2013 Alternative Transmission Development Robert H. Easton March 17, 2004 RMATS Stakeholder Meeting

Iterative Process to Finalize Alternatives RAWG Identify resource additions for each alternative Determine capital costs for new resources TAWG Identify transmission solutions for each alternative - Iterate with modelers for economics - First-pass technical review Determine capital costs for transmission Modeling Team Determine congestion/LMPs with new resources added - If no new transmission is added and if existing constraints are removed Iterate to define transmission needs (variable cost basis) Test transmission solutions provided by TAWG 1. Resource alternatives 2. Congestion and LMPs w/ new resources 4.Provide transmission solutions 3. Iterate to define needs 5. Test tx solutions Fine-tune alternatives First priority will be Alternatives 1 and 2, then Alternatives 3 & 4 Critical path to be able to start this modeling ( RAWG) - - Decide adjustments, if any, to load forecasts (outside RM); resolve any locational issues for new generation resources; create coal price “buckets” by type of mine; decide transmission solutions for 2008 that should be included in 2013 studies.

TAWG Solutions – Alts. 1 & 2 Alternative 1 Alternative 2 Alternative 1

LRS Reno DJ Bridger Miners Cheyenne Tap Ault Green Valley Existing 345 kV New 345 kV 110 miles 70 miles 115 miles 76 miles 70 miles 146 miles 65 miles 60 miles 120 miles Naughton Ben Lomond Midpoint Boise Treasureton Colstrip 345 miles 106 miles 162 miles 190 miles

Alternative 1 & 2 Estimated Costs Total Line Miles = 1658 At $500,000/mile for 345-kV construction Total Est. Cost = $829 million

Alternative 3 – Option 1 Transmission Configuration Definition Incremental Increase (MW) Solutions from Alt 1&2Amps Line – Add a Phase Shifter 230 kV Midpoint to Boise IPP DCUpgrade IPP DC500 West of ColstripColstrip Transformer 500/230 kV Colstrip to Broadview – Increase Series Compensation 500 Montana to Northwest500 kV Broadview to Garrison tap 500 kV Broadview to Ringling – Increase Series Compensation kV Broadview to Hot Springs to Ashe kV Chief Jo to Monroe1500 Bridger West500 kV Bridger to Borah Bridger to Midpoint - Convert from 345 kV to 500 kV kV Bridger to Ben Lomond (add as needed) 500 kV Ben Lomond to Midpoint (add as needed) 1000 Idaho to California500 kV Midpoint to Table Mountain to Tesla1000 TOT 3345 kV Reno to DJ to LRS to Cheyenne Tap to Ault to Green Valley 345 kV Reno to LRS 500 TOT 4A345 kV Bridger to Miners to Cheyenne500 Rocky Mountain to California SWIP to STEP1200

Colstrip Reno DJ LRS Cheyenne Tap Ault Green Valley Broadview Great Falls Hot SpringsAsh Ringling Garrison Missoula Taft Bridger Borah Midpoint Table Mt. & Tesla Alternative 3 – Option 1 - Series Compensation - Existing - “New” 500 kV - “New” 345 kV *IPP DC Ben Lomond

Alternative 3 – Option 2 Transmission ConfigurationDefinition Incremental Increase (MW) Solutions from Alt 1&2Amps Line – Add a Phase Shifter 230 kV Midpoint to Boise IPP DCUpgrade IPP DC500 Montana to WyomingColstrip Transformer 500/230 kV Colstrip to Broadview – Increase Series Compensation 500 West of Colstrip500 kV Broadview to Garrison tap 500 kV Broadview to Ringling – Increase Series Compensation kV Ringling to Borah1000 Bridger West500 kV Bridger to Borah 500 kV Bridger to Naughton to Ben Lomond 500 kV Ben Lomond to Borah Convert Borah to Midpoint 345 kV to 500kV 500 kV Borah to Midpoint 1000 Idaho to Northwest500 kV Midpoint to Grizzly1000 Utah to Market Place500 kV Ben Lomond to Mona to Red Butte to Market Place1000 Idaho to California500 kV Midpoint to Table Mountain to Tesla1000 TOT 3345 kV Reno to DJ to LRS to Cheyenne Tap to Ault to Green Valley 345 kV Reno to LRS 500 TOT 4A345 kV Bridger to Miners to Cheyenne500 Rocky Mountain to CaliforniaSWIP to STEP1200

Colstrip Reno DJ LRS Cheyenne Tap Ault Green Valley Broadview Ringling Garrison Missoula Taft Bridger Borah Midpoint Alternative 3 – Option 2 - Series Compensation - Existing - “New” 500 kV - “New” 345 kV To Grizzly Naughton Ben Lomond SWIP To STEP Red Butte Market Place *IPP DC Mona

Alternative 3 Estimated Costs Total 345-kV Line Miles = 652 At $500,000/mile = $326 million Total 500-kV Line Miles Option 1 = 1780 At $1 million/mile = $1.8 billion Total 500-kV Line Miles Option 2 = 2277 At $1 million/mile = $2.3 billion