Rocky Mountain Area Transmission Study Steering Committee Meeting 2013 Case Alt 1 & 2 - Iteration 2 – Test Transmission Solutions Alt 3 & 4 – Iteration 1 - Define Congestion March 4, 2004

Case Observation/Qualifications – Alt 1 & 2  Results from Alternative 2 (regionally “optimized”- pseudo IRP for the region) shows greater value to the Rocky Mountain region over Alternative 1 (existing & uncoordinated company IRPs)  Results: Quantify the value of Alternate 2 over Alternate 1 Validate the need to build new transmission to integrate “new” resources in the Rocky Mountain area Highlight the need to reinforce the Bridger and Central Wyoming transmission (LMP values ~$10 to $20 lower than other locations, even within the region). Pave the way to consider reinforcing export paths ($57 LMP at LADWP vs $22 at Laramie River)  Reminder, results account for just VOM costs; no consideration has been given thus far to transmission & resources capital costs

Case Generation Alternatives for 2013 runs 20% of wind nameplate applies toward capacity Designed Alternative 1 based RMATS load growth, IRPs and minimum new transmission; configured incremental resource additions in each state to meet projected load growth plus reserves in that state; major wind in CO-E and SW Wyoming close to load centers. Designed Alternative 2 based on RMATS load growth with a focus on Powder River coal and open range wind (cheaper resource cost) and may require more transmission in the region. Designed Alternative 3 as an export case (incremental resources equal to 2 times RMATS load growth) with additional Powder River (and Utah) coal and open range wind necessitating more transmission for export. Designed Alternative 4 as a larger export case (3 times RMATS load growth) Powder River (and Utah) coal and open range wind necessitating more transmission for export.

Case Iteration 2 – TAWG Solutions Alternative 1 Alternative 2 Alternative 1

Case Top Congested Paths Transmission Constraints - Alternative 1

Case Transmission Constraints - Alternative 2 Top Congested Paths

Rocky Mountain Area Transmission Study Alternative 1 Iteration 2

Case Transmission Additions – Alternative 1 RUN 1:  Bridger to Naughton to Ben Lomond 345 line (Bridger West and Naughton West)  Miners to Bridger 345 and Miners 345/230 transformer.  230 Midpoint to Boise Note: TOT 2C was the path with the highest congestion and opportunity cost, but was not included in Alternative 1 because the TAWG felt that it should be dealt with in an export case. Transmission additions to Path 2C will be analyzed in Alternatives 3 & 4.

Case Relieving Transmission Constraints- Alternative 1 Solutions Top Congested Paths

Case LMP Prices Average Annual Load LMPGeneration LMP Alternative 1- No Tx Additions Alternative 1- w/ Tx Additions

Case Change in Congestion/Congestion Costs with Tx Solutions Alternative 1 InterfaceLocation [Direction] Current Forward limit (MW) Current Reverse limit (MW) Opportunity cost of next $/MW % hours congested W/O Tx W/ Tx W/O Tx W/ Tx TOT 2CS.W Utah to S.E. Nevada [N – S] ,80467,79140%37% Bridger WestS.W. Wyoming to S.E. Idaho & to Northwest [E – W] 2,200N/A60,978028%0% West of NaughtonS.W. Wyoming to N Utah [E – W] 920N/A39,5331,37113%0% Path CN Utah/ S Idaho [S – N]1,000 19,9093,6496%*2% Bonanza WestN.E. Utah to Central Utah [N – S] 785N/A17,65918,1778%10% SW Wyoming to Bonanza S.W. Wyoming to N.E. Utah [N – S] ,60234,0189%13% Idaho to MontanaE. Idaho to W. Montana [S – N] 337 4,74123,4291%3% * Reaches seasonal capacity of 750 MW Opportunity Cost: the cost of delivering the next 1 MW of power to a particular location, or the savings from reducing load by 1 MW at that location (sometimes called shadow price)

Case Western Interconnect Impact for 2013 Alternative 1 Interface limitation Annual VOM ($000) Delta from Base Annual VOM ($000) Annual average LMPDelta from base annual average LMP Load ($/MWh) Generator ($/MWh) Load ($/MWh) Generator ($/MWh) w/o Transmission Additions 20,069, All interfaces unconstrained 19,825,590(243,809)49.38 (.49).84 Only internal RM interfaces are unconstrained 19,986,953(82,446) With Transmission Additions 20,017,760(51,639) Adjusted 2008 Base Case 24,641,0434,571,644N/A

Rocky Mountain Area Transmission Study Alternative 2 Iteration 2

Case RUN 1:  Reno to DJ to LRS to Cheyenne to Ault to Green Valley 345 line (TOT 3)  Bridger to Midpoint 345 line via Treasureton) (Bridger West)  Miners to Cheyenne 345 line and Miners 345/230 transformer (TOT 4A)  Miners to Bridger 345 and Miners 345/230 transformer.  230 Midpoint to Boise RUN 2: (Add to Run 1):  Reno to LRS to Ault to Green Valley 345 line (if TOT 3 still a problem)  Bridger to Naughton to Ben Lomond 345 line (if Bridger West or Naughton West still a problem) RUN 3: (Add to Run 1 plus Run 2):  Colstrip to Reno 345kV  Colstrip: /230 kV Transformers to integrate generation  Reno 345/230 Transformer to integrate generation  Treasureton to Ben Lomond 345kV (if Path C overloaded)  Loop Bridger to Midpoint at Treasureton  Loop Borah Ben Lomond at Treasureton Transmission Additions – Alternative 2

Case Relieving Transmission Constraints Alternative 2 Solutions Top Congested Paths

Case LMP Prices Average Annual Load LMPGeneration LMP Alternative 2- no Tx addition Alternative 2- w/ Tx additions

