# Conemaugh

PJM Conventional Steam Coal · https://askthegrid.com/assets/facilities/conemaugh

Conemaugh is a coal-fired power facility with 1,951 MW of EIA-reported nameplate capacity in Indiana County, Pennsylvania, registered as EIA Plant ID 3118. Its 1994-1995 flue-gas-desulfurization project reduced Unit 1 sulfur-dioxide emissions by approximately 95%; the project was described as one of the first U.S. plant modifications using scrubbers to meet the 1990 Clean Air Act Amendments.

## Key facts

- Technology: Conventional Steam Coal
- Power capacity: 1951 MW
- Operating status: operating

## Grid and market context

- ISO/RTO: PJM
- Balancing authority: PJM

## Source-backed facts

- Owner logo domain: talenenergy.com — Conemaugh Generating Station - Talen Energy · confidence: medium
- Identifiers: [{"value":"3118","system":"EIA plant ID"},{"value":"3118","system":"EPA ORISPL / EIS facility ID"},{"value":"2905911","system":"EPA CAMD facility ID"},{"value":"PJM","system":"ISO/RTO"},{"value":"CONEMAUGH 1 — resource 234","system":"PJM RPM capacity resource"},{"value":"CONEMAUGH 2 — resource 235","system":"PJM RPM capacity resource"},{"value":"PENELEC / MAAC","system":"PJM capacity zone"},{"value":"32-00059","system":"Pennsylvania DEP Title V operating permit"},{"value":"EPA-HQ-OLEM-2021-0281","system":"EPA CCR docket"},{"value":"031; 032","system":"Pennsylvania DEP boiler source IDs"}] — EPA ICR ID,EIA Number,Plant Name,State,SE Unit... · confidence: medium
- Identifiers: [{"value":"3118","system":"EIA plant ID"},{"value":"3118","system":"EPA ORISPL / EIS facility ID"},{"value":"2905911","system":"EPA CAMD facility ID"},{"value":"PJM","system":"ISO/RTO"},{"value":"CONEMAUGH 1 — resource 234","system":"PJM RPM capacity resource"},{"value":"CONEMAUGH 2 — resource 235","system":"PJM RPM capacity resource"},{"value":"PENELEC / MAAC","system":"PJM capacity zone"},{"value":"32-00059","system":"Pennsylvania DEP Title V operating permit"},{"value":"EPA-HQ-OLEM-2021-0281","system":"EPA CCR docket"},{"value":"031; 032","system":"Pennsylvania DEP boiler source IDs"}] — Facility Distance NPS ID Q to SHEN Q/d Class I Inventory* EIS ID (ORISPL) County Facility Name NOX SO2 (tons) · confidence: medium
- Identifiers: [{"value":"3118","system":"EIA plant ID"},{"value":"3118","system":"EPA ORISPL / EIS facility ID"},{"value":"2905911","system":"EPA CAMD facility ID"},{"value":"PJM","system":"ISO/RTO"},{"value":"CONEMAUGH 1 — resource 234","system":"PJM RPM capacity resource"},{"value":"CONEMAUGH 2 — resource 235","system":"PJM RPM capacity resource"},{"value":"PENELEC / MAAC","system":"PJM capacity zone"},{"value":"32-00059","system":"Pennsylvania DEP Title V operating permit"},{"value":"EPA-HQ-OLEM-2021-0281","system":"EPA CCR docket"},{"value":"031; 032","system":"Pennsylvania DEP boiler source IDs"}] — Sheet1 · confidence: medium
- Identifiers: [{"value":"3118","system":"EIA plant ID"},{"value":"3118","system":"EPA ORISPL / EIS facility ID"},{"value":"2905911","system":"EPA CAMD facility ID"},{"value":"PJM","system":"ISO/RTO"},{"value":"CONEMAUGH 1 — resource 234","system":"PJM RPM capacity resource"},{"value":"CONEMAUGH 2 — resource 235","system":"PJM RPM capacity resource"},{"value":"PENELEC / MAAC","system":"PJM capacity zone"},{"value":"32-00059","system":"Pennsylvania DEP Title V operating permit"},{"value":"EPA-HQ-OLEM-2021-0281","system":"EPA CCR docket"},{"value":"031; 032","system":"Pennsylvania DEP boiler source IDs"}] — 1467324[32-00059]_Pending.pdf · confidence: medium
- Identifiers: [{"value":"3118","system":"EIA plant ID"},{"value":"3118","system":"EPA ORISPL / EIS facility ID"},{"value":"2905911","system":"EPA CAMD facility ID"},{"value":"PJM","system":"ISO/RTO"},{"value":"CONEMAUGH 1 — resource 234","system":"PJM RPM capacity resource"},{"value":"CONEMAUGH 2 — resource 235","system":"PJM RPM capacity resource"},{"value":"PENELEC / MAAC","system":"PJM capacity zone"},{"value":"32-00059","system":"Pennsylvania DEP Title V operating permit"},{"value":"EPA-HQ-OLEM-2021-0281","system":"EPA CCR docket"},{"value":"031; 032","system":"Pennsylvania DEP boiler source IDs"}] — Regulations.gov · confidence: medium
- Official project url: https://www.talenenergy.com/plant/conemaugh-generating-station/ — Conemaugh Generating Station - Talen Energy · confidence: high
- Owner name: Talen Energy Corporation (22% share) — Conemaugh Generating Station - Talen Energy · confidence: medium
- Description: Conemaugh is a coal-fired electric generating station in West Wheatfield Township, Indiana County, Pennsylvania, publicly known as Conemaugh Generating Station. Pennsylvania DEP identifies two pulverized coal-fired boilers, each powering an 856-MW generator, for a combined nameplate capacity of 1,711 MW. The station provides electricity to the PJM regional electric grid and participates in PJM through the CONEMAUGH 1 and CONEMAUGH 2 capacity resources. — 1467324[32-00059]_Pending.pdf · confidence: medium
- Description: Conemaugh is a coal-fired electric generating station in West Wheatfield Township, Indiana County, Pennsylvania, publicly known as Conemaugh Generating Station. Pennsylvania DEP identifies two pulverized coal-fired boilers, each powering an 856-MW generator, for a combined nameplate capacity of 1,711 MW. The station provides electricity to the PJM regional electric grid and participates in PJM through the CONEMAUGH 1 and CONEMAUGH 2 capacity resources. — Source · confidence: medium
- Description: Conemaugh is a coal-fired electric generating station in West Wheatfield Township, Indiana County, Pennsylvania, publicly known as Conemaugh Generating Station. Pennsylvania DEP identifies two pulverized coal-fired boilers, each powering an 856-MW generator, for a combined nameplate capacity of 1,711 MW. The station provides electricity to the PJM regional electric grid and participates in PJM through the CONEMAUGH 1 and CONEMAUGH 2 capacity resources. — Sheet1 · confidence: medium
- Identifiers.0: {"value":"3118","system":"EIA plant ID"} — EPA ICR ID,EIA Number,Plant Name,State,SE Unit... · confidence: medium
