El Cajon Energy Storage
San Diego Gas & Electric CompanySan Diego County
El Cajon Energy Storage is SDG&E’s 7.5 MW / 30 MWh lithium-ion battery at an El Cajon substation in San Diego County. Its energy-to-power rating corresponds to four hours at rated output. EIA’s August 2026 inventory lists generator SES as operating, with an operating month of February 2017. AES supplied the Advancion system, using Samsung SDI batteries and Parker Hannifin power conversion equipment. El Cajon and the larger Escondido battery were procured together but are separate facilities.
EIA plant 60569 · Inventory reporting month unavailable.
| Generator | Technology | Status | Power (MW) | Energy (MWh) |
|---|---|---|---|---|
| SES | Batteries | Operating | 7.5 | Unknown |
SDG&E owns and operates this utility battery. CPUC Resolution E-4798 approved its procurement with AES alongside the separate Escondido project. El Cajon contributes 7.5 MW; the combined 37.5 MW procurement is not El Cajon’s capacity.
Source: CPUC Resolution E-4798 · as of 2026-10-22
EIA’s August 2026 inventory reports 7.5 MW of nameplate power and 30 MWh of energy for generator SES. Their ratio is four hours at rated power; that is a capacity rating rather than a guarantee of every dispatch’s duration.
Source: EIA August 2026 generator inventory · as of 2026-10-22
Similar plants ranked by technology, capacity, and distance.
Operating generator records and technology attributes reported through EIA-860.
| Generator | Capacity | Technology | Operation | Status |
|---|---|---|---|---|
| SES | 7.5 MW 7.5 MW summer | Batteries Electricity used for energy storage · BA | Feb 2017 | Operating |
Monthly EIA generation history and recent market-resource behavior where linked telemetry is available.
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Project milestones and public references behind the asset profile.
The CPUC adopted Resolution E-4791, authorizing SDG&E to use its local-capacity procurement process to assess storage resources for alleviating reliability issues related to the Aliso Canyon gas-injection moratorium.
EIA-923 reports gross generation and net grid exchange for storage plants. Gross generation is shown as a discharge proxy; it is not a cycle count or conventional capacity factor.
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| Elliott Energy Storage | 10 MW | CA | |
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Portfolio membership follows the latest EIA-860 reporting entity. It does not imply ultimate ownership.
View full reporting portfolioSDG&E filed Advice Letter (AL) 2924-E seeking CPUC approval of two utility-owned energy storage EPC contracts with AES Energy Storage LLC, covering a 30 MW/120 MWh project in Escondido and a 7.5 MW/30 MWh project in El Cajon.
CPUC issued Resolution E-4798 approving SDG&E's Advice Letter 2924-E and the utility-owned EPC contracts with AES. The resolution specifies that projects shall be online on or before January 31, 2017, describes turnkey construction by AES, and identifies a long-term service contract covering the first 10 years of operation. The resolution notes that actual project cost was confidential and that payments to AES would be fully recoverable in rates up to a cost cap.
EIA-860 lists generator SES with this operating date.
FERC asset appendix records February 1, 2017 as the in-service date for El Cajon Energy Storage (EIA plant 60569, FERC docket ER99-3426-000). Generator SES, capacity 7.50 MW.
Answered from the published record above. Questions whose inputs this profile does not carry are omitted rather than estimated.
SDG&E owns and operates this utility battery. CPUC Resolution E-4798 approved its procurement with AES alongside the separate Escondido project. El Cajon contributes 7.5 MW; the combined 37.5 MW procurement is not El Cajon’s capacity.
EIA’s August 2026 inventory reports 7.5 MW of nameplate power and 30 MWh of energy for generator SES. Their ratio is four hours at rated power; that is a capacity rating rather than a guarantee of every dispatch’s duration.
El Cajon Energy Storage reports 7.5 MW battery storage of operating nameplate capacity. These technology ratings do not establish a common export limit. Source: EIA Form 860M.
El Cajon Energy Storage is a batteries facility in San Diego County, CA, participating in the CAISO market.
El Cajon Energy Storage is in San Diego County, CA, inside the CAISO balancing area.
El Cajon Energy Storage is operated by San Diego Gas & Electric Co according to the EIA generator inventory. Reporting membership does not by itself establish ultimate ownership.
El Cajon Energy Storage reported 3.2 GWh over the twelve months to 2026-07. For a storage plant this is reported gross generation — a discharge proxy, not a cycle count or a conventional capacity factor.
By capacity, El Cajon Energy Storage ranks #653 of 1,061 operating plants of the same technology nationally. It ranks #174 of 272 in CA.
Plants within 25 km, nearest first, regardless of technology. Proximity is straight-line distance between mapped plant coordinates; it does not by itself establish a shared point of interconnection.