# Middletown Energy Center PJM Natural Gas Fired Combined Cycle · https://askthegrid.com/assets/facilities/middletown-energy-center Middletown Energy Center is a natural gas-fired power facility with 543.9 MW of EIA-reported nameplate capacity in Butler County, Ohio, registered as EIA Plant ID 59326. ArcLight Capital Partners, LLC is the current owner; Ohio Power Partners, LLC is the registered plant entity or operator. The plant's generating configuration is natural-gas-fired 1 1 combined-cycle plant with one Mitsubishi 501GAC combustion turbine, one Toshiba steam turbine, and one Vogt heat-recovery steam generator. The facility interconnects at MIDLTWN218 KV MIDDLTST at 345 kV. MIDLTWN218 KV MIDDLTST · 345 kV · Duke Energy Ohio Inc. ## Key facts - Technology: Natural Gas Fired Combined Cycle - Power capacity: 543.9 MW - Operating status: operating ## Grid and market context - ISO/RTO: PJM - Balancing authority: PJM Interconnection, LLC (PJM) - Interconnection voltage: 345 kV ## Source-backed facts - Owner logo domain: arclight.com — ARCLIGHT TO ACQUIRE MIDDLETOWN ENERGY CENTER · confidence: high - Description: Middletown Energy Center is a natural-gas-fired combined-cycle plant at 3439 Cincinnati Dayton Road in Butler County, Ohio, with initial operation in May 2018. Its two generator records, MEC1 and MEC2, have nameplate capacities of 310.2 MW and 233.7 MW, respectively, totaling 543.9 MW; both are operating. The facility sells energy and capacity into PJM and uses one Mitsubishi 501GAC combustion turbine, a Toshiba steam turbine, and a Vogt heat-recovery steam generator in a 1x1 configuration. — Research Update: Ohio Power Partners LLC's Debt A | S&P Global Ratings · confidence: medium - Parties.0: {"relationship":"Indirect owner / parent investor","name":"ArcLight Capital Partners, LLC","official_url":"https://arclight.com/"} — Research Update: Ohio Power Partners LLC's Debt A | S&P Global Ratings · confidence: high - Parties.0: {"relationship":"Indirect owner / parent investor","name":"ArcLight Capital Partners, LLC","official_url":"https://arclight.com/"} — ARCLIGHT TO ACQUIRE MIDDLETOWN ENERGY CENTER · confidence: high - Parties.1: {"relationship":"Project company / registered utility","name":"Ohio Power Partners, LLC","official_url":null} — Research Update: Ohio Power Partners LLC's Debt A | S&P Global Ratings · confidence: high - Parties.2: {"relationship":"Developer and former owner/operator","name":"NTE Energy, LLC","official_url":null} — NTE Energy Completes Middletown Energy Center · confidence: high - Parties.4: {"relationship":"EPC contractor","name":"Gemma Power Systems, LLC","official_url":"https://www.gemmapower.com/"} — Glastonbury's Gemma builds 475MW Ohio energy plant · confidence: high - Parties.4: {"relationship":"EPC contractor","name":"Gemma Power Systems, LLC","official_url":"https://www.gemmapower.com/"} — Our Work - NTE Middletown Energy Center · confidence: high - Parties.5: {"relationship":"Design engineer","name":"Sargent & Lundy","official_url":"https://www.sargentlundy.com/"} — Our Work - NTE Middletown Energy Center · confidence: high - Parties.5: {"relationship":"Design engineer","name":"Sargent & Lundy","official_url":"https://www.sargentlundy.com/"} — Sargent & Lundy: Homepage · confidence: high - Parties.7: {"relationship":"Heat-recovery steam-generator OEM","name":"Vogt Power International","official_url":"https://www.vogtpower.com/"} — Our Work - NTE Middletown Energy Center · confidence: high - Parties.7: {"relationship":"Heat-recovery steam-generator OEM","name":"Vogt Power International","official_url":"https://www.vogtpower.com/"} — Vogt Power International | Heat Recovery Steam Generators · confidence: high - Parties.8: {"relationship":"Steam-turbine OEM","name":"Toshiba America Energy Systems","official_url":"https://toshiba.com/taes/"} — Our Work - NTE Middletown Energy Center · confidence: high - Parties.8: {"relationship":"Steam-turbine OEM","name":"Toshiba America Energy Systems","official_url":"https://toshiba.com/taes/"} — Leading the Future of Clean Energy Solutions | TAES · confidence: high - Commercial operation date: 2018-06 — Source · confidence: medium - Construction scope: 1×1 natural-gas-fired combined-cycle plant comprising one Mitsubishi/MHPSA M501GAC combustion-turbine generator, one supplementary-fired Vogt HRSG, and one Toshiba steam-turbine generator. The facility was built by Gemma Power Systems, with Sargent & Lundy providing balance-of-plant engineering; substantial completion was achieved in May 2018. — Private Equity Firm Moves to Secure Ohio Gas Power Plant as Demand for Firm Power Rallies · confidence: medium - Equipment models.2: {"manufacturer_domain":"toshiba.com","product_url":"https://toshiba.com/taes/products/steam-turbine-generator/","count":1,"unit_mw":null,"name":"Toshiba tandem-compound