- Identifiers.1: {"value":"3118","system":"EPA ORISPL / EIS facility ID"} — Facility Distance NPS ID Q to SHEN Q/d Class I Inventory* EIS ID (ORISPL) County Facility Name NOX SO2 (tons) · confidence: high
- Identifiers.2: {"value":"2905911","system":"EPA CAMD facility ID"} — Facility Distance NPS ID Q to SHEN Q/d Class I Inventory* EIS ID (ORISPL) County Facility Name NOX SO2 (tons) · confidence: high
- Identifiers.3: {"value":"PJM","system":"ISO/RTO"} — Conemaugh Generating Station - Talen Energy · confidence: high
- Identifiers.4: {"value":"CONEMAUGH 1 — resource 234","system":"PJM RPM capacity resource"} — Sheet1 · confidence: medium
- Identifiers.5: {"value":"CONEMAUGH 2 — resource 235","system":"PJM RPM capacity resource"} — Sheet1 · confidence: medium
- Identifiers.6: {"value":"PENELEC / MAAC","system":"PJM capacity zone"} — Sheet1 · confidence: high
- Identifiers.7: {"value":"32-00059","system":"Pennsylvania DEP Title V operating permit"} — 1467324[32-00059]_Pending.pdf · confidence: high
- Identifiers.8: {"value":"EPA-HQ-OLEM-2021-0281","system":"EPA CCR docket"} — Regulations.gov · confidence: high
- Identifiers.9: {"value":"031; 032","system":"Pennsylvania DEP boiler source IDs"} — 1467324[32-00059]_Pending.pdf · confidence: high
- Parties.0: {"relationship":"Owner; 22% interest","name":"Talen Energy Corporation","official_url":"https://www.talenenergy.com"} — Conemaugh Generating Station - Talen Energy · confidence: high
- Parties.1: {"relationship":"Operator; Key-Con","name":"Keystone-Conemaugh Projects, LLC","official_url":null} — Shapiro Administration Files Motion to Enter Consent... · confidence: medium
- Parties.2: {"relationship":"Operating and CCR-compliance entity","name":"KeyCon Operating LLC","official_url":"http://ccr.keyconops.com/"} — KeyCon Operating LLC · confidence: medium
- Interconnection: PJM regional electric grid (PJM-PN; PENELEC/MAAC capacity zone) — Source · confidence: medium
- Interconnection: PJM regional electric grid (PJM-PN; PENELEC/MAAC capacity zone) — Source · confidence: medium
- Unit configuration: Two pulverized-coal-fired boilers, each powering an 856 MW steam-turbine generator; bituminous coal fuel. — Source · confidence: high
- Commercial operation date: 1970 — Source · confidence: medium
- Power mw: 1711 — Source · confidence: medium
- Unit count: 2 — Source · confidence: high
- Unit count: 2 — Source · confidence: high
- Construction scope: Two main pulverized-coal boilers (Source IDs 031 and 032), each powering one electrical generator; the generators are rated at 856 MW each. The station uses supercritical tangential-fired boiler technology, a steam-turbine-generator package, FGD scrubber and SCR systems. Supporting equipment includes two auxiliary boilers, four 3,600-BHP peaking diesel generators, two emergency diesel generators rated at 1,662 BHP each, two non-emergency diesel engines, limestone processing and coal-storage piles. — 1467324[32-00059]_Pending.pdf · confidence: medium
- Product url: https://www.gevernova.com/gas-power/products/steam-turbines — Steam Turbine Power Plant Solutions | GE Vernova · confidence: medium
- Product url: https://www.gevernova.com/gas-power/products/steam-turbines — In focus: Combustion Engineering | GE Vernova · confidence: medium
- Kind: thermal — 1467324[32-00059]_Pending.pdf · confidence: high
- Manufacturer domain: gevernova.com — In focus: Combustion Engineering | GE Vernova · confidence: medium
- Equipment models: [{"manufacturer_domain":"gevernova.com","product_url":"https://www.gevernova.com/steam-power/services/boilers/legacy-boiler-services","count":2,"unit_mw":900,"name":"Combustion Engineering supercritical tangential-fired boilers"},{"manufacturer_domain":"gevernova.com","product_url":"https://www.gevernova.com/gas-power/products/steam-turbines","count":2,"unit_mw":856,"name":"GE steam turbine generators"},{"manufacturer_domain":"gevernova.com","product_url":"https://www.gevernova.com/steam-power/services/boilers/legacy-boiler-services","count":1,"unit_mw":null,"name":"Combustion Engineering auxiliary boiler A"},{"manufacturer_domain":null,"product_url":null,"count":1,"unit_mw":null,"name":"Alstom PWR 32VP2180 auxiliary boiler B"},{"manufacturer_domain":null,"product_url":null,"count":4,"unit_mw":null,"name":"Peaking diesel electrical generators, 3,600 BHP each"},{"manufacturer_domain":null,"product_url":null,"count":2,"unit_mw":null,"name":"Emergency diesel generators, 1,662 BHP each"},{"manufacturer_domain":null,"product_url":null,"count":2,"unit_mw":null,"name":"Non-emergency diesel engines, 283 BHP and 380 BHP"}] — New Predictive Dynamic Controller Reduces NOx While Improving Efficiency · confidence: medium
- Product family: Supercritical tangential-fired Combustion Engineering boiler technology and GE steam-turbine-generator package — New Predictive Dynamic Controller Reduces NOx While Improving Efficiency · confidence: medium
- Manufacturer name: Combustion Engineering for the boilers; GE for the turbine generators — In focus: Combustion Engineering | GE Vernova · confidence: medium
- Equipment models.0: {"manufacturer_domain":"gevernova.com","product_url":"https://www.gevernova.com/steam-power/services/boilers/legacy-boiler-services","count":2,"unit_mw":900,"name":"Combustion Engineering supercritical tangential-fired boilers"} — New Predictive Dynamic Controller Reduces NOx While Improving Efficiency · confidence: medium
- Equipment models.1: {"manufacturer_domain":"gevernova.com","product_url":"https://www.gevernova.com/gas-power/products/steam-turbines","count":2,"unit_mw":856,"name":"GE steam turbine generators"} — 1467324[32-00059]_Pending.pdf · confidence: medium
- Equipment models.4: {"manufacturer_domain":null,"product_url":null,"count":4,"unit_mw":null,"name":"Peaking diesel electrical generators, 3,600 BHP each"} — 1467324[32-00059]_Pending.pdf · confidence: medium
