1. Puget Sound Area Northern Intertie (PSANI) Transmission History ColumbiaGrid September 24, 2007 September 24, 2007 Snohomish County Public Utility District John D. Martinsen

2. PSANI History Historical BPA Plans Historical BPA Plans April 2003 Curtailments April 2003 Curtailments Meeting of the Minds Meeting of the Minds Current Status Current Status

3. Historical BPA Plans Excerpts from the BPA 1991 – 2000 Transmission System Facilities Ten Year Development plan Excerpts from the BPA 1991 – 2000 Transmission System Facilities Ten Year Development plan King County System Reinforcements (second Monroe to Echo Lake 500kV) King County System Reinforcements (second Monroe to Echo Lake 500kV) Planned energization in 1997 Planned energization in 1997 Puget Sound Area Reinforcement (double circuit Chief Joseph to Monroe upgraded to 500kV & tie to Snohomish ) Puget Sound Area Reinforcement (double circuit Chief Joseph to Monroe upgraded to 500kV & tie to Snohomish ) (Planned energization in 2000) (Planned energization in 2000) Little support for new transmission during this period due to regulatory uncertainty – NEPA 1992 Little support for new transmission during this period due to regulatory uncertainty – NEPA 1992

4. King County System Reinforcements …New Monroe to Echo Lake 500kV line …New Monroe to Echo Lake 500kV line Reinforcement is required to eliminate the heavy loading on the underlying 230kV system during an outage of the existing Monroe-Echo Lake Reinforcement is required to eliminate the heavy loading on the underlying 230kV system during an outage of the existing Monroe-Echo Lake

5. King County System Reinforcements

6. Puget Sound Area Reinforcement Replace existing Chief Joseph – Monroe 345kV double circuit lines with a 500kV double circuit line to Monroe and Snohomish Replace existing Chief Joseph – Monroe 345kV double circuit lines with a 500kV double circuit line to Monroe and Snohomish..capacity may not be sufficient beyond 2000 if load growth is higher than expected or the Canadian Entitlement return must be delivered to Blaine..capacity may not be sufficient beyond 2000 if load growth is higher than expected or the Canadian Entitlement return must be delivered to Blaine

7. Puget Sound Area Reinforcement

8. April 2003 - Curtailments April 2003 the Canadian Entitlement return increased from 630MW to 1,149MW April 2003 the Canadian Entitlement return increased from 630MW to 1,149MW Curtailments and curtailment notices became a regular occurrence for Puget Sound utilities and Powerex Curtailments and curtailment notices became a regular occurrence for Puget Sound utilities and Powerex

9. Meeting of the Minds Soon after April 2003 BPA, Puget Sound utilities, and Powerex met Soon after April 2003 BPA, Puget Sound utilities, and Powerex met A short-term Redispatch was agreed to by the Puget Sound and Powerex parties A short-term Redispatch was agreed to by the Puget Sound and Powerex parties The Puget Sound Area Study Group (PSASG) was formed under the Northwest Power Pool (NWPP) Northwest Transmission Assessment Committee (NTAC) The Puget Sound Area Study Group (PSASG) was formed under the Northwest Power Pool (NWPP) Northwest Transmission Assessment Committee (NTAC) Puget Sound Area Upgrade Study Report was completed by the PSASG -November 2004 Puget Sound Area Upgrade Study Report was completed by the PSASG -November 2004

10. Current Status The Canadian Entitlement may increase to 1500 MW The Canadian Entitlement may increase to 1500 MW Puget Sound Area loads are growing Puget Sound Area loads are growing Both wire and non-wire alternatives have been reviewed Both wire and non-wire alternatives have been reviewed Most of the major Transmission reinforcements reviewed would take eight to ten years to complete Most of the major Transmission reinforcements reviewed would take eight to ten years to complete Incremental upgrades and operating procedures have resulted in reduced curtailment risk Incremental upgrades and operating procedures have resulted in reduced curtailment risk No major (i.e. 500 kV) Puget Sound area transmission expansion is currently moving forward No major (i.e. 500 kV) Puget Sound area transmission expansion is currently moving forward

11. Canadian Entitlement Returns Entitlement Capacity (MW) YearReturned to BC 2001-02768 2002-03630 then 1149 2003-041,154 2004-051,154 2005-061,195 2006-071,221 2007-081,217 2008-091,222 2009-101,327 2010-111,291 2011-121,289