# RE Tranquillity

CAISO Batteries, Solar Photovoltaic · https://askthegrid.com/assets/facilities/re-tranquillity

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.

## Key facts

- Technology: Batteries, Solar Photovoltaic
- Power capacity: 277.3 MW
- Energy capacity: 288 MWh
- Storage duration: 4.3 hours
- Operating status: operating

## Grid and market context

- ISO/RTO: CAISO
- Balancing authority: CISO
- Substation: Tranquillity Switching Station
- Point of interconnection: Tranquillity Switching Station
- Transmission owner: Pacific Gas and Electric Company (PG&E)
- Interconnection voltage: 230 kV

## Source-backed facts

- Owner logo domain: southernpowercompany.com — Source · confidence: high
- Owner logo domain: southernpowercompany.com — Southern Power · confidence: high
- Identifiers: [{"value":"59939","system":"EIA plant code"},{"value":"45089","system":"EIA ID"},{"value":"TQ","system":"EIA generator ID"},{"value":"BESS1","system":"EIA generator ID"},{"value":"BESS2","system":"EIA generator ID"},{"value":"643X","system":"CAISO queue ID"},{"value":"CAISO","system":"ISO/RTO market"},{"value":"CISO","system":"Balancing authority"},{"value":"TRNQLT_2_SOLAR","system":"CAISO resource ID"},{"value":"TRNQLT_2_RETBT1","system":"CAISO resource ID"},{"value":"TRANQUILLITY_643W","system":"CAISO resource group"},{"value":"2013111056","system":"California CEQA SCH number"}] — MBR | Index · confidence: medium
- Identifiers: [{"value":"59939","system":"EIA plant code"},{"value":"45089","system":"EIA ID"},{"value":"TQ","system":"EIA generator ID"},{"value":"BESS1","system":"EIA generator ID"},{"value":"BESS2","system":"EIA generator ID"},{"value":"643X","system":"CAISO queue ID"},{"value":"CAISO","system":"ISO/RTO market"},{"value":"CISO","system":"Balancing authority"},{"value":"TRNQLT_2_SOLAR","system":"CAISO resource ID"},{"value":"TRNQLT_2_RETBT1","system":"CAISO resource ID"},{"value":"TRANQUILLITY_643W","system":"CAISO resource group"},{"value":"2013111056","system":"California CEQA SCH number"}] — Public Queue Report · confidence: medium
- Identifiers: [{"value":"59939","system":"EIA plant code"},{"value":"45089","system":"EIA ID"},{"value":"TQ","system":"EIA generator ID"},{"value":"BESS1","system":"EIA generator ID"},{"value":"BESS2","system":"EIA generator ID"},{"value":"643X","system":"CAISO queue ID"},{"value":"CAISO","system":"ISO/RTO market"},{"value":"CISO","system":"Balancing authority"},{"value":"TRNQLT_2_SOLAR","system":"CAISO resource ID"},{"value":"TRNQLT_2_RETBT1","system":"CAISO resource ID"},{"value":"TRANQUILLITY_643W","system":"CAISO resource group"},{"value":"2013111056","system":"California CEQA SCH number"}] — 2026 NQC List · confidence: medium
- Identifiers: [{"value":"59939","system":"EIA plant code"},{"value":"45089","system":"EIA ID"},{"value":"TQ","system":"EIA generator ID"},{"value":"BESS1","system":"EIA generator ID"},{"value":"BESS2","system":"EIA generator ID"},{"value":"643X","system":"CAISO queue ID"},{"value":"CAISO","system":"ISO/RTO market"},{"value":"CISO","system":"Balancing authority"},{"value":"TRNQLT_2_SOLAR","system":"CAISO resource ID"},{"value":"TRNQLT_2_RETBT1","system":"CAISO resource ID"},{"value":"TRANQUILLITY_643W","system":"CAISO resource group"},{"value":"2013111056","system":"California CEQA SCH number"}] — Meter Exemptions 2024 · confidence: medium
- Identifiers: [{"value":"59939","system":"EIA plant code"},{"value":"45089","system":"EIA ID"},{"value":"TQ","system":"EIA generator ID"},{"value":"BESS1","system":"EIA generator ID"},{"value":"BESS2","system":"EIA generator ID"},{"value":"643X","system":"CAISO queue ID"},{"value":"CAISO","system":"ISO/RTO market"},{"value":"CISO","system":"Balancing authority"},{"value":"TRNQLT_2_SOLAR","system":"CAISO resource ID"},{"value":"TRNQLT_2_RETBT1","system":"CAISO resource ID"},{"value":"TRANQUILLITY_643W","system":"CAISO resource group"},{"value":"2013111056","system":"California CEQA SCH number"}] — Tranquillity Solar Generating Facility EIR · confidence: medium
- Canonical name: RE Tranquillity — MBR | Index · confidence: high
- Identifiers.1: {"value":"45089","system":"EIA ID"} — MBR | Index · confidence: medium
- Identifiers.3: {"value":"BESS1","system":"EIA generator ID"} — MBR | Index · confidence: medium
- Identifiers.5: {"value":"643X","system":"CAISO queue ID"} — Public Queue Report · confidence: high
- Identifiers.8: {"value":"TRNQLT_2_SOLAR","system":"CAISO resource ID"} — 2026 NQC List · confidence: high