- Description: Conemaugh Generating Station is located in West Wheatfield Township, Indiana County, Pennsylvania, and consists of two pulverized-coal boilers, each driving an electric generator, with a Pennsylvania DEP combined nameplate capacity of 1,711 MW. Talen Energy owns a 22% interest, while Keystone-Conemaugh Projects, LLC operates the station. The two units entered commercial operation in May 1970 and May 1971 and provide power to PJM. Major ownership changes included Allegheny Energy Supply's 2003 sale to UGI, Atlantic City Electric's 2006 sale to Duquesne Light Holdings, Exelon's 2014 sale to ArcLight-affiliated Chief Power, and PSEG's completed 2019 sale to ArcLight-affiliated entities. — Source · confidence: medium
- Description: Conemaugh Generating Station is located in West Wheatfield Township, Indiana County, Pennsylvania, and consists of two pulverized-coal boilers, each driving an electric generator, with a Pennsylvania DEP combined nameplate capacity of 1,711 MW. Talen Energy owns a 22% interest, while Keystone-Conemaugh Projects, LLC operates the station. The two units entered commercial operation in May 1970 and May 1971 and provide power to PJM. Major ownership changes included Allegheny Energy Supply's 2003 sale to UGI, Atlantic City Electric's 2006 sale to Duquesne Light Holdings, Exelon's 2014 sale to ArcLight-affiliated Chief Power, and PSEG's completed 2019 sale to ArcLight-affiliated entities. — Shapiro Administration Files Motion to Enter Consent Decree on Power | Commonwealth of Pennsylvania · confidence: medium
- Description: Conemaugh Generating Station is located in West Wheatfield Township, Indiana County, Pennsylvania, and consists of two pulverized-coal boilers, each driving an electric generator, with a Pennsylvania DEP combined nameplate capacity of 1,711 MW. Talen Energy owns a 22% interest, while Keystone-Conemaugh Projects, LLC operates the station. The two units entered commercial operation in May 1970 and May 1971 and provide power to PJM. Major ownership changes included Allegheny Energy Supply's 2003 sale to UGI, Atlantic City Electric's 2006 sale to Duquesne Light Holdings, Exelon's 2014 sale to ArcLight-affiliated Chief Power, and PSEG's completed 2019 sale to ArcLight-affiliated entities. — Conemaugh Generating Station · confidence: medium
- Description: Conemaugh Generating Station is located in West Wheatfield Township, Indiana County, Pennsylvania, and consists of two pulverized-coal boilers, each driving an electric generator, with a Pennsylvania DEP combined nameplate capacity of 1,711 MW. Talen Energy owns a 22% interest, while Keystone-Conemaugh Projects, LLC operates the station. The two units entered commercial operation in May 1970 and May 1971 and provide power to PJM. Major ownership changes included Allegheny Energy Supply's 2003 sale to UGI, Atlantic City Electric's 2006 sale to Duquesne Light Holdings, Exelon's 2014 sale to ArcLight-affiliated Chief Power, and PSEG's completed 2019 sale to ArcLight-affiliated entities. — PSEG completes sale of stakes in Keystone and... · confidence: medium
- Quality notes: ["Published capacity figures use different bases: Talen reports approximately 1,754 MW, while Pennsylvania DEP reports 1,711 MW of combined generator nameplate capacity.","The disclosed 2006 purchase price of approximately $173 million covered interests in both Keystone and Conemaugh and is not allocated to Conemaugh alone.","The 2014 Exelon transaction financing is disclosed, but the cited material does not disclose a separate purchase price; the 2019 PSEG announcement also does not disclose separate sale consideration.","The station had been scheduled to cease operations on December 31, 2028; a proposed 2026 consent decree would permit operation through 2032 subject to wastewater-treatment upgrades.","No separate generation repowering event is identified; documented major modifications are environmental-control, ash-handling, and wastewater-treatment upgrades."] — Source · confidence: medium
- Quality notes: ["Published capacity figures use different bases: Talen reports approximately 1,754 MW, while Pennsylvania DEP reports 1,711 MW of combined generator nameplate capacity.","The disclosed 2006 purchase price of approximately $173 million covered interests in both Keystone and Conemaugh and is not allocated to Conemaugh alone.","The 2014 Exelon transaction financing is disclosed, but the cited material does not disclose a separate purchase price; the 2019 PSEG announcement also does not disclose separate sale consideration.","The station had been scheduled to cease operations on December 31, 2028; a proposed 2026 consent decree would permit operation through 2032 subject to wastewater-treatment upgrades.","No separate generation repowering event is identified; documented major modifications are environmental-control, ash-handling, and wastewater-treatment upgrades."] — Shapiro Administration Files Motion to Enter Consent Decree on Power | Commonwealth of Pennsylvania · confidence: medium
- Timeline: [{"event":"Unit 1 commercial operation","date":"1970-05-21","detail":"Unit 1 entered commercial operation on May 21, 1970."},{"event":"Unit 2 commercial operation","date":"1971-05-27","detail":"Unit 2 entered commercial operation on May 27, 1971."},{"event":"Unit 1 flue-gas-desulfurization system","date":"1994-12-15","detail":"Unit 1's new FGD system entered service and reduced sulfur-dioxide emissions by approximately 95%."},{"event":"Station scrubber project","date":"1995","detail":"A second scrubber for Unit 2 was scheduled for completion in fall 1995; the two-scrubber project was expected to cost approximately $341 million and support compliance with the 1990 Clean Air Act Amendments."},{"event":"Allegheny Energy Supply acquisition","date":"2001-01","detail":"Allegheny Energy Supply acquired a 4.86% interest, described as an 83 MW share, in Conemaugh. The cited announcement does not identify the seller."},{"event":"Allegheny Energy Supply sale to UGI","date":"2003-02-26","detail":"Allegheny Energy Supply announced an agreement to sell its 83 MW share to UGI Development Co. for approximately $51.25 million, subject to a $3 million credit in favor of UGI and regulatory approvals."