1 Western Wind and Solar Integration Study Site Selection Analysis 5/14/2008

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6 Transmission Zones used in Site Selection

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Load Analysis

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23 “In Area” Sites

24 “High Capacity Factor” Sites

25 In Area Scenario

26 In Area Scenario

27 High Capacity Factor Scenario

28 High Capacity Factor Scenario

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31 RegionSites Required Annual Energy (GWH) Average Capacity Factor (%) Inside Study Footprint69986, % Outside Study Footprint1,176121, % Total1,875208, % High Capacity Factor Scenario

32 Summary Comments Pre-Selected capacity represents existing and planned sites rounded up to nearest 30 MW. -Ignore “planned” sites in Scenario creation. How much capacity can be reasonably exported (imported) at each area? Assume constant energy between scenarios rather than constant number of plants: Avg Wyoming C.F/Avg Arizona Plant = 49.1/32.0 = 1.53 ~Roughly 2 MW of wind in Wyoming produces the same energy as 3 MW of wind in Arizona. Initial Study Scenarios:Baseline (I.e. Pre-Selected Sites) High Renewables: - In Area Subsequent Scenarios:High Capacity Factor “Constrained” High Capacity Factor

33 Summary Comments Transmission costs estimated at $1350/MW mile. New Wind plant costs estimated at $1750/KW. Therefore saving a MW of wind capacity would pay for roughly 1300 miles of transmission. Phoenix, AZ to central Wyoming is about 650 miles, so a MW of Wind capacity would pay for the cost of 2 MW of transmission.

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36 Summary Comments - Solar How much existing Solar generation is there? -Can we ignore Solar in the Baseline? Does existing Solar generation match up with CSP and PV site data?