CITY OF WHITEHORSE AREAL ASSESSMENT OF GEOEXCHANGE POTENTIAL WHITEHORSE, YUKON ISSUED FOR USE W October 5, 2007

Transcription

1 CITY OF WHITEHORSE AREAL ASSESSMENT OF GEOEXCHANGE POTENTIAL WHITEHORSE, YUKON ISSUED FOR USE W EBA Engineering Consultants Ltd. p f Calcite Business Centre Unit 6, 151 Industrial Road Whitehorse, Yukon Y1A 2V3 CANADA

2 ISSUED FOR USE W i TABLE OF CONTENTS 1.0 INTRODUCTION Background Geoexchange Overview Harnessing Renewable Energy Types of Ground Heat Exchangers (GHX) Purpose and Scope INFORMATION REVIEWED AND GEOEXCHANGE DATABASE Subsurface Information City of Whitehorse Site Specific Information Delineation of Study Area Geoexchange Database ASSESSMENT METHOD Choice of GHX Types for Maps Analysis Factors Closed Loop Vertical Borehole Assessment Groundwater Open Loop Assessment Waste Heat Recovery RESULTS AND DISCUSSION Closed Loop Potential Open Loop Potential Waste Heat Potential Deep Ground Temperature Potential for District Energy Systems CONCLUSIONS AND RECOMMENDATIONS Conclusions Recommendations CLOSURE REFERENCES PAGE

3 ISSUED FOR USE W ii TABLE OF CONTENTS TABLES Table 1a Table 1b Table 2 Table 3 Table 4 Table 5 Table 6 Table 7 Table 8 Map Database (Database Parameters) Map Database (Database Scores) Database Parameters and Data Sources GHX Types and Applicability in Whitehorse Analysis Factors Commentary on Selected Analysis Factors Ease of Drilling Scores Closed Loop Assessment Method Groundwater Open Loop Assessment Method FIGURES Figure 1 Figure 2 Figure 3 Geoexchange Potential within City of Whitehorse for Vertical Borehole Closed Loop Systems Geoexchange Potential within City of Whitehorse for Groundwater Open Loop Systems Sanitary Sewer Waste Heat Potential APPENDICES Appendix A General Conditions

4 ISSUED FOR USE INTRODUCTION 1.1 BACKGROUND In accordance with our revised proposal of August 17, 2007, EBA Engineering Consultants Ltd. (EBA) has carried out an areal assessment of geoexchange potential for the City of Whitehorse (the City). This is the initial phase in developing an overall geoexchange development strategy for the City of Whitehorse. As a follow up task, EBA will cosult with the City to learn potential desired uses for geoexchange energy systems within the City limits. The results of this study will also be presented as part of the City Sustainability Planning Charette, planned for October 22-25, Our methods, technical findings, conclusions and recommendations are summarized in this report. The key deliverable of this project is a series of geoexchange potential maps included at the end of this report covering the entire City. 1.2 GEOEXCHANGE OVERVIEW Geoexchange technology relies on a specific application of refrigeration principles for moving heat energy from one location to another. By moving heat instead of converting chemical energy into heat (i.e., fossil fuel combustion), geoexchange systems can often provide space heating or cooling in a more energy-efficient manner than conventional combustion or electric resistance space-heating systems. Geoexchange heat pumps can extract energy from low-grade heat sources (e.g., at temperatures below 10 C) and concentrate the heat to a higher temperature for delivery to a space-heated environment. Heat pumps can be coupled to a ground heat exchanger so that the ground becomes the heat source for the system. The energy efficiency of a heat pump is dependent on the temperature of the source/sink that it is coupled with. In heating mode, the energy efficiency increases as the source temperature increases. In cooling mode, the energy efficiency increases as the rejection temperature decreases (and heat rejection capacity increases). Because the undisturbed earth temperature is warmer than the average winter air temperatures and cooler than average summer air temperatures, the ground makes for an attractive heat source for winter heating and heat sink for summer cooling Harnessing Renewable Energy The ground energy harnessed by geoexchange systems is renewable energy. Most of the energy captured by geoexchange is solar energy absorbed by the earth s surface while a smaller portion is geothermal energy emanating from deep earth materials. In the geologically diverse western cordillera, the Earth s geothermal component varies from site to site and in some cases can be significant with anomalously high geothermal gradients. Such higher geothermal gradients are found in parts of Yukon. In the City, warmer than ambient temperatures have been noted in the Selkirk Aquifer (Riverdale area).

