5 approved model was conducted to estimate the incremental impact of the proposed HHGS on the existing environment. Meteorological data used in the dispersion modelling analysis was obtained from the Toronto Lester B. Pearson International Airport meteorological monitoring station ( ). An analysis of the existing air quality found that local air quality has a significant loading of NO x, and PM. Particulate matter is measured in several size fractions. Suspended particulate matter (SPM) is all of the particulate matter with aerodynamic diameters less than 44 microns (µm). PM 10 is particulate matter with aerodynamic diameters less than 10 µm and PM 2.5 is particulate matter with aerodynamic diameters less than 2.5 µm. The predicted incremental concentrations of conventional pollutants resulting from the proposed HHGS were found to be below all of the applicable criteria. As would be expected, the 1 hour concentration of NO x has the greatest impact on the environment but is still less than the MOE Point of Impingement (POI) criterion. It should be noted that adding the incremental concentrations to the estimated site background concentrations also results in ambient concentrations below the associated air quality criteria. These results are conservative as maximum emission scenarios were used, which are not expected to occur regularly, if ever. In addition very conservative estimates of background concentrations were used in the assessment. For NO x, SO 2, CO and SPM the predicted annual incremental concentrations were found to be only a small fraction of the ambient concentrations in Toronto. It was conservatively assumed that all of the particulate matter from all sources was PM 2.5, as the emissions are all by-products of combustion. A screening level analysis showed that the emissions of VOCs and PAHs result in very low ambient levels, significantly below their applicable criteria. The potential human health and ecological effects of these trace contaminants are discussed in Supporting Document 5. The predicted concentrations presented represent the maximum predicted values. For example, the maximum 1 hour average concentrations are those modelled concentrations that are predicted to occur only once in the 5 years of meteorological data used. The annual average concentrations shown in the tables are more representative of the average contributions from the proposed HHGS. Predicted impacts for the proposed HHGS are well within all applicable criteria. On an annual basis, the incremental impact of the proposed HHGS on the existing air quality is predicted to be small, with less than a 4% increase above background for NO x under maximum conditions. No mitigative measures are required beyond the DLN combustion technology featured in the gas turbine packages. Continuous emissions monitors (CEM) will be installed on each of the combustion turbine stacks to measure NO x, CO and O DRAFT September 2006 ES-2 Halton Hills Generating Station

6 Water produced from the combustion of natural gas could possibly result in a visible steam plume from the main stacks during the cold winter months and other infrequent weather conditions. Due to the height of these stacks and the use of an ACC there are anticipated to be no concerns regarding fogging and icing. Emissions of greenhouse gases are reduced as compared to many other electrical generation facilities due to the use of natural gas, the efficient heat recovery system, and the use of low NO x burner technology. Under Article V of the Ozone Annex to the Canada-U.S. Air Quality Agreement, Canada is obligated to notify the U.S. of any project that is within 100 km of the Canada-U.S. border that has an estimated NO x, SO 2, CO, SPM, or VOC emission rate of greater than 90 tonnes per year. Notification is also required if the proposed project will result in releases of greater than 1 tonne per year of any one hazardous air pollutant (HAP). The Canada-U.S. border is located approximately 55 km southeast of the proposed HHGS, in the middle of Lake Ontario. The notification form is included as Appendix D. Due to the low levels of NO x emitted from the proposed HHGS and the existing levels of NO x in the surrounding areas, no appreciable changes in ozone levels are expected as a result of this project. To reduce dust emissions during the construction phase, effective dust suppression techniques, such as on-site watering, street and parking lot cleaning, and limiting the speed of vehicles travelling on the roads, will be used. No other mitigative measures are required. Negligible net effects are anticipated DRAFT September 2006 ES-3 Halton Hills Generating Station

7 TABLE OF CONTENTS Page No. EXECUTIVE SUMMARY...ES-1 ACRONYMS...AC INTRODUCTION Project Description Key Equipment Likely Interactions of the Project on the Environment Assessment Criteria Notification Criterion EXISTING ENVIRONMENTAL CONDITIONS Climate and Meteorological Data Near-Surface Temperature Precipitation Stability Wind Direction Wind Speed Mixing Height Existing Air Quality Historical Ambient Monitoring Data ATMOSPHERIC EMISSIONS Combustion of Natural Gas Conventional Pollutants VOCs and PAHs Greenhouse Gas Emissions Combustion of Diesel Fuel Conventional Pollutants Trace VOCs and PAHs Startup vs. Continuous Operation Operating Scenarios Considered Summary of Conventional Pollutant Emission Rates Summary of Trace VOCs and PAHs Annual Emissions Annual Emissions of Conventional Pollutants Annual Emissions of Greenhouse Gases Ozone Formation Visible Plumes, Fogging, and Icing Construction Phase AIR DISPERSION MODELLING Modelling Methodology AERMOD-PRIME Dispersion Model DRAFT September 2006 i Halton Hills Generating Station

8 5.0 MODELLING RESULTS Conventional Pollutants Trace VOCs and PAHs Visible Plumes, Fogging and Icing Ozone Formation MITIGATIVE MEASURES CONCLUSIONS REFERENCES...R-1 APPENDIX A APPENDIX B APPENDIX C APPENDIX D TORONTO AMBIENT AIR QUALITY STATISTICS PREDICTED INCREMENTAL ANNUAL GROUND LEVEL AIR CONCENTRATION SAMPLE EMISSION RATE CALCULATIONS CANADA/U.S. AIR QUALITY AGREEMENT NOTIFICATION FORM DRAFT September 2006 ii Halton Hills Generating Station

9 LIST OF TABLES Page No. Table 1.1 Air Quality Criteria for Conventional Pollutants Table 1.2 Air Quality Criteria for Trace VOCs and PAHs Table 2.1 Toronto Lester B. Pearson International Airport Climate Normals ( ) Table 2.2 Stability Class Distribution Toronto Lester B. Pearson International Airport Table 2.3 Parameters Measured at Local MOE AQ Stations Table 2.4 Representative Background Air Concentrations ( ) Table 2.5 Frequency Of Exceedance Of Moe Aaqc At Local Moe Aq Table 3.1 Emission Rates Used to Develop Scenarios Table 3.2 Scenario 1 - Maximum Annual Emission Rates Table 3.3 Scenario 2 Predicted Actual Operating Annual Emission Rates Table 3.4 Scenario 3 Maximum 24 Hour Emission Rates Table 3.5 Scenario 4 Emergency Diesel Generator Hourly Testing EmissionS Table 3.6 Scenario 5 Maximum Base Load 1 hour Emission Rates Table 3.7 Scenario 6 Maximum Base Load and Startup 1 hour Emission Rates Table 3.8 Summary of Maximum Conventional Pollutant Emission Rates Table 3.9 MOE Stationary Combustion Turbine Guideline Limits Table 3.10 National New Thermal Power Plant Guideline Limits Table 3.11 Summary of Annual Trace VOCs and PAHs Emission Rates (g/s) Table 3.12 Estimated Maximum Annual Emission Rates Table 4.1 Source Parameters used in Modelling Table 4.2 Dimension of Dominant Buildings Table 5.1 Modelled Conventional Pollutant Maximum Incremental Concentrations Table 5.2 Maximum 1 Hour Acrolein Emission Rates (g/s) Table 5.3 Predicted Annual Average Concentrations of Trace VOCs and PAHs (µg/m 3 ) LIST OF FIGURES Page No. Figure 1.1 Proposed HHGS Site Vicinity Figure 1.2 Proposed HHGS Site Location Figure 2.1 Wind Rose Toronto Lester B. Pearson International Airport Figure Location of Local Ambient Air Quality Monitoring Stations Figure 4.1 Air Dispersion Modelling Grid Figure 4.2 Isometric View of the Proposed hhgs Figure 4.3 Scaled Site Plan DRAFT September 2006 iii Halton Hills Generating Station

10 ACRONYMS Air Quality Assessment for the Proposed Halton Hills Generating Station Acronym µg/m 3 AAQC AP-42 CCME CEM CEPA CO CO 2 DLN EC EPA G.S. GT GWP H 2 O H 2 SO 4 ha HAP HCl HHGS HRSG IMO kg km kv kwh lb MAL m mg micron MMBtu MOE MW MWh N 2 O NAAQO NAD Description micrograms per cubic metre Ambient Air Quality Criteria U.S. EPA Compilation of Air Pollution Emission Factors Version 5 Volume 1: Stationary Point and Area Sources AP-42. Canadian Council of Ministers of the Environment Continuous Emissions Monitor Canadian Environmental Protection Act Carbon Monoxide Carbon Dioxide Dry Low NO x Environment Canada Environmental Protection Act Generating Station Gas Turbine Global Warming Potential water sulphuric acid hectares Hazardous Air Pollutant hydrochloric acid Halton Hills Generating Station Heat Recovery Steam Generator Independent Electricity Market Operator kilogram (1000 grams) Kilometre (1000 metres) kilovolt kilowatt-hour pound Maximum Acceptable Limit metre milligram (10-3 grams) micrometre (10-6 metres) Million British Thermal Units Ontario Ministry of the Environment Megawatt (million Watts) Megawatt-hour Nitrous Oxide National Ambient Air Quality Objectives North American Datum DRAFT September 2006 AC-1 Halton Hills Generating Station

11 Acronym Description NH 3 Ammonia NO Nitric Oxide NO 2 Nitrogen Dioxide NO x Nitrogen Oxides O 3 Ozone O. Reg. 419/05 Ontario Regulation 419/05 PAH Polycyclic Aromatic Hydrocarbons POI Point of Impingement PM Particulate Matter PM 10 Particulate Matter less than 10 microns in diameter - inhalable PM 2.5 Particulate Matter less than 2.5 microns in diameter - respirable S sulphur scfm standard cubic feet per minute SCR Selective Catalytic Reduction SO 2 sulphur dioxide SPM Suspended Particulate Matter STG Steam Turbine Generator TCE TransCanada Energy Ltd. U.S.EPA United States Environmental Protection Agency UTM Universal Transverse Mercator VOC Volatile Organic Compounds DRAFT September 2006 AC-2 Halton Hills Generating Station

12 1.0 INTRODUCTION TransCanada Energy Ltd. (TCE) will plan, develop, own, and operate the proposed Halton Hills Generating Station (HHGS). The proposed HHGS is a 680 Megawatt (MW) natural gas fuelled, combined cycle facility that will be located on undeveloped, industrial lands in the 401 Industrial Corridor in the Town of Halton Hills on a site located between Highway 401 and Steeles Avenue, west of 6 th Line. Figure 1.1 depicts the site location and vicinity, and Figure 1.2 shows a closer view of the site and the immediate surrounding area. FIGURE 1.1 PROPOSED HHGS SITE VICINITY Mississauga Proposed Halton Hills Generating Station Milton DRAFT September Halton Hills Generating Station

13 FIGURE 1.2 PROPOSED HHGS SITE LOCATION Proposed Halton Hills Site Note: The property boundary of the proposed Halton Hills site shown in the above figure is approximate. The proposed HHGS is being developed in response to the Ontario Power Authority s (OPA) planned procurement for new generation in the Greater Toronto Area West of Toronto Request for Proposals No.: 2006-GTA-West-Trafalger-RFP-2006 Issued: April 28, The proposed HHGS will be designed to generate power efficiently, with little or no effect on the natural and human environment. The proposed HHGS will be a natural gas fuelled 2 x 1 combined cycle power plant that will be capable of generating a nominal 680 MW of electricity. The nominal 680 MW will be derived from two 190 MW gas turbine generator sets, two heat recovery steam generators (HRSGs), and one 300 MW steam turbine generator (STG). It should be noted that to be conservative the contaminant emission rates were based upon the maximum capacity of the gas turbines, which is 199 MW. The steam leaving the STG exhaust is condensed using an Air Cooled Condenser (ACC). Equipment will be monitored and controlled from a central control room, and will be designed to meet all applicable municipal, provincial, and national standards DRAFT September Halton Hills Generating Station

14 The proposed HHGS is subject to an environmental screening as defined under the Ontario Ministry of the Environment s Guide to Environmental Assessment Requirements for Electricity Projects (March 2001). This Air Quality Assessment is being undertaken in support of the environmental review process and permitting requirements under the Environmental Protection Act. 1.1 PROJECT DESCRIPTION The proposed HHGS is a proposed 680 megawatt (MW) natural gas fuelled, combined cycle facility. The proposed HHGS site occupies approximately 34 ha of land of which 10 ha will be occupied by the generating station and its associated facilities. The land is owned by TCE. Water will be brought to the site by the municipal water system and waste water will leave the site through the municipal sanitary sewage system. Electricity produced at the proposed HHGS will be run through step-up transformers in order to elevate the voltage to 230kV. A 1.3 km connection would then be made from the proposed HHGS transformers to the Hydro One Networks Inc. (Hydro One) transmission lines (T38B & T39B). Underground transmission lines will transmit the power from the proposed HHGS to the connection point. Natural gas for the proposed HHGS will be provided via the natural gas distribution network of Union Gas at the Parkway Interchange. A new natural gas pipeline will be routed from the Interchange to the site by Union Gas. The pressure at which the natural gas is delivered to the site is high enough to meet the requirements of the gas turbines; therefore, on-site gas compression is not required. More details on the proposed HHGS may be found in the ERR DRAFT September Halton Hills Generating Station