},{"event":"Atlantic City Electric sale agreement","date":"2005-11-14","detail":"Duquesne Light Holdings entered a purchase-and-sale agreement to acquire Atlantic City Electric's 65.6 MW, or 3.83%, Conemaugh interest as part of a combined Keystone-Conemaugh transaction."},{"event":"Acquisition financing commitment","date":"2006-08-04","detail":"Two banks committed a $200 million term-loan facility primarily to finance Duquesne Light Holdings' acquisition of the Keystone and Conemaugh interests."},{"event":"Duquesne Light Holdings acquisition closing","date":"2006-09-01","detail":"Duquesne Light Holdings completed its purchase from Atlantic City Electric of a 3.83% Conemaugh interest and a 2.47% Keystone interest for an aggregate purchase price of $173 million."},{"event":"Exelon sale to ArcLight-affiliated Chief Power","date":"2014-12-09","detail":"ArcLight Energy Partners Fund V announced the purchase of Exelon's interests in Keystone and Conemaugh; the reported Conemaugh interest was 31.28% and the interests were to be held through Chief Power entities."},{"event":"Duquesne-interest succession to Chief Conemaugh Power","date":"2015-07-14","detail":"A FERC filing recorded Chief Conemaugh Power, LLC's succession to the Duquesne interests effective July 14, 2015; secondary ownership records identify the transferred Conemaugh interest as 3.83%."},{"event":"PSEG sale agreement","date":"2019-06-24","detail":"PSEG Power agreed to sell its combined 776 MW interests in Keystone and Conemaugh, together with related assets and liabilities, to ArcLight affiliates; the transaction was expected to close in the second half of 2019."},{"event":"PSEG sale completion","date":"2019-11-26","detail":"PSEG completed the sale of its Keystone and Conemaugh stakes, representing a combined 776 MW, to ArcLight Capital Partners."},{"event":"Planned retirement/deactivation","date":"2021-09-23","detail":"A KeyCon notice stated that a request for generator deactivation was expected to be submitted to PJM in 2028 or sooner."},{"event":"Ash-handling and basin modifications","date":"2005","detail":"The fourth cell of the ash-filter ponds was reconstructed."},{"event":"Cooling-tower desilting-basin expansion","date":"2013","detail":"The desilting basin was reconstructed, expanded, lined, and fitted with an under-drain system."},{"event":"Proposed operating extension","date":"2026-04-21","detail":"Pennsylvania announced a proposed consent decree under which the plants, previously scheduled to cease operations on December 31, 2028, could continue operating through 2032 after required wastewater-treatment upgrades."}] — Conemaugh Generating Station · confidence: medium
- Timeline: [{"event":"Unit 1 commercial operation","date":"1970-05-21","detail":"Unit 1 entered commercial operation on May 21, 1970."},{"event":"Unit 2 commercial operation","date":"1971-05-27","detail":"Unit 2 entered commercial operation on May 27, 1971."},{"event":"Unit 1 flue-gas-desulfurization system","date":"1994-12-15","detail":"Unit 1's new FGD system entered service and reduced sulfur-dioxide emissions by approximately 95%."},{"event":"Station scrubber project","date":"1995","detail":"A second scrubber for Unit 2 was scheduled for completion in fall 1995; the two-scrubber project was expected to cost approximately $341 million and support compliance with the 1990 Clean Air Act Amendments."},{"event":"Allegheny Energy Supply acquisition","date":"2001-01","detail":"Allegheny Energy Supply acquired a 4.86% interest, described as an 83 MW share, in Conemaugh. The cited announcement does not identify the seller."},{"event":"Allegheny Energy Supply sale to UGI","date":"2003-02-26","detail":"Allegheny Energy Supply announced an agreement to sell its 83 MW share to UGI Development Co. for approximately $51.25 million, subject to a $3 million credit in favor of UGI and regulatory approvals."},{"event":"Atlantic City Electric sale agreement","date":"2005-11-14","detail":"Duquesne Light Holdings entered a purchase-and-sale agreement to acquire Atlantic City Electric's 65.6 MW, or 3.83%, Conemaugh interest as part of a combined Keystone-Conemaugh transaction."},{"event":"Acquisition financing commitment","date":"2006-08-04","detail":"Two banks committed a $200 million term-loan facility primarily to finance Duquesne Light Holdings' acquisition of the Keystone and Conemaugh interests."},{"event":"Duquesne Light Holdings acquisition closing","date":"2006-09-01","detail":"Duquesne Light Holdings completed its purchase from Atlantic City Electric of a 3.83% Conemaugh interest and a 2.47% Keystone interest for an aggregate purchase price of $173 million."},{"event":"Exelon sale to ArcLight-affiliated Chief Power","date":"2014-12-09","detail":"ArcLight Energy Partners Fund V announced the purchase of Exelon's interests in Keystone and Conemaugh; the reported Conemaugh interest was 31.28% and the interests were to be held through Chief Power entities."},{"event":"Duquesne-interest succession to Chief Conemaugh Power","date":"2015-07-14","detail":"A FERC filing recorded Chief Conemaugh Power, LLC's succession to the Duquesne interests effective July 14, 2015; secondary ownership records identify the transferred Conemaugh interest as 3.83%."},{"event":"PSEG sale agreement","date":"2019-06-24","detail":"PSEG Power agreed to sell its combined 776 MW interests in Keystone and Conemaugh, together with related assets and liabilities, to ArcLight affiliates; the transaction was expected to close in the second half of 2019."},{"event":"PSEG sale completion","date":"2019-11-26","detail":"PSEG completed the sale of its Keystone and Conemaugh stakes, representing a combined 776 MW, to ArcLight Capital Partners."},{"event":"Planned retirement/deactivation","date":"2021-09-23","detail":"A KeyCon notice stated that a request for generator deactivation was expected to be submitted to PJM in 2028 or sooner."},{"event":"Ash-handling and basin modifications","date":"2005","detail":"The fourth cell of the ash-filter ponds was reconstructed."},{"event":"Cooling-tower desilting-basin expansion","date":"2013","detail":"The desilting basin was reconstructed, expanded, lined, and fitted with an under-drain system."},{"event":"Proposed operating extension","date":"2026-04-21","detail":"Pennsylvania announced a proposed consent decree under which the plants, previously scheduled to cease operations on December 31, 2028, could continue operating through 2032 after required wastewater-treatment upgrades."}] — Large Power Plant Effluent Study(LAPPES)Volume 4 - Instrumentation, Procedures, and Data Tabulations (1971) and Project Summary · confidence: medium
