Utah Cost of Service and Rate Design Task Force Seasonality in Costs and Loads Maurice Brubaker June 15, 2005 Salt Lake City, Utah

PacifiCorp-Utah Comparison of Monthly Peaks for Years 1994 and ,000 1,500 2,000 2,500 3,000 3,500 4,000 4,500 JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC Month Megawatts 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% Percentage Change 1994 Percentage Change 2006

0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000 0% 5% 10% 15% 20% 25% 30% PacifiCorp Comparison of Monthly Peaks for Years 1994 and 2006 JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC Month 1994 Percentage Change 2006 Megawatts Percentage Change

,200 1,600 2,000 2,400 2,800 3,200 3,600 4, Hourly Load Data - Utah PacifiCorp Hour MW

,200 1,600 2,000 2,400 2,800 3,200 3,600 4,000 Apr-05MayJunJulAugSepOctNovDecJanFebMar-06 Month MW Total Total Residential Schedule 6 PacifiCorp-Utah Contribution of Major Classes to Coincident Peak Schedule 8 Schedule 9 Schedule 23

,200 1,600 2,000 2,400 2,800 3,200 3,600 4,000 Hour PacifiCorp-Utah Hourly Load Data for Total Utah and Large Industrial Customers Maximum Winter Week Total Utah Large Industrial Customers MW % Increase = 48%

MW PacifiCorp-Utah Hourly Load Data for Total Utah and Large Industrial Customers Maximum Summer Week Hour Total Utah Large Industrial Customers % Increase = 72%

$20 $25 $30 $35 $40 $45 $50 $55 $60 $65 $70 ($/MWh) Jan-04FebMarAprMayJunJulAugSepOctNovDec Peak Off-Peak COB Average Monthly On-Peak Prices 2004

$20 $25 $30 $35 $40 $45 $50 $55 $60 $65 $70 Jan-04FebMarAprMayJunJulAugSepOctNovDec ($/MWh) Peak Off-Peak Palo Verde Average Monthly On-Peak Prices 2004

$20 $30 $40 $50 $60 $70 $80 1/2/2004 1/16/20041/30/20042/13/20042/27/20043/12/20043/26/2004 4/9/2004 4/23/2004 5/7/2004 5/21/2004 6/4/2004 6/18/2004 7/2/2004 7/16/20047/30/20048/13/20048/27/20049/10/20049/24/200410/8/ /22/ /5/ /19/ /3/ /17/200412/31/2004 COB Day Ahead On-Peak Prices 2004 ($/MWh)

1/2/2004 1/16/20041/30/20042/13/20042/27/20043/12/20043/26/2004 4/9/2004 4/23/2004 5/7/2004 5/21/2004 6/4/2004 6/18/2004 7/2/2004 7/16/20047/30/20048/13/20048/27/20049/10/20049/24/200410/8/ /22/ /5/ /19/ /3/ /17/200412/31/2004 $20 $30 $40 $50 $60 $70 $80 ($/MWh) Palo Verde Day Ahead On-Peak Prices 2004

,200 1,600 2,000 2,400 2,800 3,200 3,600 4,000 Apr-05MayJunJulAugSepOctNovDecJanFebMar-06 Month MW Total Total Residential Schedule 6 Schedule 8 Schedule 9 Schedule 23 PacifiCorp-Utah Allocations Based on Peaks (Vertical Slices) ?

Resource Portfolio  Base Load Coal  Combined Cycle – Gas Fired  Peaking Units – Gas Fired  24 x 7 x 52 Purchases  Seasonal On-Peak Purchases  Seasonal Off-Peak Purchases  Hourly Purchases PacifiCorp-Utah

Block Purchases Day 1 Load Midnight 6 AMNoon10 PM 6 x 16 Purchase Surplus

PacifiCorp-Utah Block Purchases Day 2 Load Midnight 6 AMNoon10 PM 6 x 16 Purchase Surplus

,200 1,600 2,000 2,400 2,800 3,200 3,600 4,000 Apr-05MayJunJulSepOctNovDecJanFebMar-06 Month MW PacifiCorp-Utah Horizontal Analysis - Industrial Total Industrial Aug Base

,200 1,600 2,000 2,400 2,800 3,200 3,600 4,000 Apr-05MayJunJulSepOctNovDecJanFebMar-06 Month MW Horizontal Analysis – Peaking Classes PacifiCorp-Utah Base Intermediate Peaking Super Peak Total Estimate Aug