steam turbine generator"} — Private Equity Firm Moves to Secure Ohio Gas Power Plant as Demand for Firm Power Rallies · confidence: medium - Significance: Middletown Energy Center ranks #18 of 206 Ohio power plants by annual net generation and #12 of 54 Ohio natural-gas plants. It sells energy and capacity into PJM, where it is described as a newer, highly efficient combined-cycle asset. — Research Update: Ohio Power Partners LLC's Debt A | S&P Global Ratings · confidence: medium - Description: Middletown Energy Center is a natural-gas-fired combined-cycle plant in Butler County, Ohio, configured as a 1x1 facility with one Mitsubishi 501GAC combustion turbine, one Toshiba steam turbine, and one Vogt heat-recovery steam generator. EIA generator records list MEC1 at 310.2 MW and MEC2 at 233.7 MW, for a combined recorded nameplate capacity of 543.9 MW; both units are operating. NTE Energy developed the project and Gemma Power Systems built it; construction began in October 2015, substantial completion was achieved in May 2018, and commercial operation was scheduled for June 2018. ArcLight Capital Partners indirectly owns 100% through Ohio Power Partners after acquiring the project’s economic interests from Axium Infrastructure, Guggenheim Investments on behalf of its investors, and other equity partners; the transaction was reported closed by January 2026. — Research Update: Ohio Power Partners LLC's Debt A | S&P Global Ratings · confidence: medium - Description: Middletown Energy Center is a natural-gas-fired combined-cycle plant in Butler County, Ohio, configured as a 1x1 facility with one Mitsubishi 501GAC combustion turbine, one Toshiba steam turbine, and one Vogt heat-recovery steam generator. EIA generator records list MEC1 at 310.2 MW and MEC2 at 233.7 MW, for a combined recorded nameplate capacity of 543.9 MW; both units are operating. NTE Energy developed the project and Gemma Power Systems built it; construction began in October 2015, substantial completion was achieved in May 2018, and commercial operation was scheduled for June 2018. ArcLight Capital Partners indirectly owns 100% through Ohio Power Partners after acquiring the project’s economic interests from Axium Infrastructure, Guggenheim Investments on behalf of its investors, and other equity partners; the transaction was reported closed by January 2026. — Our Work - NTE Middletown Energy Center · confidence: medium - Quality notes: ["Publicly reported capacity is not uniform: EIA generator records total 543.9 MW, while project and transaction sources describe nominal or rated capacities of 475 MW, 478 MW, and 484 MW. These figures should not be treated as interchangeable without confirming the applicable capacity definition.","The July 2025 private-sale consideration was not disclosed. The later $325 million term loan B and $40 million revolving facility were acquisition financing raised by ArcLight through Ohio Power Partners, not reported sale consideration.","Axium’s July 2025 release names Axium, Guggenheim Investments on behalf of its investors, and other equity partners as sellers, but does not identify every other partner or provide a purchase price. S&P later reported that all necessary approvals had been received and the transaction had closed, without stating the exact closing date.","The operating record lists no completed uprate or derate. No retirement or repowering date is reported for the facility."] — Research Update: Ohio Power Partners LLC's Debt A | S&P Global Ratings · confidence: medium - Quality notes: ["Publicly reported capacity is not uniform: EIA generator records total 543.9 MW, while project and transaction sources describe nominal or rated capacities of 475 MW, 478 MW, and 484 MW. These figures should not be treated as interchangeable without confirming the applicable capacity definition.","The July 2025 private-sale consideration was not disclosed. The later $325 million term loan B and $40 million revolving facility were acquisition financing raised by ArcLight through Ohio Power Partners, not reported sale consideration.","Axium’s July 2025 release names Axium, Guggenheim Investments on behalf of its investors, and other equity partners as sellers, but does not identify every other partner or provide a purchase price. S&P later reported that all necessary approvals had been received and the transaction had closed, without stating the exact closing date.","The operating record lists no completed uprate or derate. No retirement or repowering date is reported for the facility."] — Microsoft Word - 11502144_1.docx · confidence: medium - Quality notes: ["Publicly reported capacity is not uniform: EIA generator records total 543.9 MW, while project and transaction sources describe nominal or rated capacities of 475 MW, 478 MW, and 484 MW. These figures should not be treated as