- Timeline: [{"event":"Unit 1 commercial operation","date":"1970-05-21","detail":"Unit 1 entered commercial operation on May 21, 1970."},{"event":"Unit 2 commercial operation","date":"1971-05-27","detail":"Unit 2 entered commercial operation on May 27, 1971."},{"event":"Unit 1 flue-gas-desulfurization system","date":"1994-12-15","detail":"Unit 1's new FGD system entered service and reduced sulfur-dioxide emissions by approximately 95%."},{"event":"Station scrubber project","date":"1995","detail":"A second scrubber for Unit 2 was scheduled for completion in fall 1995; the two-scrubber project was expected to cost approximately $341 million and support compliance with the 1990 Clean Air Act Amendments."},{"event":"Allegheny Energy Supply acquisition","date":"2001-01","detail":"Allegheny Energy Supply acquired a 4.86% interest, described as an 83 MW share, in Conemaugh. The cited announcement does not identify the seller."},{"event":"Allegheny Energy Supply sale to UGI","date":"2003-02-26","detail":"Allegheny Energy Supply announced an agreement to sell its 83 MW share to UGI Development Co. for approximately $51.25 million, subject to a $3 million credit in favor of UGI and regulatory approvals."},{"event":"Atlantic City Electric sale agreement","date":"2005-11-14","detail":"Duquesne Light Holdings entered a purchase-and-sale agreement to acquire Atlantic City Electric's 65.6 MW, or 3.83%, Conemaugh interest as part of a combined Keystone-Conemaugh transaction."},{"event":"Acquisition financing commitment","date":"2006-08-04","detail":"Two banks committed a $200 million term-loan facility primarily to finance Duquesne Light Holdings' acquisition of the Keystone and Conemaugh interests."},{"event":"Duquesne Light Holdings acquisition closing","date":"2006-09-01","detail":"Duquesne Light Holdings completed its purchase from Atlantic City Electric of a 3.83% Conemaugh interest and a 2.47% Keystone interest for an aggregate purchase price of $173 million."},{"event":"Exelon sale to ArcLight-affiliated Chief Power","date":"2014-12-09","detail":"ArcLight Energy Partners Fund V announced the purchase of Exelon's interests in Keystone and Conemaugh; the reported Conemaugh interest was 31.28% and the interests were to be held through Chief Power entities."},{"event":"Duquesne-interest succession to Chief Conemaugh Power","date":"2015-07-14","detail":"A FERC filing recorded Chief Conemaugh Power, LLC's succession to the Duquesne interests effective July 14, 2015; secondary ownership records identify the transferred Conemaugh interest as 3.83%."},{"event":"PSEG sale agreement","date":"2019-06-24","detail":"PSEG Power agreed to sell its combined 776 MW interests in Keystone and Conemaugh, together with related assets and liabilities, to ArcLight affiliates; the transaction was expected to close in the second half of 2019."},{"event":"PSEG sale completion","date":"2019-11-26","detail":"PSEG completed the sale of its Keystone and Conemaugh stakes, representing a combined 776 MW, to ArcLight Capital Partners."},{"event":"Planned retirement/deactivation","date":"2021-09-23","detail":"A KeyCon notice stated that a request for generator deactivation was expected to be submitted to PJM in 2028 or sooner."},{"event":"Ash-handling and basin modifications","date":"2005","detail":"The fourth cell of the ash-filter ponds was reconstructed."},{"event":"Cooling-tower desilting-basin expansion","date":"2013","detail":"The desilting basin was reconstructed, expanded, lined, and fitted with an under-drain system."},{"event":"Proposed operating extension","date":"2026-04-21","detail":"Pennsylvania announced a proposed consent decree under which the plants, previously scheduled to cease operations on December 31, 2028, could continue operating through 2032 after required wastewater-treatment upgrades."}] — Conemaugh Station adds scrubbers to comply with CAAA mandates · confidence: medium
- Timeline: [{"event":"Unit 1 commercial operation","date":"1970-05-21","detail":"Unit 1 entered commercial operation on May 21, 1970."},{"event":"Unit 2 commercial operation","date":"1971-05-27","detail":"Unit 2 entered commercial operation on May 27, 1971."},{"event":"Unit 1 flue-gas-desulfurization system","date":"1994-12-15","detail":"Unit 1's new FGD system entered service and reduced sulfur-dioxide emissions by approximately 95%."},{"event":"Station scrubber project","date":"1995","detail":"A second scrubber for Unit 2 was scheduled for completion in fall 1995; the two-scrubber project was expected to cost approximately $341 million and support compliance with the 1990 Clean Air Act Amendments."},{"event":"Allegheny Energy Supply acquisition","date":"2001-01","detail":"Allegheny Energy Supply acquired a 4.86% interest, described as an 83 MW share, in Conemaugh. The cited announcement does not identify the seller."},{"event":"Allegheny Energy Supply sale to UGI","date":"2003-02-26","detail":"Allegheny Energy Supply announced an agreement to sell its 83 MW share to UGI Development Co. for approximately $51.25 million, subject to a $3 million credit in favor of UGI and regulatory approvals."},{"event":"Atlantic City Electric sale agreement","date":"2005-11-14","detail":"Duquesne Light Holdings entered a purchase-and-sale agreement to acquire Atlantic City Electric's 65.6 MW, or 3.83%, Conemaugh interest as part of a combined Keystone-Conemaugh transaction."},{"event":"Acquisition financing commitment","date":"2006-08-04","detail":"Two banks committed a $200 million term-loan facility primarily to finance Duquesne Light Holdings' acquisition of the Keystone and Conemaugh interests."