1. NREL is a national laboratory of the U.S. Department of Energy Office of Energy Efficiency and Renewable Energy operated by the Alliance for Sustainable Energy, LLC Technical Review Committee Meeting March 16, 2011 Debra Lew National Renewable Energy Laboratory Golden, Colorado USA Western Wind and Solar Integration Study - Phase 2: Base Scenario

2. NATIONAL RENEWABLE ENERGY LABORATORY Move to new production simulation tool Move from MAPS to Plexos because Plexos has capability to optimize around cycling/ramping costs/constraints and ability to model subhourly Need to build Plexos model. This is an opportunity to ensure base scenario is realistic and reflects current state of knowledge. Start with WECC TEPPC 2019 database, already built by Plexos Remember that WWSIS2 is not a siting study, so leveraging other, stakeholder-vetted siting efforts will be useful 2

3. NATIONAL RENEWABLE ENERGY LABORATORY WWSIS Phase 1: Siting Scenario Held wind energy (10, 20, 30%) and solar (1, 3, 5%) targets constant, as opposed to serving loads with the cheapest renewable source Solar was 70% CSP with 6 hrs storage and 30% rooftop PV. No centralized PV. Different targets for WestConnect and rest of WECC 3

4. NATIONAL RENEWABLE ENERGY LABORATORY Trade-offs in transmission buildouts Different siting scenarios behaved similarly in terms of operational impacts, when significant BA cooperation was assumed. Therefore we propose to select only one methodology for siting, although we will build it out to different penetration levels. 4

5. NATIONAL RENEWABLE ENERGY LABORATORY Build on other efforts Include centralized PV – now have reasonable dataset WECC considering study requests now and likely to include in next tranche: 2022 33% RPS (6 GW solar in S. NV, 9 GW WY wind) 2032 33% RPS (12 GW WY wind) 2022 dataset update by end Aug Last year’s TEPPC 2029 33% RPS Renewables sited using Western Renewable Energy Zone (WREZ) model Some issues in making this case work 5

6. NATIONAL RENEWABLE ENERGY LABORATORY 2029 WREZ 33% Base Case Source: WECC TEPPC SWG 32% 48%

7. NATIONAL RENEWABLE ENERGY LABORATORY Base Scenario Model year Equal amounts of renewables throughout WECC More solar especially in southwest Increase PV from phase 1 50/50 split of PV and CSP. PV includes centralized PV plants Wind/Solar Siting Scenario Use WREZ model results – consider starting with 2029 WREZ 33% case 7