Southern California Edison just issued a request for offers to add an additional 100 megawatts of strategically placed renewable energy and "preferred resources" to its grid. Preferred resources include renewable distributed generation, demand response, energy storage and renewables teamed with energy storage -- essentially anything but fossil-fuel power plants.

This is the second RFO supporting SCE’s Preferred Resources Pilot (PRP), a very large pilot project aiming to deploy 300 megawatts of clean-energy assets over the next five years. SCE hopes to develop an approach for orchestrating distributed assets -- building on the needs of the Johanna and Santiago substations in grid-congested Orange County,

“Now in its second full year, this pilot is a real-world test where SCE is exploring how cleaner-energy resources can help maintain or improve electric service reliability in a densely populated area,” said Caroline McAndrews, director of SCE's Preferred Resources Pilot, in a release.  

SCE needs more capacity and more energy security in southern Orange County after the closure of the 2.3-gigawatt San Onofre nuclear power plant. As GTM's Jeff St. John has reported, that closure "forced SCE and neighboring utility San Diego Gas & Electric to look at what could happen if the coastal transmission corridor linked by that power plant were to go down, along with another big transmission line loss -- a so-called “N-1-1” event."

Southern California Edison’s 2.2-gigawatt grid services procurement for the West Los Angeles Basin and the PRP are steps in replacing or coping with the loss of gigawatts' worth of nuclear and California’s planned 2020 closure of water-cooled fossil-fueled power plants.

Here's a map showing substations which SCE has ranked in terms of "locational effectiveness factors," based on their ability to mitigate grid constraints west of the Serrano substation.


Last year, SCE revealed the winners of a 250-megawatt energy storage procurement. The biggest winner was AES Energy Storage, which will build a 100-megawatt “in-front-of-meter” battery system in SCE’s West Los Angeles Basin region. SCE’s mix also included 85 megawatts of behind-the-meter batteries from startup Stem, and another 50 megawatts of battery-centered “hybrid electric building” projects from stealthy startup Advanced Microgrid Solutions. Another 25.6 megawatts of thermal energy storage will come from Ice Energy, a startup that turns rooftop air conditioners into load-shifting assets.

Few utilities have made such a large investment in customer-owned, distributed energy storage assets and distributed energy resources, making this a step into the unknown for SCE.

Jesse Bryson, principal manager of contract origination at SCE, notes that the preferred resources in this PRP "avoid reliance on natural gas" and can provide voltage support to the Southern Orange County area. Because the region was seeing load growth, SCE could choose to either "add resources to the area in the form of natural gas" or "bolster the transmission system to alleviate the constraint." 


Jeff St. John contributed to this article.