Polk Power Station - Executive Summary |
|
Tampa Electric Company (TEC) is an investor-owned electric utility which serves west-central Florida, primarily Hillsborough County and portions of Polk, Pasco, Pinellas, and Highlands Counties. In addition to other generating facilities, TEC owns and operates Polk Power Station, a nominal 260-megawatt electric generating facility located near Mulberry in southwest Polk County. The "Integrated Gasification Combined-Cycle" facility is a first-of-its-kind combination of two leading technologies. The first technology is called coal gasification which uses coal to create a clean-burning gas. The second technology is "combined cycle" which is the most efficient method of producing electricity commercially available today. The integration of these technologies allows TEC to couple the high efficiency of the combined cycle design with the low cost of coal for fuel. The gasification portion of the plant produces a clean coal gas which fuels a combustion turbine. Coal is combined with ox ygen in the gasifier to produce the gaseous fuel. The gas is then cleaned by a "gas cleanup" process. After cleaning the coal gas is used in the combustion turbine to produce electricity. The coal gas is a mixture of hydrogen and carbon monoxide at concentrations ranging from 65% to 85% by volume. The requirements of the chemical accident release prevention rule (40 CFR Part 68) apply to the hydrogen present in the gasification process. Under the threshold determination criteria, if a flammable substance is present in a process in a mixture in concentrations of greater than 1 percent by weight, the weight of the entire mixture is considered in determining the quantity of that particular flammable substance present in the process. The gasification process contains 646 pounds of hydrogen and 22,108 pounds of wet gas at any one time, or a hydrogen concentration of 3 percent by weight. Because the concentration of hydrogen is greater than 1 percent by weight, and because the 22,108 pound weight of the entire mixture is greater than the threshold trigger of 10,000 pounds, the gasification process is subject to the chemical accident prevention rule. An offsite consequence analysis was conducted for the gasification process to determine if the distance to the flammable endpoint for the worst-case release is less than the distance to any public receptor. This offsite consequence analysis was conducted using EPA's RMP Offsite Consequence Analysis Guidance document. Based on the EPA guidance document, the end point for a worst-case hydrogen vapor cloud explosion of the gasification process is no more than 0.3 mile from the gasifier. Because a circle of radius 0.3 mile centered on the gasifier is completely contained within TEC property, the offsite consequence analysis for a hydrogen release from the gasification process indicates that distance to the flammable endpoint for the worst-case release is less than the distance to any public receptor. On this basis, t he hydrogen in the gasification process is classified as Program 1 given that no accidental releases of hydrogen have occurred for the previous 5 years and that emergency response procedures have been coordinated between Polk Power Station and the local emergency response organization. Polk Power Station is committed to the safety to its employees and neighboring community. This commitment is based on established health and safety policies and procedures. These procedures are complemented by personnel training, safety drills, and facility inspections. A process safety management (PSM) program has been implemented at Polk Power Station which includes provisions for management of coal gas process hazards. The PSM program includes evaluations of process design, process technology, operational and maintenance activities and procedures, emergency preparedness plans and procedures, training programs, and other elements which impact the process. With a combination of appropriate safety design measures, preventative maintenance programs, and development and implementation of proper safety procedures, Polk Power Station manages the risk associated with coal gas handling at the facility. In the event of an emergency at the facility, emergency response has been coordinated with the local emergency response organization. In addition, Polk Power Station has established and implemented a PSM emergency response plan in the event of an accidental hazardous materials release, natural hazards, or other potential emergencies. The plan addresses potential emergencies identified by a facility-wide risk analysis conducted by a team of environmental professionals, health and safety specialists, and Polk Power Station personnel. The plan identifies specific responsibilities and procedures to be followed by all facility personnel following an accident or impending emergency to maximize employee and community safety. In summary, the offsite consequence analysis for a worst-case release of hydrogen, using EPA's OCA Guidance model, from the gasification process at Polk Power Station indicates that the distance to the flammable endpoint is completely contained within TEC property. In response to TEC's commitment to community and employee safety, risks associated with the process are managed by providing carefully established health and safety policies and procedures and implementation of process safety procedures. In the event of a release, emergency planning has been conducted and includes coordination with the local emergency response organization. |