5 ISSUED FOR USE 2 Although electrical energy is required to drive the heat pumps, efficient geoexchange systems are capable of achieving coefficients of performance (COPs) exceeding 3.0. COP is the ratio of the total heat energy delivered from the heat pumps divided by the electrical energy required to drive the heat pumps. For example, in heating mode at a COP of 3.0, 67% of the total heat energy delivered by a structure (load) is energy extracted from the earth Types of Ground Heat Exchangers (GHX) A ground heat exchanger (GHX) can take many forms, but generally belong to one of two broad categories: Closed-loop GHX systems which rely on conductive heat transfer between the earth and a network of piping through which a thermal exchange fluid is circulated in a closed circuit. Examples of closed-loop GHX include vertical closed-loop borehole systems and horizontal trenched piping systems. Open-loop GHX systems which rely on heat exchange with water (groundwater, surface water or ocean water) pumped from one source and disposed of in a different location (forming a discontinuous or open loop). GHXs are discussed in greater detail in Section PURPOSE AND SCOPE The purpose of this initial phase of work is to provide a high level overview of the potential to apply geoexchange technology across existing developed and potentially developable areas within the City. The purpose of this project is to provide an overview of geoexchange potential across the City based on subsurface conditions, land use and municipal governance factors (independent of specific building characteristics). The type of GHX most appropriate for a given project depends on subsurface site conditions, building characteristics, and project owner wishes. This work is meant to provide general guidance for municipal planning or site-specific studies required for geoexchange design. The geoexchange potential maps are not intended as a basis for immediate geoexchange design. The scope of this work involved the following tasks: Review and compile geological, hydrogeological, land use, and physical site conditions; Evaluate the potential to apply geoexchange technology across the city based on site suitability, climate, fuel cost and political/social factors; Evaluate the general potential for hybrid applications; and, Prepare a report including a series of geoexchange potential maps for the City. The geoexchange potential maps prepared as part of this project will provide the City and developers with a planning tool when applying geoexchange technology to new and existing developments.

6 ISSUED FOR USE INFORMATION REVIEWED AND GEOEXCHANGE DATABASE 2.1 SUBSURFACE INFORMATION Subsurface information was collected, compiled and reviewed from the following sources: Yukon Geologic Survey Yukon Digital Geology (bedrock and surficial geology); EBA ESEbase database of borehole logs and test pit records within the City of Whitehorse; Government of Yukon water well logs; Government of Yukon Community Services groundwater reports; and, City of Whitehorse groundwater reports. 2.2 CITY OF WHITEHORSE SITE SPECIFIC INFORMATION Municipal background information (lot size, land use, zoning etc.) within the City was collected from the following information sources: City of Whitehorse Official Community Plan; City of Whitehorse Integrated Community Sustainability Plan (Draft); and, The City of Whitehorse 2003 Water and Sewer Study. 2.3 DELINEATION OF STUDY AREA Based on a discussion and agreement with Ms. Lesley Cabott of the City, EBA restricted the study area for this work to include the existing developed and currently developable areas. We constructed the study area envelope (shown on Figure 1) as a sinuous band extending SE-NW and including all such areas. Areas within the City limits but outside of this envelope were not included in this study. If land use planning changes in the future, these upland eastern and western portions of the City could be included in an update of this work program. 2.4 GEOEXCHANGE DATABASE Using information collected from the above mentioned sources and inferred information, a spreadsheet database was created (Table 1a) summarizing applicable information at 121 discrete locations across the City. The database points were selected to coincide with the deepest and most comprehensive subsurface information available (e.g., water well logs and deep boreholes) and to provide sufficient data coverage within and adjacent to the areas of interest. In some cases, where no water well or deep borehole records were available, subsurface conditions were inferred based on the bedrock and surficial geological mapping, and bedrock and groundwater depths provided in the background documents reviewed (e.g., Gartner Lee 2003). Table 2 summarizes the subsurface parameters that were complied for each database point to a nominal depth of 100 m:

7 ISSUED FOR USE 4 TABLE 2: DATABASE PARAMETERS AND DATA SOURCES Parameter Source Data/ Estimation Method UTM Coordinates (easting and northing) borehole logs/ site location/ Gartner Lee 2003 Lot Size City of Whitehorse OCP Depth to Bedrock well and borehole logs/ Gartner Lee 2003 Dominant Overburden Type well and borehole logs/ surficial geological mapping/ EBA 1998 Bedrock Type well and borehole logs, bedrock geology mapping/ Gartner Lee 2003 Depth to Groundwater well and borehole logs/ Gartner Lee 2003 Thermal Conductivity (inferred) Hellstrom 1991 Hydraulic Conductivity (inferred) Fetter 1994 Transmissivity (calculated) calculated based on depth to groundwater and dominant overburden type (or aquifer properties where known) Ease of Drilling (inferred from material type) calculated (see Section 3.3) Based on the measured or inferred parameters for each database point, the potential to apply the various types of ground coupling was evaluated at each location using the criteria outlined below (Section 3.0). 3.0 ASSESSMENT METHOD 3.1 CHOICE OF GHX TYPES FOR MAPS Table 3 outlines nine plausible types of GHXs and their potential application in the City climate setting. TABLE 3: GHX TYPES AND APPLICABILITY IN WHITEHORSE Plausible GHX for Whitehorse Climate Building Heating Building Cooling Domestic Hot Water Pre-Heat Closed loop horizontal trench With great care Yes With great care Closed loop vertical borehole Yes Yes Yes Closed loop surface water With great care Yes With great care Open loop groundwater Yes Yes Yes Open loop surface water With great care Yes With great care Sanitary sewer waste heat Yes Yes Yes Hybrid solar Yes Yes Yes Hybrid standing column Yes Yes Yes Of the many plausible types of GHXs or hybrid combinations that could be applied in the City setting, we selected three types which cover a wide range. These are: Closed loop vertical borehole;