interchangeable without confirming the applicable capacity definition.","The July 2025 private-sale consideration was not disclosed. The later $325 million term loan B and $40 million revolving facility were acquisition financing raised by ArcLight through Ohio Power Partners, not reported sale consideration.","Axium’s July 2025 release names Axium, Guggenheim Investments on behalf of its investors, and other equity partners as sellers, but does not identify every other partner or provide a purchase price. S&P later reported that all necessary approvals had been received and the transaction had closed, without stating the exact closing date.","The operating record lists no completed uprate or derate. No retirement or repowering date is reported for the facility."] — Axium acquires interest in Canadian & US Wind Portfolio · confidence: medium - Timeline: [{"event":"Original project financing closed","date":"2015-10-02","detail":"NTE Ohio LLC closed $645 million of project financing for construction and operation. The financing comprised $243 million of equity commitments and $402 million of senior-secured credit facilities."},{"event":"Construction began","date":"2015-10","detail":"The project’s construction start was reported as October 2015; Gemma later reported that full notice to proceed was received on October 2, 2015."},{"event":"Axium acquired minority equity interest","date":"2017-03-16","detail":"Axium Infrastructure acquired an approximately 19.6% equity interest in Middletown Energy Center from Capital Dynamics while the project was under construction."},{"event":"Substantial completion and inauguration","date":"2018-05","detail":"Gemma reported substantial completion in May 2018, and the facility was inaugurated on May 21, 2018."},{"event":"Commercial operation","date":"2018-06","detail":"The project fact sheet identified June 2018 as the commercial-operation date; EIA-derived records identify initial operation in May 2018."},{"event":"Project-company control period","date":"2021-2024","detail":"Power Magazine reported that Ohio Power Partners LLC assumed control after the original developer/operator period associated with NTE Ohio LLC. The reported operator-year range predates or overlaps other project dates and should not be read as a revised commercial-operation date."},{"event":"ArcLight acquisition agreement announced","date":"2025-07-10","detail":"ArcLight announced definitive agreements to acquire 100% of Middletown’s economic interests through a series of transactions from a consortium of sellers. Sale consideration was not disclosed."},{"event":"Seller-side agreement announced","date":"2025-07-23","detail":"Axium Infrastructure, Guggenheim Investments on behalf of its investors, and other equity partners announced an agreement to sell their respective interests to ArcLight affiliates."},{"event":"Acquisition closed","date":"2026-01-21","detail":"S&P Global Ratings reported that the transaction had received all necessary regulatory approvals and had closed by the date of its January 2026 update; the exact closing date was not stated."}] — NTE Energy closes financing for 475 MW power project in Ohio | Energy Finance & Investment · confidence: medium - Timeline: [{"event":"Original project financing closed","date":"2015-10-02","detail":"NTE Ohio LLC closed $645 million of project financing for construction and operation. The financing comprised $243 million of equity commitments and $402 million of senior-secured credit facilities."},{"event":"Construction began","date":"2015-10","detail":"The project’s construction start was reported as October 2015; Gemma later reported that full notice to proceed was received on October 2, 2015."},{"event":"Axium acquired minority equity interest","date":"2017-03-16","detail":"Axium Infrastructure acquired an approximately 19.6% equity interest in Middletown Energy Center from Capital Dynamics while the project was under construction."},{"event":"Substantial completion and inauguration","date":"2018-05","detail":"Gemma reported substantial completion in May 2018, and the facility was inaugurated on May 21, 2018."},{"event":"Commercial operation","date":"2018-06","detail":"The project fact sheet identified June 2018 as the commercial-operation date; EIA-derived records identify initial operation in May 2018."},{"event":"Project-company control period","date":"2021-2024","detail":"Power Magazine reported that Ohio Power Partners LLC assumed control after the original developer/operator period associated with NTE Ohio LLC. The reported operator-year range predates or overlaps other project dates and should not be read as a revised commercial-operation date."},{"event":"ArcLight acquisition agreement announced","date":"2025-07-10","detail":"ArcLight announced definitive agreements to acquire 100% of Middletown’s economic interests through a series of transactions from a consortium of sellers. Sale consideration was not disclosed."