- Identifiers.9: {"value":"TRNQLT_2_RETBT1","system":"CAISO resource ID"} — Meter Exemptions 2024 · confidence: high
- Identifiers.10: {"value":"TRANQUILLITY_643W","system":"CAISO resource group"} — 2026 NQC List · confidence: high
- Identifiers.11: {"value":"2013111056","system":"California CEQA SCH number"} — Tranquillity Solar Generating Facility EIR · confidence: high
- Parties.8: {"relationship":"Solar engineering, procurement, and construction contractor","name":"Signal Energy Constructors","official_url":"https://www.signalenergy.com/projects/tranquillity-solar-project"} — Signal Energy | Tranquillity Solar Project · confidence: high
- Parties.12: {"relationship":"Photovoltaic module manufacturer","name":"REC Solar","official_url":"https://www.recgroup.com/"} — Source · confidence: high
- Parties.13: {"relationship":"Power-purchase-agreement offtaker","name":"Southern California Edison","official_url":"https://www.sce.com/"} — Battery-based energy storage projects at Southern Power’s Garland and Tranquillity solar facilities are now operational · confidence: high
- Interconnection: 230 kV substation with interconnection to a PG&E switching station — Source · confidence: medium
- Site acres: 1900 — Source · confidence: medium
- Construction scope: The hybrid facility comprises a 200 MWac/258 MWp solar plant on approximately 1,900 acres, with more than 800,000 polycrystalline PV modules on tracking tables. Signal Energy's solar EPC scope included geotechnical, civil, structural, mechanical, DC/AC electrical work, a 230-kV substation, PG&E switching-station interconnection, and SCADA. The retrofit BESS is 72 MWac/288 MWh with four-hour duration and includes 81 battery units, 27 inverters, and 19 pad-mounted auxiliary power transformers and switchboards. Rosendin constructed the BESS, Sukut performed its civil scope, Powin supplied the batteries, and Mitsubishi Power Americas supplied the BESS equipment. — Tranquillity Solar Facility · confidence: medium
- Construction scope: The hybrid facility comprises a 200 MWac/258 MWp solar plant on approximately 1,900 acres, with more than 800,000 polycrystalline PV modules on tracking tables. Signal Energy's solar EPC scope included geotechnical, civil, structural, mechanical, DC/AC electrical work, a 230-kV substation, PG&E switching-station interconnection, and SCADA. The retrofit BESS is 72 MWac/288 MWh with four-hour duration and includes 81 battery units, 27 inverters, and 19 pad-mounted auxiliary power transformers and switchboards. Rosendin constructed the BESS, Sukut performed its civil scope, Powin supplied the batteries, and Mitsubishi Power Americas supplied the BESS equipment. — Source · confidence: medium
- Construction scope: The hybrid facility comprises a 200 MWac/258 MWp solar plant on approximately 1,900 acres, with more than 800,000 polycrystalline PV modules on tracking tables. Signal Energy's solar EPC scope included geotechnical, civil, structural, mechanical, DC/AC electrical work, a 230-kV substation, PG&E switching-station interconnection, and SCADA. The retrofit BESS is 72 MWac/288 MWh with four-hour duration and includes 81 battery units, 27 inverters, and 19 pad-mounted auxiliary power transformers and switchboards. Rosendin constructed the BESS, Sukut performed its civil scope, Powin supplied the batteries, and Mitsubishi Power Americas supplied the BESS equipment. — Sukut Construction, LLC - Tranquillity BESS Project · confidence: medium
- Equipment models.1: {"manufacturer_domain":"canadiansolar.com","product_url":"https://www.canadiansolar.com/solar-panels/","count":null,"unit_mw":null,"name":"MaxPower CS6U-P"} — 257.7 MW Tranquility Solar Plant – Canadian Solar – Global · confidence: medium
- Description: RE Tranquillity is an operational hybrid solar-and-battery facility in Fresno County, California, with 277.3 MW of EIA nameplate capacity across three generating units. Southern Power operates the facility and holds the 51% majority interest through Southern Power Renewable Partnerships; PKA acquired Canadian Solar/Recurrent Energy’s 49% passive solar-project interest in October 2018 as part of a combined Garland and Tranquillity transaction. Solar construction began in July 2015 and commercial operation was announced in September 2016. A 72 MW/288 MWh battery addition became fully operational in March 2022, with its resource-adequacy benefits sold to Southern California Edison under a 20-year power-purchase agreement. — Source · confidence: medium
