Illustrative FCRPS Examples Comparing Capacity Adequacy Calculations for Federal Hydro- Dominated System Mary Johannis PNW Resource Adequacy Technical Committee Mtg August 24, 2007

PNW Resource Adequacy Technical Committee Meeting 2 Winter Planning Reserve Margin (PRM) Why Illustrative Examples of FCRPS Capacity? –BPA awaits Finalization of Capacity Adequacy Standard to develop White Book Methodology for calculating FCRPS PRMs –FCRPS Capacity Example for Recommended Approach based on 2007 Historical Winter Day, which simulates a 1 in 20 Probability Event, such as Feb 89 load and Average Hydro –FCRPS Capacity Example for Pilot Standard based on 2006 Hydro Subgroup Work led by Eric King of BPA Loads based on historical load shape and 2010 expected (1 in 2) peak February Load from 2006 White Book 6 hour duration for 1 day used for simplicity rather than 6 hours over 3 days ( Recommended 18-hour sustained peaking period) More work is needed before Capacity Adequacy of FCRPS can be evaluated

August 24, 2007PNW Resource Adequacy Technical Committee Meeting 3 Capacity to meet expected load Surplus + Capacity for PRM needs

August 24, 2007PNW Resource Adequacy Technical Committee Meeting 4 Capacity to meet expected load Surplus + Capacity for PRM needs

August 24, 2007PNW Resource Adequacy Technical Committee Meeting 5

August 24, 2007PNW Resource Adequacy Technical Committee Meeting 6 Comparison of PRMs Recommended Approach using values from ILLUSTRATIVE EXAMPLE: –6-hour sustained peaking capacity = 16,800 MW Hydro = 14,500 MW CGS = 1140 MW Firm Contracts = 550 MW Operating Reserves = 630 MW –6-hour sustained peak load = 11,900 MW –PRM = 40.9% > Regional PRM of 25% –BPA PRM = ? –1 Hour Snapshot for possible reporting to WECC: Hydro = 15,600 MW Load = 12,960 MW PRM = 38.7%

August 24, 2007PNW Resource Adequacy Technical Committee Meeting 7 Comparison of PRMs Pilot Standard Approach –10-hour 1/ sustained peaking capacity = 15,900 MW Hydro = 13,700 MW CGS = 1140 MW Firm Contracts = 520 MW Operating Reserves = 570 MW –10-hour sustained peak load = 10,800 MW –PRM = 47.5% > Regional PRM of 25% –BPA PRM = ? –1 Hour Snapshot for possible reporting to WECC: Hydro = 14,000 MW Load = 12,960 MW PRM = 26.2 % 1/ Peak day selected from 50-hour Sustained Peaking Analysis

August 24, 2007PNW Resource Adequacy Technical Committee Meeting 8 Pros & Cons of Approaches PROS of Recommended Approach –Use of 1 in 20 year combination probability event is about the right probability when considering linkage to GENESYS 5% LOLP –Analysis of 6 peak load hours captures peak capacity needs –Methodology uses Realistic FCRPS Cold Snap Operation –Compatible with Translation to 1 hour Reporting to WECC CONS of Recommended Approach –Difficult to estimate for Region because Trapezoidal Approximation cannot depict sustained Hydro Peaking Capacities for discontinuous peak load hours

August 24, 2007PNW Resource Adequacy Technical Committee Meeting 9 Pros & Cons of Approaches PROS of Pilot Standard Approach –50 hour sustained peaking period is an accepted concept in PNW –Trapezoidal Approximation can be used to estimate 10 hour sustained Hydro Peaking Capacity CONS of Pilot Standard Approach –Evaluation of Hydro under Critical Water and for 1 in 20 temperatures is a very rare event; Hydro resources are used differently in GENESYS to meet regional load pursuant to 5% LOLP –Sequential 10 hour period misses winter afternoon peak load  Peak Capacity Needs not captured in Evaluation –Methodology uses Unrealistic FCRPS Cold Snap Operation

August 24, 2007PNW Resource Adequacy Technical Committee Meeting 10 Capacity to meet expected load Surplus + Capacity for PRM needs

August 24, 2007PNW Resource Adequacy Technical Committee Meeting 11 Illustrative Summer Example Only Recommended Approach shown because FCRPS Sustained Peaking Capacity not evaluated under Pilot Standard –6-hour sustained peaking capacity = 15,000 MW Hydro = 13,000 MW CGS = 950 MW Firm Contracts = 510 MW Operating Reserves = 580 MW –6-hour sustained peak load = 10,950 MW –PRM = 37.2% > Regional PRM of 19% –BPA PRM = ? –1 Hour Snapshot for possible reporting to WECC: Hydro = 13,160 MW Load = 11,150 MW PRM = 36.3 %

August 24, 2007PNW Resource Adequacy Technical Committee Meeting 12 Next Steps Evaluate output from GENESYS to see how Hydro is used in simulations with curtailments to understand if BPA’s use of 1 in 20 year event is a reasonable condition under which to evaluate Hydro Select appropriate depiction of hydro for regional standard based on above analysis BPA and other hydro utilities to fine tune their hydro depiction based on GENESYS analysis BPA to develop FCRPS Capacity Adequacy Evaluation for inclusion in White Book