Keystone Generating Station
| Company type | Power station |
|---|---|
| Industry | Energy |
| Founded | 1967 |
| Headquarters | Shelocta , United States |
Area served | Mid-Atlantic United States |
Key people | Reliant Resources (operator) |
| Products | Electricity |
| Owner | Public Service Enterprise Group (22.84%), ArcLight Capital Partners (20.91%), Reliant Energy (16%), PPL Montour LLC (12.34%), NRG Energy (3.7%), Duquesne Light Holdings (2.47%) |
The Keystone Generating Station is a coal-powered facility with a capacity of 1.71 gigawatts (1,711 MW), situated on roughly in Plumcreek Township, Armstrong County, Pennsylvania. It lies near Crooked Creek and to the west of Shelocta.
Commissioned initially in 1967 and expanded the following year, the station has seen several modernization efforts aimed at lowering emissions, particularly targeting nitrogen oxides and sulfur oxides.
Due to a newly implemented wastewater regulation prohibiting coal-fired plants from releasing mercury, arsenic, and selenium into water bodies, the plant is planned to cease operations by December 31, 2028. This mandate impacts Keystone as well as the Conemaugh Generating Station and more than twenty other facilities across fourteen states.
Technical specifications
The Keystone facility consists of two steam turbines brought online in 1967 and 1968, complemented by four cooling towers. Each turbine is powered by steam from paired 850 MW boilers that burn over four million tons of coal annually. The plant is recognized for its high operational availability among U.S. coal stations.
Both units utilize Westinghouse cross-compound dual steam turbine-generators functioning under supercritical steam parameters. At the time of their installation, Units 1 and 2 were the world's largest power generation units. Keystone was notable for being located away from major natural cooling water sources; instead, the Keystone Reservoir was constructed on Plum Creek to provide consistent cooling water throughout the year. Its cooling tower system was an early major environmental measure addressing thermal discharge concerns.
The steam generators yield approximately seven million pounds of steam per hour at pressures of 3,800 psi and temperatures reaching 1,005°F with a single reheating stage. Boiler feedwater pumps include one powered by a dedicated steam turbine and another driven through a low-pressure turbine-generator coupled with a fluid coupling for precise flow regulation. An auxiliary boiler supplies startup steam independently to reduce reliance on grid electricity during startup. The supercritical boiler design incorporates a recirculation loop that improves water circulation around the lower furnace walls during startup, enhancing component protection and fuel efficiency.
Environmental mitigation technologies have been progressively installed: electrostatic precipitators upgraded with ammonia-based flue gas conditioning; low-NOx burner systems; Selective Catalytic Reduction (SCR) units that decrease nitrogen oxide emissions; and a wet flue-gas desulfurization system introduced in 2009 to reduce sulfur dioxide and heavy metal pollutants. Continuous emissions monitoring ensures compliance with Pennsylvania’s strict environmental regulations.
Ownership is shared among several Mid-Atlantic energy companies. PSEG Fossil holds a 22.84% share (equivalent to 391 net MW including peaker capacity), while Reliant Resources manages plant operations. Keystone shares many design similarities with the nearby Conemaugh Generating Station, which is also partially owned by PSEG Fossil.
Key Details: Location: Shelocta, Pennsylvania Capacity: 1,711 MW Fuel Source: Coal Operational Since: Unit 1 (1967), Unit 2 (1968) Ownership Stake: PSEG Fossil – 22.84%
Owners
(partial list accounting for 78.26% ownership)
- Public Service Enterprise Group: 22.84% (391 MW)
- ArcLight Capital Partners: 20.91% (358 MW)
- Reliant Energy (operator): 16% (274 MW)
- PPL Montour LLC: 12.34% (211 MW)
- NRG Energy: 3.7% (63 MW)
- Duquesne Light Holdings: 2.47% (42.3 MW), previously held by Atlantic City Electric
Emissions
In 2009, Keystone implemented a wet limestone scrubber system aimed at minimizing emissions of heavy metals and sulfur dioxide. Although selective catalytic reduction (SCR) technology had been operational since 2003 to reduce nitrogen oxides (NOx), its use during the ozone season (May–September) was considerably restricted after 2010. As a result, NOx emissions increased by roughly 9,000 tons per season in 2011 and 2012 compared to the reductions achievable with full SCR utilization.
With the introduction of Pennsylvania’s Reasonably Available Control Technology regulation (RACT 2) in 2017, which imposed more rigorous emission limits, NOx emissions dropped by 79% relative to the peak restriction year of 2011.