8 ISSUED FOR USE 5 Open loop (using groundwater); and Waste Heat (e.g., recoverable from sewer lines). Other GHX configurations are possible, but these cover the main types and we consider them to be adequate for the purposes of this study. 3.2 ANALYSIS FACTORS The potential for applying a particular GHX at a given site can be assessed based on the following 10 analysis factors for a given site and project (EBA 2007). Table 4 describes the 10 analysis factors and their relevance to this particular study. TABLE 4: ANALYSIS FACTORS Analysis Factors Included (Yes/ No) Explanation 1. Sustainability (physical factors) YES Included in closed and open loop potential assessments (Section 3.3 and 3.4) 2. Effects on human neighbours NO Site and project specific not included 3. Effects on ecological neighbours NO Site and project specific not included 4. Capital and operational costs YES See Table 5 (minimum acceptable rate of return) 5. Energy performance YES See Table 5 6. System complexity and YES Included in closed loop assessment (Section 3.4) constructability 7. Resale equity potential NO Resale potential is project specific not included 8. Time required for GHX construction NO Specific to a project schedule not included 9. Contractor capabilities YES See Table Potential for required further studies YES See Table 5 As this high-level overview is focused on areal site and land use conditions rather than specific building or development characteristics, only factors 1 and 6 were used to compile the potential maps. Other factors such as effects on neighbours, resale potential and time for construction (2, 3, 7, and 8) are building or development specific and have not been included in this assessment. Factors such as cost, energy performance, and contractor capability have been addressed for each type of GHX with the commentary provided in Table 5. TABLE 5: COMMENTARY ON SELECTED ANALYSIS FACTORS GHX Options Analysis Factors Open Loop (Groundwater) Closed Loop (Vertical Borehole) Waste Heat Sanitary Sewer Figure 3 outlines sanitary sewer mains > 0.400m diameter within the City. MARR would depend on 4. Capital and operational costs (minimum acceptable rate of return (MARR)) MARR is impacted by size of load. In general the MARR with groundwater systems decreases as the building load increases. In general the comparative capital costs are highest for a closed loop vertical borehole

9 ISSUED FOR USE 6 TABLE 5: COMMENTARY ON SELECTED ANALYSIS FACTORS GHX Options Analysis Factors Open Loop (Groundwater) 5. Energy performance System efficiency is dependent on the site conditions (temperature and depth to groundwater) and the specifics of the system design. Energy performance is dependent on what geoexchange is being compared to. As this is a site and building specific parameter, it has not been addressed as part of the areal assessment. 9. Contractor capabilities 10. Potential for required further studies Water well contractor capabilities have been established through the domestic and municipal water supply industries. As contractor capabilities exist within the Yukon, this has not been addressed as part of the areal assessment. Further studies likely required on a site specific basis to address aquifer conditions, and potential off site impacts. A water license would be required for any system extracting more than 1.1 L/sec (18 USgpm). This is site and design specific and has not been addressed in the areal assessment. Closed Loop (Vertical Borehole) system (as compared to other types of GHX). MARR is impacted by size and distribution of the building load. System efficiency is dependent on the site conditions (thermal conductivity), and the details of the specific design. Energy performance is dependent on what geoexchange is being compared to. As this is a site and building specific parameter, it has not been addressed as part of the areal assessment. No local geoexchange specific drilling contractors. Local contractors would require training, or contractors would have to be brought in from elsewhere. Further studies may be required on a site specific basis to address design, and potential off site impacts. This type of project may classify as a Reviewable Project under the Yukon Environmental and Socioeconomic Assessment Act. This is site specific and has not been addressed in the areal assessment. Waste Heat Sanitary Sewer the accessibility of the waste stream for GHX. This is site specific and has not been addressed as part of this areal assessment. Waste heat from sanitary sewer has only been considered for existing sewer mains > m diameter. Energy performance will depend on the flow and temperature of the discharging waste stream. Local contractor capabilities do not exist. This application would likely involve specialty heat exchangers requiring either training local contractors, or bringing in contractors from elsewhere. Further study required to characterize extent of resource and harnessing options.

