Demand-Side DG in SCE’s Sales Forecast Presented at the DAWG Workshop December 10, 2012 Draft Copy - For Discussion Only

Bypass Distributed Generation (DG) Forecast Methodology SCE relies on a comprehensive data set identifying customers having self-generation units either on-line, under construction or with plans to install. For each unit SCE tracks customer name, total nameplate capacity in kilowatts (kW), bypass kW, operating mode and interconnection date. The units are categorized as either thermal or solar and other renewables. SCE applies technology-specific capacity factors to estimate annual energy production (bypass) by customer class. The forecast includes current projects, projects in the pipeline, and an extrapolation of recent trends within each customer class. However, SCE applies a load shape model that provides stochastic variation around the trend. This variation is designed to capture the randomness of when the thermal units will peak. Forecast for solar projects is provided by SCE’s Customer Solar Group.

Bypass DG SCE Service Territory – Energy September 2012 Vintage

Bypass DG SCE Service Territory – Peak (Coincident) September 2012 Vintage System Peak Hour is HR16 through 2021 and HR17 2022 through 2030. The shift in the peak hour does not affect the thermal coincident peak much but significantly affects the solar coincident peak.

SCE Retail Sales With & Without Energy Efficiency, Self Generation & New Electric Technologies September 2012 Vintage

Solar By-Pass Generation, SCE Service Area, 2010-2030 by Forecast Vintage Solar by-pass generation has been revised upwards in this update compared to both the October 2011 and GRC forecasts. Solar installations have significantly exceeded past forecasts. Solar companies have introduced a new business model that allows customers to amortize the large installation cost under a lease contract. Also, the cost of solar panels has come down. Draft Copy - For Discussion Only

Scenario Descriptions – Residential Solar By-Pass Generation September 2012 Vintage Base Case Solar Generation (Base Case Load Forecast Scenario) This forecast is based on historical installation rates of residential solar experienced over the past 5 years at SCE, and on expected growth patterns in the future, within our existing CPUC regulatory and SCE utility environments. High Solar Generation (Low Case Load Forecast Scenario) The high case assumes electric prices increase faster than expected, the cost of PV systems drop faster than expected, the Federal ITC of 30% will be available through 2022 instead of 2016, and interconnections are simplified. Low Solar Generation (High Case Load Forecast Scenario) The low case assumes electric prices don’t increase as fast as expected, the cost of PV systems don’t drop as fast as expected, credit and financing isn’t as available to contractors and customers, and interconnections become more complex.

Base, High & Low Case Forecast of Residential Solar Generation (GWh), 2010 to 2030 – September 2012 Vintage A higher level of Solar generation is associated with the Low Case sales forecast and a lower level of Solar generation is matched with the High Case sales forecast. Higher electric rate levels in the Low Case encourage more solar generation while lower electric rates in the High Case discourage additional solar generation.