2014–2015 Local Idaho Power Transmission Plan Delivery Planning Final Report December 2015 © 2015 Idaho Power Idaho Power Company 2014–2015 Local Transmission Plan TABLE OF CONTENTS Table of Contents ............................................................................................................................. i List of Tables .................................................................................................................................. ii List of Figures ................................................................................................................................ iii List of Appendices ......................................................................................................................... iii 1. Introduction ..................................................................................................................................1 1.1. Local Planning ..................................................................................................................1 1.2. Regional and Interconnection-Wide Coordination ...........................................................1 2. Planning Process and Time Line..................................................................................................2 3. Transmission System Plan Inputs and Components ....................................................................3 3.1. Idaho Power’s Transmission System ................................................................................3 3.2. Load Forecast ....................................................................................................................3 3.2.1. Western Load Area ..................................................................................................5 3.2.2. Treasure Valley Load Area ......................................................................................5 3.2.3. Southern Load Area .................................................................................................6 3.2.4. Eastern Load Area....................................................................................................7 3.3. Forecasted Resources ........................................................................................................8 3.4. Transmission Use Forecast ...............................................................................................9 3.5. Area Planning ..................................................................................................................10 3.6. Economic studies ............................................................................................................16 4. System Conditions Studied ........................................................................................................16 4.1. Scenarios Studied ............................................................................................................16 4.2. Transmission System Model ...........................................................................................17 5. Reliability Evaluation ................................................................................................................18 5.1. Transmission System Analysis .......................................................................................18 5.2. 2020 Heavy Winter Study Results ..................................................................................19 5.3. 2024 Heavy Summer Study Results................................................................................19 5.4. 2024 NTTG case Study Results ......................................................................................21 2014–2015 Local Transmission Plan Page i 2014–2015 Local Transmission Plan Idaho Power Company 5.5. 2034 Heavy Summer Study Results................................................................................21 6. Summary and Conclusions ........................................................................................................21 LIST OF TABLES Table 1 Meeting dates and descriptions .....................................................................................................2 Table 2. Load forecasts for areas of Idaho Power .......................................................................................4 Table 3 2013 IRP Preferred Portfolio ........................................................................................................8 Table 4 Generation Interconnection Projects with signed GIAs or PPAs since 2013 ...............................8 Table 5 Transmission Service Obligations submitted in Quarter 5 ...........................................................9 Table 6 Transmission Capacity Needed in the year 2024 ..........................................................................9 Table 7 Comparison of 2024 Transmission Needs with Expected TTC for various RTPs .....................10 Table 8 Modeled loads in 2034 power flow case .....................................................................................17 Table 9 Summary of performance criteria issues .....................................................................................19 Table B-1 Projects planned for 1-5 year horizon .........................................................................................27 Table B-2 Projects planned for 5-10 year horizon .......................................................................................28 Table B-3 Projects planned for 10-20 year horizon .....................................................................................30 Page ii 2014–2015 Local Transmission Plan Idaho Power Company 2014–2015 Local Transmission Plan LIST OF FIGURES Figure 1 Planning cycle schedule ................................................................................................................2 Figure 2 Idaho Power transmission system .................................................................................................3 Figure 3 Idaho Power load areas .................................................................................................................4 Figure 4 Western load area ..........................................................................................................................5 Figure 5 Treasure Valley load area .............................................................................................................6 Figure 6 Southern load area .........................................................................................................................7 Figure 7 Eastern load area ...........................................................................................................................7 Figure 8 Treasure Valley electrical plan ...................................................................................................11 Figure 9 Magic Valley electrical plan .......................................................................................................12 Figure 10 Wood River Valley electrical plan ..............................................................................................12 Figure 11 Eastern Idaho electrical plan .......................................................................................................13 Figure 12 Western Treasure Valley electrical plan .....................................................................................14 Figure 13 Eastern Treasure Valley electrical plan—Ada County ...............................................................15 Figure 14 Eastern Treasure Valley electrical plan—Elmore County ..........................................................16 LIST OF APPENDICES Appendix A Community Advisory Committee Process ..................................................................................23 2014–2015 Local Transmission Plan Page iii 2014–2015 Local Transmission Plan Idaho Power Company Appendix B Twenty-year project list ..............................................................................................................27 Page iv 2014–2015 Local Transmission Plan Idaho Power Company 2014–2015 Local Transmission Plan This page left blank intentionally. 2014–2015 Local Transmission Plan Page v Idaho Power Company 2014–2015 Local Transmission Plan 1. INTRODUCTION The 2015 Local Transmission Plan is the culmination of the 2014-2015 local transmission planning process as described in Idaho Power’s Open Access Transmission Tariff (OATT) Attachment K. The plan includes all transmissions system facility improvements identified through this planning process. A power flow reliability assessment of the plan was performed which demonstrated that the planned facility additions will meet NERC and WECC reliability standards. Idaho Power’s OATT is located on its Open Access Same-time Information System (OASIS) at http://www.oatioasis.com/ipco. Additional information regarding Transmission Planning is located in the Transmission Planning folder on Idaho Power’s OASIS. Unless otherwise specified, capitalized terms used herein are defined in either Section 1 of Idaho Power’s OATT or Section 1 of Idaho Power’s OATT Attachment K. 1.1. Local Planning This Local Transmission Plan (LTP) has been prepared within the two-year process as defined in Idaho Power’s OATT Attachment K. The LTP identifies the Transmission System facility additions required to reliably interconnect forecasted generation resources and serve the forecasted Network