B O N N E V I L L E P O W E R A D M I N I S T R A T I O N 1 5/09/2011 West of Cascades – North (WOCN) Path BPA Studies Path Definition (for studies)  Chief Joe – Monroe #1 500kV  Schultz – Echo Lake 500kV  Schultz – Raver #1 500kV  Schultz – Raver #3 500kV  Schultz – Raver #4 500kV  Chief Joe – Snohomish #3 345kV  Chief Joe – Snohomish #4 345kV  Rocky Reach – Maple Valley 345kV  Grand Coulee – Olympia 300kV  Bettas Road – Covington 230kV  Rocky Reach – White River 230kV (PSE)  Kittitas – Woledale 115kV (PSE)  Gold Brite – Beverly 115kV (PSE)

B O N N E V I L L E P O W E R A D M I N I S T R A T I O N 2 5/09/2011 West of Cascades – North (WOCN) Path BPA Studies Purpose  To explore system additions and upgrades to increase path capacity. Critical Seasons  heavy winter due to increased westside loads (typically voltage stability limited)  late spring / early summer due to hydro runoff and low westside thermal gen (typically thermally limited)

B O N N E V I L L E P O W E R A D M I N I S T R A T I O N 3 5/09/2011 West of Cascades – North (WOCN) Path BPA Studies Study Assumptions  17hw1 WECC basecase as modified in 2009 BPA screening studies  +/- 5% Load Levels for interpolation  680MW PSA generation level  1500MW SN NI flow  Northwest load areas tuned for peak winter conditions. This optimizes the lower voltage reactive and transformer tap settings. (use what we have before building new)  Only BPA lines are reported in path totals

B O N N E V I L L E P O W E R A D M I N I S T R A T I O N 4 5/09/2011 West of Cascades – North (WOCN) Path BPA Studies Study Methodology  QV Curves for Critical Contingencies at 500kV Busses  Interpolation used to find WOCN flow where the reactive margin=0  Use of a “probing bus” for busses with shunt devices  Thermal limits were found via the ATC Tool using the Full-AC solution option  All devices were locked at pre-contingency levels except 500kV shunt reactors and capacitors (use RAS to switch in if needed)  SVCs were modeled as continuous shunts with discreet elements included

B O N N E V I L L E P O W E R A D M I N I S T R A T I O N 5 5/09/2011 West of Cascades – North (WOCN) Path BPA Studies Study Results (Existing System – Thermal) Winter Spring / Summer

B O N N E V I L L E P O W E R A D M I N I S T R A T I O N 6 5/09/2011 West of Cascades – North (WOCN) Path BPA Studies Study Results (Voltage Stability) Winter

B O N N E V I L L E P O W E R A D M I N I S T R A T I O N 7 5/09/2011 West of Cascades – North (WOCN) Path BPA Studies Projects  For Spring / Summer Thermal limitations BPA will upgrade the Columbia-Bettas Road 230kV line. (energized 2012)  For Winter Thermal limitations BPA will replace 7 bushings on the 345/230kV transformers at Snohomish and Chief Joe. (energized 2012)  For Winter Voltage Stability limitations BPA is proposing: –316.5MVAR shunt capacitor at Monroe 500kV (targeted 2014) –Series Capacitors on the Schultz-Raver 3&4 500kV lines (24 & 16 ohms respectively) (not launched yet)

B O N N E V I L L E P O W E R A D M I N I S T R A T I O N 8 5/09/2011 West of Cascades – North (WOCN) Path BPA Studies Next Steps (Study with Regional entities)  Evaluate various transmission line alternatives. (Initial studies show Sickler-Monroe 500kV is promising) –Utilize all smaller fixes first  Redispatch is a possible “non-wires” solution that would essentially negate the current generation displacement trend for the peak load hours when needed. (Initial studies show ~ 2-year delay per 1000MW displacement)