# Garrison Energy Center LLC

PJM Natural Gas Fired Combined Cycle · https://askthegrid.com/assets/facilities/garrison-energy-center-llc

Garrison Energy Center LLC is a natural gas-fired power facility with 361 MW of EIA-reported nameplate capacity in Kent County, Delaware, registered as EIA Plant ID 57349. Cobalt Power, L. L. C. is the current owner; Garrison Energy Center LLC is the registered plant entity or operator. At 361 MW of EIA nameplate capacity, Garrison Energy Center is ranked third among Delaware power plants by capacity in the cited EIA-based directory.

## Key facts

- Technology: Natural Gas Fired Combined Cycle
- Power capacity: 361 MW
- Operating status: operating

## Grid and market context

- ISO/RTO: PJM
- Balancing authority: PJM Interconnection, LLC (PJM)
- Interconnection voltage: 230 kV

## Source-backed facts

- Owner logo domain: vistracorp.com — Delaware – Vistra Corp Legislative Hub · confidence: medium
- Identifiers: [{"value":"57349","system":"EIA plant ID"},{"value":"56691","system":"EIA utility/operator ID"},{"value":"PJM Interconnection, LLC (PJM)","system":"Balancing authority / ISO-RTO"},{"value":"CTG1","system":"EIA generator ID"},{"value":"STG2","system":"EIA generator ID"},{"value":"135389815","system":"PJM RTO/ISO LMP node (CTG1)"},{"value":"1132294357","system":"PJM RTO/ISO wholesale-reporting location (CTG1)"},{"value":"W3-032A","system":"PJM interconnection queue"},{"value":"ER15-748-000","system":"FERC docket"}] — Federal Register :: Garrison Energy Center LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for Blanket Section 204 Authorization · confidence: medium
- Official project url: https://hub.vistracorp.com/state-and-federal/delaware/ — Delaware – Vistra Corp Legislative Hub · confidence: high
- Identifiers.8: {"value":"ER15-748-000","system":"FERC docket"} — Federal Register :: Garrison Energy Center LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for Blanket Section 204 Authorization · confidence: high
- Parties.1: {"relationship":"Registered plant owner/operator","name":"Garrison Energy Center LLC","official_url":null} — Title V Permit Renewal Applications: Garrison Energy Center, LLC - DNREC · confidence: high
- Parties.7: {"relationship":"2019 acquisition/investment owner","name":"Starwood Energy Group Global, LLC","official_url":null} — Lotus Closes Acquisitions of Two Gas-Fired Plants From Calpine - Lotus · confidence: high
- Construction scope: The built asset is a 309-MW greenfield combined-cycle gas-fired plant in Dover, Delaware, delivered through lump-sum EPC by Matrix NAC with Parsons Brinckerhoff. The installed scope includes one General Electric 7FA combustion turbine, one heat-recovery steam generator, one steam turbine, one 86,000-gal/min cooling-water tower, one 1.4-million-gallon ULSD storage tank, a 230-kV transmission line, and two 230-kV substations, with advanced environmental controls. The EIA plant record separately reports two operating generator records totaling 361 MW nameplate capacity. — Calpine Corporation – Garrison Energy Center Combined Cycle Power Plant - Matrix Service Company · confidence: medium
- Product url: https://www.gevernova.com/gas-power/products/gas-turbines/7f — Garrison Energy Center combined-cycle gas-fired facility, Dover, Delaware · confidence: medium
- Product url: https://www.gevernova.com/gas-power/products/gas-turbines/7f — 7F Heavy Duty Gas Turbine | 7F.04/7F.05 | GE Vernova · confidence: medium
- Manufacturer domain: gevernova.com — 7F Heavy Duty Gas Turbine | 7F.04/7F.05 | GE Vernova · confidence: medium
- Quality notes: ["Capacity figures use different definitions: EIA records 361 MW of total nameplate capacity, 309 MW of summer capacity, and 323 MW of winter capacity, while the 2019 sale filing and EPC sources describe the facility as 309 MW.","Calpine disclosed a proposed second phase of approximately 430 MW in 2015, but the current EIA record shows no planned units and no completed uprate or derate; the available record does not show that phase entering service.","The approximately $360 million 2019 consideration covered Garrison and RockGen together, and the $1.9 billion 2025 consideration covered seven plants; neither amount is allocated to Garrison alone. The 2025 transaction also involved assumption of an existing Lotus term loan and cash, rather than disclosed Garrison-specific project financing."] — Source · confidence: medium