- Financing summary: On September 10, 2015, Recurrent Energy closed a $337 million combined construction-and-term debt facility for the 200 MW Tranquillity Solar Power Project. The structure comprised project-level construction debt, letter-of-credit facilities, and a back-leveraged term facility; NORD/LB acted as coordinating lead arranger with Rabobank, Santander, KeyBanc, CIT, and CIBC in the six-bank syndicate. Separately, on October 25, 2018, PKA acquired Canadian Solar/Recurrent Energy’s 49% passive equity interests in the Garland and Tranquillity facilities for approximately $307 million in a combined 260 MWp portfolio transaction; no project-specific allocation is disclosed for Tranquillity. — Source · confidence: medium
- Timeline: [{"event":"Solar construction began","date":"2015-07","detail":"Construction began on the 1,900-acre Fresno County site, with Signal Energy Constructors providing engineering, procurement, and construction services."},{"event":"Controlling-interest acquisition agreement","date":"2015-08","detail":"Southern 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."},{"event":"Solar project financing closed","date":"2015-09-10","detail":"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."},{"event":"First solar unit online","date":"2016-07-01","detail":"The EIA plant record lists the first Tranquillity generating unit as online on July 1, 2016."},{"event":"Solar commercial operation","date":"2016-09-26","detail":"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."},{"event":"Passive equity stake transaction","date":"2018-10-25","detail":"PKA acquired Canadian Solar/Recurrent Energy’s 49% passive equity interests in the Garland and Tranquillity facilities in a combined transaction valued at approximately $307 million; Southern Power retained the 51% majority stake and continued asset-management services."},{"event":"Battery expansion announced","date":"2021-02-04","detail":"Southern Power announced a 72 MW/288 MWh battery-based energy-storage addition at Tranquillity under a 20-year power-purchase agreement with Southern California Edison."},{"event":"Battery development partnership announced","date":"2021-06-22","detail":"Recurrent Energy announced a partnership with Southern Power and AIP Management to provide development services for the 72 MW/288 MWh Tranquillity storage addition."},{"event":"BESS1 operating","date":"2021-11","detail":"The EIA generator record lists battery unit BESS1 as operating from November 2021."},{"event":"BESS2 operating","date":"2022-03","detail":"The EIA generator record lists battery unit BESS2 as operating from March 2022."},{"event":"Battery storage fully operational","date":"2022-03-29","detail":"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."}] — Source · confidence: medium
- Timeline: [{"event":"Solar construction began","date":"2015-07","detail":"Construction began on the 1,900-acre Fresno County site, with Signal Energy Constructors providing engineering, procurement, and construction services."},{"event":"Controlling-interest acquisition agreement","date":"2015-08","detail":"Southern 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."},{"event":"Solar project financing closed","date":"2015-09-10","detail":"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."},{"event":"First solar unit online","date":"2016-07-01","detail":"The EIA plant record lists the first Tranquillity generating unit as online on July 1, 2016."},{"event":"Solar commercial operation","date":"2016-09-26","detail":"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."},{"event":"Passive equity stake transaction","date":"2018-10-25","detail":"PKA acquired Canadian Solar/Recurrent Energy’s 49% passive equity interests in the Garland and Tranquillity facilities in a combined transaction valued at approximately $307 million; Southern Power retained the 51% majority stake and continued asset-management services."},{"event":"Battery expansion announced","date":"2021-02-04","detail":"Southern Power announced a 72 MW/288 MWh battery-based energy-storage addition at Tranquillity under a 20-year power-purchase agreement with Southern California Edison."},{"event":"Battery development partnership announced","date":"2021-06-22","detail":"Recurrent Energy announced a partnership with Southern Power and AIP Management to provide development services for the 72 MW/288 MWh Tranquillity storage addition."},{"event":"BESS1 operating","date":"2021-11","detail":"The EIA generator record lists battery unit BESS1 as operating from November 2021."},{"event":"BESS2 operating","date":"2022-03","detail":"The EIA generator record lists battery unit BESS2 as operating from March 2022."},{"event":"Battery storage fully operational","date":"2022-03-29","detail":"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."}] — Canadian Solar Subsidiary Recurrent Energy Completes 200 Megawatt Tranquillity Solar Project - Recurrent Energy · confidence: medium