10 ISSUED FOR USE CLOSED LOOP VERTICAL BOREHOLE ASSESSMENT The feasibility of a closed loop GHX depends on the conductive heat transfer properties of the subsurface, the ability to economically install the GHX and the subsurface ground temperature. Factors affecting the feasibility of a closed loop GHX include the following: The lithologic profile and stability of subsurface material underlying the site; The depth to bedrock; The hydraulic gradient of groundwater flow; and, The thermal conductivity and temperature of the subsurface material. Thermal conductivity has been estimated based on typical ranges for the dominant soil and bedrock types at each database point. The ease of drilling and installation is primarily dependent on the subsurface material (type of soils and/or bedrock) and whether the depth of a soil/bedrock interface would require two different drilling methods for the same borehole. Overburden and bedrock types were assigned a score between 1 (most difficult) and 5 (easiest) for the ease of as shown in Table 6: TABLE 6: EASE OF DRILLING SCORES Ease of Drilling and Closed Loop Overburden or Bedrock Type Installation Score ( 1 = most difficult to drill, 5 = easiest to drill) Silt and Sand/ Silt/ Silt and Gravel Unsaturated 3 Saturated 5 Sand/ Sand and Gravel/ Gravel Unsaturated 1 Saturated 1 Till/ Silt and Clay/ Clay Unsaturated 3 Saturated 5 Basalt 2 Limestone/ Sandstone 3 Granodiorite 3 The score for each data point was also weighted based on the overburden thickness. A weighting penalty of either 0.6 or 0.8 was incorporated for data points that had a bedrock interface between 15 m and 50 m (0.6) of ground surface and between 50 and 100 m (0.8) of ground surface. The weighting factor was 1.0 if depth to bedrock was known or inferred to be <15 m or >100 m. The weighting penalty is heavier for shallow bedrock since this would require a costly changeover of drilling methods for every hole. If the depth to bedrock is 15 m or less then the drilling changeover is not a significant extra cost. The weighting penalty is lighter for deeper bedrock since some systems might be workable with bore holes installed completely in overburden. The weighted score is labelled a closed-loop completion rating (CCR) on Table 1b.

11 ISSUED FOR USE 8 Closed loop conditions at each database point were assigned and scored based on the following scoring criteria outlined in the following table: TABLE 7: CLOSED LOOP ASSESSMENT METHOD Parameter Data Range Units Scoring Criteria (1-10) Depth to Groundwater m 1 = = 0.15 Thermal Conductivity of Subsurface Material (based on dominant overburden, bedrock types and thicknesses) W/m- K 1 = = 3.5 Ease of Drilling and Installation Rating unitless 1 = = 5 Easiest Hardest Lot Size m 2 1 = = The total score assigned to each database point was determined using the following formula: Total Score = (Depth to Groundwater Score) x (Thermal Conductivity Score) x (Ease of Drilling and Installation Score) x (Lot Size Score) The possible total score range was therefore 1 to 10,000. The final score (for mapping at each control point) was determined by taking the log 10 of the total score to give a potential score between 0 and 4 for each point. A poor label was assigned for point scores less than 1.6 based on the combination of a set of site conditions leading to unfavourable closed loop coupling. A good label was assigned for point scores greater than 3.2 based on a typical set of site conditions leading to favourable closed loop ground coupling. The results are included in Table 1b, and shown graphically on Figure 1. The point scores were contoured to give the distribution shown on Figure 1. A solid line defines the boundary between ratings where the scores are based on known data points (e.g., well logs and deep boreholes); a dashed line defines the boundary where the scores are based on inferred data points (e.g., geologic mapping, shallow boreholes). Results are discussed in Section 4.0. The hypothetical conditions used to define the threshold scores for favourable and unfavourable closed loop ground coupling are described as follows: Good = thermal conductivity >2 W/m- K, depth to groundwater <20 m, drilling and completion score >3.75 and lot size >5,000m 2, and Poor = thermal conductivity < 1 W/m- K, depth to groundwater >60 m, drilling and completion score <1.75, and lot size <1,000m GROUNDWATER OPEN LOOP ASSESSMENT Factors affecting the feasibility of a groundwater supplied open loop systems depend on the following:

12 ISSUED FOR USE 9 The presence of extractable groundwater sources at sufficient flow rates. This is largely controlled by the depth to groundwater (pumping effort) and aquifer transmissivity; Suitable groundwater quality; and, Space to economically extract and dispose of the groundwater (either through reinjection or disposal). This is controlled by lot size. Groundwater quality data within the City is limited to information within the Selkirk well field, and discrete well locations throughout other neighbourhoods (Wolf Creek, MacPherson, and Hillcrest). In general, groundwater within the City is a hard calciumbicarbonate type water. Groundwater quality can affect the operation and maintenance of an open loop system; however insufficient data exists to incorporate this parameter into the areal assessment. The groundwater conditions at each database point assigned a score between one and ten according to the range of values as shown in Table 8: TABLE 8: GROUNDWATER OPEN LOOP ASSESSMENT METHOD Database Parameter Data Range Units Scoring Criteria (1-10) Depth to Groundwater m 1 = = 0.15 Transmissivity (of dominant overburden ,820 m2/day 1 = = 5820 type, or aquifer where established) Lot Size ,000 m2 1 = = The product of these three parameters was than calculated, to provide a score between 1 and 100 for each data point: Total Score = (Depth to Groundwater Score) x (Transmissivity Score) x (Lot Size Score) The final score for mapping purposes was determined by taking the log 10 of the total score to give a potential score between 1 and 3 for each point. A poor label was assigned for point scores less than 1.1 based on the combination of a set of site conditions leading to unfavourable open loop coupling. A good label was assigned to point scores greater than 1.9 based on a typical set of site conditions leading to favourable open loop ground coupling. A fair label was assigned for values between good and poor. The results are included in Table 1b and shown graphically on Figure 2. The point scores were contoured to give the distribution shown on Figure 2. A solid line defines the boundary between ratings where the scores are based on known data points (e.g., well logs and deep boreholes) a dashed line defines the boundary where the scores are based on inferred data points (e.g., geologic mapping, shallow boreholes). Results are discussed in Section 4.0. The hypothetical conditions used to define the threshold scores for favourable and unfavourable open loop ground coupling are described as follows:

13 ISSUED FOR USE 10 Good = transmissivity >1000 m 2 /day, depth to groundwater <20 m, lot size >5,000m 2, and Poor = transmissivity <100 m 2 /day, depth to groundwater >60 m, lot size <1,000 m WASTE HEAT RECOVERY The potential for waste heat recovery was evaluated based on the proximity to accessible sanitary sewer waste heat sources. The ability to use and store waste heat is dependent both on the magnitude of the waste heat source and the ability to harness, store and use the waste heat source. The following waste heat sources have been identified within Whitehorse: Sanitary sewer mains > m diameter (shown on Figure 3); Waste heat from indoor arenas (Canada Games Centre, Takhini, Mt. McIntyre Curling Facility); and Waste heat from the landfill and community composting facility. 4.0 RESULTS AND DISCUSSION 4.1 CLOSED LOOP POTENTIAL Figure 1 shows geoexchange potential for vertical borehole closed loop systems within the City. Notable items include the following: Almost the entire City has fair to good potential (split roughly half and half) for closed loop applications. The only poor area is near the confluence of the Takhini and Yukon Rivers. The potential for applying closed loop geoexchange within the City tends to increase with elevation and distance from the base of the Yukon River channel. This is consistent with bedrock occurring at or near surface at higher elevations and decreasing density of development (hence increasing lot size). 4.2 OPEN LOOP POTENTIAL Figure 2 shows the geoexchange potential for groundwater supplied open loop systems within the City. Notable items include the following: Most of the City study area shows fair to good potential for open loop applications. Poor areas are distributed mainly within the central part of the study area; In general, three areas with economically extractable groundwater for drinking water use have been identified within the City; Riverdale (Selkirk Aquifer), MacPherson, and Spruce Hill. These areas also show good open loop potential. Productive aquifers suitable to supply single residences may exist at other locations throughout the City,

14 ISSUED FOR USE 11 however, their sustainable yields and suitability to supply an open loop geoexchange system is unknown. Estimates for transmissivity are based on the saturated thickness of the dominant type of overburden, or on the aquifer characteristics (where aquifers have been defined). This does not account for the potential presence of aquifers where no information exists. Thus, the potential map is a conservative estimate which accounts for the presence of known, but not potential aquifers. With site specific hydrogeology testing, a given project site in a fair area may possibly be elevated to good. As lot size governs the space available for extraction and injection wells, in general, larger lots can better accommodate the required separation between extraction and injection wells. If direct disposal of extracted water is possible (either to storm sewer or other), then the lot size restriction is eliminated. For example, the McRae area is known to be underlain by a moderately productive aquifer (Miles Canyon Basalt), however, the small lot sizes restrict allowable spacing and result in a low potential rating for open loop applications. Areas with small lot sizes are also conducive to district energy systems with common extraction and injection wells. 4.3 WASTE HEAT POTENTIAL Figure 3 shows the distribution of sanitary sewers of 450 mm (blue), 560 mm (yellow) and 610 mm (red) diameters throughout the City. This sewerage is restricted to the northern part of the City, from Riverdale (south) up to the sewage treatment plant north of the Whistle Bend. The longest continuous sewer section is the 610 mm diameter pipe leading from the north end of Granger/ Copper Ridge area north to the sewage treatment plant (approximately 11.5 km). There could be an opportunity to incorporate heat recovery from such sewer lines into a hybrid geoexchange system. The practicability and economics of such a concept will depend on proximity to the sewer line, access to the sewer for heat recovery, individual project needs and owner s interests. Heat recovery prospects would typically be most favourable for large pipe diameters closer to their termination. 4.4 DEEP GROUND TEMPERATURE Deep ground temperature data was only available at two locations within the City within the Selkirk aquifer area and at the location of the Yukon Honda test ground heat exchanger borehole (Downtown, point 49). Temperatures within the Selkirk aquifer are known to be anomalously high (above the typical geothermal gradient and up to 9.4 C at 155 m depth (Stanley 1978)) which may lead to more favourable conditions for closed loop applications. However, there are insufficient data to incorporate this parameter into the scoring method. Deep ground temperature is a critical design parameter for closed loop systems and should be measured at each site as part of engineering design.