- Quality notes.1: Calpine disclosed a proposed second phase of approximately 430 MW in 2015, but the current EIA record shows no planned units and no completed uprate or derate; the available record does not show that phase entering service. — Source · confidence: medium
- Quality notes.2: The approximately $360 million 2019 consideration covered Garrison and RockGen together, and the $1.9 billion 2025 consideration covered seven plants; neither amount is allocated to Garrison alone. The 2025 transaction also involved assumption of an existing Lotus term loan and cash, rather than disclosed Garrison-specific project financing. — Vistra to Acquire Natural Gas Assets, Building on Industry-Leading Generation Portfolio to Better Serve Customers - May 15, 2025 · confidence: medium
- Commercial parties.2: {"relationship":"Former portfolio owner and 2025 seller","name":"Lotus Infrastructure Partners","detail":"Owned the portfolio containing Garrison and sold the seven-plant gas-generation portfolio to Vistra in 2025.","official_url":"https://www.lotusinfrastructure.com/"} — Vistra to Acquire Natural Gas Assets, Building on Industry-Leading Generation Portfolio to Better Serve Customers - May 15, 2025 · confidence: medium
- Commercial parties.4: {"relationship":"Original developer and former owner","name":"Calpine Corporation","detail":"Advanced and developed the Garrison project, owned the plant through commercial operation, and sold Garrison Energy Center LLC in July 2019.","official_url":"https://www.calpine.com/"} — Calpine Advances Development of 309 MW Garrison Energy Center · confidence: medium
- Commercial parties.6: {"relationship":"EPC joint-venture partner","name":"Parsons Brinckerhoff","detail":"Participated with Matrix NAC in the EPC joint venture for the Calpine Garrison project.","official_url":null} — Calpine Corporation – Garrison Energy Center Combined Cycle Power Plant - Matrix Service Company · confidence: high
- Commercial parties.7: {"relationship":"2019 acquisition sponsor/investment firm","name":"Starwood Energy Group Global, LLC","detail":"Starwood Energy announced completion of the 2019 acquisition from Calpine, while Calpine’s SEC filing identified Cobalt Power, L.L.C. as the purchaser.","official_url":null} — Lotus Closes Acquisitions of Two Gas-Fired Plants From Calpine - Lotus · confidence: medium
- Timeline.0: {"event":"Predecessor corporate acquisition","date":"2010-07","detail":"Calpine acquired the Conectiv Energy fleet from Pepco Holdings; Calpine later identified that acquisition as the context for its Delaware development commitment. The cited record does not establish that Garrison itself was an operating Conectiv asset before Calpine’s development work."} — Calpine Advances Development of 309 MW Garrison... · confidence: medium
- Timeline.1: {"event":"Development advanced","date":"2012-11-01","detail":"Calpine announced full-scale development of a proposed 309 MW natural-gas-fired combined-cycle facility in Dover, expected construction in early 2013 and commercial operation by June 1, 2015."} — Calpine Advances Development of 309 MW Garrison Energy Center · confidence: high
- Timeline.2: {"event":"Planned construction start","date":"2013","detail":"Calpine’s November 2012 announcement identified early 2013 as the expected construction start. — Calpine Advances Development of 309 MW Garrison Energy Center · confidence: medium
- Timeline.3: {"event":"FERC market-based-rate and financing authorization proceeding","date":"2015-01-09","detail":"The Federal Register published FERC’s supplemental notice for Garrison’s market-based-rate filing, which included a request for blanket Section 204 authorization for future securities issuances and assumptions of liability."} — Federal Register :: Garrison Energy Center LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for Blanket Section 204 Authorization · confidence: high
- Timeline.5: {"event":"Proposed expansion phase","date":"2015","detail":"Calpine reported that a second Garrison phase was in early development and would add approximately 430 MW of dual-fuel combined-cycle capacity; PJM had completed the feasibility study and the system-impact study was underway."} — Source · confidence: medium
- Status detail: The exact plant is currently operational with two operating generators, CTG1 and STG2, totaling 361 MW. A January 2026 PJM filing lists Garrison (Vistra) as a 309 MW natural-gas/fuel-oil facility whose Title V permit may constrain availability when operating on fuel oil; this is an operating limitation, not a retirement status. — Source · confidence: medium
- Operating status: operating — Source · confidence: medium