15 1.2 KEY EQUIPMENT The proposed undertaking will consist of the following key pieces of equipment: Two Siemens Model SGT-PAC 5000F gas turbine generator sets with a reported output of 190 MW each using natural gas as the only fuel. Each gas turbine is equipped with a Dry Low NO x (DLN) combustion system that has a nominal natural gas firing rate of 56,820 m 3 /hr * or roughly 2117 * GJ/hr (HHV). The gas turbines are also equipped with evaporative coolers to chill inlet air. Two horizontal HRSGs in multiple-pressure configuration which generate steam to feed the STG. Each HRSG produces a nominal 465,000 kg/hr * of steam without duct firing and 675,000 kg/hr * with maximum duct firing. Two sets of low NO x duct burners, one in each HRSG. Each duct burner has a maximum natural gas firing rate of 11,055 m 3 /hr * or 412 GJ/hr (HHV). The total maximum exhaust flow rate through each HRSG stack (including that of the gas turbine and assuming duct burners are at 100%) is about 515 m 3 /s *. Each HRSG stack has an inner diameter of about 6.1 m and extends 61 m above grade. One three casing arrangement, three pressure, single reheat double flow STG rated nominally at 300 MW. One multi fan steam to air heat exchange Air Cooled Condenser (ACC) (essentially a large bank of fans used for air cooling). One natural gas fuelled auxiliary boiler equipped with low NO x burners with a nominal rating of 11,800 kg/hr of steam at a heat input of 34 GJ/hr (HHV), exhausting to the atmosphere through a stack at a rate of 6.8 m 3 /s and a temperature of 149 C having an exit diameter of 0.76 m and extending 40 m above grade. One standby diesel generator rated at 1.8 MW (heat input 17 GJ/hr (HHV), firing diesel fuel at a maximum rate of 465 L/hr and exhausting at a maximum flow rate of 8.5 m 3 /s, through a stack of 0.51 m in diameter and extending 23 m above grade. It will be tested for approximately 2 hours per week during normal operation of the plant. Natural gas fuelled roof mounted comfort heaters for the main building with a total capacity of 28 GJ/hr. 1.3 LIKELY INTERACTIONS OF THE PROJECT ON THE ENVIRONMENT The proposed project consists of two natural gas fuelled combustion turbine generator sets, an auxiliary boiler, and a standby diesel generator which will supply power to the station to allow for the safe shutdown of the turbines in an emergency. * Values are at average conditions, of 7.5 C and 75% Relative Humidity DRAFT September Halton Hills Generating Station

16 The principal contaminant released during operation of this equipment is nitrogen oxides (NO x ). Minor contaminants are particulate matter (PM), sulphur dioxide (SO 2 ) and carbon monoxide (CO). There will be trace emissions of volatile organic compounds (VOCs) and polycyclic aromatic hydrocarbons (PAHs). As with the combustion of any fossil fuel, there are atmospheric emissions of greenhouse gases, predominately carbon dioxide (CO 2 ). The NO x releases from the proposed HHGS could affect the formation of ground level ozone downwind of the site. However, due to the small mass of NO x being released from the proposed HHGS in comparison to the mass of NO x being released from all of the stationary and mobile sources in the surrounding areas, such as Mississauga and Brampton, together with the level of NO x that arrives as a result of transboundary flow, the effect on ground level ozone is expected to be insignificant. The proposed HHGS has been designed such that there will be no steam releases to atmosphere during normal operating conditions. Steam will be directed to the ACC to be recycled. 1.4 ASSESSMENT CRITERIA Environment Canada (EC) and the Ontario Ministry of Environment (MOE) have set air quality objectives, air quality standards and criteria, respectively. Ontario Regulation 419/05 (O. Reg. 419/05) defines maximum concentration levels for various chemicals at a Point of Impingement (POI). A specific definition of POI is not provided in O. Reg. 419/05; however, MOE (1984) provides the following description: The point of impingement, which is used in a calculation to assess the compliance of an emission source, must have some significance, i.e. there must be somebody or something there that can be adversely affected. The POI is the off-property location at which the maximum concentration of a given contaminant occurs. Section 14 of the Environmental Protection Act (EPA) prohibits the causing (or likely causing) of an adverse effect. The definition for adverse effect in the EPA includes: 1) impairment of the quality of the natural environment for any use that can be made of it; and, 2) loss of enjoyment of normal use of property. Ontario Regulation 337 sets desirable Ambient Air Quality Criteria (AAQC) for various pollutants. The Standards Development Branch of the MOE publishes a set of standards, DRAFT September Halton Hills Generating Station

17 guidelines, and AAQC in the document Summary of O. Reg. 419/05 Standards and Point of Impingement Guidelines & Ambient Air Quality Criteria (AAQCs) [MOE December 2005]. Federal Air Quality Objectives encompass three levels of air quality objectives: maximum desirable level, maximum acceptable level and maximum tolerable level. The maximum acceptable level (MAL) is intended to provide adequate protection against effects on soil, water, vegetation, materials, visibility, personal comfort and well-being. The MAL is considered to be a realistic objective. Table 1.1 summarizes the applicable criteria from MOE, EC and the Canadian Council of the Ministers of the Environment (CCME). TABLE AIR QUALITY CRITERIA FOR CONVENTIONAL POLLUTANTS Contaminant NO x (as NO 2 ) SO 2 Averaging Time MOE 3 POI and AAQC (μg/m 3 ) Federal 4 AQ Objectives Maximum Acceptable Level (MAL) (μg/m 3 ) CCME 5 Canada Wide Standard (μg/m 3 ) NO 2 1 hr NO 2 24 hr NO 2 Annual hr hr Annual hr 36,200 35,000 - CO 8 hr 15,700 15, hr SPM 24 hr annual PM hr 50 (interim) PM hr (by 2010) 1 hr O 3 24 hr annual Notes: NO x nitrogen oxides sum of nitrogen dioxide (NO 2 ) and nitric oxide (NO), SO 2 sulphur dioxide, CO carbon monoxide. SPM includes all particulate matter with an aerodynamic diameter less than 44 µm that can become suspended in the atmosphere. PM 10 includes all particulate matter with an aerodynamic diameter less than 10 µm considered inhalable. PM 2.5 includes all particulate matter with an aerodynamic diameter less than 2.5 µm considered respirable. O 3 Ozone 165 µg/m = 80 ppb. Environment Canada O 3 level is 65 ppb by Indicates no criterion available. 1 ½ hr POI is for NO x all ambient criteria are for NO 2. 2 MOE Air Quality in Ontario 2002 Report Appendix. 3 MOE Summary of O. Reg. 419/05 Standards and Point of Impingement Guidelines & Ambient Air Quality Criteria (AAQCs); Standards Development Branch. December. 4 FPCAP Criteria for National Air Quality Objectives: Sulphur Dioxide, Suspended Particulates, Carbon Monoxide, Oxidants (Ozone) and Nitrogen Dioxide. 5 CCME Canada Wide Standards for Particulate Matter (PM) and Ozone. June. From the proposed HHGS, nitrogen oxides (NO x ) is the contaminant whose predicted concentrations are closest to their MOE POI limit, and thus have the greatest potential to impact the local air quality. NO x is the sum of nitrogen dioxide (NO 2 ) plus nitric oxide (NO). Note that DRAFT September Halton Hills Generating Station

18 while the predicted concentrations are for NO x, the criteria are for NO 2. In the ambient air in Toronto, approximately 50% of the measured NO x is as NO 2 (MOE 1998, 1999, 2000), which is typical of other urban areas. For the trace VOCs and PAHs, the available criteria are summarized in Table 1.2. TABLE AIR QUALITY CRITERIA FOR TRACE VOCS AND PAHS Contaminant CAS # MOE 24hr AAQC (µg/m 3 ) Benzene CARC Ethyl Benzene * Toluene Xylenes Propylene Propylene Oxide * 1,3-Butadiene VOCs Formaldehyde * Acetaldehyde * Dichlorobezene Acrolein * Ethane Butane Hexane * Pentane Propane Naphthalene Acenaphthylene Acenaphthene Fluorene Phenanthrene Anthracene Fluoranthene Pyrene Benzo(a)anthracene PAHs Chrysene Benzo(b)fluoranthene Benzo(k)fluoranthene Benzo(a)pyrene Indeno(1,2,3-cd)pyrene Dibenz(a,h)anthracene Methylnapthalene Methylchloranthrene ,12 Dimethylbenz(a)anthracene Benzo(g,h,l)perylene Notes: - Indicates no criterion available * Schedule 3, O. Reg 419/ DRAFT September Halton Hills Generating Station

19 1.5 NOTIFICATION CRITERION Under Article V of the Ozone Annex to the Canada-U.S. Air Quality Agreement Canada is obligated to notify the U.S of any proposed projects in Canada that are within 100 km of the Canada-U.S. border and are expected to emit more than 90 tonnes per year of any one of the following air pollutants: SO 2, NO x, CO, SPM and VOCs. Notification is also required if the proposed project will result in releases of greater than 1 tonne per year of any one hazardous air pollutant (HAP). A HAP was considered to be any contaminant listed in Table DRAFT September Halton Hills Generating Station

20 2.0 EXISTING ENVIRONMENTAL CONDITIONS 2.1 CLIMATE AND METEOROLOGICAL DATA The Toronto area has a middle latitude humid continental climate affected by Lake Ontario and the Niagara Escarpment. The region is characterized by pronounced seasonal differences of weather and by a highly variable day-to-day weather pattern. Some periods in summer are essentially humid tropical (high temperatures, high humidity, afternoon thunderstorms, etc.). Some periods in winter are effectively polar (very cold, clear, dry). Precipitation occurs throughout the year. The surface meteorological data used in the air dispersion modelling was obtained from the Toronto Lester B. Pearson International Airport meteorological monitoring station ( ), which is approximately 22 km east of the site. The upper air measurements used are from the closest upper air station, Buffalo, New York, which is located approximately 100 km south southeast of the proposed HHGS site. In order to be considered representative of the local conditions, the wind and temperature data used should be obtained from within 100 km of the study area, and upper air data should be obtained from within 300 km. The stations used for this study are well within these parameters. Characterization of the existing climate and meteorological conditions in the vicinity of the proposed HHGS site is important because these are the main forces driving contaminant transport (dispersion) in the atmosphere. The direction and speed of the wind dictates the location and distance from the source that the pollutants may travel. The factors that influence the contaminant mixing in the atmosphere are described below Near-Surface Temperature Temperature and precipitation normals for the Toronto Lester B. Pearson International Airport ( ) are presented in Table 2.1. Normals is the term commonly used for values of climatic elements averaged over a fixed standard period of years (usually 30 years). Temperature near the surface of the earth controls the buoyant component of turbulence (vertical motion). Heat from the earth's surface heats the air near the ground causing it to rise. This mechanism reaches a maximum in early afternoon and is at a minimum near sunrise. Table 2.1 indicates that the daily mean minimum temperature is 6.3 C in January and daily mean maximum temperature is 20.8 C in July. The annual mean temperature is 7.5 C at the Toronto Lester B. Pearson International Airport site DRAFT September Halton Hills Generating Station

21 TABLE TORONTO LESTER B. PEARSON INTERNATIONAL AIRPORT CLIMATE NORMALS ( ) Temperature Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year Daily Average ( C) Standard Deviation Daily Maximum ( C) Daily Minimum ( C) Precipitation Rainfall (mm) Snowfall (cm) Precipitation (mm) Days with Rainfall >= 0.2 mm Days With Snowfall >= 0.2 cm Days with Precipitation >= 0.2 mm Days with Wind Days with Winds >= 52 km/hr Days with Winds >= 63 km/hr Note: Source Environment Canada Website, Precipitation Contaminants in the air may be washed out by precipitation. More precipitation produces more washout. For this study, the role of precipitation in the removal of pollutants from the air was not considered, thereby generally providing conservatively high ground level concentrations. As shown in Table 2.1 above, the Toronto area receives a total of mm of precipitation per year, including mm of rainfall and cm of snowfall. The maximum mean monthly rainfall is 79.6 mm, which occurs in August Stability Normally, temperature decreases with increasing height. The relationship of the actual vertical temperature to the near-surface temperature determines the atmosphere's ability to resist or enhance vertical motion. The amount of vertical motion is a measure of the stability of the atmosphere. The atmosphere can have three general stability states - unstable, neutral and stable. The stability scale normally used for air quality simulations varies from very unstable (A) through neutral (D) to very stable (F). The stability class distribution for the Toronto Lester B. Pearson International Airport for the period is presented in Table 2.2. At this station, neutral stability conditions {D (neutral) + C (near neutral)} occur approximately 65% of the time and stable conditions (E, F) about 30% of the time. Stable conditions can produce higher concentrations of contaminants because of reduced turbulent mixing DRAFT September Halton Hills Generating Station