- Timeline: [{"event":"Solar construction began","date":"2015-07","detail":"Construction began on the 1,900-acre Fresno County site, with Signal Energy Constructors providing engineering, procurement, and construction services."},{"event":"Controlling-interest acquisition agreement","date":"2015-08","detail":"Southern 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."},{"event":"Solar project financing closed","date":"2015-09-10","detail":"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."},{"event":"First solar unit online","date":"2016-07-01","detail":"The EIA plant record lists the first Tranquillity generating unit as online on July 1, 2016."},{"event":"Solar commercial operation","date":"2016-09-26","detail":"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."},{"event":"Passive equity stake transaction","date":"2018-10-25","detail":"PKA acquired Canadian Solar/Recurrent Energy’s 49% passive equity interests in the Garland and Tranquillity facilities in a combined transaction valued at approximately $307 million; Southern Power retained the 51% majority stake and continued asset-management services."},{"event":"Battery expansion announced","date":"2021-02-04","detail":"Southern Power announced a 72 MW/288 MWh battery-based energy-storage addition at Tranquillity under a 20-year power-purchase agreement with Southern California Edison."},{"event":"Battery development partnership announced","date":"2021-06-22","detail":"Recurrent Energy announced a partnership with Southern Power and AIP Management to provide development services for the 72 MW/288 MWh Tranquillity storage addition."},{"event":"BESS1 operating","date":"2021-11","detail":"The EIA generator record lists battery unit BESS1 as operating from November 2021."},{"event":"BESS2 operating","date":"2022-03","detail":"The EIA generator record lists battery unit BESS2 as operating from March 2022."},{"event":"Battery storage fully operational","date":"2022-03-29","detail":"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."}] — Source · confidence: medium
- Timeline: [{"event":"Solar construction began","date":"2015-07","detail":"Construction began on the 1,900-acre Fresno County site, with Signal Energy Constructors providing engineering, procurement, and construction services."},{"event":"Controlling-interest acquisition agreement","date":"2015-08","detail":"Southern 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."},{"event":"Solar project financing closed","date":"2015-09-10","detail":"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."},{"event":"First solar unit online","date":"2016-07-01","detail":"The EIA plant record lists the first Tranquillity generating unit as online on July 1, 2016."},{"event":"Solar commercial operation","date":"2016-09-26","detail":"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."},{"event":"Passive equity stake transaction","date":"2018-10-25","detail":"PKA acquired Canadian Solar/Recurrent Energy’s 49% passive equity interests in the Garland and Tranquillity facilities in a combined transaction valued at approximately $307 million; Southern Power retained the 51% majority stake and continued asset-management services."},{"event":"Battery expansion announced","date":"2021-02-04","detail":"Southern Power announced a 72 MW/288 MWh battery-based energy-storage addition at Tranquillity under a 20-year power-purchase agreement with Southern California Edison."},{"event":"Battery development partnership announced","date":"2021-06-22","detail":"Recurrent Energy announced a partnership with Southern Power and AIP Management to provide development services for the 72 MW/288 MWh Tranquillity storage addition."},{"event":"BESS1 operating","date":"2021-11","detail":"The EIA generator record lists battery unit BESS1 as operating from November 2021."},{"event":"BESS2 operating","date":"2022-03","detail":"The EIA generator record lists battery unit BESS2 as operating from March 2022."},{"event":"Battery storage fully operational","date":"2022-03-29","detail":"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."}] — Recurrent Energy Amps Up Battery Storage Activity... · confidence: medium