## Timeline

- 2015-01-09 — FERC market-based-rate and financing authorization proceeding
  The Federal Register published FERC’s supplemental notice for Garrison’s market-based-rate filing, which included a request for blanket Section 204 authorization for future securities issuances and assumptions of liability.
  Source: Federal Register :: Garrison Energy Center LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for Blanket Section 204 Authorization (https://www.federalregister.gov/documents/2015/01/09/2015-00187/garrison-energy-center-llc-supplemental-notice-that-initial-market-based-rate-filing-includes)

## Sources

- [Delaware – Vistra Corp Legislative Hub](https://hub.vistracorp.com/state-and-federal/delaware/) — hub.vistracorp.com · tier other
- [Federal Register :: Garrison Energy Center LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for Blanket Section 204 Authorization](https://www.federalregister.gov/documents/2015/01/09/2015-00187/garrison-energy-center-llc-supplemental-notice-that-initial-market-based-rate-filing-includes) — federalregister.gov · tier regulatory
- [Vistra to Acquire Natural Gas Assets, Building on Industry-Leading Generation Portfolio to Better Serve Customers - May 15, 2025](https://investor.vistracorp.com/2025-05-15-Vistra-to-Acquire-Natural-Gas-Assets%2C-Building-on-Industry-Leading-Generation-Portfolio-to-Better-Serve-Customers) — investor.vistracorp.com · tier other
- [Title V Permit Renewal Applications: Garrison Energy Center, LLC - DNREC](https://www.dnrec.delaware.gov/public-notices/aq20250397/) — dnrec.delaware.gov · tier regulatory
- [Lotus Closes Acquisitions of Two Gas-Fired Plants From Calpine - Lotus](https://www.lotusinfrastructure.com/news/lotus-closes-acquisitions-of-two-gas-fired-plants-from-calpine/) — lotusinfrastructure.com · tier other
- [Garrison Energy Center combined-cycle gas-fired facility, Dover, Delaware](https://www.power-technology.com/projects/garrison-energy-center-dover-delaware/) — power-technology.com · tier other
- [Calpine Corporation – Garrison Energy Center Combined Cycle Power Plant - Matrix Service Company](https://matrixservicecompany.com/project/calpine-corporation-garrison-energy-center-combined-cycle-power-plant/) — matrixservicecompany.com · tier other
- [7F Heavy Duty Gas Turbine | 7F.04/7F.05 | GE Vernova](https://www.gevernova.com/gas-power/products/gas-turbines/7f) — gevernova.com · tier other
- [Source](https://www.sec.gov/Archives/edgar/data/916457/000091645716000057/cpn_10kx12312015.htm) — sec.gov · tier regulatory
- [Calpine Advances Development of 309 MW Garrison Energy Center](https://www.cnbc.com/2012/11/01/calpine-advances-development-of-309-mw-garrison-energy-center.html) — cnbc.com · tier other
- [Source](https://www.energy.gov/documents/pjm-202c-application-exhibit-updated-feb-1-2026-1245-pm-est) — energy.gov · tier regulatory
- [Sheet1](https://www.pjm.com/-/media/DotCom/markets-ops/rpm/rpm-auction-info/2025-2026/2025-2026-rpm-existing-resource-list-post.xlsx) — pjm.com · tier other

## Data quality

- Capacity figures use different definitions: EIA records 361 MW of total nameplate capacity, 309 MW of summer capacity, and 323 MW of winter capacity, while the 2019 sale filing and EPC sources describe the facility as 309 MW. Calpine disclosed a proposed second phase of approximately 430 MW in 2015, but the current EIA record shows no planned units and no completed uprate or derate; the available record does not show that phase entering service. The approximately $360 million 2019 consideration covered Garrison and RockGen together, and the $1.9 billion 2025 consideration covered seven plants; neither amount is allocated to Garrison alone. The 2025 transaction also involved assumption of an existing Lotus term loan and cash, rather than disclosed Garrison-specific project financing.

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