Keystone Generating Station
The Keystone Generating Station is a coal-fired electric generating plant located near the town of Shelocta, Pennsylvania. Owned by a consortium of power companies in the eastern part of the country, the facility is operated by RRI Energy Inc. The power station has a nameplate total of over 1,700 megawatts of electricity, and consists of two very large boiler units that are noted for their large (14-stories tall) cooling towers.
Keystone Generating Station began operations in 1967, using coal from nearby mines as well as brought in from more distant sources. The boiler units are cross-compound dual steam in design, and each has a twin set of cooling towers. At the time the plant opened and for some months afterward, these were the two largest such boiler units in the world. Built at some distance from a major water supply, Keystone was designed to use water tapped from the distant Crooked Creek, and a large reservoir was constructed on the site to allow for adequate cooling. This design was welcomed with accolades from environmentalists and others who sought to reduce the dangers of thermal pollution in rivers and streams; the water at Keystone Generating Station cools gradually in the reservoir and no running creeks or major watershed is affected.
Several other environmental concerns have also been addressed over the years at the power station. An ammonia flue gas conditioning system was installed to help with the efficiency of the electrostatic precipitators and a nitrous oxide burner mechanism was added to reduce or entirely scrub the oxygen from nitrogen emissions. A modern wet lime scrubber system was installed in 2009 that removes a majority of heavy metals from the flue emissions.
Asbestos was used at many power plants prior to the 1980s. For nearly a century, asbestos had been the preferred material as a heat shield and general flame retardant. Asbestos is naturally occurring and is a silicate compound that breaks easily into tiny fibers. Protective clothing for workers, ceiling tiles, and steam pipe wraps were often made with asbestos; this provided excellent shielding from extreme temperatures. Entire walls made from asbestos mixed with drywall were regularly constructed near steam boilers at plants such as the Keystone Generating Station.
Eventually the public became aware that asbestos fibers, which are easily inhaled by plant workers, have been linked to a number of diseases including asbestosis and various cancers. Mesothelioma is rarer but usually fatal; it is caused almost exclusively by long-term exposure to asbestos. Most buildings in the United States have long since been asbestos-free but past workers at plants like the Keystone Generating Station may have inhaled loose asbestos fibers in decades past and do not yet show symptoms of illness.