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GAS QUALITY: HOW IT IMPACTS QUESTAR GAS

GAS QUALITY: HOW IT IMPACTS QUESTAR GAS. Docket 04-057-09 October 13, 2004. COMBUSTION THEORY 101. HEAT + H. 0 + CO. + CO + Other Stuff. 2. 2. Try to keep as low as possible. Try to keep as high as possible. NATURAL GAS. AIR. Orifice size adjusted for specific.

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GAS QUALITY: HOW IT IMPACTS QUESTAR GAS

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  1. GAS QUALITY: HOW IT IMPACTS QUESTAR GAS Docket 04-057-09 October 13, 2004

  2. COMBUSTION THEORY 101 HEAT + H 0 + CO + CO + Other Stuff 2 2 Try to keep as low as possible Try to keep as high as possible NATURAL GAS AIR Orifice size adjusted for specific installation conditions: Efficient and safe combustion requires • - Altitude the correct ratio of oxygen and fuel - Gas Composition • The ability of an appliance to properly combust a fuel different than what it was adjusted for depends on the heating value and specific gravity of the fuel Heating Value Wobbe Number = Specific Gravity

  3. IMPACT OF GAS QUALITY CHANGE ON APPLIANCE PERFORMANCE Case 1: Ideal Conditions Appliance Properly Adjusted for Altitude and 1088 Btu/CF & .62 Specific Gravity (Wobbe # 1382) Proper flame characteristics • Appliance will perform as rated • Low carbon monoxide emissions • 1060 Btu/CF & .61 S.G. (Wobbe # 1357) NATURAL GAS AIR

  4. IMPACT OF GAS QUALITY CHANGE ON APPLIANCE PERFORMANCE Case 2: Introduction of Coal Seam Gas Appliance Properly Adjusted for Altitude and 1088 Btu/CF & .62 Specific Gravity Gas (Wobbe # 1382) Flame instability (liftoff and possible blow - off) • Appliance will produce less heat than rated • Increase in carbon monoxide emissions • 985 Btu/CF & .575 S.G. (Wobbe # 1299) NATURAL GAS AIR

  5. IMPACT OF GAS QUALITY CHANGE ON APPLIANCE PERFORMANCE Case 3: Re - Orifice Appliance Southern System Set - Point Appliance Properly Adjusted for Altitude and 1003 Btu/CF & .56 Specific Gravity Gas (Wobbe #1340) Proper flame characteristics • Appliance will perform as rated • Low carbon monoxide emissions • 985 Btu/CF & .575 S.G. (Wobbe #1329) NATURAL GAS AIR Change orifice out with larger diameter orifice

  6. PIPELINE BTU SPECIFICATIONS(September, 2004)

  7. Questar Pipeline – Downstream Btu Delivery Specs. KRGT (Roberson Creek) Min. - 970 Btu/CF Max.– No Limit Btu/CF CIG Min.– 968 Btu/CF Max.– 1235 Btu/CF WIC Min.– 950 Btu/CF Max. –No Limit Southern Star Btu Delivery Requirements Min.– 970 Max.– No Limit Overthrust Pipeline ML’s 1/13/15 Eakin Kanda ML 22 QGC (Northern Wasatch Front) Min. - 950 Btu/CF Max.– 1150 Btu/CF NPC (XO-16) Min. - 985 Btu/CF Max. – No Limit Legend: ML58/101 NPC (Clay Basin) Min. - 985 Btu/CF Max. – No Limit Compressor Station Delivery Point ML 80 QGC (Payson) Min. - 950 Btu/Cf Max. – 1150 Btu/CF JL 47 Price Fidlar Greasewood ML 40/41 ML 40 Davis Plant - 3rd Party ML 68 Oak Spring Questar Pipeline Tariff Min.- 950 Btu/CF Max.- 1150 Btu/CF TransColorado Min.- 967 Btu/Cf Max.- No Limit Btu/CF ML 104 CO2 Plant KRGT (Goshen) Min. – 970 Btu/CF Max.– No Limit Btu/CF Natural Gas Producers