},{"event":"Duquesne Light Holdings acquisition closing","date":"2006-09-01","detail":"Duquesne Light Holdings completed its purchase from Atlantic City Electric of a 3.83% Conemaugh interest and a 2.47% Keystone interest for an aggregate purchase price of $173 million."},{"event":"Exelon sale to ArcLight-affiliated Chief Power","date":"2014-12-09","detail":"ArcLight Energy Partners Fund V announced the purchase of Exelon's interests in Keystone and Conemaugh; the reported Conemaugh interest was 31.28% and the interests were to be held through Chief Power entities."},{"event":"Duquesne-interest succession to Chief Conemaugh Power","date":"2015-07-14","detail":"A FERC filing recorded Chief Conemaugh Power, LLC's succession to the Duquesne interests effective July 14, 2015; secondary ownership records identify the transferred Conemaugh interest as 3.83%."},{"event":"PSEG sale agreement","date":"2019-06-24","detail":"PSEG Power agreed to sell its combined 776 MW interests in Keystone and Conemaugh, together with related assets and liabilities, to ArcLight affiliates; the transaction was expected to close in the second half of 2019."},{"event":"PSEG sale completion","date":"2019-11-26","detail":"PSEG completed the sale of its Keystone and Conemaugh stakes, representing a combined 776 MW, to ArcLight Capital Partners."},{"event":"Planned retirement/deactivation","date":"2021-09-23","detail":"A KeyCon notice stated that a request for generator deactivation was expected to be submitted to PJM in 2028 or sooner."},{"event":"Ash-handling and basin modifications","date":"2005","detail":"The fourth cell of the ash-filter ponds was reconstructed."},{"event":"Cooling-tower desilting-basin expansion","date":"2013","detail":"The desilting basin was reconstructed, expanded, lined, and fitted with an under-drain system."},{"event":"Proposed operating extension","date":"2026-04-21","detail":"Pennsylvania announced a proposed consent decree under which the plants, previously scheduled to cease operations on December 31, 2028, could continue operating through 2032 after required wastewater-treatment upgrades."}] — Duquesne Light Holdings Completes Purchase of 108-Megawatt Share of Two Coal-Fired Pennsylvania Generation Plants · confidence: medium
- Timeline: [{"event":"Unit 1 commercial operation","date":"1970-05-21","detail":"Unit 1 entered commercial operation on May 21, 1970."},{"event":"Unit 2 commercial operation","date":"1971-05-27","detail":"Unit 2 entered commercial operation on May 27, 1971."},{"event":"Unit 1 flue-gas-desulfurization system","date":"1994-12-15","detail":"Unit 1's new FGD system entered service and reduced sulfur-dioxide emissions by approximately 95%."},{"event":"Station scrubber project","date":"1995","detail":"A second scrubber for Unit 2 was scheduled for completion in fall 1995; the two-scrubber project was expected to cost approximately $341 million and support compliance with the 1990 Clean Air Act Amendments."},{"event":"Allegheny Energy Supply acquisition","date":"2001-01","detail":"Allegheny Energy Supply acquired a 4.86% interest, described as an 83 MW share, in Conemaugh. The cited announcement does not identify the seller."},{"event":"Allegheny Energy Supply sale to UGI","date":"2003-02-26","detail":"Allegheny Energy Supply announced an agreement to sell its 83 MW share to UGI Development Co. for approximately $51.25 million, subject to a $3 million credit in favor of UGI and regulatory approvals."},{"event":"Atlantic City Electric sale agreement","date":"2005-11-14","detail":"Duquesne Light Holdings entered a purchase-and-sale agreement to acquire Atlantic City Electric's 65.6 MW, or 3.83%, Conemaugh interest as part of a combined Keystone-Conemaugh transaction."},{"event":"Acquisition financing commitment","date":"2006-08-04","detail":"Two banks committed a $200 million term-loan facility primarily to finance Duquesne Light Holdings' acquisition of the Keystone and Conemaugh interests."},{"event":"Duquesne Light Holdings acquisition closing","date":"2006-09-01","detail":"Duquesne Light Holdings completed its purchase from Atlantic City Electric of a 3.83% Conemaugh interest and a 2.47% Keystone interest for an aggregate purchase price of $173 million."},{"event":"Exelon sale to ArcLight-affiliated Chief Power","date":"2014-12-09","detail":"ArcLight Energy Partners Fund V announced the purchase of Exelon's interests in Keystone and Conemaugh; the reported Conemaugh interest was 31.28% and the interests were to be held through Chief Power entities."},{"event":"Duquesne-interest succession to Chief Conemaugh Power","date":"2015-07-14","detail":"A FERC filing recorded Chief Conemaugh Power, LLC's succession to the Duquesne interests effective July 14, 2015; secondary ownership records identify the transferred Conemaugh interest as 3.83%."},{"event":"PSEG sale agreement","date":"2019-06-24","detail":"PSEG Power agreed to sell its combined 776 MW interests in Keystone and Conemaugh, together with related assets and liabilities, to ArcLight affiliates; the transaction was expected to close in the second half of 2019."},{"event":"PSEG sale completion","date":"2019-11-26","detail":"PSEG completed the sale of its Keystone and Conemaugh stakes, representing a combined 776 MW, to ArcLight Capital Partners."},{"event":"Planned retirement/deactivation","date":"2021-09-23","detail":"A KeyCon notice stated that a request for generator deactivation was expected to be submitted to PJM in 2028 or sooner."},{"event":"Ash-handling and basin modifications","date":"2005","detail":"The fourth cell of the ash-filter ponds was reconstructed."},{"event":"Cooling-tower desilting-basin expansion","date":"2013","detail":"The desilting basin was reconstructed, expanded, lined, and fitted with an under-drain system."},{"event":"Proposed operating extension","date":"2026-04-21","detail":"Pennsylvania announced a proposed consent decree under which the plants, previously scheduled to cease operations on December 31, 2028, could continue operating through 2032 after required wastewater-treatment upgrades."}] — Combined Notice of Filings #1 · confidence: medium

