1. 2015 IEPR Lead Commissioner Workshop Southern California Reliability University of California, Irvine August 17, 2015 Tom Doughty Director, State Regulatory Strategy

2. SONGS closure created reliability issues in Southern California - Los Angeles and San Diego are load pockets with limited options Real power (Watts) Powers lights and appliances Requires correct voltage for delivery (like pressure in water pipes) Reactive power (Vars) Over or under supply of Vars causes voltages to climb or fall Local needs must be met locally Real-Time Response to contingencies System must stand ready to respond Some events are instantaneous; others have 30 minutes response time Page 2

3. Immediate solutions mitigated some reliability risk Page 3 Jun 2012: Sunrise Power Link into San Diego Jun 2013: Huntington Beach units 3 & 4 converted to synchronous condensers and renewed annually Jul 2013: Voltage support capacitors in South Orange County Aug 2013: New non-OTC generation in LA Basin – El Segundo Dec 2013: Barre-Ellis transmission in South Orange County Reconfigured Flex Alerts Demand response Existing generation properly maintained and available for summer peak loads

4. Page 4 An added challenge: Managing the Retirement of Once-through-cooled Resources Installed OTC capacity: 4,476 MW* Installed OTC capacity: 946 MW* Notes: *Assumed retired in the long-term LCR studies

5. Findings: If authorized resources materialize and assumptions remain valid, supplies are adequate Authorized in LTPP Tracks 1&4: 2,500 MW for SCE and 1,100 MW for SDG&E –SCE RFO Applications = 1,882 MW proposed (awaiting approval 2015) –SDG&E: 905 MW approved + 200 MW preferred (pending 2016) 2014/2015 TPP suggests concern if remaining 608 MW fails to materialize for SCE: Western LA Basin most impacted area, or AAEE does not materialize as forecasted Repurposed DR or additional procurement could help mitigate shortfalls As part of TPP studies, ISO is conducting additional LCR study for years 2021 and 2025; for use in next LTPP cycle Slide 5

6. Approved grid upgrades are underway through 2020 Slide 6 Viejo Santiago Johanna New Voltage Support Mira Loma ` Barre Ellis Miguel San Luis Rey Suncrest Talega Mesa Tehachapi Renewable Transmission Project Mesa Loop-in New Phase Shifter Imperial Valley New Tx line Sycamore-Canyon