},{"event":"Seller-side agreement announced","date":"2025-07-23","detail":"Axium Infrastructure, Guggenheim Investments on behalf of its investors, and other equity partners announced an agreement to sell their respective interests to ArcLight affiliates."},{"event":"Acquisition closed","date":"2026-01-21","detail":"S&P Global Ratings reported that the transaction had received all necessary regulatory approvals and had closed by the date of its January 2026 update; the exact closing date was not stated."}] — Our Work - NTE Middletown Energy Center · confidence: medium - Timeline: [{"event":"Original project financing closed","date":"2015-10-02","detail":"NTE Ohio LLC closed $645 million of project financing for construction and operation. The financing comprised $243 million of equity commitments and $402 million of senior-secured credit facilities."},{"event":"Construction began","date":"2015-10","detail":"The project’s construction start was reported as October 2015; Gemma later reported that full notice to proceed was received on October 2, 2015."},{"event":"Axium acquired minority equity interest","date":"2017-03-16","detail":"Axium Infrastructure acquired an approximately 19.6% equity interest in Middletown Energy Center from Capital Dynamics while the project was under construction."},{"event":"Substantial completion and inauguration","date":"2018-05","detail":"Gemma reported substantial completion in May 2018, and the facility was inaugurated on May 21, 2018."},{"event":"Commercial operation","date":"2018-06","detail":"The project fact sheet identified June 2018 as the commercial-operation date; EIA-derived records identify initial operation in May 2018."},{"event":"Project-company control period","date":"2021-2024","detail":"Power Magazine reported that Ohio Power Partners LLC assumed control after the original developer/operator period associated with NTE Ohio LLC. The reported operator-year range predates or overlaps other project dates and should not be read as a revised commercial-operation date."},{"event":"ArcLight acquisition agreement announced","date":"2025-07-10","detail":"ArcLight announced definitive agreements to acquire 100% of Middletown’s economic interests through a series of transactions from a consortium of sellers. Sale consideration was not disclosed."},{"event":"Seller-side agreement announced","date":"2025-07-23","detail":"Axium Infrastructure, Guggenheim Investments on behalf of its investors, and other equity partners announced an agreement to sell their respective interests to ArcLight affiliates."},{"event":"Acquisition closed","date":"2026-01-21","detail":"S&P Global Ratings reported that the transaction had received all necessary regulatory approvals and had closed by the date of its January 2026 update; the exact closing date was not stated."}] — March 16, 2017 - AXIUM INFRASTRUCTURE CLOSES ACQUISITION OF EQUITY INTERESTS IN NATURAL-GAS POWER GENERATION PORTFOLIO FROM CAPITAL DYNAMICS – Axium Infrastructure · confidence: medium - Timeline: [{"event":"Original project financing closed","date":"2015-10-02","detail":"NTE Ohio LLC closed $645 million of project financing for construction and operation. The financing comprised $243 million of equity commitments and $402 million of senior-secured credit facilities."},{"event":"Construction began","date":"2015-10","detail":"The project’s construction start was reported as October 2015; Gemma later reported that full notice to proceed was received on October 2, 2015."},{"event":"Axium acquired minority equity interest","date":"2017-03-16","detail":"Axium Infrastructure acquired an approximately 19.6% equity interest in Middletown Energy Center from Capital Dynamics while the project was under construction."},{"event":"Substantial completion and inauguration","date":"2018-05","detail":"Gemma reported substantial completion in May 2018, and the facility was inaugurated on May 21, 2018."},{"event":"Commercial operation","date":"2018-06","detail":"The project fact sheet identified June 2018 as the commercial-operation date; EIA-derived records identify initial operation in May 2018."},{"event":"Project-company control period","date":"2021-2024","detail":"Power Magazine reported that Ohio Power Partners LLC assumed control after the original developer/operator period associated with NTE Ohio LLC. The reported operator-year range predates or overlaps other project dates and should not be read as a revised commercial-operation date."},{"event":"ArcLight acquisition agreement announced","date":"2025-07-10","detail":"ArcLight announced definitive agreements to acquire 100% of Middletown’s economic interests through a series of transactions from a consortium of sellers. Sale consideration was not disclosed."