22 TABLE STABILITY CLASS DISTRIBUTION TORONTO LESTER B. PEARSON INTERNATIONAL AIRPORT Stability Class % Frequency Descriptor A 0.55 Unstable B 4.42 C Neutral D E Stable F Wind Direction Wind direction is reported as the direction from which the wind blows and is based on surface (10 metre) observations. In general terms, if the wind does not blow toward a receptor, there will be no impact from an emission source upwind. The wind blows in all directions with varying frequencies. Certain directions occur more frequently than others. These are known as the prevailing wind directions. Figure 2.1 presents a wind rose for the Toronto Lester B. Pearson International Airport for the years The prevailing winds are from either the north or the west DRAFT September Halton Hills Generating Station

23 FIGURE WIND ROSE TORONTO LESTER B. PEARSON INTERNATIONAL AIRPORT Wind Direction Frequency (%) NNW NW WNW N NNE NE ENE W E WSW ESE SW SSW S SSE SE Average Wind Speed (m/s) NNW NW WNW W N NNE NE ENE E WSW ESE SW SSW S SSE SE Percentage of Calms = 5.7 % DRAFT September Halton Hills Generating Station

24 2.1.5 Wind Speed Air Quality Assessment for the Proposed Halton Hills Generating Station Contaminant concentrations decrease with increasing wind speed as a result of mixing. The wind speed used in the air quality modelling is based on surface observations from the Toronto Lester B. Pearson International Airport. Wind speed increases with height as surface friction is reduced. This variation with height is built into the dispersion model used in this assessment. When wind speeds are high, there is good dispersion of gases and particles, but more potential for resuspending surface dusts. When wind speeds are near zero, local circulation can lead to very high pollutant concentrations near the ground. There are calms recorded 5.7% of the time at the Toronto Lester B. Pearson Airport meteorological station (Figure 2.1). The average wind speed based on the period is 4.1 m/s Mixing Height Another very important parameter in the dispersion of contaminants from a source is the "mixing height". This is the vertical extent through which the plume can be mixed. With a higher mixing height, there is a larger volume of air available within which the pollutants can mix producing lower concentrations. With a lower mixing height, the plume may become trapped resulting in higher concentrations. The concept of mixing height is founded on the principle that heat transferred to the atmosphere at the earth's surface results in convection, vigorous vertical mixing and the establishment of a dry-adiabatic lapse rate [Holzworth 1967]. For annual and 24 hour averages, the mixing height does not have much effect on the modelled ground level concentrations [Young & Radonjic 1993]. For 1 hour concentrations, however, mixing height is very important. The use of variable mixing heights, that are as close to the actual conditions as possible, improves the ability of the model to accurately predict downwind concentrations. For the sources that are close to the ground, the mixing heights do not play a major role. The closest station having the upper air data necessary for this study is the Buffalo, New York Airport station. The mixing height data for each day for the 5-year simulation period ( ) was developed using the AERMET meteorological pre-processor. The albedo, bowen ratio and surface roughness surface characteristics were determined for each wind sector and merged with the upper air data from Buffalo and the surface meteorological data from Toronto to create the hourly mixing heights which are required by the dispersion model. Missing data was filled in by interpolation with AERMET. There were no significant blocks of data missing from this meteorological data set DRAFT September Halton Hills Generating Station

25 2.2 EXISTING AIR QUALITY The existing air quality is influenced by local and long-range (cross-border) contaminants generated in upwind urban and industrial areas. The predominant wind directions at the Toronto Lester B. Pearson International Airport are from the west and north. Air quality in southwestern Ontario is affected in large part by emissions from the United States, which contribute approximately 50% of the ground level-ozone (smog) [MOE 2000]. The remaining 50% is largely due to fossil fuel combustion in Canada. The principal contaminant related to combustion emissions for the proposed HHGS is NO x. Minor combustion emissions related to the proposed HHGS are SO 2, CO and SPM. To assess the current air quality in the area, seven years of historical air quality monitoring data from MOE stations in urban areas surrounding the site were considered Historical Ambient Monitoring Data The following MOE air quality monitoring stations were selected for use in this study. TABLE 2.3 PARAMETERS MEASURED AT LOCAL MOE AQ STATIONS Station # City Location Contaminants Measured Hamilton Main St W/Hwy403 SPM, NO 2, SO 2, CO, O Hamilton Dundurn/York SPM Toronto West Elmcrest Rd., Centennial Park SPM, PM 10, PM 2.5, NO 2, SO 2, CO, O Etobicoke Evans/Arnold Ave. SPM, PM 10, PM 2.5, NO 2, SO 2, CO, O Burlington Hwy2/North Shore Blvd E SPM, PM 10, PM 2.5, NO 2, SO 2, CO, O Burlington 3900 Mainway Blvd. SPM Oakville Bronte Rd/Woburn Cres NO 2, SO 2, CO, O Oakville 8th Line/Glenashton Dr., Halton Reserv. PM 2.5, NO 2, SO 2, CO, O Brampton 525 Main St. N., Peel Manor PM 2.5, NO 2, SO 2, CO, O Mississauga Frank Mckechnie Comm. Ctr. PM 2.5, SO 2, CO, O Mississuaga Queensway W/Hurontario St. PM 2.5, NO 2, SO 2, CO, O Mississauga Apple Lane, Meadow Park SPM, NO 2, SO 2 Figure 2.2 is a map showing the location of the local stations DRAFT September Halton Hills Generating Station

26 FIGURE LOCATION OF LOCAL AMBIENT AIR QUALITY MONITORING STATIONS LEGEND Scale: 0km 5.3km 10.6km 21.2km N HHGS Site Toronto Lester B. Pearson Airport Local MOE Air Quality Monitoring Station (No ) DRAFT September Halton Hills Generating Station

27 Representative background concentrations are used in the air dispersion modelling stage of the assessment. The contribution due to the proposed HHGS is added to the appropriate background concentration to establish total predicted ambient levels, if the proposed HHGS was in operation. Seven years of MOE air quality monitoring data were examined (1998 through 2004), although not all contaminants were measured in all years. The following methodology was used to determine representative background concentrations of the contaminants monitored. For each contaminant, the reported annual mean data for all representative MOE stations was averaged on a year-by-year basis. It is important to note that to represent background concentrations for the short term time frames (1 hour and 24 hour average time periods), the maximum 90 th percentiles of the data were used, with the exception of SPM which are 24 hour averages. Ontario last reported Suspended Particulate Matter (SPM) in 2000 and PM 10 in A review of the historic data indicated that the measured air concentrations of contaminants have generally decreased over time. Therefore to characterize the existing environment for current conditions, the most recent three years of data (2002 through 2004) were used. SPM and PM 10, data has not been measured in the most recent years, therefore concentrations for current conditions were estimated by multiplying the PM through 2004 concentrations by the ratio of the SPM or PM 10 to PM 2.5 concentrations from earlier years when both contaminants were measured. Table 2.4 shows the representative background concentrations. Details of the values used in these calculations are contained in Appendix A of Supporting Document 1. Several monitoring stations were included in the analysis in order to obtain data for all contaminants for as many years as possible. It should be recognized that while a few of the stations, such as Station which is located in a park, could be representative of areas having lower background concentration than the proposed HHGS site, many of the stations, such as Station located near the intersection of two major highways (the QEW and HWY 427), are thought to be overly conservative as they are located at industrial sites or in areas with higher volumes of traffic in the surrounding area than expected at the proposed HHGS site. Overall, the background concentrations are considered conservative DRAFT September Halton Hills Generating Station

28 TABLE REPRESENTATIVE BACKGROUND AIR CONCENTRATIONS ( ) SPM PM 10 PM 2.5 NO 2 SO 2 CO O 3 (µg/m 3 ) (µg/m 3 ) (µg/m 3 ) (µg/m 3 ) (µg/m 3 ) (µg/m 3 ) (ppb) Maximum of Annual Means Annual AAQC (MOE) Annual EC NAAQO (MAL) Maximum of 90 th Percentiles 1 hour average data hour AAQC (MOE) hour EC NAAQO (MAL) Maximum of 90 th Percentiles 8 hour average data hour AAQC (MOE) hour EC NAAQO (MAL) Maximum of 90 th Percentiles 24 hour average data hour AAQC (MOE) hour EC NAAQC (MAL) Notes: Details are available in Appendix A of Supporting Document 1 - no applicable criteria AAQC Ambient Air Quality Criteria MOE EC NAAQO Environment Canada National Ambient Air Quality Objectives MAL Maximum Acceptable Limit Environment Canada Annual values for SPM, PM 10 and PM 2.5 are based on geometric means O 3 Canada Wide Standard to be 65 ppb in 2010 PM 2.5 Canada Wide Standard to be 30 μg/m 3 (24 hour average) in 2010 Table 2.5 presents the average frequency of exceedance of the AAQC at the local MOE AQ stations. For example, in the year 2000 the 24 hour AAQC for PM 10 was exceeded an average of 2 times at the local MOE AQ stations that measure PM 10. TABLE FREQUENCY OF EXCEEDANCE OF MOE AAQC AT LOCAL MOE AQ Contaminant AAQC Average Times Exceeded SPM 24 h y PM 10 24h PM h NO 2 1 h h h SO 2 24 h y CO 1 h h O 3 1 h Note: Data not published / not available DRAFT September Halton Hills Generating Station

29 PM SPM is a measure of particulate matter (PM), with aerodynamic diameters less than 44 μm, suspended in the air. The representative annual and 24 hour SPM background air concentration of 28 µg/m 3 and 64 µg/m 3 are approximately 50% of the annual and 24 hour Ambient Air Quality Criteria (AAQC) of 60 µg/m 3 and 120 µg/m 3, respectively. The annual AAQC was exceeded an average of zero times per year and the 24 hour AAQC was exceeded on average one time per year at the local MOE AQ stations (Table 2.5). PM 10 is the fraction of SPM with aerodynamic diameters less than 10 μm. The MOE introduced an interim AAQC for this parameter of 50 μg/m 3 as a 24 hour average (MOE 2001b), but annual criteria are not currently available. PM 2.5 is the fraction of SPM with aerodynamic diameters less than 2.5 μm. The Canadian Council of Ministers of the Environment (CCME) has developed a Canada Wide Standard (CWS) for PM 2.5 of 30 µg/m 3 (98 th percentile over 3 years) that will apply in 2010 to all new and existing facilities. The representative background air concentrations of both PM 10 and PM 2.5 are approximately 60% of their respective AAQC s. The interim 24 hour criteria for PM 10 was exceeded an average number of times ranging from 2.5 to 12.5 between 1998 and The interim 24 hour criteria for PM 2.5 was exceeded an average number of times ranging from 1.3 to 13 between 1999 and 2004 at local MOE AQ stations. NO x / NO 2 NO x are present in the atmosphere as the sum of nitrogen dioxide (NO 2 ) and nitric oxide (NO). NO x emissions are primarily from high-temperature combustion processes such as the burning of fossil fuels. In Ontario, vehicle emissions account for approximately 60% of the NO x emissions (MOE 2000a). While the primary chemical parameter emitted from combustion processes is NO, it oxidizes rapidly, in the presence of hydrocarbons and sunlight, to NO 2. NO 2 is a major contributor to the formation of acid rain. The annual representative background air NO 2 concentration of 41 µg/m 3 may be compared to the federal MAL of 100 µg/m 3 for NO 2. In urban areas, the annual average NO 2 concentrations are approximately 40% of the federal MAL for NO 2. The 24 hour average representative background air NO 2 concentration of 51 µg/m 3 may be compared to the MOE AAQC of 200 µg/m 3 for NO DRAFT September Halton Hills Generating Station

30 SO 2 SO 2, another combustion by-product, is a major contributor to the formation of acid rain. The combustion of natural gas results in the release of only trace levels of SO 2 due the low level of sulphur in the fuel. The measured annual average SO 2 concentrations were less than 20% of the AAQC. The 1 hour, 24 hour and annual SO 2 AAQC were not exceeded at any of the local MOE AQ station during the years 1998 to CO CO is produced primarily through the incomplete combustion of fossil fuels. Over 75% of the CO produced in Ontario is from the transportation sector. The remaining 25% is the result of other sources of fossil fuel combustion including heating buildings, commercial and industrial operations. The measured concentrations are generally only a small fraction of the applicable 1 hour and 8 hour AAQC. The 1 hour and 8 hour AAQC were not exceeded at any of the local MOE AQ stations during the years 1998 to O 3 Ground level ozone results from chemical reactions between volatile organic compounds (VOCs) and NO x in the presence of sunlight. Exposure to ground level ozone can cause irritation of the respiratory tract and eyes. There have been a number of exceedances of the current 1 hour average AAQC (80 ppb). Table 2.5 shows average exceedances ranging between 3 and 61 times per year for the years 1998 through 2004 at the local MOE AQ stations. The CWS for ozone is to be revised down to 65 ppb by the year There is no federal or provincial 24 hour average or annual average AAQC for ozone. The annual average ozone concentration is approximately 23 ppb in the Greater Toronto Area (GTA) DRAFT September Halton Hills Generating Station