  8. WYOMING IDAHO NPC MUDDY CREEK M SOUTH LAKE NPC M CIG NPC WHITNEY CANYON WIC HAYSTACK HYRUM GATE OT M KANDA/COLEMAN OT M M XO-16 C KRGT J.. L 36 M WGPC M QGC M C NIGHTINGALE C SKULL CREEK EAKIN LEROY M Overthrust East Fields S Green River Basin DRIPPING ROCK M.L.58 STATE LINE SUNSET GATE NPC SIMON M.L. 1,13,15 C C C QGC M CHALK CREEK S S S CRAIG COALVILLE CLAY BASIN QGC M PORTERS LANE COLORADO QGC M M.L.80 LITTLE MOUNTAIN UTAH Uinta Basin RED WASH QGC NEPHI CITY KRGT INDIANOLA M M Ferron M DRAGON TRAIL C RMNG M.L.40 M QGC M C C PRICE PAYSON GATE FIDLAR OAK SPRING NATURAL BUTTES RIFLE TCGT M M CIG M Piceance Basin C M CO2 PLT ELBERTA Basin Map

  9. Questar Pipeline – Gas Quality Distribution KRGT (Roberson Creek) CIG WIC Southern Star Overthrust Pipeline ML’s 1/13/15 Eakin Kanda ML 22 Green River Basin Max. Btu-1176 Min. Btu-1025 QGC (Northern Wasatch Front) Min. - 950 Btu/CF Max.– 1150 Btu/CF East Fields Max. Btu-1150 Min. Btu-950 ML58/101 Overthrust Max. Btu-1170 Min. Btu-1000 NPC (Clay Basin) ML 80 QGC (Payson) Min. - 950 Btu/Cf Max. – 1150 Btu/CF JL 47 Price Fidlar Greasewood ML 40/41 ML 40 ML 68 Davis Plant - 3rd Party Oak Spring Piceance Basin Max. Btu-1200 Min. Btu-1020 Uinta Basin Max. Btu-1150 Min. Btu-1020 ML 104 TransColorado Ferron Max. Btu-1060 Min. Btu-984 CO2 Plant KRGT (Goshen) Min. – 970 Btu/CF Max.– No Limit Btu/CF

  10. TYPES OF NATURAL GAS Supply Source Btu Range Traditional Supplies 970 – 1250 • Associated Gas • Dry Gas • Sour Gas Current/Future Supplies • Coal Seam Gas 970 - 1030 • LNG 1040 - 1200 Manufactured Gas 500 – 1000 • Coal Gasification • Landfill/Biomass

  11. WOBBE - INDEXIts Importance to Gas Interchangeability • Wobbe Number – Relationship between the heating Value and Specific Gravity, defined as • Wobbe Number is a good first-order predictor of appliance performance relative to a base or adjustment gas • Wobbe Number is used throughout the world as the most common interchangeability metric • Gas is generally considered interchangeable when the Wobbe number lies within a +/- 5% tolerance band around a set-point Heating Value Wobbe Number = Specific Gravity

  12. Gas Composition Coal Seam Gas 984 0.588 96.4% 0.27% 0.0543% 0.0139% 0.0018% 2.5% -110.5° 0.18% 1283 Uinta Basin Gas 1115 0.632 90.7% 5.06% 1.95% 0.863% 0.5923% 0.629% 70.4° 0.24% 1402 Northern Gates Gas 1070 0.616 92.0% 4.35% 1.20% 0.491% 0.315% 0.629% 40.9° 0.48% 1363 Representative Btu Specific Gravity Percent Methane(1010 Btu/Scf) Percent Ethane(1789 Btu/Scf) Percent Propane(2516 Btu/Scf) Percent Butane(3250 Btu/Scf) Percent C5+(5500+ Btu/Scf) Percent Inerts(CO2, etc.) Hydrocarbon Dewpoint Percent Nitrogen Wobbe (W = HV/G)

  13. Questar Gas Btu Delivery Ranges(1995 – Present)

  14. QGC BTU SET-POINTS RELATIVE TO BTU OF GAS DELIVERED TO 26 MAJOR URBAN AREAS1/ National LDC Btu Range Encompasses 90% of Data 1023 QGC NORTH POST 1998 1003 QGC SOUTH POST-1998 1088 Pre-1998 Base Gas 1048 1006 1100 1050 1000 Btu/SCF 1/”Variability of Natural Gas Composition in Select Major Metropolitan Areas of the United States,” prepared by the American Gas Association Laboratories for Gas Research Institute, GRI-92/0123, March 1992

  15. Questar Gas Position Points 1. An improperly adjusted appliance creates a safety hazard. • QGC and QPC constantly manage heat content and other gas quality criteria for safe, reliable use. 3. Post FERC regulations, Rocky Mountain pipelines have adopted national interstate grid gas quality specifications. 4. QGC’s gas sources (QPC & Kern River), as part of the interstate pipeline grid, supply volumes whose gas quality is aligned to the national market. • Markets, beyond the Rocky Mountains, have a major influence on gas quality and the physical flows of Rocky Mountain production.

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