Case InterfaceLocation [Direction] Current Forward limit (MW) Current Reverse limit (MW) Opportunity cost of next $/MW % hours congested W/O Tx W/ Tx W/O Tx W/ Tx C. Wyoming to Black Hills C. Wyoming to N.E. Wyoming [SE – NE] ,61721,22084%9% TOT 3S.E. Wyoming to N.E. Colorado [N – S] 1,424N/A238,9699,21376%10% Bridger WestS.W. Wyoming to S.E. Idaho & to Northwest [E – W] 2,200N/A228, %0% West of BroadviewSouth Central Montana [E – W] 2,573N/A172,68198,49951%36% West of NaughtonS.W. Wyoming to N Utah [E – W] 920N/A97,73616,13832%6% TOT 2CS.W Utah to S.E. Nevada [N – S] ,83082,75931% Montana to NorthwestW. Montana to E. Washington [E – W] 2,2001,35024,36128,4938%11% Idaho to MontanaE. Idaho to W. Montana [S – N] ,98226,9744%2% Change in Congestion/Congestion Costs with Tx Solutions Alternative 2

Case Western Interconnect Impact for 2013 Alternative 2 Interface limitationAnnu al VOM ($000 ) Delta from Base Annual VOM ($000) Annual average LMP Delta from base annual average LMP Load ($/MWh Generator ($/MWh) Load ($/MWh) Generator ($/MWh) w/o Transmission Additions 20,075, All interfaces unconstrained 19,653,573 (421,513)49.41 (.40)1.87 Only internal RM interfaces are unconstrained 19,846,737 (228,354) (.04)1.24 With Transmission Additions 19,850,473 (224,618) (.01)1.16 Adjusted 2008 Base Case 24,641,043 4,565,952N/A

Rocky Mountain Area Transmission Study Alternatives 3 & 4 Iteration 1

Case Top Congested Paths Transmission Constraints - Alternative 3 (w/o new transmission)

Case Transmission Congestion/Congestion Costs Alternative 3 InterfaceLocation [Direction] Forward limit (MW) Reverse limit (MW) Opportunity cost of next MW % hours congested Black Hills to C WyomingE. Wyoming to C. Wyoming [E – W] ,85499% Bridger WestS.W. Wyoming to S.E. Idaho & to Northwest [E – W] 2,200N/A244,74383% PAVANT, INTRMTN - GONDER 230 KV C. Utah to C. Nevada [E – W] ,84060% TOT 2CS. Utah to S.E. Nevada [N – S] ,87346% West of BroadviewCentral Montana [E – W]2,573N/A181,72160% Montana to NorthwestW. Montana to E. Washington2,2001,350173,05171% TOT 3S.E. Wyoming to N.E. Colorado [N – S] 1,424N/A136,47050% INTERMOUNTAIN - MONA 345 KV Central Utah [W – E]1,4001,200131,12165% Idaho to MontanaE. Idaho to W. Montana [S – N]337 65,0546% TOT 2B2S. Utah to N. Arizona [N – S] ,14233% SW of 4 CornersS.E. Utah to N.W. New Mexico [SE – NW] 2,325N/A41,11216%

Case Western Interconnect Impact for 2008 Alternative 3 Interface limitation Annual VOM ($000) Delta from Base Annual VOM ($000) Annual average LMP Delta from base annual average LMP Load ($/MW) Generator ($/MW) Load ($/MW) Generator ($/MW) Base Case19,583, All interfaces unconstrained 18,297,721(1,285,313)47.65 (.75)2.20 Only internal RM interfaces are unconstrained 18,814,479(768,555) (1.85)(.45) 2008 Base case (Adjusted) 24,641,043(5,058,009)N/A

Case Top Congested Paths Transmission Constraints - Alternative 4 (w/o new transmission)

Case InterfaceLocation [Direction] Forward limit (MW) Reverse limit (MW) Opportunity cost of next MW % hours congested Bridger WestS.W. Wyoming to S.E. Idaho & to Northwest [E – W] 2,200N/A273,32996% Montana to NorthwestW. Montana to E. Washington2,2001,350253,68779% Black Hills to C Wyoming E. Wyoming to C. Wyoming [E – W] ,30279%+ TOT 2CS. Utah to S.E. Nevada [N – S] ,15143% West of BroadviewCentral Montana [E – W]2,573N/A130,39242% Bonanza WestE. Utah to C. Utah [E – W]785N/A120,82959% TOT 3S.E. Wyoming to N.E. Colorado [N – S] 1,424N/A102,05656% Idaho to MontanaE. Idaho to W. Montana [S – N]337 99,6778% TOT 2AS.W. Colorado [N – S]690N/A97,25350% IPP DCC. Utah to S. California [NE – SW]1, ,87985% TOT 1AW. Colorado to E. Utah [E – W]650N/A64,26359% West of NaughtonS.E. Wyoming to N. Utah [E – W]920N/A47,92820% SW of 4 CornersS.E. Utah to N.W. New Mexico [SE – NW] 2,325N/A36,86315% TOT 2B2S. Utah to N. Arizona [N – S] ,40523% Transmission Congestion/Congestion Costs Alternative 4

Case Western Interconnect Impact for 2008 Alternative 4 Interface limitation Annual VOM ($000) Delta from Base Annual VOM ($000) Annual average LMP Delta from base annual average LMP Load ($/MW) Generator ($/MW) Load ($/MW) Generator ($/MW) Base Case18,694, All interfaces unconstrained 16,609,281(2,085,592)45.71 (1.14)1.90 Only internal RM interfaces are unconstrained 18,136,071(558,802) (1.85)(1.38) 2008 Base case (Adjusted) 24,641,043(5,946,170)N/A