31 3.0 ATMOSPHERIC EMISSIONS 3.1 COMBUSTION OF NATURAL GAS Natural gas will be used in the two combustion turbines, their associated duct burners, the auxiliary boiler, and the comfort heating units Conventional Pollutants Airborne contaminants resulting from the combustion of natural gas are: NO x - principal contaminant resulting from nitrogen in air passing through the hot combustion process CO minor contaminant resulting from incomplete combustion SO 2 minor contaminant largely resulting from trace quantities of mercaptans (odorant added to natural gas for safety reasons) SPM minor contaminant for assessment purposes assumed to be all PM 2.5 (below 2.5 microns). The proposed gas turbines will use state-of-the-art dry low-no x (DLN) emissions technology to control NO x emissions. Duct burners (also low-no x ) are available to supply additional heat, when required. Each combustion turbine exhausts via its heat recovery steam generator to the atmosphere through its own 61 m stack. The steam generated via the heat recovery steam generators will be used in the steam turbine to generate more electricity. For conservatism in this assessment, the manufacturer s guarantee of 9 ppm NO x in the HRSG stack was doubled to 18 ppm to account for extreme degradation in performance between maintenance. It is extremely unlikely that a level of 18ppm NO x would ever be reached in the HRSG stacks. The U.S. Environmental Protection Agency publishes a document, known as AP-42, containing air emission factors for a wide range of industrial processes. The SO 2 emission factor from AP- 42 is based on the sulphur content in the fuel. The primary source of sulphur in natural gas is the trace odorant used, however it should be noted that the main equipment at the proposed HHGS, including the HRSGs and auxiliary boiler, use unodorized gas. There is a CSA standard for sulphur content in gas pipelines limiting average hydrogen sulphide concentration to 7 mg/m 3 (6.6 mg/m 3 as S). To be conservative, a sulphur content of 10 mg/m 3 was assumed. The emission estimates provided by the manufacturer for a much higher sulphur content were adjusted to account for the lower sulphur content. A natural gas fuelled auxiliary boiler operating at full load will supply steam for initial start-up (i.e. the first time the facility operates) and after prolonged shutdowns. The auxiliary boiler will DRAFT September Halton Hills Generating Station

32 operate in standby mode between expected daily shutdowns. The auxiliary boiler exhausts to the atmosphere through a 40 m stack. It was very conservatively assumed that all of the particulate emitted from the natural gas fuelled combustion turbine is smaller than 2.5 microns (PM 2.5 ). From a health perspective, the inhalable particulate (PM 2.5 ) has the most restrictive limits. Natural gas fuelled roof mounted comfort heaters will be installed in the main building. The total capacity of these units will be approximately 28 GJ/h. When both turbines are operating, it is expected that, even in the winter, there will be sufficient heat from the operating equipment that no comfort heaters will be required. These heaters are being installed to supply heat when one or both turbines are not operating. The total potential NO x emissions from the comfort heaters are approximately 1% of the emissions from the two gas turbines VOCs and PAHs The combustion of natural gas also produce trace quantities of various volatile organic compounds (VOCs) and polycyclic aromatic hydrocarbons (PAHs). Emission factors were obtained from AP-42, which are specifically applicable to gas turbines, for the following compounds. VOCs benzene, ethylbenzene, toluene, xylenes, propylene oxide, 1,3-butadiene, formaldehyde; and acetaldehyde, and, PAHs - naphthalene. Emission factors were obtained from AP-42 for the following compounds from natural gas combustion, and were used to estimate emissions from the duct burners and the auxiliary boiler. VOCs benzene, toluene, formaldehyde, dichlorobenzene, ethane, butane, hexane, pentane, and propane; and, PAHs - naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benzo(a)anthracene, chrysene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene, indeno(1,2,3-cd)pyrene, dibenz(a,h)anthracene, 2-methylnapthalene, 3-methylchloroanthrene, 7,12 dimethylbenz(a)anthracene benzo(g,h,l)perylene. The potential human health and ecological effects of these trace contaminants are discussed in Supporting Document DRAFT September Halton Hills Generating Station

33 3.1.3 Greenhouse Gas Emissions The combustion of any fuel will result in the production of greenhouse gases. The predominant greenhouse gas emission from the proposed HHGS will be carbon dioxide (CO 2 ). Small quantities of nitrous oxide (N 2 O) are also released. N 2 O has a global warming potential (GWP) that is 310 times higher compared to the GWP of CO 2. Comparing the emission factors of CO 2 and N 2 O found in AP-42 for gas turbines shows that, on a mass basis, approximately 187,500 times as much CO 2 is emitted compared to N 2 O. On a GWP basis, the emissions of CO 2 are 604 times (187,500 / 310) greater than those of N 2 O. Thus, the emissions of N 2 O are insignificant. During start-up, there may be some unburned methane released but quantities will be very low. The emissions of greenhouse gases from the proposed HHGS are minimized by: the use of natural gas which results in a reduced mass of CO 2 emitted per unit of useful energy released as compared to other types of fossil fuels; the use of heat recovery reduces total fuel requirements and therefore results in lower emissions of CO 2 (and all other contaminants); and the use of low NO x burner technology also reduces the formation of N 2 O. 3.2 COMBUSTION OF DIESEL FUEL A 1.8 MW standby diesel generator will be installed to supply emergency power in the event of a power failure to allow for the safe shutdown of the plant. It is proposed that the unit will be operated approximately two hours a week for testing purposes only. It will exhaust to the atmosphere through its own 23 m high stack Conventional Pollutants The following conventional pollutants have been identified to be emitted during the operation of diesel engines: NO x, SO 2, CO and SPM [U.S. EPA 1996] Trace VOCs and PAHs The following trace VOCs and PAHs have been identified in AP-42 as potential contaminants from a reciprocating diesel engine [U.S. EPA 1996]: VOCs including benzene, toluene, xylene, propylene, 1,3-butadiene, formaldehyde, and acrolein; and, PAHs including naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benzo(a)anthracene, chrysene, benzo(b)fluoranthene, DRAFT September Halton Hills Generating Station

34 benzo(k)fluoranthene, benzo(a)pyrene, indeno(1,2,3-cd)pyrene, dibenz(a,h)anthracene, and benzo(g,h,l)perylene. Potential health impacts of these trace contaminants are discussed in Supporting Document STARTUP VS. CONTINUOUS OPERATION The NO x emissions of a combustion turbine vary with load. When the unit is warming up, operating under no load or light load, emissions are higher than when the unit is operating at a steady state full load. Warm startups result in lower emissions, as the equipment does not take as long to achieve full operating temperature and steady state full load conditions. For a baseloaded facility, the emissions would be essentially constant at the steady state full load levels. 3.4 OPERATING SCENARIOS CONSIDERED In order to properly assess the potential environmental impact from the proposed HHGS, six different emission scenarios were considered. Contaminant emission rates for particulate, NO x, CO, and SO 2 were based on manufacturers information. It should be noted that while the turbine manufacturer s guarantee for NO x is 9 ppm in the stack under maximum steady state conditions, to be conservative it was assumed that the NO x concentration in the stack was doubled to 18 ppm. This was to account for extreme degradation of performance between maintenance. The operation of the duct burners is determined by: number of units operating; electricity price; and, instructions from the Independent Electricity Market Operator (IMO) Table 3.1 presents the emission rates used to develop the emission scenarios studied DRAFT September Halton Hills Generating Station

35 Contaminant Notes: Air Quality Assessment for the Proposed Halton Hills Generating Station TABLE 3.1 EMISSION RATES USED TO DEVELOP SCENARIOS Each Gas Turbine (lb/hr) Max load Startup Full Duct Burner (lb/hr) Emergency Diesel (lb/hr) Auxiliary Boiler (lb/hr) Full Standby Load Comfort Heaters (lb/hr) PM NO x SO CO NO x emission rate used for gas turbine is double manufacturer s guarantee It can be seen from Table 3.1 that maximum NO x emissions from the comfort heaters are only a small fraction of the NO x emissions from the gas turbines. When both gas turbines are operating, it is expected that no natural gas-fired comfort heaters will be required, even in the winter, due to the heat from the operating equipment. Since the comfort heaters will only be used when one or both of the turbines are not operating, the comfort heaters will not contribute to a maximum emission scenario. The following six scenarios represent the maximum annual, 24 hour and 1 hour emission scenarios. The shaded boxes contain data that was used in the air dispersion modelling. The maximum annual emission rates (Scenario 1- Table 3.2) were found to occur with: both gas turbines operating at 100% load and full duct fire on both duct burners for 24 hours per day, 365 days per year for a total of 8,760 hours per year; auxiliary boiler at full load for 50 hours, standby the remaining time; and testing of the standby diesel generator occurring 2 hours per week. TABLE 3.2 SCENARIO 1 - MAXIMUM ANNUAL EMISSION RATES Description Tonnes / year Grams / second Both units base loaded GT1 GT2 Gen Aux GT1 GT2 Gen Aux 100% duct burners PM Test Diesel 2 hrs/week NO x Aux boiler on 50 hrs/year, SO remaining standby CO Notes: GT1, GT2 = gas turbine 1 and gas turbine 2 Gen = standby diesel generator Aux = auxiliary boiler The predicted actual operating annual emission rates (Scenario 2 Table 3.3) were found to occur with: both gas turbines operating at 100% load for 4,600 hours per year; DRAFT September Halton Hills Generating Station

36 both gas turbines operating at 100% load and full duct fire on both duct burners for 4,100 hours per year; auxiliary boiler on full load for 50 hours per year, off the remaining time; and testing of the standby diesel generator occurring 2 hours per week. TABLE 3.3 SCENARIO 2 PREDICTED ACTUAL OPERATING ANNUAL EMISSION RATES Description Tonnes / year Grams / second Both units base loaded GT1 GT2 Gen Aux GT1 GT2 Gen Aux 50% duct burners PM Test Diesel 2 hrs/week NO x Aux boiler on 50 hrs/yr, SO remaining standby CO Notes: GT1, GT2 = gas turbine 1 and gas turbine 2 Gen = standby diesel generator Aux = auxiliary boiler The maximum 24 hour emission rates (Scenario 3 - Table 3.4) were found to occur with: one gas turbine operating at 100% load for 2 hours, gas turbine operating at 100% load and full duct fire for remaining 22 hours; one gas turbine start-up for 2 hours, gas turbine at 100% load and full duct fire for remaining 22 hours; auxiliary boiler on full load for 2 hours, standby for remaining 22 hours; and the standby diesel generator off. TABLE SCENARIO 3 MAXIMUM 24 HOUR EMISSION RATES Description Kilograms / 24 hour Grams / second One unit base loaded with 100% duct burners Second unit startup 2 hrs, 100% duct burner 22 hrs Aux boiler on, 2 hr full load, 20 hr standby Diesel Gen off GT1 GT2 Gen Aux GT1 GT2 Gen Aux PM NO x SO CO For all contaminants, with the exception of CO, the maximum hourly emission rates were found to occur while the standby diesel generator is being tested. The maximum standby diesel generator hourly test emission rates (Scenario 4 Table 3.5) were found to occur with: both gas turbines operating at 100% load and full duct fire on both duct burners; auxiliary boiler on standby; and testing of the standby diesel generator occurring DRAFT September Halton Hills Generating Station

37 TABLE SCENARIO 4 EMERGENCY DIESEL GENERATOR HOURLY TESTING EMISSIONS Description Kilograms / hour Grams / second Both units base loaded 100% duct burners Testing Diesel Aux boiler on standby GT1 GT2 Gen Aux GT1 GT2 Gen Aux PM NO x SO CO The maximum base load 1 hour emission rates (Scenario 5 Table 3.6) were found to occur with: both gas turbines operating at 100% load and full duct fire on both duct burners; auxiliary boiler on standby; and the standby diesel generator off. TABLE 3.6- SCENARIO 5 MAXIMUM BASE LOAD 1 HOUR EMISSION RATES Description Kilograms / hour Grams / second Both units base loaded 100% duct burners Aux boiler on standby Diesel off GT1 GT2 Gen Aux GT1 GT2 Gen Aux PM NO x SO CO For CO, it was determined that the maximum hourly emission rate occurs during the startup of one of the gas turbines (Scenario 6 - Table 3.7). For Scenario 6 the following assumptions were made: one gas turbine operating at 100% load; one gas turbine start-up; auxiliary boiler operating; and the standby diesel generator off. TABLE SCENARIO 6 MAXIMUM BASE LOAD AND STARTUP 1 HOUR EMISSION RATES Description Kilograms / hour Grams / second One unit base loaded 100% Second unit start-up Aux boiler on full load Diesel off GT1 GT2 Gen Aux GT1 GT2 Gen Aux PM NO x 1,224 2, SO CO , , DRAFT September Halton Hills Generating Station

