December 2007 Conference Call Richard Perez, SUNY PV Capacity Methodologies

2. OBJECTIVE The U.S. Department of Energy’s Solar America Initiative has provided funding to evaluate the variety of photovoltaic capacity valuation methods and to bring the solar industry, electric utility, and research communities together with the goal of consensus on the most appropriate PV generation capacity valuation methodology .

3. LOAD PV At Issue: Quantifying PV Capacity Credit Perez, Taylor, Hoff & Ross

4. LOAD PV At Issue: Quantifying PV Capacity Credit Perez, Taylor, Hoff & Ross

7. ELCC LOAD Perez, Taylor, Hoff & Ross

8. X MW PV ELCC LOAD NEW LOAD Perez, Taylor, Hoff & Ross

9. Load increase, constant LOLP X MW PV ELCC LOAD NEW LOAD Perez, Taylor, Hoff & Ross

10. Y MW = ELCC Load increase, constant LOLP X MW PV %ELCC = Y / X ELCC LOAD NEW LOAD Perez, Taylor, Hoff & Ross

11. Perez, Taylor, Hoff & Ross

12. LDMC Simple Load Duration Methods Perez, Taylor, Hoff & Ross

13. LDMC LDTC Simple Load Duration Methods Perez, Taylor, Hoff & Ross

14. Load Control Synergy Perez, Taylor, Hoff & Ross

15. X = Installed PV L Load duration curve Load duration curve with PV Upper section of load duration curve Load Control Synergy Solar-Load-Control-based Capacity SLC Perez, Taylor, Hoff & Ross

16. X = Installed PV L Load duration curve Load duration curve with PV SLC: demand response needed to achieve peak demand reduction = X Upper section of load duration curve Load Control Synergy Solar-Load-Control-based Capacity SLC %SLC = (X-Y) / X Perez, Taylor, Hoff & Ross

17. X = Installed PV L Y Load duration curve Load duration curve with PV SLC: demand response needed to achieve peak demand reduction = X Same amount of demand response, but applied without PV Upper section of load duration curve Load Control Synergy Solar-Load-Control-based Capacity SLC Perez, Taylor, Hoff & Ross

18. X = Installed PV L Y Load duration curve Load duration curve with PV SLC: demand response needed to achieve peak demand reduction = X Same amount of demand response, but applied without PV Upper section of load duration curve Effective capacity = X - Y Load Control Synergy Solar-Load-Control-based Capacity SLC %SLC = (X-Y) / X Perez, Taylor, Hoff & Ross

19. Minimum Buffer Storage MBESC Perez, Taylor, Hoff & Ross Installed PV capacity x 0 500 1000 1500 2000 2500 3000 Time of Day Load (MW) 0 200 400 600 800 1000 1200 1400 1600 1800 2000 Load - PV LOAD Peak reduction threshold PV output Nominal PV output W/kW-ptc o o

20. Minimum Buffer Storage MBESC Perez, Taylor, Hoff & Ross Installed PV capacity x Minimum Buffer Energy Storage (MBES) 0 500 1000 1500 2000 2500 3000 Time of Day Load (MW) 0 200 400 600 800 1000 1200 1400 1600 1800 2000 Load - PV LOAD Peak reduction threshold PV output Nominal PV output W/kW-ptc o o

21. Minimum Buffer Storage MBESC Perez, Taylor, Hoff & Ross Installed PV capacity x Minimum Buffer Energy Storage (MBES) Same storage applied without PV 0 500 1000 1500 2000 2500 3000 Time of Day Load (MW) 0 200 400 600 800 1000 1200 1400 1600 1800 2000 Load - PV LOAD Peak reduction threshold PV output Nominal PV output W/kW-ptc o o

22. Minimum Buffer Storage MBESC Perez, Taylor, Hoff & Ross Installed PV capacity x Minimum Buffer Energy Storage (MBES) Same storage applied without PV Achieved peak reduction with MBES, but w/o PV Y’ 0 500 1000 1500 2000 2500 3000 Time of Day Load (MW) 0 200 400 600 800 1000 1200 1400 1600 1800 2000 Load - PV LOAD Peak reduction threshold PV output Nominal PV output W/kW-ptc o o

