ERS Forward Looking Measures 1, 2 & 4 Elena Melloni Associate Engineer II, System Stability Planning Western Electricity Coordinating Council

ERS Forward Looking Measures 1: Synchronous Inertia Response Under Minimum SIR Conditions 2: Rate of Change of Frequency (RoCoF) 4: Interconnection Frequency Response Western Electricity Coordinating Council

Avg Dispatch (% of Cap), Weighted by Cap, Type, & Area Case Creation Target Renewable Capacity by Base Case Area 2021 Light Spring (21LSP1) Adjustments Renewable gen by BC Area based on latest PCM data EPCL to adjust wind and solar based on turbine type Redispatch gen to solve case Baseload flags DER netted with load Simulated double PV outage   Avg Dispatch (% of Cap), Weighted by Cap, Type, & Area Area WT Solar PV ALBERTA 40% ARIZONA 41% 84% B.C.HYDRO 20% EL PASO 82% IDAHO 62% 64% IMPERIALCA 97% LADWP 45% 94% MEXICO-CFE 42% 80% MONTANA 47% NEVADA 86% NEW MEXICO 46% NORTHWEST 57% 50% PACE 48% 63% PG AND E 61% 90% PSCOLORADO 37% 72% SANDIEGO 91% SIERRA 52% SOCALIF WAPA R.M. 49% WAPA U.M. Western Electricity Coordinating Council

Western Electricity Coordinating Council Results Highest Spread 230kV bus 1706.50 MW 0.1Hz 500kV bus 1750.95 MW 0.1Hz IFRO for WI: 840 MW 0.1Hz WI median: 1350 MW 0.1Hz Western Electricity Coordinating Council

SIR Case Number Case Name Total System’s Synchronous Inertia (MVA*s) Total Non-synchronous Generation Dispatched (Pgen [MW]) Total Synchronous Generation Dispatched (Pgen [MW]) Total DC Tie-Line Imports (MW)  Total System Load (MW) 1 2021 Light Spring Scenario ORIGINAL 537526 8014 88653 -56 93746 2 2021 Light Spring Scenario ADJUSTED 497671 19813 77189 Western Electricity Coordinating Council

Western Electricity Coordinating Council RoCoF Resource Contingency Criteria (RCC) for WECC: 2740 MW UFLS: 59.5 Hz RoCoF 0.5 : -0.05986 RoCoF RCC : -0.17 Western Electricity Coordinating Council

Interconnection Frequency Response Performance Ratios A:B (MW/.1Hz) Adjusted: 2874.4 Original: 3369.2 A:C (MW/.1Hz) Adjusted: 1751.0 Original: 1954.6 C:B (unitless) Adjusted: 1.6 Original: 1.7 Time to UFLS: 0.343Hz Western Electricity Coordinating Council

Looking Forward on the Forward Looking Measures WECC would like to build a case using the Base Case Compilation process More accurate & vetted data Incorporate DER in the base cases Track these measures to determine trends Western Electricity Coordinating Council