1. 1 Putting things in Perspective I&M Plan Workshop July 9, 2008 or, “Why bother with your Natural Gas Engine?”

2. 2 Relative Cost per Btu Energy Unit BTU Content $ / Unit EnergyCents per MBtu 1 Lb. Coal 12,500 $.06 0.47 1 Therm Natural Gas 100,000 $ 1.28 1.28 1 Gal. Propane 91,000 $ 4.75 5.22 1 Gal. Diesel #2 139,000 $ 5.00 3.60 1 Gal. Gasoline 125,000 $ 4.57 3.66 SCE TOU-8 Primary (Summer) Off-Peak kWh3412.0894 2.62 Mid-Peak kWh3412.1515 4.44 On-Peak kWh3412.2896 8.49 Annual Average kWh3412.1297 3.80 July, 2008

3. 3 Energy UnitCost/MBtuC.O.PCents per Ton-Hr Natural Gas Engine 1.281.9 8.1 SCE TOU-8 Secondary (Summer) Off-Peak kWh 2.62 5.5 5.7 Mid-Peak kWh 4.44 5.5 9.7 On-Peak kWh 8.49 5.5 18.5 400 Ton Electric Chiller costs $74 per Hour to operate On-Peak Gas Chiller cost is $32 to $56 per Hour at all times… Relative Cost per Btu (IC Engine Driven HVAC Chiller)

4. 4 Engine Cost/MBtu Heat Rate Cents per HP-Hr Natural Gas 1.288890 11.4 SCE TOU-8 Secondary (Summer) Electric Motor Efficiency Off-Peak kWh 2.62.95 7.0 Mid-Peak kWh 4.44.95 11.9 On-Peak kWh 8.49.95 22.8 200 HP Electric Motor costs $46 per Hour to operate On-Peak Gas Engine cost is $23 per Hour at all times… Relative Cost per Btu (IC Engine Prime Mover)

5. 5 “When Do Engines Save Money?”

6. 6 Steve Rawski Principal Engineer (714) 634-3246 srawski@semprautilities.com Remember, your Gas company Representatives are here to help…  Understanding the Regulations  Developing and Implementing a Long Term Plan.