RE Tranquillity is a hybrid solar and battery storage facility with 277.3 MW of EIA-reported nameplate capacity and 288 MWh of reported storage energy capacity in Fresno County, California, registered as EIA Plant ID 59939. Southern Power owns and operates the plant. in August 2015.
Reported plant capacity and configuration.
Primary generation technology.
Southern Power Co · Fresno County · CAISO
Battery subsystem rating.
RE Tranquillity is operating.
230 kV · Pacific Gas and Electric Company (PG&E)
Installed equipment documented in public project records.
Batteries, Solar Photovoltaic
4.3-hour storage duration
RE Tranquillity is operating.
230 kV · Pacific Gas and Electric Company (PG&E)
Similar plants ranked by technology, capacity, and distance.
Operating generator records and technology attributes reported through EIA-860.
| Generator | Capacity | Technology | Operation | Status |
|---|---|---|---|---|
| BESS1 | 37 MW 37 MW summer | Batteries Electricity used for energy storage · BA | Nov 2021 | Operating |
| BESS2 | 35 MW 35 MW summer | Batteries Electricity used for energy storage · BA | Mar 2022 | Operating |
| TQ | 205.3 MW 200 MW summer | Solar Photovoltaic Solar · PV | Jul 2016 | Operating |
Monthly EIA generation history and recent market-resource behavior where linked telemetry is available.
Deterministic links to ERCOT market resources, price records, outage disclosures, queue records, and nearby infrastructure. Candidate joins remain labeled until corroborated.
Source-backed project transactions, agreements, land records, permits, and environmental disclosures. Portfolio and adjacent-project facts remain explicitly scoped.
Parties, market resources, and identifiers tied to this asset, with owner, operator, developer, EPC, compliance provider, and interconnecting entity roles kept separate.
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Project milestones and public references behind the asset profile.
Construction began on the 1,900-acre Fresno County site, with Signal Energy Constructors providing engineering, procurement, and construction services.
CAISO
CAISO · Fresno County
Monthly generation is reported through EIA-923. Capacity factor uses the current EIA nameplate capacity and is shown only for complete calendar years.
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|---|---|---|---|
| H Allen Franklin Combined Cycle | 1,995.7 MW | AL | |
| E B Harris Electric Generating Plant | 1,304 MW | AL | |
| Wansley Combined Cycle | 1,239 MW | GA | |
| Rowan | 1,192 MW | NC | |
| Dahlberg | 919 MW | GA | |
| Cleveland Cnty Generating Facility | 736 MW | NC | |
| Edward L. Addison Generating Plant | 701.2 MW | GA | |
| Deuel Harvest Wind Energy LLC | 300 MW | SD |
Portfolio membership follows the latest EIA-860 reporting entity. It does not imply ultimate ownership.
View full reporting portfolioSouthern Power signed an agreement to acquire a 51% controlling interest in the Tranquillity solar project from Recurrent Energy; Canadian Solar retained the remaining 49% at project completion.
Recurrent Energy closed a $337 million combined construction and term debt facility, including project-level construction debt, LC facilities, and a back-leveraged term facility.
EIA-860 lists generator TQ with this operating date.
Southern Power and Recurrent Energy announced commercial operation of the 200 MW Tranquillity Solar Facility; the solar output and renewable-energy credits were contracted under long-term PPAs including Southern California Edison.
EIA-860 lists generator BESS1 with this operating date.
EIA-860 lists generator BESS2 with this operating date.
Southern Power announced that the Tranquillity battery project was fully operational; Rosendin Electric constructed the site, Mitsubishi Power Americas supplied the equipment using Powin batteries, and Mitsubishi Power Americas provided long-term service.
Answered from the published record above. Questions whose inputs this profile does not carry are omitted rather than estimated.
RE Tranquillity has a reported capacity of 277.3 MW and an energy capacity of 288 MWh. That is roughly 4.3 hours at full output. Source: EIA Form 860.
RE Tranquillity is a Batteries, Solar Photovoltaic facility in Fresno County, CA, participating in the CAISO market.
RE Tranquillity is in Fresno County, CA, inside the CAISO balancing area.
RE Tranquillity is operated by Southern Power Co according to the EIA generator inventory. Reporting membership does not by itself establish ultimate ownership.
RE Tranquillity reported 491.4 GWh over the twelve months to 2024-12. Figures are net generation as filed to EIA-923.
RE Tranquillity interconnects at Tranquillity Switching Station, on the Pacific Gas and Electric Company (PG&E) system.
By capacity, RE Tranquillity ranks #133 of 7,234 operating plants of the same technology nationally. It ranks #25 of 939 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.
