Virtual Power Plant (VPP) Pilot Phase I Impact Evaluation

The behind-the-meter (BTM) battery systems will be administered by Sunrun® and used to provide planned and real-time demand response grid services. The VPP project will enroll 200-500 customers in the project from a population of approximately 1,000 customers with existing or new Sunrun PV-paired battery systems. Customers will use the systems for TOU rate arbitrage and emergency backup services when the systems are not providing demand response grid services. SCE will execute demand response events by dispatching signals to Sunrun via its demand response automation system (DRAS). Customers will be compensated for participating and able to override events. Sunrun will reserve at least 20% of customer’s battery power for emergency backup. The project will be implemented for at least 12 months to cover the heating and cooling seasons.

SCE’s Pathway 2045 calls for 40 GW of battery storage, with 10 GW estimated to come from behind-the-meter resources. To achieve this target, and to help coordinate distributed energy resources (DERs) in managing anticipated growth in SCE’s system peak, in 2020, SCE launched Phase I of its Virtual Power Plant (VPP) pilot. The pilot dispatches residential solar-paired battery systems and smart inverters to provide grid services both systemwide and at local levels during demand response events.[1] The enrolled systems are dispatched through SCE’s demand response automation server (DRAS) central control but remain independently owned and operated. Eventually, SCE envisions VPP as a cloud-based power plant that aggregates the capacities of multiple DERs. Phase I of the VPP pilot began in June 1, 2020, and concluded on May 31, 2021. For Phase I, SCE partnered exclusively with vendor Sunrun to enroll customers with Sunrun’s Brightbox systems (consisting of a battery, a smart inverter, and control systems) in the pilot. The battery storage systems provide customers with backup power during power outages and lower monthly electric bills through arbitrage of SCE’s time-of-use (TOU) rates.[2] [1] In Phase I, SCE tested the peak management and demand response capabilities of VPP. VPP is capable of providing numerous additional grid services in future phases, including frequency regulation, system capacity, local voltage reduction, and congestion relief. [2] The batteries are charged from customers’ solar generation during off-peak hours and are discharged in the evening during peak hours (from 4 p.m. to 9 p.m. on weekdays), thereby lowering customers’ on-peak electricity consumption.