38 3.4.1 Summary of Conventional Pollutant Emission Rates Table 3.8 provides a summary of the estimated emission rates of the conventional pollutants used in the dispersion modelling for various time periods (shaded data from Tables ). TABLE SUMMARY OF MAXIMUM CONVENTIONAL POLLUTANT EMISSION RATES Emission Source Gas Turbine GT1 with Duct Burner Gas Turbine GT2 with Duct Burner Standby Diesel Generator Auxilary Boiler Contaminant Maximum Annual Emission Rate (g/s) % of total mass emission Predicted Actual Annual Operation Emission Rate (g/s) % of total mass emission Maximum 24 hour Emission Rate (g/s) % of total mass emission Maximum 1 hour Diesel Generator % of total Emission mass Rate (g/s) emission Maximum 1 hour Base Load % of total Emission mass Rate (g/s) emission Maximum 1 hour Start-up and Base Load Emission Rate (g/s) % of total mass emission PM % % % % % % NO x % % % % % % SO % % % % % % CO % % % % % % PM % % % % % % NO x % % % % % % SO % % % % % % CO % % % % % % PM % % n/a n/a % n/a n/a n/a n/a NO x % % n/a n/a % n/a n/a n/a n/a SO % % n/a n/a % n/a n/a n/a n/a CO % % n/a n/a % n/a n/a n/a n/a PM % % % % % % NO x % % % % % % SO % % % % % % CO % % % % % % The MOE s (1994) Guideline A-5 regulates the atmospheric emissions from stationary gas turbines. The limits for the mass emission rate of NO x per GJ of energy depends on the size of the unit, fuel used, the amount of useful heat recovered and whether it is used in a peaking on non-peaking mode. There is also a formula presented for the emissions of SO 2. The guideline recommends the concentration of CO in the stack be less than 60 ppmv, which is equivalent to approximately 35.4 g/s. Table 3.9 shows the calculated Guideline A-5 emission rates for the gas combustion turbines. TABLE MOE STATIONARY COMBUSTION TURBINE GUIDELINE LIMITS HHGS Max 1 Hour NO x 46 g/s 28 g/s 19 g/s CO 60 ppmv (35 g/s) 5.3 g/s Emission Source Contaminant Peaking mode Non peaking mode Each combustion turbine w/duct burner SO g/s 214 g/s 0.32 g/s Source: MOE Guideline A-5 Atmospheric Emissions from Stationary Combustion Turbines 1994 The proposed equipment will have emissions that are below the A-5 guidelines. From Table 3.9 it can be seen that under maximum annual baseload conditions the proposed HHGS will be emitting approximately 68% of the non-peaking NO x guideline limit, 15% of the CO guideline limit, and less than 1% of the SO 2 guideline limit DRAFT September Halton Hills Generating Station

39 In April 2003, the national emission guidelines for new thermal power plants came into effect [Environment Canada 2003A]. Table 3.10 presents the guideline limits for PM, NO x and SO 2. TABLE 3.10 NATIONAL NEW THERMAL POWER PLANT GUIDELINE LIMITS National Emission Guideline HHGS Max 1 Hour Emission Source Contaminant kg/mwh/hr g/s (Scenario 5) (g/s) PM Each combustion turbine NO x w/duct burner SO Note: National Emission g/s Guideline Limits based on maximum electrical output of 190 MW per unit The national guideline has an opacity limit of 20%. Since the proposed HHGS burns natural gas there will be no concerns with opacity. Continuous emissions monitors (CEMs) will be installed in each of the HRSG stacks to measure NO x, CO and O 2. The MOE A-9 Guideline (2001) NO x Emissions from Boilers and Heaters regulates emissions from new boilers. The A-9 Guideline sets out a NO x emission limit of 26 g/gj for boilers having a capacity between 10.5 and 105 GJ/hr when burning gaseous fuel. The auxiliary boiler planned for the proposed HHGS has a NOx emission rate of 15 g/gj and therefore meets the A-9 requirement Summary of Trace VOCs and PAHs Table 3.11 summarizes the estimated emission rates of trace VOCs and PAHs. This is based on the maximum annual emission rate (baseload) scenario (Scenario 1) DRAFT September Halton Hills Generating Station

40 V O C s P A H s Air Quality Assessment for the Proposed Halton Hills Generating Station TABLE SUMMARY OF ANNUAL TRACE VOCS AND PAHS EMISSION RATES (G/S) Notes: Contaminant Both Turbines (g/s) Data Quality Both Duct Burners (g/s) Auxiliary Boiler (g/s) Data Quality Diesel Generator (g/s) Data Quality Plant Total (g/s) Benzene 6.08E-03 A 3.72E E-06 B 5.09E-06 E 6.46E-03 Ethyl Benzene 1.62E-02 C E-02 Toluene 6.58E-02 C 6.02E E-06 C 2.23E-06 E 6.64E-02 Xylenes 3.24E-02 C E-06 E 3.24E-02 Propylene E-05 E 1.41E-05 Propylene Oxide 1.47E-02 D E 1.47E-02 1,3-Butadiene 2.18E-04 D E-07 E 2.18E-04 Formaldehyde 3.60E-01 A 1.33E E-05 B 6.44E-06 E 3.73E-01 Acetaldehyde 2.03E-02 C E-06 E 2.03E-02 Dichlorobenzene E E-06 E E-04 Acrolein 3.24E E-07 E 3.24E-03 Ethane E E-03 E E-01 Butane E E-03 E E-01 Hexane E E-03 E E-01 Pentane E E-03 E E-01 Propane E E-03 E E-01 Naphthalene 6.58E E E-07 E 4.63E-07 E 7.67E-04 Acenaphthylene E E-09 E 2.76E-08 E 3.48E-07 Acenaphthene E E-09 E 7.75E-09 E 3.28E-07 Fluorene E E-09 E 1.59E-07 E 6.58E-07 Phenanthrene E E-08 D 1.60E-07 E 3.28E-06 Anthracene E E-09 E 1.02E-08 E 4.38E-07 Fluoranthene E E-09 E 4.15E-08 E 5.76E-07 Pyrene E E-09 E 2.61E-08 E 9.16E-07 Benzo(a)anthracene E E-09 E 9.17E-09 E 3.30E-07 Chrysene E E-09 E 1.93E-09 E 3.22E-07 Benzo(b)fluoranthene E E-09 E 5.41E-10 E 3.21E-07 Benzo(k)fluoranthene E E-09 E 8.46E-10 E 3.21E-07 Benzo(a)pyrene E E-09 E 1.03E-09 E 2.15E-07 Indeno(1,2,3-cd)pyrene E E-09 E 2.05E-09 E 3.23E-07 Dibenz(a,h)anthracene E E-09 E 3.18E-09 E 2.17E-07 2-Methylnapthalene E E-08 D E-06 3-Methylchloranthrene E E-09 E E-07 7,12 Dimethylbenz(a)anthracene E E-09 E E-07 Benzo(g,h,l)perylene E E-09 E 2.67E-09 E 2.16E-07 - Indicates no criterion available All emissions based on emission factors in U.S. EPA AP-42 (1996) (2000a) Data quality indicates a rating of data quality from AP-42 Bold plant total emissions above Canada/U.S. Transboundary Agreement criterion of 1 tonne per year of hazardous air pollutant - Indicates no emission data available DRAFT September Halton Hills Generating Station

41 The Canada-U.S. Air Quality Agreement requires the proponent to submit estimated emission rates of hazardous air pollutants with annual emission rates greater than 1 tonne. The annual 1 tonne criterion is equivalent to 3E-02 g/s. There are eight pollutants (toluene, xylenes, formaldehyde, ethane, butane, hexane, pentane, and propane) that have estimated annual emission rates above this reporting threshold. These pollutants are shown in bold in Table The notification form is available in Appendix D. 3.5 ANNUAL EMISSIONS Annual Emissions of Conventional Pollutants For the maximum annual emissions scenario (Scenario 1), the estimated annual mass emission rates of the conventional pollutants are shown in Table TABLE ESTIMATED MAXIMUM ANNUAL EMISSION RATES Contaminant Annual Emission rate (tonnes/year) SPM / PM 10 / PM NO x 1201 SO CO 338 The actual annual emission rates will be less than these values as: the emissions from the turbines are overstated at double the manufacturer s guarantee; and, both turbine units may not operate all the time. Any emission offsets that result from the use of steam or electricity generated by the proposed HHGS have not been taken into account in this study. The estimated emission rates are above the reporting thresholds given in O. Reg. 127/01 and these emissions will have to be reported to the MOE Annual Emissions of Greenhouse Gases The maximum annual emissions of CO 2 are estimated to be 2.6 million tonnes assuming both turbines operating all of the time (Scenario 1). The CO 2 emissions from electrical generation involving the burning of fuel in 1995 for Ontario were 21 million tonnes [Environment Canada 1999b]. The Canada-wide emissions from the same sector and year were 100 million tonnes [Environment Canada 1999b] DRAFT September Halton Hills Generating Station

42 3.6 OZONE FORMATION O 3 will not be emitted directly from the proposed HHGS. Ground level O 3 is formed via a complex, non-linear photochemical reaction involving reactive species of VOCs, NO x and the hydroxyl radical (OH). As discussed in Sections 3.1 and 3.2, the proposed HHGS will emit NO x and trace levels of VOCs, which are precursors of O 3. The resulting O 3 concentrations formed depend upon sunlight strength, concentrations of NO x, and the availability of OH radicals to drive the reaction mechanisms. 3.7 VISIBLE PLUMES, FOGGING, AND ICING The combustion products of natural gas are water and CO 2. This water content would potentially result in a visible vapour plume from the main stacks during the cold winter months and other weather conditions. Due to the height of the stacks, there will be no concerns regarding icing and fogging. It should be noted that an ACC was chosen to avoid the potential impact of icing and fogging from the proposed facility. 3.8 CONSTRUCTION PHASE The proposed HHGS has the potential to affect the air quality in the vicinity of the site during the construction phase. Emissions that are associated with construction activities are SPM and typical combustion emissions, such as CO, NO x, SO 2 and VOCs, from construction equipment. As with any construction site, these emissions will be of relatively short duration and unlikely to have any effect on the surrounding industrial area. The use of well-maintained equipment will ensure that combustion emissions are kept to a minimum. To reduce SPM emissions, effective dust suppression techniques, such as on-site watering, street cleaning and limiting the speed of vehicles travelling on the roads, will be used. During construction the practices and procedures outlined in the document Best Practices for the Reduction of Air Emissions from Construction and Demolition Activities (March, 2005) prepared by ChemInfo Services Inc. in conjunction with Construction & Demolition Multi- Stakeholders Working Group for Environment Canada will be followed. No other mitigative measures are required. Negligible net effects are anticipated DRAFT September Halton Hills Generating Station

43 4.0 AIR DISPERSION MODELLING 4.1 MODELLING METHODOLOGY In order to assess the impact of the proposed HHGS, it is important to study the short-range atmospheric dispersion capability of the area. This capability to dilute contaminants is usually assessed using a computer dispersion model that simulates the pathways of pollutants from their point of emission to their point of reception in the environment AERMOD-PRIME Dispersion Model The U.S. EPA AERMOD-PRIME model (AERMOD) was used for the atmospheric dispersion modelling of the emissions from the proposed HHGS. The AERMOD Modelling System is a steady state air quality modelling system developed by the AMS/EPA Regulatory Model Improvement Committee, (AERMIC) to enhance the dated ISC3 algorithms and ultimately replace ISC3 as the workhorse regulatory model. AERMOD is a steady state Gaussian plume dispersion model which can be used to assess pollutant concentrations from a wide variety of complex industrial settings including multiple stacks, fugitive emissions, and building wake effects. The AERMOD Modelling System consists of two pre-processors (AERMET and AERMAP) and the dispersion model AERMOD. The AERMOD model is the regulatory model currently recommended by the U.S.EPA and the MOE for simulating short-term air quality impacts from industrial complexes. In AERMOD, basic boundary layer parameters are calculated from the raw upper air data and are used to control the vertical travel of the pollutant plume. This is a refinement of the discrete stability classes used by many other models such as ISC. The stability is described by the Monin-Obukhov (M/O) length. The M/O length is a function of the surface roughness, the surface albedo (reflectivity) and surface soil moisture content as well as the upper air data. AERMET was used to combine and format the surface and upper air data. AERMOD then processes the meteorological data directly without the need of a preprocessor. The AERMOD-PRIME model is a steady-state Gaussian Plume model that provides options to model emissions from a wide range of sources. The model accepts hourly meteorological data records to define the conditions for plume rise, transport and dispersion. The model estimates the concentration or deposition value for each source-receptor combination, for each hour of input meteorology, and calculates short-term averages, such as 1 hour, 8 hour and 24 hour averages. The hourly averages can also be combined into longer averages (monthly, seasonal, annual or period) DRAFT September Halton Hills Generating Station