},{"event":"Seller-side agreement announced","date":"2025-07-23","detail":"Axium Infrastructure, Guggenheim Investments on behalf of its investors, and other equity partners announced an agreement to sell their respective interests to ArcLight affiliates."},{"event":"Acquisition closed","date":"2026-01-21","detail":"S&P Global Ratings reported that the transaction had received all necessary regulatory approvals and had closed by the date of its January 2026 update; the exact closing date was not stated."}] — Private Equity Firm Moves to Secure Ohio Gas Power Plant as Demand for Firm Power Rallies · confidence: medium - Timeline: [{"event":"Original project financing closed","date":"2015-10-02","detail":"NTE Ohio LLC closed $645 million of project financing for construction and operation. The financing comprised $243 million of equity commitments and $402 million of senior-secured credit facilities."},{"event":"Construction began","date":"2015-10","detail":"The project’s construction start was reported as October 2015; Gemma later reported that full notice to proceed was received on October 2, 2015."},{"event":"Axium acquired minority equity interest","date":"2017-03-16","detail":"Axium Infrastructure acquired an approximately 19.6% equity interest in Middletown Energy Center from Capital Dynamics while the project was under construction."},{"event":"Substantial completion and inauguration","date":"2018-05","detail":"Gemma reported substantial completion in May 2018, and the facility was inaugurated on May 21, 2018."},{"event":"Commercial operation","date":"2018-06","detail":"The project fact sheet identified June 2018 as the commercial-operation date; EIA-derived records identify initial operation in May 2018."},{"event":"Project-company control period","date":"2021-2024","detail":"Power Magazine reported that Ohio Power Partners LLC assumed control after the original developer/operator period associated with NTE Ohio LLC. The reported operator-year range predates or overlaps other project dates and should not be read as a revised commercial-operation date."},{"event":"ArcLight acquisition agreement announced","date":"2025-07-10","detail":"ArcLight announced definitive agreements to acquire 100% of Middletown’s economic interests through a series of transactions from a consortium of sellers. Sale consideration was not disclosed."},{"event":"Seller-side agreement announced","date":"2025-07-23","detail":"Axium Infrastructure, Guggenheim Investments on behalf of its investors, and other equity partners announced an agreement to sell their respective interests to ArcLight affiliates."},{"event":"Acquisition closed","date":"2026-01-21","detail":"S&P Global Ratings reported that the transaction had received all necessary regulatory approvals and had closed by the date of its January 2026 update; the exact closing date was not stated."}] — JULY 23, 2025 - AXIUM INFRASTRUCTURE AND ITS EQUITY PARTNERS SELL 100% OF MIDDLETOWN ENERGY CENTER TO ARCLIGHT CAPITAL – Axium Infrastructure · confidence: medium - Timeline: [{"event":"Original project financing closed","date":"2015-10-02","detail":"NTE Ohio LLC closed $645 million of project financing for construction and operation. The financing comprised $243 million of equity commitments and $402 million of senior-secured credit facilities."},{"event":"Construction began","date":"2015-10","detail":"The project’s construction start was reported as October 2015; Gemma later reported that full notice to proceed was received on October 2, 2015."},{"event":"Axium acquired minority equity interest","date":"2017-03-16","detail":"Axium Infrastructure acquired an approximately 19.6% equity interest in Middletown Energy Center from Capital Dynamics while the project was under construction."},{"event":"Substantial completion and inauguration","date":"2018-05","detail":"Gemma reported substantial completion in May 2018, and the facility was inaugurated on May 21, 2018."},{"event":"Commercial operation","date":"2018-06","detail":"The project fact sheet identified June 2018 as the commercial-operation date; EIA-derived records identify initial operation in May 2018."},{"event":"Project-company control period","date":"2021-2024","detail":"Power Magazine reported that Ohio Power Partners LLC assumed control after the original developer/operator period associated with NTE Ohio LLC. The reported operator-year range predates or overlaps other project dates and should not be read as a revised commercial-operation date."},{"event":"ArcLight acquisition agreement announced","date":"2025-07-10","detail":"ArcLight announced definitive agreements to acquire 100% of Middletown’s economic interests through a series of transactions from a consortium of sellers. Sale consideration was not disclosed."