- Timeline.0: {"event":"Solar construction began","date":"2015-07","detail":"Construction began on the 1,900-acre Fresno County site, with Signal Energy Constructors providing engineering, procurement, and construction services."} — Source · confidence: high
- Timeline.1: {"event":"Controlling-interest acquisition agreement","date":"2015-08","detail":"Southern 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."} — Canadian Solar Subsidiary Recurrent Energy Completes 200 Megawatt Tranquillity Solar Project - Recurrent Energy · confidence: medium
- Timeline.2: {"event":"Solar project financing closed","date":"2015-09-10","detail":"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."} — Source · confidence: high
- Timeline.7: {"event":"Battery development partnership announced","date":"2021-06-22","detail":"Recurrent Energy announced a partnership with Southern Power and AIP Management to provide development services for the 72 MW/288 MWh Tranquillity storage addition."} — Recurrent Energy Amps Up Battery Storage Activity... · confidence: medium
- Commercial parties.2: {"relationship":"Original developer and predecessor solar-project owner","name":"Recurrent Energy","detail":"Developed the solar project, signed the 2015 controlling-interest agreement with Southern Power, and transferred its passive interest through the Canadian Solar/Recurrent Energy ownership structure.","official_url":"https://recurrentenergy.com/"} — Canadian Solar Subsidiary Recurrent Energy Completes 200 Megawatt Tranquillity Solar Project - Recurrent Energy · confidence: medium
- Commercial parties.4: {"relationship":"Passive equity purchaser and solar ownership partner","name":"PKA, Ltd.","detail":"Acquired Canadian Solar/Recurrent Energy’s 49% passive equity interests in the Garland and Tranquillity facilities in October 2018.","official_url":"https://pka.dk/"} — Canadian Solar and PKA Complete a Large Scale Solar Transaction in California - Recurrent Energy · confidence: high
- Commercial parties.10: {"relationship":"Solar EPC contractor","name":"Signal Energy Constructors","detail":"Provided engineering, procurement, and construction services for the solar facility.","official_url":"https://www.signalenergy.com/"} — Canadian Solar Subsidiary Recurrent Energy Completes 200 Megawatt Tranquillity Solar Project - Recurrent Energy · confidence: high
- Commercial parties.11: {"relationship":"Construction-debt coordinating lead arranger","name":"NORD/LB","detail":"Coordinating lead arranger for the $337 million 2015 construction-and-term debt facility.","official_url":"https://www.nordlb.com/"} — Source · confidence: high
- Commercial parties.12: {"relationship":"Construction-debt lender","name":"Rabobank","detail":"Member of the six-bank syndicate providing the 2015 project financing.","official_url":"https://www.rabobank.com/"} — Source · confidence: high
- Commercial parties.13: {"relationship":"Construction-debt lender","name":"Santander","detail":"Member of the six-bank syndicate providing the 2015 project financing.","official_url":"https://www.santander.com/"} — Source · confidence: high
- Commercial parties.14: {"relationship":"Construction-debt lender","name":"KeyBanc","detail":"Member of the six-bank syndicate providing the 2015 project financing.","official_url":"https://www.key.com/"} — Source · confidence: high
- Commercial parties.15: {"relationship":"Construction-debt lender","name":"CIT","detail":"Member of the six-bank syndicate providing the 2015 project financing.","official_url":"https://www.cit.com/"} — Source · confidence: medium
- Commercial parties.16: {"relationship":"Construction-debt lender","name":"CIBC","detail":"Member of the six-bank syndicate providing the 2015 project financing.","official_url":"https://www.cibc.com/"} — Source · confidence: high
- Commercial parties.20: {"relationship":"Solar photovoltaic module manufacturer","name":"REC Solar","detail":"Manufactured the more than 800,000 polycrystalline photovoltaic modules used at the solar facility.","official_url":"https://www.recgroup.com/"} — Source · confidence: high

