1. CALIFORNIA ENERGY COMMISSION Gas Quality Stakeholders’ Technical Committee Meeting September 20, 2005 Natural Gas Quality: Power Turbine Performance During Heat Content Surge Updated Information and Schedule William Walters Aspen Environmental Group Sponsored by the California Energy Commission

2. CALIFORNIA ENERGY COMMISSION Update and Schedule Sutter Natural Gas Fuel Wobbe was determined. Los Medanos, Delta, and Redding as used fuel Wobbe cannot be determined with available data. Western Midway Sunset had events of reduced fuel heat content which caused significant increases in CO emissions, but did not significantly impact NOx emissions. Study will go out for CEC management and data provider review later this week, and the Draft Study with excel raw data tables should be made public as early as late next week. Additional work will be funded by the CEC to determine potential natural gas quality emissions/operations impacts to large power boilers. Scope of work should be completed by the end of this week and work should begin in approximately two weeks.

3. CALIFORNIA ENERGY COMMISSION Sutter Natural Gas Fuel Heat Content and Wobbe

4. CALIFORNIA ENERGY COMMISSION Sutter CT2 Uncontrolled NOx vs Wobbe

5. CALIFORNIA ENERGY COMMISSION Sutter CT2 Ammonia Use vs Wobbe

6. CALIFORNIA ENERGY COMMISSION Sutter CT2 Controlled NOx vs. Wobbe Summary: Uncontrolled NOx 15% increase for 3.5% increase in Wobbe Ammonia use 10% increase for 3.5% increase in Wobbe Controlled NOx no increase

7. CALIFORNIA ENERGY COMMISSION Western Midway Sunset CO Emissions vs Fuel Heat Content

8. CALIFORNIA ENERGY COMMISSION Western Midway Sunset Description Cogeneration 7E turbines with SCR and no CO catalyst – 25 ppm CO permit limit. No significant controlled NOx impacts (i.e. reduction) during heat content drop. Expensive (~$250,000) burner modification fixed problem. Subsequent burner modifications to second turbine affected earlier CO emissions fix.