The Largest U.S. Fossil Fuel Power Station, Located in Fort Bend County, Texas, Keeps Pace with Air Quality Environmental Regulations

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Researched by Industrialinfo.com (Industrial Information Resources, Incorporated; Houston, Texas). Texas Genco Holdings Incorporated (Houston, Texas), a new private wholesale energy producer, is keeping its W. A. Parish Power Station in Thompsons, Fort Bend County, Texas, in line with Clean Air Act environmental regulations through a series of plant retrofits to add necessary pollution control equipment. The W. A. Parish Station has been providing electrical generation for the greater Houston and Sugar Land area since 1958. W. A. Parish was originally owned by Houston Lighting & Power, which became Reliant Energy. When Reliant Energy split, W. A. Parish became part of the regulated utility, CenterPoint Energy. Due to deregulation, a new company, Texas Genco was formed, with CenterPoint owning 81%. Then in December 2004, Texas Genco was sold to a private investor group, becoming Texas Genco Holdings Incorporated. Today, the station has an operating capacity of 3,661 megawatts, making it the largest fossil fuel power plant in the country. The amount of electricity produced from the station has the capability of supplying over three million homes. It also incorporates a diverse fuel mix to make operations more economical and to meet varying load requirements.

Future plans include installing technology that should reduce mercury emissions 30% by 2010 and 70% by 2018. Studies currently underway at Texas Genco’s Limestone Electric Generating Station near Jewett in Limestone County, Texas, will determine future courses of action at the W. A. Parish station. Additional flue gas desulfurization (FGD) scrubbers for reducing sulfur dioxide (SO2) emissions, as well as additional nitrogen oxide (NOx) controls would be added if required.

The W. A. Parish plant includes four natural gas- and oil-fired steam turbine/generator sets (ST 1-4) and one natural gas-fired turbine/generator (GT-13). These five units came online between 1958 and 1968. The next four units constructed (ST 5-8) were coal-fired units, which came online between 1977 and 1982. To meet air quality issues, Texas Genco installed several emission reduction technologies, and now burns 36,000 tons per day of low-sulfur Powder River Basin (PRB) coal, which is railed in all the way from Wyoming. To meet NOx emission levels, the steam units have been installed with one or more of the following technologies: Overfired Air (OFA); Low-NOx Burners (LNB); Low Excess Air (LEA); Flue Gas Recirculation (FGR); Selective Catalytic Reduction (SCR) units; and Intelligent Sootblowers (ISB). W. A. Parish meets the SO2 emission regulations by using low-sulfur sub-bituminous coal on all four of the coal units, and Unit 8 has a FGD wet scrubber that reduces SO2 emissions by around 70-80%. W. A. Parish coal units use fabric filter baghouses (Units 5-7 originally had electrostatic precipitators, which were replaced in the 1980’s) to catch 99.8% of the particulate matter being emitted by the boilers. To insure that the emissions limits are met, the plant has continuous emissions monitoring systems (CEMS) on each steam unit, ascertaining that they remain below required levels.

W. A. Parish sits on a 4,650-acre site off Smithers Lake near the Brazos River and utilizes about 500 personnel to operate the station. Fuel requirements are met by a number of natural gas suppliers, and coal is delivered daily from Wyoming from three 115-car trains. W. A. Parish attempts to keep a 45-day coal stockpile reserve. The ash from the boilers and sludge from the scrubber are sold to manufacturers of construction materials, such as concrete, gypsum wallboard, and road paving material.

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