## Timeline

- 2015-07 — Solar construction began
  Construction began on the 1,900-acre Fresno County site, with Signal Energy Constructors providing engineering, procurement, and construction services.
  Source: Source (https://www.southernpowercompany.com/content/dam/southernpower/pdfs/fact-sheets/Tranquillity_Solar_Facility_factsheet.pdf)
- 2015-08 — Controlling-interest acquisition agreement
  Southern 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.
  Source: Canadian Solar Subsidiary Recurrent Energy Completes 200 Megawatt Tranquillity Solar Project - Recurrent Energy (https://recurrentenergy.com/tranquillity-launch/)
- 2015-09-10 — Solar project financing closed
  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.
  Source: Source (https://www.sec.gov/Archives/edgar/data/1375877/000110465915064635/a15-19245_1ex99d1.htm)
- 2016-09-26 — Solar commercial operation
  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.
  Source: Canadian Solar Subsidiary Recurrent Energy Completes 200 Megawatt Tranquillity Solar Project - Recurrent Energy (https://recurrentenergy.com/tranquillity-launch/)
- 2022-03-29 — Battery storage fully operational
  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.
  Source: Battery-based energy storage projects at Southern Power's Garland and Tranquillity solar facilities are now operational - Mar 29, 2022 (https://southerncompany.mediaroom.com/2022-03-29-Battery-based-energy-storage-projects-at-Southern-Powers-Garland-and-Tranquillity-solar-facilities-are-now-operational)