},{"event":"Seller-side agreement announced","date":"2025-07-23","detail":"Axium Infrastructure, Guggenheim Investments on behalf of its investors, and other equity partners announced an agreement to sell their respective interests to ArcLight affiliates."},{"event":"Acquisition closed","date":"2026-01-21","detail":"S&P Global Ratings reported that the transaction had received all necessary regulatory approvals and had closed by the date of its January 2026 update; the exact closing date was not stated."}] — Research Update: Ohio Power Partners LLC's Debt A | S&P Global Ratings · confidence: medium - Quality notes.1: The July 2025 private-sale consideration was not disclosed. The later $325 million term loan B and $40 million revolving facility were acquisition financing raised by ArcLight through Ohio Power Partners, not reported sale consideration. — ARCLIGHT TO ACQUIRE MIDDLETOWN ENERGY CENTER · confidence: high - Quality notes.1: The July 2025 private-sale consideration was not disclosed. The later $325 million term loan B and $40 million revolving facility were acquisition financing raised by ArcLight through Ohio Power Partners, not reported sale consideration. — Research Update: Ohio Power Partners LLC's Debt A | S&P Global Ratings · confidence: high - Quality notes.2: Axium’s July 2025 release names Axium, Guggenheim Investments on behalf of its investors, and other equity partners as sellers, but does not identify every other partner or provide a purchase price. S&P later reported that all necessary approvals had been received and the transaction had closed, without stating the exact closing date. — Axium acquires interest in Canadian & US Wind Portfolio · confidence: high - Quality notes.2: Axium’s July 2025 release names Axium, Guggenheim Investments on behalf of its investors, and other equity partners as sellers, but does not identify every other partner or provide a purchase price. S&P later reported that all necessary approvals had been received and the transaction had closed, without stating the exact closing date. — Research Update: Ohio Power Partners LLC's Debt A | S&P Global Ratings · confidence: high - Timeline.0: {"event":"Original project financing closed","date":"2015-10-02","detail":"NTE Ohio LLC closed $645 million of project financing for construction and operation. The financing comprised $243 million of equity commitments and $402 million of senior-secured credit facilities."} — NTE Energy closes financing for 475 MW power project in Ohio | Energy Finance & Investment · confidence: high - Timeline.0: {"event":"Original project financing closed","date":"2015-10-02","detail":"NTE Ohio LLC closed $645 million of project financing for construction and operation. The financing comprised $243 million of equity commitments and $402 million of senior-secured credit facilities."} — Financial close on 475MW Ohio gas plant · confidence: high - Timeline.1: {"event":"Construction began","date":"2015-10","detail":"The project’s construction start was reported as October 2015; Gemma later reported that full notice to proceed was received on October 2, 2015."} — Microsoft Word - 11502144_1.docx · confidence: medium - Timeline.1: {"event":"Construction began","date":"2015-10","detail":"The project’s construction start was reported as October 2015; Gemma later reported that full notice to proceed was received on October 2, 2015."} — Our Work - NTE Middletown Energy Center · confidence: medium - Timeline.2: {"event":"Axium acquired minority equity interest","date":"2017-03-16","detail":"Axium Infrastructure acquired an approximately 19.6% equity interest in Middletown Energy Center from Capital Dynamics while the project was under construction."} — March 16, 2017 - AXIUM INFRASTRUCTURE CLOSES ACQUISITION OF EQUITY INTERESTS IN NATURAL-GAS POWER GENERATION PORTFOLIO FROM CAPITAL DYNAMICS – Axium Infrastructure · confidence: high - Timeline.3: {"event":"Substantial completion and inauguration","date":"2018-05","detail":"Gemma reported substantial completion in May 2018, and the facility was inaugurated on May 21, 2018."} — Our Work - NTE Middletown Energy Center · confidence: high - Timeline.3: {"event":"Substantial completion and inauguration","date":"2018-05","detail":"Gemma reported substantial completion in May 2018, and the facility was inaugurated on May 21, 2018."} — NTE Opens Gas-Fired Middletown Plant in Ohio · confidence: high - Timeline.4: {"event":"Commercial operation","date":"2018-06","detail":"The project fact sheet identified June 2018 as the commercial-operation date; EIA-derived records identify initial operation in May 2018."} — Microsoft Word - 11502144_1.docx · confidence: medium - Timeline.5: {"event":"Project-company control period","date":"2021-2024","detail":"Power Magazine reported that Ohio Power Partners LLC assumed control after the original developer/operator period associated with NTE Ohio LLC. The reported operator-year range predates or overlaps other project dates and should not be read as a revised commercial-operation date."