15 ISSUED FOR USE POTENTIAL FOR DISTRICT ENERGY SYSTEMS Several areas currently developed or developable lend themselves to possible local district energy systems (DESs) based on the geoexchange potential shown in Figures 1 and 2. For open loop systems, theses are the good areas in Hidden Valley/ MacPherson, Riverdale, parts of Wolf Creek and Spruce Hill areas and Cowley Creek. A DES is particularly appealing for groundwater open loop to distribute costs. For closed loop systems, these are the good areas in Hidden Valley, parts of Whistle Bend, the north end of Takhini, the area south and west of Schwatka Lake, the southwest side of McRae, Wolf Creek, Spruce Hill, Mary Lake and Cowley Creek. Areas that have both good open loop and closed loop potential are the southwest side of Hidden Valley, the area just north of Crestview, the area east of the Yukon River opposite Marwell, the east side of Schwatka Lake, the west side of McRae, the west part of Wolf Creek, Spruce Hill and Cowley Creek. 5.0 CONCLUSIONS AND RECOMMENDATIONS 5.1 CONCLUSIONS 1. Almost all of the City of Whitehorse area studied has fair to good potential (spilt roughly half and half) for vertical borehole closed loop geoexchange systems. The only poor area is near the confluence of the Takhini and Yukon River. 2. Most of the City has fair potential with lesser good potential for groundwater open loop geoexchange systems. Five separate poor potential areas are identified within the central part of the City. 3. Waste heat potential by heat recovery from sanitary sewer lines is most favourable near the larger sewer pipes (450 to 610 mm diameter) which occur between Riverdale and the sewage treatment plant area (across the Yukon River from the Whistle Bend area). Heat recovery prospects would be most favourable for larger diameter pipes closest to their termination. 4. Potential areas for local district energy systems are presented for good closed or open loop potential areas around the City. Areas with both good closed loop and open loop potential are identified and would offer the widest rage of ground heat exchanger options for site specific characterization and geoexchange design. 5.2 RECOMMENDATIONS 1. The City, through its sustainability planning and engineering staff, should assess the demand for different geoexchange applications and energy use (including prospects, for district energy systems). This will be completed as Phase 2 of this geoexchange assessment carried out by EBA. 2. The City should include geoexchange technology in future planning and sustainability initiatives, given the large areas of fair to good potential within the City limits.

16

17 ISSUED FOR USE 14 REFERENCES Associated Engineering Services Ltd Report to the Government of the Yukon Territory on the Results of a Well Drilling Program. January EBA Engineering Ltd Professional Guidelines for Geoexchange Systems in British Columbia. Part 1 Assessing Site Suitability and Ground Coupling Options. Report prepared for Geoexchange BC. May EBA Engineering Ltd City of Whitehorse Geotherm Design Manual. Report prepared for the City of Whitehorse. October Fetter, C.W Applied Hydrogeology 3 rd Ed. Prentice Hall, New Jersey Gartner Lee Limited City of Whitehorse Groundwater Inventory. Report prepared for City of Whitehorse, DIAND and Yukon Government. March Gartner Lee Limited Wolf Creek and Pineridge Water Well Database and Pilot Project. Report prepared for DIAND Water Resources. February Gartner Lee Limited Yukon Groundwater and Ground Source Heat Potential Inventory. Report prepared for Energy Solutions Centre. December Gordey S.P. and Makepeace, A.J. (compilers) Geological Survey of Canada. Open File Yukon Geological Survey, Open File (D). Yukon Digital Geology (Version 2.0). Hellstrom, G Ground Heat Storage. Department of Mathematical Physics, University of Lund. Sweden Klohn Leonoff Yukon Consulting Engineers MacPherson Subdivision - Phase II Site Suitability Study Test Well. Report Prepared for Yukon Community and Transportation Services. January Stanley Associates Engineering Ltd City of Whitehorse 1978 Groundwater Exploration Program. Hilcrest and Selkirk Areas. Report prepared for City of Whitehorse. November Stantec Consulting Ltd The City of Whitehorse 2003 Water and Sewer Study. Report Prepared for the City of Whitehorse. January 2004.

