Load Impact Estimates for Southern California Edison's Demand Response Programs: Agricultural and Pumping Interruptible Program Real Time Pricing

This report provides 2011 ex post load impact estimates and 2012-2022 ex ante load impact estimates for the following Southern California Edison demand response programs: Agricultural and Pumping Interruptible program and Real Time Pricing tariff. The report contains an executive summary and one section for each demand response resource. Each section starts with a brief overview of the program objectives, history and current enrollment values. This is followed by a discussion of analysis methodology, including an assessment of the validity of the models and estimates. The remainder of each section presents the 2011 ex post load impact estimates and 2012-2022 ex ante load impact estimates.

In 2011, there was one AP-I event. This event took place on September 21 and lasted from 1:48 PM to 3:01 PM. From 2 PM to 3 PM, the load drop was 34.9 kW per participant with an aggregate load drop of 33.4 MW. The aggregate impact represents an 80.5% reduction relative to the reference load of 41.5 MW. In addition, AP-I ex ante load impact estimates were developed for the years 2012 through 2022. Once enrollment and the switch success rate reach their expected steady state in the 2015 to 2022 time period, the program is projected to be capable of delivering nearly 55 MW of load reduction, which occurs during the May monthly peak under 1-in-10 weather conditions. If SCE reaches its forecast target of a 95% switch success rate by August 2014, the aggregate 1-in-2 load impact is 47.9 MW and the 1-in-10 result is 51.7 MW.

For RTP, the largest estimated load impact in 2011 occurred on September 7, for which the program generated an average load drop of 159.7 kW and an aggregate load drop of nearly 21 MW during the peak period from 1 PM to 6 PM. The aggregate impact represents a 15.8% reduction relative to the reference load of 133.1 MW. In addition, RTP ex ante load impact estimates were developed for the years 2012 through 2022. Once enrollment reaches its expected steady state in August 2015, the program is projected to be capable of delivering 32.5 MW of load reduction on the days with the highest RTP prices during the summer. In August and September for a 1-in-2 weather year, aggregate impacts are expected to increase by 38% and 44% respectively from 2012 to 2015 as a result of new enrollment.

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