EASTERN PLAINS TRANSMISSION PROJECT TriState Generation Transmission and

EASTERN PLAINS TRANSMISSION PROJECT Tri-State Generation & Transmission and Western Area Power Administration

EASTERN PLAINS TRANSMISSION PROJECT n Resource Additions ► 2 x 600 MW supercritical coal units at Holcomb substation 2011, 2012 – near Garden City, Kansas ► Possible 600 MW addition at Lamar Energy Center in 2020. ► Task was how to integrate into existing Western Interconnection transmission system

EASTERN PLAINS TRANSMISSION PROJECT n Transmission Additions ► Began with 345 -k. V alternatives and corridors ► ► Expanded to look into 500 -k. V alternative along same corridors Following slides show this progression

Initial Design S A-1 PAWNEE STORY WRAY SMOKY HILL DANIELS PARK 3 X 345/230 CORNER POINT New 345 New 230 Planned 345 Existing 230 WATERTON 2 X 345/230 BURLINGTON 3 X 345/230 BIG SANDY 2 X 345/230 Sensitivities with and without BOONE COMANCHE LAMAR 2 X 345/230 LAMAR ENERGY CENTER HOLCOMB 1200 MW

345 k. V Minimum for 1200 MW PAWNEE STORY WRAY 65 miles SMOKY HILL DANIELS PARK 3 X 345/230 CORNER POINT New 345 New 230 Planned 345 Existing 230 WATERTON 2 X 345/230 80 miles BURLINGTON BIG SANDY 2 X 345/230 MIDWAY 1 X 345/230 2 X 345/230 125 Mile Rd. Sub 80 miles B. Sandy – Midway 70 miles 45 miles 100 miles 150 miles BOONE 2 X 345/230 80 miles Sensitivities with 0 autos COMANCHE 3/09/06 LAMAR 2 X 345/230 LAMAR ENERGY CENTER HOLCOMB 1200 MW 3 mile separation

345 k. V Minimum for 1800 MW PAWNEE STORY WRAY 65 miles SMOKY HILL DANIELS PARK 3 X 345/230 CORNER POINT New 345 New 230 Planned 345 Existing 230 WATERTON 2 X 345/230 80 miles BURLINGTON 80 miles MIDWAY 1 X 345/230 125 Mile Rd. Sub 2 X 345/230 BIG SANDY 2 X 345/230 Preliminary Stability Sensitivities evaluated two lines. Not preferred Preferred instead of 2 Holcomb-Burlington 135 miles 70 miles 45 miles 100 miles 150 miles BOONE 2 X 345/230 80 miles Sensitivities with 0 autos COMANCHE 3/09/06 LAMAR 2 X 345/230 LAMAR ENERGY CENTER 600 MW 3 mile separation HOLCOMB 1200 MW

500 k. V Minimum for 1200 MW PAWNEE STORY 65 miles WRAY SMOKY HILL DANIELS PARK 3 X 345/230 New 500 New 345 New 230 Planned 345 Existing 230 CORNER POINT WATERTON 2 X 345/230 80 miles 125 Mile Rd. Sub BURLINGTON 2 X 500/230 BIG SANDY 2 X 500/230 MIDWAY 2 X 500/230 80 miles 150 miles 70 miles 45 miles 100 miles 80 miles BOONE 2 X 500/230 HOLCOMB COMANCHE 3/09/06 LAMAR 210 +90 2 X 500/230 Double-ckt 230 1200 MW

500 k. V Minimum for 1800 MW PAWNEE STORY 65 miles WRAY SMOKY HILL DANIELS PARK 3 X 345/230 CORNER POINT WATERTON 2 X 345/230 New 500 New 345 New 230 Planned 345 Existing 230 80 miles 125 Mile Rd. Sub BURLINGTON 2 X 500/230 BIG SANDY 2 X 500/230 MIDWAY 2 X 500/230 80 miles 150 miles 70 miles 45 miles 100 miles 80 miles BOONE 2 X 500/230 HOLCOMB COMANCHE 3/09/06 LAMAR 210 +90 LAMAR ENERGY CENTER Double-ckt 230 2 X 500/230 600 MW 1200 MW

EASTERN PLAINS TRANSMISSION PROJECT 1200 MW Cost Comparison n Minimum 345 k. V Cost – $598. 1 Million Minimum 500 k. V Cost – $715. 8 Million Difference of $117. 7 Million 20 MW Less Losses on 500 k. V System ► Average Cost of Energy $32. 7/MWh ► 70% Plant Factor ► 26. 4 Years to Payback ►

EASTERN PLAINS TRANSMISSION PROJECT 1800 MW Cost Comparison n Minimum 345 k. V Cost – $676. 7 Million Minimum 500 k. V Cost – $786. 4 Million Difference of $109. 7 Million 30 MW Less Losses on 500 k. V System ► Average Cost of Energy $32. 7/MWh ► 70% Plant Factor ► 16. 5 Years to Payback ►

EASTERN PLAINS TRANSMISSION PROJECT Questions?