Generation and Loads

    Avista maintains a diversified portfolio of generation resources.

    2010 Generation Resource Mix
    Company-owned hydro 41%
    Long-term contracts 8%
    Natural Gas 33%*
    Coal 9%
    Biomass 2%
    Wind contract 2%
    Other contracts 5%

    *This includes the Lancaster Purchased Power Agreement that became part of the resource mix as of Jan. 1, 2010.

    Installed capacity, generation capability by primary energy source and Net Energy Output by primary energy source
    Project Name Present Generation Capability (MW) Nameplate Rating (Installed Capacity) (MW) Net energy output (MWh) Primary Energy Source Regulatory Regime*
    Upper Falls 10.2 10.0 52,000 Hydro WUTC and IPUC
    Monroe Street 15.0 14.8 104,000 Hydro WUTC and IPUC
    Nine Mile** 17.6 26.4 106,000 Hydro WUTC and IPUC
    Post Falls 18.0 14.8 84,000 Hydro WUTC and IPUC
    Little Falls 34.6 32.0 199,000 Hydro WUTC and IPUC
    Long Lake 83.3 70.0 487,000 Hydro WUTC and IPUC
    Cabinet Gorge 254.6 265.0 1,061,000 Hydro WUTC and IPUC
    Noxon Rapids 556.6 480.6 1,673,000 Hydro WUTC and IPUC
    Total Hydro 989.9 913.6
    Kettle Falls GS 50.0 50.7 184,000 Biomass (Wood Waste) WUTC and IPUC
    Kettle Falls CT 6.9 7.2 33,000 w/Boulder Park Natural Gas WUTC and IPUC
    Boulder Park 24.0 24.6 Natural Gas WUTC and IPUC
    Coyote Springs 2 278.3 287.0 1,559,000 Natural Gas WUTC and IPUC
    Northeast CT 56.3 61.8 44,000 w/Rathdrum Natural Gas WUTC and IPUC
    Rathdrum CT 149.0 166.5 Natural Gas WUTC and IPUC
    Colstrip Units 3 & 4 222.0 233.4 1,277,000 Coal (Mine Mouth) WUTC and IPUC
    Total thermal 786.5 831.2
    Total Generation 1,776.4 1,744.8

    * Even though projects are located in Idaho and Washington, neither the IPUC nor the WUTC exercises exclusive jurisdiction since none of our company-owned generation assets are currently assigned to a specific state where they are located. Generation assets are split with about 65 percent being attributed to Washington and about 35 percent to Idaho.

    ** We are in the process of upgrading units 1 and 2 at the Nine Mile Hydroelectric plant. With the upgrade, planned for completion in 2010, we anticipate a total additional 16 MW capability for this plant.

    Average generation efficiency of thermal plants by energy source

    Thermal generation is approximately 40 percent of Avista's total generation capability. Each facility has a specific purpose in Avista's diversified generation portfolio - whether it is for economic or load demand efficiencies.

    Plant Name Energy Source Heat Rate (Btu/kWh)
    Boulder Park Natural Gas 9,025
    Colstrip Coal 10,735
    Coyote Springs 2 Natural Gas 6,880
    Coyote Springs 2 Duct Burner Natural Gas 8,500
    Kettle Falls Biomass 13,500
    Kettle Falls CT Natural Gas 8,750
    Northeast Natural Gas 12,825
    Rathdrum Natural Gas 11,950

    Average plant availability factor by energy source
    Colstrip* Coal 68.30%
    Coyote Springs 2 Natural Gas 97.30%
    Kettle Falls Biomass 96.20%
    Hydroelectric facilities Hydro 92.39%
    Rathdrum Natural Gas 95.30%
    Northeast CT ** Natural Gas 44.60%

    *Extended 2009 outage from March - November

    ** Peaker unit - used only in times of significant energy demand

    Total water discharge by quality and destination - thermal generation

    Coyote Springs 2-Natural Gas

    Annual Water Use

    Combustion turbine (CT) make up -- For cooling; it replenishes the evaporation and blow down in the cooling tower.

    398 million gallons

    Evaporation pond -- This is the site storm water drainage off of the pavement and outside areas. The water is only pumped off site if there is more water in the flow than can be evaporated. It dries up in the summer.

    250,000 gallons

    CT Blow down -- This is to remove the concentrated solids that result from the evaporation rate in the CT.

    87 million gallons

    Waste -- This is the water that is collected from the drains inside of the plant buildings and includes the water going through the sample panels and various small bleeds for coolers, air compressor, accumulator blow down, loop seal overflow, along with any leaks we might have in valves or seals.

    92 million gallons

    Boiler make up -- This is water that is made for the steam turbine use.

    3.9 million gallons

    Kettle Falls-Biomass

    Discharge Water

    23 million gallons

    Make-up Water

    130 million gallons


    Waste water, storm water

    Zero discharge plant. All water is captured and stored in facility storage ponds.

    Length of above and underground transmission by voltage


    • 17,800 miles of distribution lines
    • 660 miles of 230 kV transmission lines
    • 1,500 miles of 115 kV transmission lines
    • 500 miles of 500 kV transmission lines (11% ownership in Colstrip to Townsend, MT line)

    Natural Gas

    • 141 miles of natural gas distribution mains (74 miles in the North Division and 67 miles in the South Division).
    • 7,000 miles of distribution lines (5,000 miles in the North Division and 2,000 miles in the South Division).

    Avista does not own any interstate gas transportation pipelines, only contractual rights, and receives gas at over 60 points along interstate pipelines (over 40 points in the North Division and over 20 points in the South Division).

    2009 Electric and Natural Gas Loads

    • Electric Average Hourly Load (aMW) 1,082
    • Peak Electric Native Load (aMW)
      • Summer (retail) 1,522
      • Winter (retail) 1,763
    • Peak Natural Gas Day Demand (Dth) 291,613