44 Building Downwash Air Quality Assessment for the Proposed Halton Hills Generating Station AERMOD incorporates the PRIME (Plume RIse Model Enhancement) [Schulman et al. 1997], downwash algorithm. The PRIME algorithm is designed to incorporate the two fundamental features associated with building downwash: enhanced plume dispersion coefficients due to the turbulent wake, and reduced plume rise caused by a combination of the descending streamlines in the lee of the building and the increased entrainment in the wake. Building downwash occurs when the aerodynamic turbulence induced by a nearby building causes a pollutant emitted from an elevated source to be mixed rapidly toward the ground (downwash), resulting in higher ground-level concentrations. The emissions from the stacks for the auxiliary boiler will be trapped within the wake of the main steam turbine building at this site. Terrain Due to the change in elevations in the area surrounding the HHGS site, terrain data was included in the dispersion modelling. AERMAP is the terrain pre-processor used to calculate a representative terrain-influence height hill scale associated with each receptor within the modelling domain. The terrain data input into AERMAP was obtained from the MOE. Grid All modelling was undertaken in the Universal Transverse Mercator (UTM) coordinate system. The coordinate system used for mapping was North American Datum 1983 (NAD 1983), Zone 17. An orthogonally corrected aerial photograph (flown in 1999) geo-referenced to NAD83 was used as a base map. The proposed HHGS supplied electronic drawings of the plant facilities and property boundary that were overlaid onto the base map for digitization of the building, property and stack coordinates. The model was based on a rectangular receptor grid centered on the proposed HHGS and extended out to a distance of approximately 4 km. A tiered grid was used for receptor placement, which ranged from 50m spacing within 200 m of the site to 200 m spacing from 1800 m to the extent of the grid. Discrete grid points were also added along the property boundary bringing the total number of grid points to approximately The calculated concentrations at these points were used to prepare concentration isopleths and to determine the maximum concentrations (outside of the plant boundary). Specific Receptors In addition to the modelling grid, a series of six specific receptors was chosen to help summarize the modelling results and at which a comparison was made to applicable criteria. These receptors were also used in the Human Health and Ecological Risk Impact Assessment, Supporting Document 5. They are: DRAFT September Halton Hills Generating Station

45 CR1 Farm approximately 250 m northeast of the HHGS; CR2 Residence approximately 100 m north; CR3 Residence approximately 200 m south; CR4 Residential Area approximately 250 m northwest; CR5 Park approximately 150 m east; and CR6 Residence approximately 150 m west. Figure 4.1 shows the grid points used for modelling, the six specific receptor locations, the sources and the property boundary. FIGURE 4.1 AIR DISPERSION MODELLING GRID Note: x indicates location of modelling grid points indicates location of specific receptor DRAFT September Halton Hills Generating Station

46 Sources All sources were considered to be point sources. The table below lists the stack height and stack diameter of the sources that were used in the dispersion modelling. The other stack parameters were dependent upon the scenario. All stack parameters for all six scenarios assessed have been included in Appendix C. TABLE SOURCE PARAMETERS USED IN MODELLING Stack Stack Height (m) Stack Diameter (m) HRSG North HRSG South Aux Boiler Generator Buildings To take into account building wake, the following buildings were entered into the air dispersion model: main steam turbine building; the HRSG building; and, the condenser building. The dimensions of the dominant buildings have been included below in Table 4.2. TABLE 4.2 DIMENSION OF DOMINANT BUILDINGS Structure Length (m) Width (m) Height (m) Steam Turbine HRSG Condenser * * adjusted to account for piping on top of structure Figure 4.2 is an isometric view of the proposed HHGS DRAFT September Halton Hills Generating Station

47 FIGURE 4.2 ISOMETRIC VIEW OF THE PROPOSED HHGS DRAFT September Halton Hills Generating Station

48 Figure 4.3 is a scaled map of the site showing all of the on-site buildings as well as the property boundary. FIGURE 4.3 SCALED SITE PLAN Auxiliary Boiler Stack HRSG Building Steam Turbine Building HRSG North Stack HRSG South Stack Condenser Building Generator Stack DRAFT September Halton Hills Generating Station

49 5.0 MODELLING RESULTS 5.1 CONVENTIONAL POLLUTANTS Table 5.1 summarizes the output from the dispersion model under the maximum emission rates for the conventional pollutants. TABLE MODELLED CONVENTIONAL POLLUTANT MAXIMUM INCREMENTAL CONCENTRATIONS Contaminant Averaging time MOE POI and AAQC 1 Federal AQ Objectives MAL (μg/m 3 ) (μg/m 3 ) Scenario Producing Maximum Value Along Property Boundary Calculated Maximum Incremental Concentration at Receptors (µg/m 3 ) 1 hr n/a PM 24 hr annual PM hr 50 (interim) PM hr - 30 (by 2010) hr NO 2 1 hr n/a n/a hr n/a n/a n/a n/a n/a n/a hr annual hr SO 2 24 hr annual hr ,656 4,608 2,487 2,003 3,543 3,616 2,220 3, CO 8 hr ,009 3,953 1, ,969 2,775 1,236 2, hr annual Off Site CR-1 (farm) CR-2 (house) CR-3 (house) CR-4 (house) CR-5 (park) CR-6 (house) Existing Conditions Worst Case 2 Notes 1 AAQC are applicable for ambient conditions (facility plus background) 2 Average 90 th percentile of MOE data used for short term (1 hr and 24 h), maximum of average annual MOE data used for long term 3 MAL is for NO 2 modelled results are for NO x (NO 2 plus NO). Note that the higher NOx limit applies when the emergency standby generator testing is occurring, however the lower limit applies at sensitive receptors regardless of generator testing. The MOE currently has ½ hour average Point of Impingement (POI) criteria, which are to be applied with the MOE Ontario Regulation 346 air dispersion model. These ½ hour average criteria, however, are being phased out. For new facilities, such as the HHGS, they are not applicable and the new Ontario Regulation 419/05 regulation now applies. Ontario Regulation 419/05 requires more detailed modelling, in this case AERMOD, and predicted incremental concentrations are compared against the appropriate effects based standards. For most contaminants, these are 24 hour average criteria, however for certain contaminants there are also 1 hour and/or 8 hour average criteria. For the assessment of the proposed HHGS with respect to the ambient 1 hour, 8 hour, 24 hour and annual AAQCs and MALs, it is necessary to add the representative background concentration from all other sources that were determined in Section The last column in the Table 5.1 above shows the appropriate background concentrations DRAFT September Halton Hills Generating Station

50 Table 5.1 clearly shows that the predicted incremental concentrations of conventional pollutants resulting from the proposed HHGS are below the applicable air quality criteria. In addition, all incremental concentrations are below the applicable criteria when adding the 90 th percentile of measured background values. The maximum predicted short term NO x concentrations are compared against two separate air quality criteria. Scenario 4 considers the operation of the standby generator, which will supply emergency power for lighting and fire fighting, as well as for all of the equipment required for a safe and controlled shut down of the plant in the event of an emergency shutdown. For permitting purposes, the MOE has a separate ½ hour average NO x criteria specifically applicable to testing of emergency/standby equipment, of 1,880 μg/m 3. However, this higher limit only applies to non-sensitive receptors. When converted to a 1 hour average, this MOE NO x standard is 1567 μg/m 3. The maximum predicted 1 hour average NO x concentration in air during the testing of the standby generator is 428 μg/m 3 at non-sensitive receptors, which is well below the applicable criteria. It should be noted that the standby generator is operated for short time periods, for testing purposes (approximately 104 hours per year). Therefore, it is unlikely that the generator would operate during the meteorological conditions that lead to the maximum predicted air concentrations. The maximum predicted 1 hour average NO x concentration during normal operating conditions (131.5 μg/m 3 ) is well below the applicable criterion (400 μg/m 3 ), even when adding the 90 th percentile of measured background values (66 μg/m 3 ). A further consideration with respect to the predicted incremental NO x, concentrations, is that the emissions were modelled as total NO x and the resultant air concentrations are compared to an NO 2 standard. In reality, emissions from combustion sources are largely comprised of NO at the point of emission. A portion of the NO then converts photochemically to NO 2 in the presence of ozone. Consequently, the comparison of predicted total NO x concentrations to the ambient NO 2 standard is a very conservative approach. For SO 2, CO and SPM the predicted annual incremental concentrations are only a small fraction of the ambient concentrations in the surrounding areas. Recall that the study conservatively assumed that all of the particulate matter from the turbines was PM 2.5. The annual concentrations of all of the contaminants at the nearest locations where people live or could enjoy recreational activities (nearby houses and park) are all below the respective criteria. Graphical representations of the predicted incremental annual concentrations for the four conventional pollutants are presented in Appendix B DRAFT September Halton Hills Generating Station

51 5.2 TRACE VOCS AND PAHS To investigate the short-term impact of the trace VOCs and PAHs, a conservative screening approach was used. The maximum plant wide mass emission rate for each compound for which there was a 24 hour POI was divided by its respective 24 hour POI criteria to determine which compound potentially had the greatest impact. Acrolein was found to be the most restrictive contaminant. Propylene Oxide had the next highest ratio of emission rates divided by POI criteria but it is a four times less restrictive ratio compared to acrolein. GT1 w/ duct burners TABLE MAXIMUM 1 HOUR ACROLEIN EMISSION RATES (g/s) GT2 w/ duct burners Aux Boiler (standby) Emergency Generator (not running) Plant Total 1.62E E E E-03 Modelling of acrolein emissions under the worst-case condition of both combustion turbines and their duct burners running at maximum capacity and the auxiliary boiler on standby resulted in a maximum annual off property acrolein concentration of 1.1E-04 µg/m 3. The maximum 24 hour average off property acrolein concentration was predicted to be 4.4E-03 µg/m 3, which is less than 6% of the applicable POI 24-hour air quality criteria of 0.08 µg/m 3. The short-term impact of all of the other trace VOCs and PAHs would be much less than this and therefore, are considered insignificant. The annual concentrations for all of the trace VOCs and PAHs based on Scenario 1 (turbines at maximum capacity, duct burners operating 100% of the time, auxiliary boiler on standby and the standby diesel generator tested two hours a week) are presented in Table 5.3 below. The potential human health and environmental effects of these compounds are presented in Supporting Document DRAFT September Halton Hills Generating Station

52 TABLE PREDICTED ANNUAL AVERAGE CONCENTRATIONS OF TRACE VOCS AND PAHS (µg/m 3 ) VOCs PAHs Contaminant CAS # Maximum Off Maximum Along Property Property Line Benzene E E-04 Ethyl Benzene E E-04 Toluene E E-03 Xylenes E E-03 Propylene E E-05 Propylene Oxide E E-04 1,3-Butadiene E E-06 Formaldehyde E E-02 Acetaldehyde E E-04 Dichlorobenzene E E-06 Acrolein E E-04 Ethane E E-02 Butane E E-02 Hexane E E-02 Pentane E E-02 Propane E E-02 Naphthalene E E-05 Acenaphthylene E E-08 Acenaphthene E E-08 Fluorene E E-07 Phenanthrene E E-07 Anthracene E E-08 Fluoranthene E E-08 Pyrene E E-08 Benzo(a)anthracene E E-08 Chrysene E E-08 Benzo(b)fluoranthene E E-08 Benzo(k)fluoranthene E E-08 Benzo(a)pyrene E E-08 Indeno( 1,2,3-cd)pyrene E E-08 Dibenzo(a,h)anthracene E E-08 2-Methylnapthalene E E-07 3-Methylchloranthrene E E-08 7,12 Dimethylbenz(a)anthracene E E-08 Benzo(g,h,l)perylene E E DRAFT September Halton Hills Generating Station

53 5.3 VISIBLE PLUMES, FOGGING AND ICING The combustion products of natural gas are water and CO 2. This water content could possibly result in a visible vapour plume from the main stacks during the cold winter months and other weather conditions. Due to the height of these stacks and the use of an ACC, there will be no concerns regarding fogging and icing. There should be no interference with Toronto Pearson Airport operation or Highway 401 due to the low height of the stacks and the distance to the airport (~22 km). 5.4 OZONE FORMATION The proposed HHGS does not emit O 3 directly. The facility would emit NO x however, that can react, with sufficient sunlight and hydrocarbons, to form O 3 downwind of the NO x source. On an annual basis, the predicted incremental increase in NO x levels at the residence with the highest concentration is 1.1 µg/m 3. Compared to the annual background level of 41 µg/m 3, the increase due to the proposed HHGS would not be significant (2.7%). Compared to all of the NO x emissions that currently exist in the surrounding areas, including all of the mobile sources, the NO x emissions from the proposed HHGS are small. No detectable changes in ozone levels are expected as a result of this project DRAFT September Halton Hills Generating Station