} — Private Equity Firm Moves to Secure Ohio Gas Power Plant as Demand for Firm Power Rallies · confidence: low - Timeline.6: {"event":"ArcLight acquisition agreement announced","date":"2025-07-10","detail":"ArcLight announced definitive agreements to acquire 100% of Middletown’s economic interests through a series of transactions from a consortium of sellers. Sale consideration was not disclosed."} — ARCLIGHT TO ACQUIRE MIDDLETOWN ENERGY CENTER · confidence: high - Timeline.7: {"event":"Seller-side agreement announced","date":"2025-07-23","detail":"Axium Infrastructure, Guggenheim Investments on behalf of its investors, and other equity partners announced an agreement to sell their respective interests to ArcLight affiliates."} — Axium acquires interest in Canadian & US Wind Portfolio · confidence: high - Timeline.8: {"event":"Acquisition closed","date":"2026-01-21","detail":"S&P Global Ratings reported that the transaction had received all necessary regulatory approvals and had closed by the date of its January 2026 update; the exact closing date was not stated."} — Research Update: Ohio Power Partners LLC's Debt A | S&P Global Ratings · confidence: medium - Commercial parties.0: {"relationship":"Indirect owner and acquisition buyer","name":"ArcLight Capital Partners, LLC","detail":"ArcLight affiliates acquired 100% of Middletown Energy Center’s economic interests in the July 2025 transaction and indirectly own the facility through Ohio Power Partners LLC.","official_url":"https://arclight.com/"} — ARCLIGHT TO ACQUIRE MIDDLETOWN ENERGY CENTER · confidence: high - Commercial parties.0: {"relationship":"Indirect owner and acquisition buyer","name":"ArcLight Capital Partners, LLC","detail":"ArcLight affiliates acquired 100% of Middletown Energy Center’s economic interests in the July 2025 transaction and indirectly own the facility through Ohio Power Partners LLC.","official_url":"https://arclight.com/"} — Research Update: Ohio Power Partners LLC's Debt A | S&P Global Ratings · confidence: high - Commercial parties.1: {"relationship":"Project company and registered utility","name":"Ohio Power Partners, LLC","detail":"Project company through which ArcLight owns the facility and the EIA-registered utility associated with Middletown Energy Center.","official_url":null} — Research Update: Ohio Power Partners LLC's Debt A | S&P Global Ratings · confidence: high - Commercial parties.2: {"relationship":"Seller and former equity investor","name":"Axium Infrastructure Inc.","detail":"Acquired an approximately 19.6% equity interest in 2017 and later sold its respective interest, together with other equity partners, to ArcLight affiliates.","official_url":"https://www.axiuminfra.com/"} — March 16, 2017 - AXIUM INFRASTRUCTURE CLOSES ACQUISITION OF EQUITY INTERESTS IN NATURAL-GAS POWER GENERATION PORTFOLIO FROM CAPITAL DYNAMICS – Axium Infrastructure · confidence: high - Commercial parties.2: {"relationship":"Seller and former equity investor","name":"Axium Infrastructure Inc.","detail":"Acquired an approximately 19.6% equity interest in 2017 and later sold its respective interest, together with other equity partners, to ArcLight affiliates.","official_url":"https://www.axiuminfra.com/"} — Axium acquires interest in Canadian & US Wind Portfolio · confidence: high - Commercial parties.3: {"relationship":"Seller on behalf of investors","name":"Guggenheim Investments","detail":"Named by Axium as a seller participating on behalf of its investors in the 2025 sale of the project’s equity interests.","official_url":"https://www.guggenheiminvestments.com/"} — Axium acquires interest in Canadian & US Wind Portfolio · confidence: high ## Timeline - 2018-06 — Commercial operation The project fact sheet identified June 2018 as the commercial-operation date; EIA-derived records identify initial operation in May 2018. Source: Microsoft Word - 11502144_1.docx (https://ohioipp.org/wp-content/uploads/2018/05/Fact-Sheet_NTE-Middletown-Energy-Center.pdf) - 2021-2024 — Project-company control period Power Magazine reported that Ohio Power Partners LLC assumed control after the original developer/operator period associated with NTE Ohio LLC. The reported operator-year range predates or overlaps other project dates and should not be read as a revised commercial-operation date. Source: Private Equity Firm Moves to Secure Ohio Gas Power Plant as Demand for Firm Power Rallies (https://www.powermag.com/private-equity-firm-moves-to-secure-ohio-gas-power-plant-as-demand-for-firm-power-rallies/) - 2025-07-23 — Seller-side agreement announced Axium Infrastructure, Guggenheim Investments on behalf of its investors, and other equity partners announced an agreement