## Timeline

- 1970-05-21 — Unit 1 commercial operation
  Unit 1 entered commercial operation on May 21, 1970.
  Source: Conemaugh Generating Station (https://www.olympuspower.com/node/28)
- 1971-05-27 — Unit 2 commercial operation
  Unit 2 entered commercial operation on May 27, 1971.
  Source: Conemaugh Generating Station (https://www.olympuspower.com/node/28)
- 1994-12-15 — Unit 1 flue-gas-desulfurization system
  Unit 1's new FGD system entered service and reduced sulfur-dioxide emissions by approximately 95%.
  Source: Conemaugh Station adds scrubbers to comply with CAAA mandates (https://www.power-eng.com/environmental-emissions/conemaugh-station-adds-scrubbers-to-comply-with-caaa-mandates/)
- 1995 — Station scrubber project
  A second scrubber for Unit 2 was scheduled for completion in fall 1995; the two-scrubber project was expected to cost approximately $341 million and support compliance with the 1990 Clean Air Act Amendments.
  Source: Conemaugh Station adds scrubbers to comply with CAAA mandates (https://www.power-eng.com/environmental-emissions/conemaugh-station-adds-scrubbers-to-comply-with-caaa-mandates/)
- 2001-01 — Allegheny Energy Supply acquisition
  Allegheny Energy Supply acquired a 4.86% interest, described as an 83 MW share, in Conemaugh. The cited announcement does not identify the seller.
  Source: Allegheny Energy announces sale of interest in Conemaugh Generating Station for $51.25 million (https://www.power-eng.com/operations-maintenance/allegheny-energy-announces-sale-of-interest-in-conemaugh-generating-station-for-5125-million/)
- 2003-02-26 — Allegheny Energy Supply sale to UGI
  Allegheny Energy Supply announced an agreement to sell its 83 MW share to UGI Development Co. for approximately $51.25 million, subject to a $3 million credit in favor of UGI and regulatory approvals.
  Source: Allegheny Energy announces sale of interest in Conemaugh Generating Station for $51.25 million (https://www.power-eng.com/operations-maintenance/allegheny-energy-announces-sale-of-interest-in-conemaugh-generating-station-for-5125-million/)
- 2005 — Ash-handling and basin modifications
  The fourth cell of the ash-filter ponds was reconstructed.
  Source: Coal Combustion Residue Impoundment Round 12 - Dam Assessment Report - Final Version | US EPA ARCHIVE DOCUMENT (https://archive.epa.gov/epawaste/nonhaz/industrial/special/fossil/web/pdf/genon_conemaugh_fnl_rpt.pdf)
- 2013 — Cooling-tower desilting-basin expansion
  The desilting basin was reconstructed, expanded, lined, and fitted with an under-drain system.
  Source: Coal Combustion Residue Impoundment Round 12 - Dam Assessment Report - Final Version | US EPA ARCHIVE DOCUMENT (https://archive.epa.gov/epawaste/nonhaz/industrial/special/fossil/web/pdf/genon_conemaugh_fnl_rpt.pdf)
- 2026-04-21 — Proposed operating extension
  Pennsylvania announced a proposed consent decree under which the plants, previously scheduled to cease operations on December 31, 2028, could continue operating through 2032 after required wastewater-treatment upgrades.
  Source: Shapiro Administration Files Motion to Enter Consent Decree on Power | Commonwealth of Pennsylvania (https://pa.gov/governor/newsroom/2026-press-releases/shapiro-administration-files-motion-to-enter-consent-decree-on-p)

