SAC500 Transmission Project Sacramento Municipal Utility District (SMUD) Western Area Power Administration – Sierra Nevada Region (WASN) SAC500 Transmission Project

SAC500 Transmission Project Feb 2015 - SMUD Board approved agreements to evaluate the feasibility of jointly developing a new 500 kV transmission project with the Western Area Power Administration. The agreements allow initiation of environmental review and to begin regional transmission review activities.

Project Overview Joint project between SMUD & WASN Construct ~50 miles, 500 kV transmission line from near Maxwell to near O'Banion & 500/230 kV transformer at O'Banion. Configure the new Maxwell switchyard to “double bus, double breaker”

Project Objectives / Benefits: Carbon footprint reduction Increased flexibility to access low carbon and renewable generation Meeting SMUD load serving capability for 2024 and beyond Improve system reliability locally and regionally Less reliance on SMUD’s thermal generation fleet More independence, preserves local decision making

COI Impacts: Base Case Assumptions: WECC 2024HS Table Mt. – Rio Oso 230 kV reconductor Palermo – Rio Oso 230 kV line reconductor South of Palermo Transmission project, which consists of reconductoring the southern portion of the Palermo-Rio Oso 115 kV lines #1 & #2 and the Palermo-Pease-Rio Oso 115 kV lines DWR RAS unavailable for COI N-S N-2 Contingency

Contingency Screen: N-1 Credible N-2 Loss of 2 Nuclear Units COI Impacts: Contingency Screen: N-1 Credible N-2 Loss of 2 Nuclear Units

COI Impacts: Study Results: Provides thermal loading relief on the limiting elements Improves reactive power support to the northern California transmission grid   Contingency / Loading COI Flow (MW) NCH TMS DLO RM-TM #1 SLO Pre - Project 4800 70% TM – RIO OSO (111%) RM-TM #2 (99%) Post - Project TM – RIO OSO (109%)

Reactive Margin (MVAR) COI Impacts:   Reactive Margin (MVAR) Base Case Contingency ELVERTAS 230 OBANION 230 MALIN 500 TABLE MT 500 TRACY 500 Pre - Project 2024hs-3353-BASE.sav CptJ-Olinda-slo-ns 478 479 >1000 MPDCI-NS-bipole 551 549 PaloVerde-g2-RAS 389 391 Post – Project 2024hs-3353-MAOB.sav 812 901 909 703 780

Transmission Alternatives: Other transmission alternatives were evaluated: Alternative LSC Increase (MW) Line Length (mi) Loss Savings (MW) CVP Flow Reduction (MW) Cost Estimate ($M) 1 Maxwell – O’Banion 500kV 364 44 19 295 $250 2 Tracy – SMUD Area 500kV 43 21 270 $330 3 Tracy – SMUD Area 230kV 254 17 179 <$330 4 Loop Table Mtn. – Tesla into O’Banion 290 < 1 331 $77 5 Solano - SMUD 230kV 316 40 192

Transmission Alternatives: Conclusions: More expensive to construct Unable to meet the project objectives Requires significant upgrades of existing facilities Infeasible due to space and zoning concerns

WECC Project Review Group: Invitation to WECC members to be part of the SAC500 Project Coordination Review Group Contacts: SMUD: Craig Cameron – (916) 732-5363 craig.cameron@smud.org Patrick Truong – (916) 732-5267 patrick.truong@smud.org WAPA: Kirk Sornborger – (916) 353-4063 sornborg@wapa.gov

Supplemental Slides

Pease-E. Marysville (96%) 4615 90% RM – TM (98%)   Contingency COI Flow (MW) NCH R. Mtn – Table Mtn TM – VD SLO Existing System 4800 60% RM – TM (97%) 70% 4680 80% RM – TM (99%) Pease-E. Marysville (96%) 4615 90% RM – TM (98%) Pease-E. Marysville (99%) 4373 100% RM – TM (94%) Post-Project 2021 System RM – TM (90%) Pease-E. Marysville (<90%) RM – TM (95%) 4682 RM – TM (96%) 4617 4372 RM – TM (91%)

MW BASE MAOB DIFF COI 4763 4766 3 PACIFIC DC INTERTIE (PDCI) 3100 NORTHERN - SOUTHERN CALIFORNIA 3141 3142 1 Bellota-Rancho Seco 230kV: 270.53 199.5 -71.03 Camanch-Rancho Seco 230kV: 265.03 194.33 -70.7 Gold Hill - Lake 230: 167.76 127.06 -40.7 Elverta 230kV Bus Tie: 223.28 188.96 -34.32 Tracy - Hurley #1 230: 257.99 190.77 -67.22 Tracy - Hurley #2 230: 264.01 195.81 -68.2 Folsom - OrangeVale 230: 180.31 155.4 -24.91 Folsom - Lake 230: -68.37 -1.76 -66.61 Maxwell - O’Banion 500:   413.68 Round MT - COTWD 230 #1: 94.27 86.98 -7.29 Tesla - Tracy 230 #1: 49.62 39.65 -9.97 Tesla - Tracy 230 #2: Tracy 500/230 kV Bnk #1 423.45 364.43 -59.02 Tracy 500230 kV Bnk #2 Keswick - O’Banion 230 #1: 249.9 209.22 -40.68 Keswick - Flanagan 230 #1: -81.81 -81.2 -0.61 Hurley - Procter 230 #1: -159.56 -83.81 -75.75