54 6.0 MITIGATIVE MEASURES The predicted annual incremental concentrations of all conventional contaminants are only a small fraction of the ambient concentrations discussed in Section 2 and well within all applicable ambient air quality criteria. For these constituents, no measurable increase in ambient concentrations should be experienced on an annual basis. The NO x and CO concentrations predicted for shorter time periods (1 hour and 24 hour) appear to be more significant with respect to existing conditions. It should be recognized that the concentrations included in Table 5.1 correspond to the maximum emission rate conditions, and for the shorter time periods this often corresponds with start-up conditions and/or testing of the standby diesel generator. While these conditions will occur, they will not be continuous over many hours. It should also be noted that the likelihood of these conditions occurring during the meteorological conditions that lead to the maximum predicted air concentrations is low. Continuous emissions monitors (CEM) will be installed on each of the combustion turbine stacks to measure NO x, CO and O 2. The use of DLN technology will achieve NO x emission rates better than the provincial air emission requirements. No further mitigation measures are proposed. The emissions of greenhouse gases from the proposed HHGS are minimized by: the use of natural gas which results in a reduced mass of CO 2 emitted per unit of useful energy released as compared to other types of fossil fuels; the use of heat recovery reduces total fuel requirements and therefore results in lower emissions of CO 2 (and all other contaminants); and the use of low NO x burner technology reduces emissions of N 2 O. To reduce SPM emissions during the construction phase, effective dust suppression techniques, such as on-site watering, street cleaning and limiting the speed of vehicles traveling on the roads, will be used. The use of well-maintained equipment will ensure that combustion emissions are kept to a minimum. No other mitigative measures are required DRAFT September Halton Hills Generating Station

55 7.0 CONCLUSIONS Emissions were estimated from the proposed HHGS under six conservative operating scenarios. The maximum annual emission rates were found to occur with both turbine units base loaded and both duct burners operating. The maximum 24 hour emission rates were found to occur with one turbine base loaded and the second unit starting up. The maximum 1 hour emission rates were found to occur under base loaded conditions with duct burners operating and the standby diesel generator being tested for all contaminants except CO. The maximum 1 hour CO emission rate was found to occur with one gas turbine base loaded and the other starting up. The actual NO x emissions from the proposed HHGS will be less than predicted since the units will operate, at least most of the time, at or below the manufacturer s guarantee level of 9 ppm instead of the 18 ppm assumed for conservative modelling purposes. All modelling was undertaken using maximum emission scenarios for each of the time averaging periods studied. Predicted incremental concentrations of conventional pollutants resulting from the proposed HHGS are below any of the applicable ambient air quality criteria. The predicted maximum 1 hour incremental concentrations of NO x are less than 35% of the MOE POI criterion. The predicted maximum CO 1 hour and SPM 24 hour concentrations are less than 15% of their respective MOE POI criteria. The predicted maximum SO 2 1 hour concentration is less than 1% of its respective MOE POI 1 hour criterion. The maximum 1 hour concentration of NO x, including the background concentration, is less than the MOE criterion. The maximum 24 hour predicted ambient NO x concentration, including the background, is less than the MOE criterion. Note that the values represented in the tables are the maximum predicted values. For example, the maximum 1 hour concentration is the highest hour predicted to occur once in 5 years. The annual values are more representative of the average conditions near the site. On an annual basis, the proposed HHGS is predicted to have a maximum increase of the local NO x concentrations of less than 4% south of the Highway 401. At all other locations the increase is even less. For example, at the residence with the highest concentration, the annual incremental concentration of NO x will be approximately 2.7%. Including representative background, the predicted ambient concentrations are below any of the applicable ambient air quality criteria. These results are conservative as it was assumed that the HRSGs NO x emission rate was double the manufacturer s guarantee level and that both units would be operating all of the year. The predicted short term VOC and PAH concentrations in air are only a small fraction of applicable criteria FINAL September Halton Hills Generating Station

56 The use of DLN technology reduces NO x emissions to much lower than the Provincial Guidelines for combustion turbines. The proposed HHGS will achieve NO x emission rates better than those set out in the MOE A-5 Guideline and EC national emission guideline for new thermal power plants. The water produced from the combustion of natural gas could possibly result in a visible vapour plume from the main stacks during the cold winter months and other weather conditions. Due to the height of these stacks and the use of an ACC, there are anticipated to be no concerns regarding fogging and icing. Emissions of greenhouse gases are reduced as compared to many other electrical generation facilities due to the use of natural gas, the efficient heat recovery system, and the use of low NO x burner technology. Any emission offsets that result from the use of steam or electricity generated by the proposed HHGS have not been taken into account in this study Notification is required under the Canada-U.S. Air Quality Agreement since the proposed HHGS is within 100 km of the Canada-U.S. border and will emit more than 90 tonnes per year of NO x. There also are eleven hazardous air pollutants that have conservative estimated annual emission rates greater than 1 tonne. Due to the low levels of NO x emitted from the proposed HHGS and the existing levels of NO x in the surrounding areas, no detectable changes in ozone levels are expected because of this project. To reduce dust emissions, effective suppression techniques, such as on-site watering, street and parking lot cleaning, and limiting the speed of vehicles travelling on the roads, will be used. During construction the practices and procedures outlined in the document Best Practices for the Reduction of Air Emissions from Construction and Demolition Activities (March 2005) prepared by ChemInfo Services Inc. in conjunction with Construction & Demolition Multi- Stakeholders Working Group for Environment Canada will be followed. No other mitigative measures are required. Negligible net effects are anticipated FINAL September Halton Hills Generating Station

57 REFERENCES Air Quality Assessment for the Proposed Halton Hills Generating Station Environment Canada Canadian Climate Normals, , Ontario, Canadian Climate Program Environment Canada, 2003a. New Source Emission Guidelines for Thermal Electricity Generation Canadian Environmental Protection Act, April - Canadian Standards Association (CSA) Z Oil and Gas Pipeline Systems. CCME Canada Wide Standards for Particulate Matter (PM) and Ozone. June. FPCAP Criteria for National Air Quality Objectives: Sulphur Dioxide, Suspended Particulates, Carbon Monoxide, Oxidants (Ozone) and Nitrogen Dioxide Federal- Provincial Committee on Air Pollution (FPCAP), Subcommittee on Air Quality Objectives, Fisheries and Environment Canada, November Gas Research Institute, GRI-HAPCalc Version 3.0, November Holzworth, G.C Mixing Depths, Wind Speeds and Air Pollution Potential for Selected Locations in the United States. J. Applied Met., 6: Ontario Ministry of the Environment (MOE) Air Pollution Regulation 308, Appendices A- G, Appendix C. Ontario Ministry of the Environment, November. Ontario Ministry of the Environment (MOE), Air Quality in Ontario Appendix. Ontario Ministry of the Environment. Ontario Ministry of the Environment (MOE), Air Quality in Ontario, Appendix. Ontario Ministry of the Environment. Ontario Ministry of the Environment (MOE), Air Quality in Ontario Appendix. Ontario Ministry of the Environment. Ontario Ministry of Environment (MOE), Guideline A-5: Atmospheric Emissions from Stationary Combustion Turbines, March. Ontario Ministry of Environment (MOE), Summary of O. Reg. 419/05 Standards and Point of Impingement Guidelines & Ambient Air Quality Criteria (AAQCs), December. Pasquill, F The Estimation of the Dispersion of Windborne Material. Meteorology Magazine DRAFT September 2006 R-1 Halton Hills Generating Station

58 Schulman L.L., D.G. Strimaitis and J.S. Scire Addendum to ISC3 User s Guide - The Prime Plume Rise and Building Downwash Model. Submitted by: Electric Power Research Institute. November. SENES Consultants Limited (SENES) A Mixing Height Study for North America ( ). Prepared for the Atmospheric Environment Service. Turner, D.B A Diffusion Model for an Urban Area. Journal of Applied Meteorology. Turner, B.D Workbook on Atmospheric Dispersion Estimates. United States Department of Health, Education and Welfare, Revised Edition. United States Environmental Protection Agency (U.S. EPA) 2000a. Compilation of air pollution emission factors Volume 1: Stationary point and area sources AP-42 Section 3.1-Stationary gas turbines April. United States Environmental Protection Agency (U.S. EPA) Compilation of Air Pollution Emission Factors Version 5 Volume 1: Stationary Point and Area Sources AP-42 Section 3.3-Gasoline and Diesel Industrial Engines. October. Young, J.W.S. and Radonjic, Z Air Quality Simulations How Much Bias and Error Can Climate Introduce? Paper presented at the 27th CMOS Congress, Fredericton N.B., June DRAFT September 2006 R-2 Halton Hills Generating Station

59 APPENDIX A TORONTO AMBIENT AIR QUALITY STATISTICS DRAFT September 2006 Halton Hills Generating Station

60 Year Station Number Table A1 - Annual Mean Contaminant Concentrations Station Location Annual Mean Contaminant Concentration SPM PM 10 PM 2.5 NO x SO 2 CO O 3 (µg/m 3 ) (µg/m 3 ) (µg/m 3 ) (µg/m 3 ) (µg/m 3 ) (µg/m 3 ) (ppb) Hamilton: Main St W/Hwy Hamilton: Dundurn/York Toronto West: Elmcrest Rd., Centennial Park Etobicoke: Evans/Arnold Ave Burlington: Hwy2/North Shore Blvd E Burlington: 3900 Mainway Blvd Oakville: Bronte Rd/Woburn Cres Oakville: 8th Line/Glenashton Dr., Halton Reserv Brampton: 525 Main St. N., Peel Manor Mississauga: Frank Mckechnie Comm. Ctr Mississauga: Queensway W/Hurontario St Mississauga: Apple Lane, Meadow Park Hamilton: Main St W/Hwy Hamilton: Dundurn/York Toronto West: Elmcrest Rd., Centennial Park Etobicoke: Evans/Arnold Ave Burlington: Hwy2/North Shore Blvd E Burlington: 3900 Mainway Blvd Oakville: Bronte Rd/Woburn Cres Oakville: 8th Line/Glenashton Dr., Halton Reserv Brampton: 525 Main St. N., Peel Manor Mississauga: Frank Mckechnie Comm. Ctr Mississauga: Queensway W/Hurontario St Mississauga: Apple Lane, Meadow Park Hamilton: Main St W/Hwy Hamilton: Dundurn/York Toronto West: Elmcrest Rd., Centennial Park Etobicoke: Evans/Arnold Ave Burlington: Hwy2/North Shore Blvd E Burlington: 3900 Mainway Blvd Oakville: Bronte Rd/Woburn Cres Oakville: 8th Line/Glenashton Dr., Halton Reserv Brampton: 525 Main St. N., Peel Manor Mississauga: Frank Mckechnie Comm. Ctr Mississauga: Queensway W/Hurontario St Mississauga: Apple Lane, Meadow Park Hamilton: Main St W/Hwy Hamilton: Dundurn/York Toronto West: Elmcrest Rd., Centennial Park Etobicoke: Evans/Arnold Ave Burlington: Hwy2/North Shore Blvd E Burlington: 3900 Mainway Blvd Oakville: Bronte Rd/Woburn Cres Oakville: 8th Line/Glenashton Dr., Halton Reserv Brampton: 525 Main St. N., Peel Manor Mississauga: Frank Mckechnie Comm. Ctr Mississauga: Queensway W/Hurontario St Mississauga: Apple Lane, Meadow Park Hamilton: Main St W/Hwy Hamilton: Dundurn/York Toronto West: Elmcrest Rd., Centennial Park Etobicoke: Evans/Arnold Ave Burlington: Hwy2/North Shore Blvd E Burlington: 3900 Mainway Blvd Oakville: Bronte Rd/Woburn Cres Oakville: 8th Line/Glenashton Dr., Halton Reserv Brampton: 525 Main St. N., Peel Manor Mississauga: Frank Mckechnie Comm. Ctr Mississauga: Queensway W/Hurontario St Mississauga: Apple Lane, Meadow Park DRAFT September 2006 A-1 Halton Hills Generating Station

