PC21 Coal Retirement Study TAS/TEPPC – Nov. 2015 WECC System Adequacy Planning Western Electricity Coordinating Council

Western Electricity Coordinating Council Study Requestors Center for Energy Efficiency and Renewable Technologies (CEERT) Natural Resource Defense Council (NRDC) PacifiCorp (PAC)* State and Provincial Steering Committee (SPSC) Scenario Planning Steering Group (SPSG) Western Grid Group (WGG) Western Interconnection Regional Advisory Body (WIRAB) *PAC later withdrew from study request when scope was changed to indefinitely postpone a reliability analysis. Western Electricity Coordinating Council

Western Electricity Coordinating Council Overview Study Description Scope Input assumptions Study qualifications Study Results Details Generation Paths Other Observations Western Electricity Coordinating Council

Western Electricity Coordinating Council Study Description Western Electricity Coordinating Council

Study Description - Purpose Model a scenario that approaches the 2024 trajectory of reducing carbon emissions to 80% below the 2005 levels by 2050. 248 in 2024 This trajectory has a 34% reduction by 2024 and a 44% reduction by 2030. Western Electricity Coordinating Council

Study Description - Assumptions Modeling assumptions include: Retirement of several high CO2 intensity coal-fired generators based on vintage and location Addition of renewable resources (wind + solar) Additional energy efficiency Addition of gas-fired generation Addition of energy storage resources More details on next slides Western Electricity Coordinating Council

Western Electricity Coordinating Council PC21 Additional Coal Retirements AB AZ CA CO MT UT WY Battle River 4,5 [537] Apache 2,3 [350] ACE Cogen [103] Comanche 1,2 [660] Colstrip 1,2,3 [1354] Huntington 1,2 [909] Dave Johnston 1-4 [762] Genesse 2 [390] Cholla 1,3 [387] Argus 8,9 [50] Craig 1,2 [863] Intermountain 1,2 [1800] Jim Bridger 1,2,3 [1581] Sheerness 1,2 [780] Coronado 1 [380] Casterville [1] Hayden 1,2 [446] NM KUCC 1-4 [175] Naughton 1,2 [357] Sundance 3 [362] H.W. Sundt 4 [156] Fellow M Drake 5,6,7 [254] Four Corners 4,5 [1540] Sunnyside [53] Neil Simpson 2 [80] Navajo 2,3 [1500] Jackson Valley [21] Nucla 1-4 [100] Wygen 1,2 [180] Lassen [22] R D Nixon 1 [208] NV WA Wyodak [340] Mt Poso [35] N Valmy 2 [268] Centralia 2 [688] Phillips Carbon [16] TS Power 1 [227] Portland Cement [28] Port of Stockton [44] Western Electricity Coordinating Council

Western Electricity Coordinating Council PC01 Common Case Coal Retirements [6418 MW] AB AZ CA CO MT UT WY Battle River 3 [148] Cholla 2 [262] RioBravo Jasm [35] Arapahoe 3,4 [153] JE Corette [153] Carbon 1,2 [172] Neil Simpson 1 [18] HR Milner [144] Four Corners 1-3 [560] Cherokee 3 [152] Osage 1-3 [30] Sundance 1,2 [576] Navajo 1 [750] Lamar 4,6 [38] NM Valmont 5 [184] San Juan 2,3 [839] WN Clark 1,2 [40] NV WA Reid Gardner 1-4 [587] Centralia 1 [688] Valmy 1 [254] OR Boardman [610] Western Electricity Coordinating Council

PC21 Coal Retirements by State/Province These are summations by state/province of the capacity and energy from the PC01 Common case v1.5. The lower capacity factor of the Utah retirements is related to the direct impact of AB32 on the Intermountain Generating Station. Western Electricity Coordinating Council

Western Electricity Coordinating Council Replacement Sources The Retired MWh represents the energy produced by the PC21 retired coal resources in the 2024 v1.5 common case. The EE energy was modeled as a load reduction and resulted in a total reduction of about 1700 GWh. The estimated energy values for CC, CT, and ES are based on the assumed capacity factors in the bottom table. Note that the replacement assumptions only replace 53% of the energy that was retired. Will there be any unserved load? Western Electricity Coordinating Council

Western Electricity Coordinating Council Study Qualifications Path Ratings: The WECC paths associated with a few of the retired generators and their replacements would likely need to be re- rated through the path rating process. No changes in path or branch ratings were assumed for this study. Constraints: Other operating constraints and nomograms were also not modified. Flexibility Reserves: The flexibility reserve adders for each reserve area are derived from the loads and amount of variable generation. The flexibility reserve adders were not recalculated for this study. Resource Adequacy: A check of the peak planning reserve margins was not done. System Stability: Tests of system stability were not conducted. Western Electricity Coordinating Council

Western Electricity Coordinating Council Results Western Electricity Coordinating Council