18 ISSUED FOR USE W TABLES

19 Ocotober 2007 Page 1 of 2 TABLE 1a: MAP DATABASE PARAMETERS EASTING NORTHING ID TYPICAL LOT SIZE IN VICINITY (m 2 ) DEPTH TO BEDROCK OVERRBURDEN TYPE BEDROCK TYPE DEPTH TO GW KNOWN/ INFERRED (m) KNOWN/ INFERRED (m) bg/l Unsaturated Overburden Thickness UNIT THICKNESSES Saturated Overburden Thickness Unsaturated Bedrock Thickness Saturated Bedrock Thickness Unsaturated Overburden THERMAL CONDUCTIVITY k (W/m-K) Saturated Overburden Unsaturated Bedrock Saturated Bedrock HYDRAULIC CONDUCTIVITY K (m/day) TRANSMISSIVITY T (m 2 /day) K eq Overburden Bedrock Teq Tfav Teff OVBDN BR EASE OF DRILLING AND INSTALLATION 1 = HARDEST 5 = EASIEST COMBINE D WEIGHTING FACTOR Rating INFERRED 40 Silt and Sand Basalt KNOWN KNOWN 50.9 Sand and Gravel Basalt KNOWN INFERRED 35 Silt and Sand Basalt KNOWN INFERRED 25 Silt and Sand Basalt KNOWN KNOWN 5.5 Gravel Granodiorite INFERRED KNOWN 9.1 Silt and Clay Basalt KNOWN KNOWN 14.6 Silt and Sand Granodiorite KNOWN KNOWN 18 Silt Granodiorite KNOWN KNOWN 49.7 Silt Basalt KNOWN KNOWN 16.3 Silt and Gravel Basalt KNOWN KNOWN 41.1 Silt and Clay Granodiorite KNOWN KNOWN 9.8 Sand and Gravel Granodiorite KNOWN KNOWN 34.1 Silt and Sand Basalt KNOWN KNOWN 57.9 Silt and Sand Granodiorite KNOWN KNOWN 27.4 Silt and Sand Granodiorite KNOWN KNOWN 46.6 Silt Granodiorite INFERRED KNOWN 44.5 Silt and Sand Granodiorite INFERRED INFERRED 55 Silt and Clay Granodiorite INFERRED KNOWN 42.7 Silt and Sand Granodiorite KNOWN KNOWN 2 Sand Granodiorite KNOWN KNOWN 0.9 Till Granodiorite KNOWN KNOWN 6 Silt and Sand Granodiorite KNOWN KNOWN 20 Silt and Clay Basalt KNOWN INFERRED 30 Silt Basalt INFERRED INFERRED 25 Silt Basalt INFERRED INFERRED 25 Silt Granodiorite INFERRED INFERRED 30 Silt Granodiorite INFERRED INFERRED 45 Silt and Sand Basalt INFERRED INFERRED 100 Silt and Clay Granodiorite INFERRED KNOWN 52.1 Sand Basalt INFERRED KNOWN 57.3 Sand and Gravel Basalt KNOWN KNOWN 52.4 Sand and Gravel Basalt KNOWN KNOWN 50.3 Sand Granodiorite KNOWN KNOWN 24.3 Silt Limestone KNOWN KNOWN 38.7 Sand and Gravel Limestone KNOWN KNOWN 5.8 Silt Limestone KNOWN INFERRED 40 Silt Limestone KNOWN KNOWN 44.1 Sand and Gravel Granodiorite KNOWN INFERRED 55 Silt Granodiorite INFERRED INFERRED 55 Silt Granodiorite INFERRED INFERRED 55 Silt Granodiorite KNOWN KNOWN 71 Silt Granodiorite KNOWN KNOWN 69.2 Silt Granodiorite KNOWN INFERRED 100 Sand and Gravel Limestone KNOWN INFERRED 100 Silt and Clay Limestone KNOWN INFERRED 130 Silt and Clay Limestone KNOWN INFERRED 100 Silt and Clay Limestone KNOWN KNOWN 94 Sand Limestone KNOWN KNOWN 55 Silt and Sand Granodiorite INFERRED INFERRED 125 Silt and Clay Granodiorite INFERRED INFERRED 50 Gravel Limestone INFERRED INFERRED 50 Gravel Limestone KNOWN INFERRED 40 Clay Limestone KNOWN INFERRED 80 Silt and Sand Granodiorite INFERRED INFERRED 80 Silt Granodiorite KNOWN KNOWN 73 Silt Limestone INFERRED KNOWN 108 Silt Limestone INFERRED KNOWN 32.3 Silt Granodiorite INFERRED KNOWN 23.5 Silt and Clay Sandstone INFERRED INFERRED 40 Sand and Gravel Granodiorite INFERRED INFERRED 40 Sand and Gravel Basalt INFERRED

