Vanadium Redox Flow Battery Plant
San Diego Gas & Electric CompanySan Diego County
The Vanadium Redox Flow Battery Plant is SDG&E’s 2 MW / 8 MWh flow-battery system at Miguel Substation in Bonita, San Diego County. EIA lists generator VRF as operating in August 2026, with an operating month of June 2017. Sumitomo Electric supplied the system for a NEDO-commissioned demonstration that tested grid services and microgrid operation. The battery entered CAISO markets in 2018. Its later 2022 purchase-option milestone is distinct from the battery’s original 2017 operating start.
EIA plant 61107 · Inventory reporting month unavailable.
| Generator | Technology | Status | Power (MW) | Energy (MWh) |
|---|---|---|---|---|
| VRF | Batteries | Operating | 2 | Unknown |
SDG&E owns and operates the 2 MW / 8 MWh system at Miguel Substation. Sumitomo Electric supplied it for the NEDO-commissioned demonstration. The original battery entered operation in June 2017; a purchase-option milestone reported for 2022 describes its later ownership history.
Source: EIA August 2026 generator inventory · as of 2026-10-22
Sumitomo reports that test runs powered 66 residential and commercial customers for up to five hours and demonstrated black start and transition to microgrid operation. Those results describe the demonstration period; they are not a current service commitment to those customers.
Source: Sumitomo Electric SDG&E case study · as of 2026-10-22
The nameplate ratings are 2 MW of power and 8 MWh of energy, a four-hour ratio at full rated output. A test serving a varying customer load can last longer than four hours without changing the nameplate rating.
Source: Sumitomo Electric SDG&E case study · as of 2026-10-22
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Operating generator records and technology attributes reported through EIA-860.
| Generator | Capacity | Technology | Operation | Status |
|---|---|---|---|---|
| VRF | 2 MW 2 MW summer | Batteries Electricity used for energy storage · BA | Jun 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.
NEDO commissioned Sumitomo Electric in September 2015 to implement the San Diego flow-battery demonstration.
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.
| Largest reported plants | Capacity | State | |
|---|---|---|---|
| Vanadium Redox Flow Battery PlantCurrent | 2 MW | CA | |
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| Ortega Highway Energy Storage | 1 MW | CA | |
| Pala Energy Storage Yard | 1 MW | CA | |
| Canyon Crest Academy | 1 MW | CA |
Portfolio membership follows the latest EIA-860 reporting entity. It does not imply ultimate ownership.
View full reporting portfolioSDG&E and Sumitomo Electric signed an agreement; construction of the battery facility began in 2016.
The battery became the first flow battery in the United States to receive UL1973 certification for its cell stacks.
The vanadium redox flow battery was commissioned and fully operational in June 2017.
The collaboration was extended through the end of 2021 to test the battery's microgrid capabilities and ancillary services including voltage and frequency regulation.
The microgrid demonstration used the flow battery on an actual distribution network serving 66 customers. Sumitomo reports up to five hours of supply during test runs; this is a historical test result rather than a present continuous-service claim.
Sumitomo describes completion of the demonstration stages at the end of 2021. The separately reported purchase-option execution and asset transfer occurred in 2022.
Sumitomo Electric’s 2025 presentation reports SDG&E’s purchase-option execution and asset transfer in 2022. This is distinct from the June 2017 operating start; no purchase price is disclosed.
Answered from the published record above. Questions whose inputs this profile does not carry are omitted rather than estimated.
SDG&E owns and operates the 2 MW / 8 MWh system at Miguel Substation. Sumitomo Electric supplied it for the NEDO-commissioned demonstration. The original battery entered operation in June 2017; a purchase-option milestone reported for 2022 describes its later ownership history.
Sumitomo reports that test runs powered 66 residential and commercial customers for up to five hours and demonstrated black start and transition to microgrid operation. Those results describe the demonstration period; they are not a current service commitment to those customers.
The nameplate ratings are 2 MW of power and 8 MWh of energy, a four-hour ratio at full rated output. A test serving a varying customer load can last longer than four hours without changing the nameplate rating.
Vanadium Redox Flow Battery Plant reports 2 MW battery storage of operating nameplate capacity. These technology ratings do not establish a common export limit. Source: EIA Form 860M.
Vanadium Redox Flow Battery Plant is a batteries facility in San Diego County, CA, participating in the CAISO market.
Vanadium Redox Flow Battery Plant is in San Diego County, CA, inside the CAISO balancing area.
Vanadium Redox Flow Battery Plant is operated by SDGE Batteries according to the EIA generator inventory. Reporting membership does not by itself establish ultimate ownership.
Vanadium Redox Flow Battery Plant reported 638 MWh over the twelve months to 2024-12. For a storage plant this is reported gross generation — a discharge proxy, not a cycle count or a conventional capacity factor.
By capacity, Vanadium Redox Flow Battery Plant ranks #840 of 1,061 operating plants of the same technology nationally. It ranks #193 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.