## Sources

- [Source](https://www.southernpowercompany.com/content/dam/southernpower/pdfs/fact-sheets/Tranquillity_Energy_Storage_factsheet.pdf) — southernpowercompany.com · tier other
- [Southern Power](https://www.southernpowercompany.com/) — southernpowercompany.com · tier other
- [MBR | Index](https://mbrweb.ferc.gov/SearchlkpEIA/Index?page=677) — mbrweb.ferc.gov · tier regulatory
- [Public Queue Report](https://www.caiso.com/documents/publicqueuereport.xlsx) — caiso.com · tier other
- [2026 NQC List](https://www.caiso.com/documents/net-qualifying-capacity-report-for-compliance-year-2026.xlsx) — caiso.com · tier other
- [Meter Exemptions 2024](https://www.caiso.com/documents/meteringexemptionlistingreportjan2024.pdf) — caiso.com · tier other
- [Tranquillity Solar Generating Facility EIR](https://ceqanet.lci.ca.gov/2013111056/2) — ceqanet.lci.ca.gov · tier regulatory
- [Southern Company subsidiary's Tranquillity Solar Facility in California begins operation](https://www.southerncompany.com/newsroom/clean-energy/2016-09-26-spc-tranquillity.html) — southerncompany.com · tier other
- [Canadian Solar Subsidiary Recurrent Energy Completes 200 Megawatt Tranquillity Solar Project - Recurrent Energy](https://recurrentenergy.com/tranquillity-launch/) — recurrentenergy.com · tier other
- [Source](https://www.southernpowercompany.com/content/dam/southernpower/pdfs/fact-sheets/Tranquillity_Solar_Facility_factsheet.pdf) — southernpowercompany.com · tier other
- [Battery-based energy storage projects at Southern Power’s Garland and Tranquillity solar facilities are now operational](https://www.southerncompany.com/newsroom/clean-energy/battery-based-energy-storage-projects-at-southern-power%E2%80%99s-garland-and-tranquillity-solar-facilities-are-now-operational.html) — southerncompany.com · tier other
- [Signal Energy | Tranquillity Solar Project](https://www.signalenergy.com/projects/tranquillity-solar-project) — signalenergy.com · tier other
- [Source](https://signalenergy.com/projects/tranquillity-solar-project) — signalenergy.com · tier other
- [Source](https://southernpowercompany.com/content/dam/southernpower/pdfs/fact-sheets/Tranquillity_Solar_Facility_factsheet.pdf) — southernpowercompany.com · tier other
- [Sukut Construction, LLC - Tranquillity BESS Project](https://www.sukut.com/energy/projects/tranquillity-bess-project/) — sukut.com · tier other
- [Battery-based energy storage projects at Southern Power's Garland and Tranquillity solar facilities are now operational - Mar 29, 2022](https://southerncompany.mediaroom.com/2022-03-29-Battery-based-energy-storage-projects-at-Southern-Powers-Garland-and-Tranquillity-solar-facilities-are-now-operational) — southerncompany.mediaroom.com · tier other
- [Tranquility BESS in Fresno County, California (Recurrent Energy) | Rosendin](https://www.rosendin.com/projects/tranquility-bess) — rosendin.com · tier other
- [257.7 MW Tranquility Solar Plant – Canadian Solar – Global](https://www.canadiansolar.com/257-7-mw-tranquility-utility-solar-plant) — canadiansolar.com · tier other
- [Canadian Solar and PKA Complete a Large Scale Solar Transaction in California - Recurrent Energy](https://recurrentenergy.com/canadian-solar-and-pka-complete-a-large-scale-solar-transaction-in-california/) — recurrentenergy.com · tier other
- [Source](https://www.sec.gov/Archives/edgar/data/1375877/000110465915064635/a15-19245_1ex99d1.htm) — sec.gov · tier regulatory
- [Recurrent Energy Amps Up Battery Storage Activity ...](https://recurrentenergy.com/recurrent-energy-amps-up-battery-storage-activity-executing-on-2-3-gwh-of-storage-projects/) — recurrentenergy.com · tier other
- [Canadian Solar Subsidiary Recurrent Energy Completes 200 Megawatt Tranquillity Solar Project - Recurrent Energy](https://recurrentenergy.com/tranquillity-launch) — recurrentenergy.com · tier other

## Data quality

- The 2016 project announcement reported 200 MWac/258 MWp for the solar project, while the EIA plant record reports 277.3 MW of current hybrid-plant nameplate capacity, reflecting different capacity bases and the later battery addition. Public storage-ownership descriptions differ by announcement: the 2021 fact sheet names AIP Management for PKA and PenSam together with Global Atlantic Financial Group, while the 2022 operational announcement names KKR and AIP Management. No retirement or repowering milestone is established in the cited project history.

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