## Sources

- [Conemaugh Generating Station - Talen Energy](https://www.talenenergy.com/plant/conemaugh-generating-station/) — talenenergy.com · tier other
- [EPA ICR ID,EIA Number,Plant Name,State,SE Unit ...](https://downloads.regulations.gov/EPA-HQ-OW-2009-0819-8800/attachment_1.pdf) — downloads.regulations.gov · tier regulatory
- [Facility Distance NPS ID Q to SHEN Q/d Class I Inventory* EIS ID (ORISPL) County Facility Name NOX SO2 (tons)](https://files.dep.state.pa.us/Air/AirQuality/AQPortalFiles/Pollutants/Haze/NPS%20Q%20over%20d%20analysis%20-%20PA%20facilities%202020.pdf) — files.dep.state.pa.us · tier other
- [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
- [1467324[32-00059]_Pending.pdf](https://files.dep.state.pa.us/RegionalResources/NWRO/NWROPortalFiles/RACT_II/1-16-24/Conemaugh/1467324%5B32-00059%5D_Pending%20Conemaugh%20Station.pdf) — files.dep.state.pa.us · tier other
- [Regulations.gov](https://www.regulations.gov/docket/EPA-HQ-OLEM-2021-0281) — regulations.gov · tier regulatory
- [Source](https://files.dep.state.pa.us/RegionalResources/NWRO/NWROPortalFiles/RACT_II/Permit_Modification_Review_Memo.pdf) — files.dep.state.pa.us · tier other
- [Shapiro Administration Files Motion to Enter Consent ...](https://www.pa.gov/governor/newsroom/2026-press-releases/shapiro-administration-files-motion-to-enter-consent-decree-on-p) — pa.gov · tier regulatory
- [KeyCon Operating LLC](https://ccr.keyconops.com/) — ccr.keyconops.com · tier other
- [Conemaugh Generating Station](https://www.olympuspower.com/node/28) — olympuspower.com · tier other
- [Source](https://talenenergy.com/plant/conemaugh-generating-station) — talenenergy.com · tier other
- [Source](https://pjm.com/-/media/DotCom/markets-ops/rpm/rpm-auction-info/2025-2026/2025-2026-rpm-existing-resource-list-post.xlsx) — pjm.com · tier other
- [Steam Turbine Power Plant Solutions | GE Vernova](https://www.gevernova.com/gas-power/products/steam-turbines) — gevernova.com · tier other
- [In focus: Combustion Engineering | GE Vernova](https://www.gevernova.com/steam-power/services/boilers/legacy-boiler-services) — gevernova.com · tier other
- [New Predictive Dynamic Controller Reduces NOx While Improving Efficiency](https://www.power-eng.com/environmental-emissions/new-predictive-dynamic-controller-reduces-nosubx-sub-while-improving-efficiency/) — power-eng.com · tier other
- [Conemaugh Station adds scrubbers to comply with CAAA mandates](https://www.power-eng.com/environmental-emissions/conemaugh-station-adds-scrubbers-to-comply-with-caaa-mandates/) — power-eng.com · tier other
- [Shapiro Administration Files Motion to Enter Consent Decree on Power | Commonwealth of Pennsylvania](https://pa.gov/governor/newsroom/2026-press-releases/shapiro-administration-files-motion-to-enter-consent-decree-on-p) — pa.gov · tier regulatory
- [PSEG completes sale of stakes in Keystone and ...](https://ippjournal.com/update/pseg-completes-sale-of-stakes-in-keystone-and-conemaugh-coal-fired-power-plants) — ippjournal.com · tier other
- [Source](https://www.sec.gov/Archives/edgar/data/30573/000095015206006772/l21304ae10vq.htm) — sec.gov · tier regulatory
- [Duquesne Light Holdings Completes Purchase of 108-Megawatt Share of Two Coal-Fired Pennsylvania Generation Plants](https://www.advfn.com/stock-market/NYSE/DQE/stock-news/16689017/duquesne-light-holdings-completes-purchase-of-108) — advfn.com · tier other
- [Large Power Plant Effluent Study(LAPPES)Volume 4 - Instrumentation, Procedures, and Data Tabulations (1971) and Project Summary](https://nepis.epa.gov/Exe/ZyPURL.cgi?Dockey=9100278D.TXT) — nepis.epa.gov · tier regulatory
- [Allegheny Energy announces sale of interest in Conemaugh Generating Station for $51.25 million](https://www.power-eng.com/operations-maintenance/allegheny-energy-announces-sale-of-interest-in-conemaugh-generating-station-for-5125-million/) — power-eng.com · tier other
- [Combined Notice of Filings #1](https://www.federalregister.gov/documents/2015/07/20/2015-17693/combined-notice-of-filings-1) — federalregister.gov · tier regulatory
- [PSEG Power Has Agreed to Sell Its Interest in Keystone and Conemaugh Coal Plants](https://nj.pseg.com/newsroom/newsrelease91) — nj.pseg.com · tier other
- [Conemaugh Generating Station - KeyCon Operating LLC](https://ccr.keyconops.com/wp-content/uploads/2024/06/CON_ELG_Rule-NoticeofPlannedParticipation_09-23-2021.pdf) — ccr.keyconops.com · tier other
- [Coal Combustion Residue Impoundment Round 12 - Dam Assessment Report - Final Version | US EPA ARCHIVE DOCUMENT](https://archive.epa.gov/epawaste/nonhaz/industrial/special/fossil/web/pdf/genon_conemaugh_fnl_rpt.pdf) — archive.epa.gov · tier regulatory
- [PSEG taking $400M hit to sell off coal-fired interests](https://www.power-eng.com/environmental-emissions/pseg-taking-400m-hit-to-sell-off-coal-fired-interests/) — power-eng.com · tier other
- [Duquesne Light Holdings Completes Purchase of 108 ...](https://br.advfn.com/noticias/PRNUS/2006/artigo/16689017) — br.advfn.com · tier other
- [ArcLight to Fund Coal Power Plants Acquisition With $365 ...](https://www.wsj.com/articles/DJFHYW0120141210eacaifeni) — wsj.com · tier other
- [ugi-20200930](https://www.sec.gov/Archives/edgar/data/884614/000088461420000052/ugi-20200930.htm) — sec.gov · tier regulatory
- [Talen Energy Presentation](https://ir.talenenergy.com/static-files/6666cf70-90d5-44f7-bfac-81fd803848b7) — ir.talenenergy.com · tier other
- [Data Miner 2 - Pricing Nodes](https://dataminer2.pjm.com/feed/pnode) — dataminer2.pjm.com · tier other

## Data quality

- Published capacity figures use different bases: Talen reports approximately 1,754 MW, while Pennsylvania DEP reports 1,711 MW of combined generator nameplate capacity. The disclosed 2006 purchase price of approximately $173 million covered interests in both Keystone and Conemaugh and is not allocated to Conemaugh alone. The 2014 Exelon transaction financing is disclosed, but the cited material does not disclose a separate purchase price; the 2019 PSEG announcement also does not disclose separate sale consideration. No separate generation repowering event is identified; documented major modifications are environmental-control, ash-handling, and wastewater-treatment upgrades.

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Canonical page: https://askthegrid.com/assets/facilities/conemaugh

Source: Ask the Grid — https://askthegrid.com/