to sell their respective interests to ArcLight affiliates. Source: JULY 23, 2025 - AXIUM INFRASTRUCTURE AND ITS EQUITY PARTNERS SELL 100% OF MIDDLETOWN ENERGY CENTER TO ARCLIGHT CAPITAL – Axium Infrastructure (https://www.axiuminfra.com/2025/07/25/july-23-2025-axium-infrastructure-and-its-equity-partners-sell-100-of-middletown-energy-center-to-arclight-capital/?lang=en) ## Sources - [ARCLIGHT TO ACQUIRE MIDDLETOWN ENERGY CENTER](https://www.prnewswire.com/news-releases/arclight-to-acquire-middletown-energy-center-302501772.html) — prnewswire.com · tier other - [Our Work - NTE Middletown Energy Center](https://www.gemmapower.com/our-work/combined-cycle/nte-middletown-energy-center) — gemmapower.com · tier other - [Research Update: Ohio Power Partners LLC's Debt A | S&P Global Ratings](https://www.spglobal.com/ratings/en/regulatory/article/-/view/type/HTML/id/3505788) — spglobal.com · tier other - [Microsoft Word - 11502144_1.docx](https://ohioipp.org/wp-content/uploads/2018/05/Fact-Sheet_NTE-Middletown-Energy-Center.pdf) — ohioipp.org · tier other - [Glastonbury's Gemma builds 475MW Ohio energy plant](https://hartfordbusiness.com/article/glastonburys-gemma-builds-475mw-ohio-energy-plant/) — hartfordbusiness.com · tier other - [NTE Energy Completes Middletown Energy Center](https://www.power-eng.com/gas/nte-energy-completes-middletown-energy-center/) — power-eng.com · tier other - [Sargent & Lundy: Homepage](https://www.sargentlundy.com/) — sargentlundy.com · tier other - [Vogt Power International | Heat Recovery Steam Generators](https://www.vogtpower.com/) — vogtpower.com · tier other - [Leading the Future of Clean Energy Solutions | TAES](https://toshiba.com/taes/) — toshiba.com · tier other - [Private Equity Firm Moves to Secure Ohio Gas Power Plant as Demand for Firm Power Rallies](https://www.powermag.com/private-equity-firm-moves-to-secure-ohio-gas-power-plant-as-demand-for-firm-power-rallies/) — powermag.com · tier other - [M501G/GAC Series | Mitsubishi Power](https://power.mhi.com/products/gasturbines/lineup/m501g) — power.mhi.com · tier other - [Heat Recovery Steam Generators (HRSGs) | Vogt](https://www.vogtpower.com/hrsgs) — vogtpower.com · tier other - [Steam Turbine Generators | TAES](https://toshiba.com/taes/products/steam-turbine-generator/) — toshiba.com · tier other - [Ohio Power Partners LLC's Term Loan B Assigned Pr | S&P Global Ratings](https://www.spglobal.com/ratings/en/regulatory/article/-/view/type/HTML/id/3464281) — spglobal.com · tier other - [Source](https://www.axiuminfra.com/wp-content/uploads/2025/07/Axium-Infrastructure_Divestiture-MEC_Final1.pdf) — axiuminfra.com · tier other - [NTE Energy closes financing for 475 MW power project in Ohio | Energy Finance & Investment](https://www.ippjournal.com/news/nte-energy-closes-financing-for-475-mw-power-project-in-ohio) — ippjournal.com · tier other - [March 16, 2017 - AXIUM INFRASTRUCTURE CLOSES ACQUISITION OF EQUITY INTERESTS IN NATURAL-GAS POWER GENERATION PORTFOLIO FROM CAPITAL DYNAMICS – Axium Infrastructure](https://www.axiuminfra.com/2017/03/16/march-16-2017-axium-infrastructure-closes-acquisition-of-equity-interests-in-natural-gas-power-generation-portfolio-from-capital-dynamics/?lang=en) — axiuminfra.com · tier other - [JULY 23, 2025 - AXIUM INFRASTRUCTURE AND ITS EQUITY PARTNERS SELL 100% OF MIDDLETOWN ENERGY CENTER TO ARCLIGHT CAPITAL – Axium Infrastructure](https://www.axiuminfra.com/2025/07/25/july-23-2025-axium-infrastructure-and-its-equity-partners-sell-100-of-middletown-energy-center-to-arclight-capital/?lang=en) — axiuminfra.com · tier other - [Financial close on 475MW Ohio gas plant](https://www.infrastructureinvestor.com/financial-close-on-475mw-ohio-gas-plant/) — infrastructureinvestor.com · tier other - [NTE Opens Gas-Fired Middletown Plant in Ohio](https://www.powermag.com/nte-opens-gas-fired-middletown-plant-in-ohio/) — powermag.com · tier other - [Sheet1](https://www.pjm.com/-/media/DotCom/markets-ops/energy/day-ahead/valid-bidding-locations-for-virtual-bids.xls) — pjm.com · tier other - [Source](https://dataminer2.pjm.com/feed/pnode/definition) — dataminer2.pjm.com · tier other ## Data quality - Publicly reported capacity is not uniform: EIA generator records total 543.9 MW, while project and transaction sources describe nominal or rated capacities of 475 MW, 478 MW, and 484 MW. These figures should not be treated as interchangeable without confirming the applicable capacity definition. S&P later reported that all necessary approvals had been received and the transaction had closed, without stating the exact closing date. The operating record lists no completed uprate or derate. No retirement or repowering date is reported for the facility. --- Canonical page: https://askthegrid.com/assets/facilities/middletown-energy-center Source: Ask the Grid — https://askthegrid.com/