61 Year Station Number Station Location Annual Mean Contaminant Concentration SPM PM 10 PM 2.5 NO x SO 2 CO O 3 (µg/m 3 ) (µg/m 3 ) (µg/m 3 ) (µg/m 3 ) (µg/m 3 ) (µg/m 3 ) (ppb) Hamilton: Main St W/Hwy Hamilton: Dundurn/York Toronto West: Elmcrest Rd., Centennial Park Etobicoke: Evans/Arnold Ave Burlington: Hwy2/North Shore Blvd E Burlington: 3900 Mainway Blvd Oakville: Bronte Rd/Woburn Cres Oakville: 8th Line/Glenashton Dr., Halton Reserv Brampton: 525 Main St. N., Peel Manor Mississauga: Frank Mckechnie Comm. Ctr Mississauga: Queensway W/Hurontario St Mississauga: Apple Lane, Meadow Park Hamilton: Main St W/Hwy Hamilton: Dundurn/York Toronto West: Elmcrest Rd., Centennial Park Etobicoke: Evans/Arnold Ave Burlington: Hwy2/North Shore Blvd E Burlington: 3900 Mainway Blvd Oakville: Bronte Rd/Woburn Cres Oakville: 8th Line/Glenashton Dr., Halton Reserv Brampton: 525 Main St. N., Peel Manor Mississauga: Frank Mckechnie Comm. Ctr Mississauga: Queensway W/Hurontario St Mississauga: Apple Lane, Meadow Park mw Year SPM PM 10 PM 2.5 NO 2 SO 2 CO O 3 (µg/m 3 ) (µg/m 3 ) (µg/m 3 ) (µg/m 3 ) (µg/m 3 ) (µg/m 3 ) (ppb) 1998 Mean Mean Mean Mean Mean Mean Mean Maximum of Average all years Average of most recent 3 years Max of most recent 3 years Ratio Based on PM DRAFT September 2006 A-2 Halton Hills Generating Station

62 Table A2-90 th Percentile Contaminant Concentrations Year th Percentile Contaminant Concentration Station Station Location SPM PM 10 PM 2.5 NO 2 SO 2 CO Number (µg/m 3 ) (µg/m 3 ) (µg/m 3 ) (µg/m 3 ) (µg/m 3 ) (µg/m 3 ) 24-hr 1-hr 24-hr 1-hr 24-hr 1-hr 24-hr 1-hr 24-hr 1 hr 8-hr 24-hr Hamilton: Main St W/Hwy Hamilton: Dundurn/York Toronto West: Elmcrest Rd., Centennial Park Etobicoke: Evans/Arnold Ave Burlington: Hwy2/North Shore Blvd E Burlington: 3900 Mainway Blvd Oakville: Bronte Rd/Woburn Cres Oakville: 8th Line/Glenashton Dr., Halton Reserv Brampton: 525 Main St. N., Peel Manor Mississauga: Frank Mckechnie Comm. Ctr Mississauga: Queensway W/Hurontario St Mississauga: Apple Lane, Meadow Park Hamilton: Main St W/Hwy Hamilton: Dundurn/York Toronto West: Elmcrest Rd., Centennial Park Etobicoke: Evans/Arnold Ave Burlington: Hwy2/North Shore Blvd E Burlington: 3900 Mainway Blvd Oakville: Bronte Rd/Woburn Cres Oakville: 8th Line/Glenashton Dr., Halton Reserv Brampton: 525 Main St. N., Peel Manor Mississauga: Frank Mckechnie Comm. Ctr Mississauga: Queensway W/Hurontario St Mississauga: Apple Lane, Meadow Park Hamilton: Main St W/Hwy Hamilton: Dundurn/York Toronto West: Elmcrest Rd., Centennial Park Etobicoke: Evans/Arnold Ave Burlington: Hwy2/North Shore Blvd E Burlington: 3900 Mainway Blvd Oakville: Bronte Rd/Woburn Cres Oakville: 8th Line/Glenashton Dr., Halton Reserv Brampton: 525 Main St. N., Peel Manor Mississauga: Frank Mckechnie Comm. Ctr Mississauga: Queensway W/Hurontario St Mississauga: Apple Lane, Meadow Park Hamilton: Main St W/Hwy Hamilton: Dundurn/York Toronto West: Elmcrest Rd., Centennial Park Etobicoke: Evans/Arnold Ave Burlington: Hwy2/North Shore Blvd E Burlington: 3900 Mainway Blvd Oakville: Bronte Rd/Woburn Cres Oakville: 8th Line/Glenashton Dr., Halton Reserv Brampton: 525 Main St. N., Peel Manor Mississauga: Frank Mckechnie Comm. Ctr Mississauga: Queensway W/Hurontario St Mississauga: Apple Lane, Meadow Park Hamilton: Main St W/Hwy Hamilton: Dundurn/York Toronto West: Elmcrest Rd., Centennial Park Etobicoke: Evans/Arnold Ave Burlington: Hwy2/North Shore Blvd E Burlington: 3900 Mainway Blvd Oakville: Bronte Rd/Woburn Cres Oakville: 8th Line/Glenashton Dr., Halton Reserv Brampton: 525 Main St. N., Peel Manor Mississauga: Frank Mckechnie Comm. Ctr Mississauga: Queensway W/Hurontario St Mississauga: Apple Lane, Meadow Park 53 O 3 (ppb) 1 hr 8-hr 24-hr DRAFT September 2006 A-3 Halton Hills Generating Station

63 Hamilton: Main St W/Hwy Hamilton: Dundurn/York Toronto West: Elmcrest Rd., Centennial Park Etobicoke: Evans/Arnold Ave Burlington: Hwy2/North Shore Blvd E Burlington: 3900 Mainway Blvd Oakville: Bronte Rd/Woburn Cres Oakville: 8th Line/Glenashton Dr., Halton Reserv Brampton: 525 Main St. N., Peel Manor Mississauga: Frank Mckechnie Comm. Ctr Mississauga: Queensway W/Hurontario St Mississauga: Apple Lane, Meadow Park Hamilton: Main St W/Hwy Hamilton: Dundurn/York Toronto West: Elmcrest Rd., Centennial Park Etobicoke: Evans/Arnold Ave Burlington: Hwy2/North Shore Blvd E Burlington: 3900 Mainway Blvd Oakville: Bronte Rd/Woburn Cres Oakville: 8th Line/Glenashton Dr., Halton Reserv Brampton: 525 Main St. N., Peel Manor Mississauga: Frank Mckechnie Comm. Ctr Mississauga: Queensway W/Hurontario St Mississauga: Apple Lane, Meadow Park Year SPM PM 10 PM 2.5 NO 2 SO 2 CO (µg/m 3 ) (µg/m 3 ) (µg/m 3 ) (µg/m 3 ) (µg/m 3 ) (µg/m 3 ) 1998 Mean Mean Mean Mean Mean Mean Mean Maximum of Average all years Average of most recent 3 years Max of most recent 3 years Ratio Based on PM O 3 (ppb) DRAFT September 2006 A-4 Halton Hills Generating Station

64 Table A3 - Number of Exceedances of AAQC at Local MOE Stations Year Station Number 90th Percentile Contaminant Concentration Station Location SPM PM 10 PM 2.5 NO 2 SO 2 CO O 3 24hr 1yr 24hr 24hr 1hr 24 hr 1 hr 24hr 1yr 1hr 8 hr 1hr Hamilton: Main St W/Hwy Hamilton: Dundurn/York Toronto West: Elmcrest Rd., Centennial Park Etobicoke: Evans/Arnold Ave Burlington: Hwy2/North Shore Blvd E Burlington: 3900 Mainway Blvd Oakville: Bronte Rd/Woburn Cres Oakville: 8th Line/Glenashton Dr., Halton Reserv Brampton: 525 Main St. N., Peel Manor Mississauga: Frank Mckechnie Comm. Ctr Mississauga: Queensway W/Hurontario St Mississauga: Apple Lane, Meadow Park Hamilton: Main St W/Hwy Hamilton: Dundurn/York Toronto West: Elmcrest Rd., Centennial Park Etobicoke: Evans/Arnold Ave Burlington: Hwy2/North Shore Blvd E Burlington: 3900 Mainway Blvd. 0 INS Oakville: Bronte Rd/Woburn Cres Oakville: 8th Line/Glenashton Dr., Halton Reserv Brampton: 525 Main St. N., Peel Manor Mississauga: Frank Mckechnie Comm. Ctr Mississauga: Queensway W/Hurontario St Mississauga: Apple Lane, Meadow Park Hamilton: Main St W/Hwy Hamilton: Dundurn/York Toronto West: Elmcrest Rd., Centennial Park Etobicoke: Evans/Arnold Ave Burlington: Hwy2/North Shore Blvd E Burlington: 3900 Mainway Blvd Oakville: Bronte Rd/Woburn Cres Oakville: 8th Line/Glenashton Dr., Halton Reserv Brampton: 525 Main St. N., Peel Manor Mississauga: Frank Mckechnie Comm. Ctr Mississauga: Queensway W/Hurontario St Mississauga: Apple Lane, Meadow Park Hamilton: Main St W/Hwy Hamilton: Dundurn/York Toronto West: Elmcrest Rd., Centennial Park Etobicoke: Evans/Arnold Ave Burlington: Hwy2/North Shore Blvd E Burlington: 3900 Mainway Blvd Oakville: Bronte Rd/Woburn Cres Oakville: 8th Line/Glenashton Dr., Halton Reserv Brampton: 525 Main St. N., Peel Manor Mississauga: Frank Mckechnie Comm. Ctr Mississauga: Queensway W/Hurontario St Mississauga: Apple Lane, Meadow Park Hamilton: Main St W/Hwy Hamilton: Dundurn/York Toronto West: Elmcrest Rd., Centennial Park Etobicoke: Evans/Arnold Ave Burlington: Hwy2/North Shore Blvd E Burlington: 3900 Mainway Blvd Oakville: Bronte Rd/Woburn Cres Oakville: 8th Line/Glenashton Dr., Halton Reserv Brampton: 525 Main St. N., Peel Manor Mississauga: Frank Mckechnie Comm. Ctr Mississauga: Queensway W/Hurontario St Mississauga: Apple Lane, Meadow Park DRAFT September 2006 A-5 Halton Hills Generating Station

65 Year Station Number Station Location 90th Percentile Contaminant Concentration SPM PM 10 PM 2.5 NO 2 SO 2 CO O 3 24hr 1yr 24hr 24hr 1hr 24 hr 1 hr 24hr 1yr 1hr 8 hr 1hr Hamilton: Main St W/Hwy Hamilton: Dundurn/York Toronto West: Elmcrest Rd., Centennial Park Etobicoke: Evans/Arnold Ave Burlington: Hwy2/North Shore Blvd E Burlington: 3900 Mainway Blvd Oakville: Bronte Rd/Woburn Cres Oakville: 8th Line/Glenashton Dr., Halton Reserv Brampton: 525 Main St. N., Peel Manor Mississauga: Frank Mckechnie Comm. Ctr Mississauga: Queensway W/Hurontario St Mississauga: Apple Lane, Meadow Park Hamilton: Main St W/Hwy Hamilton: Dundurn/York Toronto West: Elmcrest Rd., Centennial Park Etobicoke: Evans/Arnold Ave Burlington: Hwy2/North Shore Blvd E Burlington: 3900 Mainway Blvd Oakville: Bronte Rd/Woburn Cres Oakville: 8th Line/Glenashton Dr., Halton Reserv Brampton: 525 Main St. N., Peel Manor Mississauga: Frank Mckechnie Comm. Ctr Mississauga: Queensway W/Hurontario St Mississauga: Apple Lane, Meadow Park DRAFT September 2006 A-6 Halton Hills Generating Station

66 APPENDIX B PREDICTED MAXIMUM INCREMENTAL ANNUAL GROUND LEVEL AIR CONCENTRATIONS DRAFT September 2006 Halton Hills Generating Station

67 Figure B1 Predicted Maximum Annual Incremental Ground Level NO x Concentrations Legend: HHGS Property Boundary 1.5 Concentration (µg/m 3 ) Maximum Concentration = 1.6 µg/m 3 Discrete Receptor DRAFT September 2006 B-1 Halton Hills Generating Station

68 Figure B2 Predicted Maximum Annual Incremental Ground Level CO Concentrations Legend: HHGS Property Boundary 1.5 Concentration (µg/m 3 ) Maximum Concentration = 0.55 µg/m 3 Discrete Receptor DRAFT September 2006 B-2 Halton Hills Generating Station

69 Figure B3 Predicted Maximum Annual Incremental Ground Level SPM Concentrations Legend: HHGS Property Boundary 1.5 Concentration (µg/m 3 ) Maximum Concentration = 0.19 µg/m 3 Discrete Receptor DRAFT September 2006 B-3 Halton Hills Generating Station

70 Figure B4 Predicted Maximum Annual Incremental Ground Level SO 2 Concentrations Legend: HHGS Property Boundary 1.5 Concentration (µg/m 3 ) Maximum Concentration = 0.03 µg/m 3 Discrete Receptor DRAFT September 2006 B-4 Halton Hills Generating Station