20 Ocotober 2007 Page 2 of 2 TABLE 1a: MAP DATABASE PARAMETERS EASTING NORTHING ID TYPICAL LOT SIZE IN VICINITY (m 2 ) DEPTH TO BEDROCK OVERRBURDEN TYPE BEDROCK TYPE DEPTH TO GW KNOWN/ INFERRED (m) KNOWN/ INFERRED (m) bg/l Unsaturated Overburden Thickness UNIT THICKNESSES Saturated Overburden Thickness Unsaturated Bedrock Thickness Saturated Bedrock Thickness Unsaturated Overburden THERMAL CONDUCTIVITY k (W/m-K) Saturated Overburden Unsaturated Bedrock Saturated Bedrock HYDRAULIC CONDUCTIVITY K (m/day) TRANSMISSIVITY T (m 2 /day) K eq Overburden Bedrock Teq Tfav Teff OVBDN BR EASE OF DRILLING AND INSTALLATION 1 = HARDEST 5 = EASIEST COMBINE D WEIGHTING FACTOR Rating KNOWN 43 Silt and Sand Basalt INFERRED INFERRED 40 Silt and Sand Basalt INFERRED INFERRED 40 Sand and Gravel Basalt INFERRED INFERRED 80 Till Limestone INFERRED INFERRED 40 Sand and Gravel Basalt INFERRED INFERRED 50 Silt and Sand Granodiorite INFERRED INFERRED 100 Silt and Sand Granodiorite INFERRED INFERRED 30 Gravel Granodiorite INFERRED INFERRED 50 Silt and Sand Granodiorite INFERRED INFERRED 50 Silt and Sand Granodiorite INFERRED INFERRED 100 Silt and Sand Granodiorite INFERRED INFERRED 50 Silt and Sand Granodiorite INFERRED INFERRED 60 Sand and Gravel Granodiorite INFERRED INFERRED 50 Silt Granodiorite INFERRED INFERRED 50 Silt Granodiorite INFERRED INFERRED 50 Silt Granodiorite INFERRED INFERRED 10 Silt and Sand Limestone INFERRED INFERRED 15 Till Limestone INFERRED INFERRED 50 Silt and Clay Granodiorite INFERRED INFERRED 50 Silt and Clay Granodiorite INFERRED INFERRED 50 Silt and Clay Granodiorite INFERRED INFERRED 50 Silt and Clay Limestone INFERRED INFERRED 15 Till Limestone INFERRED INFERRED 2 Gravel Granodiorite INFERRED INFERRED 50 Silt and Sand Granodiorite INFERRED INFERRED 50 Silt and Sand Granodiorite INFERRED INFERRED 10 Till Limestone INFERRED INFERRED 2 Till Granodiorite INFERRED INFERRED 15 Till Limestone INFERRED KNOWN 12.2 Silt Granodiorite INFERRED KNOWN 6.1 Till Limestone INFERRED INFERRED 50 Silt and Clay Limestone INFERRED INFERRED 50 Silt and Clay Limestone INFERRED INFERRED 50 Silt and Clay Limestone INFERRED INFERRED 50 Silt and Clay Limestone INFERRED INFERRED 10 Till Limestone INFERRED INFERRED 10 Silt Limestone INFERRED INFERRED 15 Silt Limestone INFERRED INFERRED 15 Silt Limestone INFERRED INFERRED 10 Silt Limestone INFERRED INFERRED 100 Silt Sandstone INFERRED INFERRED 100 Silt Sandstone INFERRED INFERRED 100 Silt Sandstone INFERRED INFERRED 20 Till Limestone INFERRED INFERRED 50 Silt Limestone INFERRED INFERRED 40 Silt Granodiorite INFERRED INFERRED 10 Till Granodiorite INFERRED INFERRED 25 Till Granodiorite INFERRED INFERRED 25 Till Granodiorite INFERRED INFERRED 25 Till Granodiorite INFERRED INFERRED 50 Till Limestone INFERRED INFERRED 50 Till Limestone INFERRED INFERRED 50 Silt and Clay Basalt INFERRED INFERRED 100 Silt and Clay Granodiorite INFERRED INFERRED 25 Silt and Clay Granodiorite INFERRED INFERRED 15 Silt and Clay Granodiorite INFERRED INFERRED 35 Silt and Clay Granodiorite INFERRED INFERRED 35 Silt and Clay Granodiorite INFERRED INFERRED 35 Silt and Clay Granodiorite INFERRED INFERRED 40 Silt and Clay Basalt INFERRED