Western Electricity Coordinating Council Dump Energy Generation that is chosen by the PSM model for commitment and dispatch for a least-cost solution may be dumped if its dispatch will break a modeling constraint regarding generation, transmission, reserves, and/or nomograms. Reserves Nomograms Cost Deliverable Constraints Western Electricity Coordinating Council

Western Electricity Coordinating Council From New Gen 269,923 2,409,645 1,801,747 Load side 18,820,604 38,636,263 61,938,182 -1,731,070 This is a summation of the annual generation by category for the PC01 (common case) and the PC21 (coal retirement case), showing the differences between the two cases. The table on the right (blue heading) provides the portion of the change that came from the PC21 replacement resources. Keep in mind that additional EE was applied to reduce the loads in AZ, NM, NV, UT, and WA. 629,356 Western Electricity Coordinating Council

Category Change – Estimated/Actual This is a graphical comparison of the change for a few categories relative to the PC21 replacement units and the PC01 units that were carried forward. The floating blue marker shows the estimated energy for the replacement units; the red bar shows the resultant energy from the replacement units; and the green bar shows the change from the “carried forward” units. Western Electricity Coordinating Council

Western Electricity Coordinating Council

Generation Comparison Western Electricity Coordinating Council

Difference in Annual Energy - WECC Western Electricity Coordinating Council

2024 CO2 PC21 Coal Retirement Case Western Electricity Coordinating Council

Generation Change by State and Fuel Provides the changes from the retirements, the replacements, and the redispatch. Western Electricity Coordinating Council

Western Electricity Coordinating Council

Western Electricity Coordinating Council The chart shows the relationship of the pump storage operation with the LMP price. Negative denotes pumping and positive denotes generating periods. This was the only replacement ES unit that had any significant operation. The others didn’t seem to reach the price thresholds. Western Electricity Coordinating Council

Western Electricity Coordinating Council WECC Paths Western Electricity Coordinating Council

Top 15 Heavily Utilized in PC21 General practice is to ignore paths 52 and 60 since they are low voltage and controllable via phase shifters. The minor congestion on path 83 is from Alberta to Montana. Western Electricity Coordinating Council

Comparison of Net Annual Flow – Top 15 U90 Note that a few paths had a reversal of net annual flow. Western Electricity Coordinating Council

PC-21 Heavily Utilized Paths P83 Montana Alberta Tie Line Path 75% 90% 99% P60 Inyo-Control 115 kV Tie 38% 25% 18% P52 Silver Peak-Control 55 kV 34% 23% 0% P83 Montana Alberta Tie Line 20% 11% 7% P52 Silver Peak-Control P60 Inyo-Control Western Electricity Coordinating Council

Western Electricity Coordinating Council Path 8 The retirement of the base load generation at Colstrip 1,2,3 had an impact on the Path 8 flows. It is also possible that the path rating would be reduced. Western Electricity Coordinating Council

Western Electricity Coordinating Council Path 65+66 (COI plus PDCI) Western Electricity Coordinating Council

Western Electricity Coordinating Council Path 27 In the past a nomogram has been used to define a relationship between generation and path 27 flows. The nomogram was not modified to specify how the replacement generation in Utah would be treated with respect to southern California. Western Electricity Coordinating Council

Western Electricity Coordinating Council Path 46 Western Electricity Coordinating Council

Western Electricity Coordinating Council More Results Western Electricity Coordinating Council

Western Electricity Coordinating Council WECC Peak Week Interesting here how much the simple-cycle combustion turbines were dispatched. Next slide shows the percentage breakdown for the peak hour. Western Electricity Coordinating Council

Western Electricity Coordinating Council WECC Peak Hour – PC21 Western Electricity Coordinating Council

Western Electricity Coordinating Council WECC Early April Windy month. A lot of ramping of base-load coal units. Late peaks = 8:00 pm or 9:00 pm Western Electricity Coordinating Council

Western Electricity Coordinating Council Dump Energy 4/7/24 – PC21 Western Electricity Coordinating Council

Peak hour on April 2 – WECC PC21 Western Electricity Coordinating Council

Western Electricity Coordinating Council California Peak Week Western Electricity Coordinating Council

California Early April The dump energy here is likely from over-generation due to must-take generation and generator constraints in California and also in the interconnected regions. The gaps between the demand and generation represent energy imports. The hours where the generation exceeds the demand represents exports. Western Electricity Coordinating Council

Western Electricity Coordinating Council Imports are negative; exports positive. Western Electricity Coordinating Council

Western Electricity Coordinating Council Observations The PC21 study had no unserved load. PC21 CO2 was 29 million metric tons short of goal Overall energy from PC01 CC and CT units increased Overall energy from remaining coal units increased Share of annual energy from renewable resources is 23.1% in PC21 vs. 17.7% in PC01 Poor performance of PC21 pump storage projects except for project added in SRP area Western Electricity Coordinating Council

Western Electricity Coordinating Council Contact Stan Holland Western Electricity Coordinating Council Senior Engineer stan@wecc.biz (801) 883-6858 Western Electricity Coordinating Council