23. Achieved peak reduction with MBES, but w/o PV Installed PV capacity x Y’ Minimum Buffer Energy Storage (MBES) Same storage applied without PV Effective capacity = X – Y’ Minimum Buffer Storage MBESC %MBESC = (X-Y’) / X Perez, Taylor, Hoff & Ross 0 500 1000 1500 2000 2500 3000 Time of Day Load (MW) 0 200 400 600 800 1000 1200 1400 1600 1800 2000 Load - PV LOAD Peak reduction threshold PV output Nominal PV output W/kW-ptc o o

24. Time Season Window TSW Perez, Taylor, Hoff & Ross

25. Time Season Window TSW Perez, Taylor, Hoff & Ross

26. Time Season Window TSW Perez, Taylor, Hoff & Ross

27. Time Season Window TSW Perez, Taylor, Hoff & Ross 0% 20% 40% 60% 80% 100% Probability

28. Capacity credit Time Season Window TSW Perez, Taylor, Hoff & Ross 0% 20% 40% 60% 80% 100% Probability

29. Capacity Factor Average Output Installed Capacity %CF = Perez, Taylor, Hoff & Ross

30. Demand Time Interval matching DTIM Sampling interval  a few seconds Dispatch cycle  several sampling intervals Evaluation period  day/time window PV Power generation 10 seconds variability Maximum PV output MaxSolarPower DC defines best solar output capacity Minimum PV output MinSolarPower DC defines least solar output capacity Three time references Perez, Taylor, Hoff & Ross Source: T. HANSEN

31. X = installed PV Capacity ≈ MaxSolarPower DC Load Duration Curves with Time Resolution Equal to Dispatch Sampling Interval Demand Time Interval matching DTIM Perez, Taylor, Hoff & Ross Perez, Taylor, Hoff & Ross Source: T. HANSEN

32. Top of LD curve w/o PV Top of LD curve with PV X = installed PV Capacity ≈ MaxSolarPower DC Z = difference between tops of LD curves ≈ MinSolarPower DC Capacity Credit %DTIM = Z/X Load Duration Curves with Time Resolution Equal to Dispatch Sampling Interval Demand Time Interval matching DTIM Perez, Taylor, Hoff & Ross Perez, Taylor, Hoff & Ross Source: T. HANSEN

34. Case Studies NEVADA POWER Perez, Taylor, Hoff & Ross

35. Case Studies PORTLAND GENERAL Perez, Taylor, Hoff & Ross

36. Case Studies ROCHESTER GAS & ELECTRIC Perez, Taylor, Hoff & Ross

37. Case Studies ROCHESTER GAS & ELECTRIC General agreement between most metrics based upon a physical definition of capacity Perez, Taylor, Hoff & Ross

38. Case Studies Demand-Time Interval Matching (DTIM) 4.6 MW Springerville PV Plant Actual Production Data Tucson Electric Power Perez, Taylor, Hoff & Ross Springerville

39. Case Studies Demand-Time Interval Matching (DTIM) 4.6 MW Springerville PV Plant Actual Production Data Tucson Electric Power Perez, Taylor, Hoff & Ross Springerville

40. Case Studies Demand-Time Interval Matching (DTIM) 4.6 MW Springerville PV Plant Actual Production Data Tucson Electric Power Perez, Taylor, Hoff & Ross Springerville

41. Case Studies Demand-Time Interval Matching (DTIM) 4.6 MW Springerville PV Plant Actual Production Data Tucson Electric Power Capacity credit Perez, Taylor, Hoff & Ross Springerville

44. Stakeholders Workshop SolarPower 2007, Long Beach, CA, 9/27/07

45. Stakeholders Workshop SolarPower 2007, Long Beach, CA, 9/27/07 40 participants almost 50% from utilities

46. Stakeholders Workshop SolarPower 2007, Long Beach, CA, 9/27/07 40 participants almost 50% from utilities FOCUS ON METHODOLOGY

50. Stakeholders Workshop SolarPower 2007, Long Beach, CA, 9/27/07 40 participants almost 50% from utilities FOCUS ON METHODOLOGY Geography Time scale

52. Stakeholders Workshop SolarPower 2007, Long Beach, CA, 9/27/07 40 participants almost 50% from utilities FOCUS ON METHODOLOGY Geography Time scale Input data and logistics

54. Stakeholders Workshop SolarPower 2007, Long Beach, CA, 9/27/07 40 participants almost 50% from utilities FOCUS ON METHODOLOGY Geography Time scale Input data and logistics Value of capacity (who pays for it and how) Cost of PV Ownership of PV Very high penetration of PV PV alone, vs. synergy with storage and controls Rigorous LOLP simulation

57. Geography Time scale Continued discussion with stakeholders via workshops and publications