EME Homer City Generating, L.P. - Executive Summary |
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EME Homer City Generation L.P. Homer City, PA Risk Management Plan: Executive Summary EME Homer City Generation L.P. operates a coal-fired power plant in Homer City, Pennsylvania, that is subject to U.S. Environmental Protection Agency (U.S. EPA) regulations governing Accidental Release Prevention (ARP) Requirements: Risk Management Programs under Section 112(r) of the Clean Air Act (40 CFR Part 68). This Risk Management Plan (RMPlan) has been developed in accordance with the requirements specified under 40 CFR Part 68, Subpart G. 1.0 ACCIDENTAL PREVENTION AND EMERGENCY RESPONSE POLICY 1.1 Edison Mission Energy Policy on the Environment, Accident Prevention and Emergency Response Edison Mission Energy (EME) is committed to full compliance and adherence with all applicable laws and regulations regarding environmental protection, accident prevention and emergency response and the integration of sound environmental practices into business decisions. To advance this policy, we will: * Ensure that environmental requirements are routinely assessed and incorporated throughout our business development process. * Seek opportunities to establish programs to achieve continuous improvement of our environmental performance. * Periodically review operations to confirm compliance and adherence with environmental requirements and identify opportunities where technically and economically feasible that will 1) reduce risk liabilities, 2) reduce potential environmental impacts, and 3) improve environmental practices. * Anticipate and respond to community interests and concerns about the actual and potential impact of our operations on safety and the environment. * Establish and maintain positive, constructive working relationships with regulators and public policy makers. * Design, build, and maintain facilities to ensure that they can be operated in an environmentally sound and safe manner so as to minimize the risk of exposure to employees and the public at large to hazardous materials and in conformity with all governmental regulations and corporate guidelines. * Maintain a safety and security plan, provide safety training and enforce a safety and security policy. * Establish policies and procedures that reconfirm the importance of health and safety and safe operation of EME facilities. * Develop programs and systems for identifying and abating potential hazards in the workplace, educate employees about hazards, and train employees on how to prevent accidental releases and avoid hazards. * Coordinate its safety and emergency response program with local community emergency response officials to insure safe, effective, and swift response to emergencies in the workplace. This includes forthrightly disclosing to the community, through its emergency response officials, facts regarding the hazards and risks in operating the facilities, the prevention techniques in place, and assistance in devising the most appropriate and effective protection plans f or the community and the plant. * Ensure that EME's environmental and safety policies are adequately communicated and that all employees are aware of the essential need for sustaining the environment and of their responsibility to support and contribute to EME's compliance efforts. * Establish programs and systems to facilitate compliance with this policy by employees as well as EME contractors. * All EME facilities shall have written programs that addresses the facility's response to emergencies and shall include: Personnel notification and reporting responsibilities; All emergency notification components required by government regulation and EME policy; Drills that include a notification and reporting component coordinated with local agencies (police, fire, hospital, environmental); Current phone numbers of resources required for internal and governmental notifications and a training program for emergency response team members that includes a notification and reporting component . 1.2 Risk Management System EME Homer City Generation L. P. has developed a management system to implement and maintain compliance with the Accidental Release Prevention (ARP) and related Process Safety Management and emergency response programs. This management system identifies lines of responsibility for the entire program and each of its key elements. During an emergency situation, communications with and assistance from the EME Homer City Generation L. P. organization may be required. Table 1-1 identifies the key positions within the EME corporate structure that will provide this support. The Director of the Generating Station and the Environmental Health & Safety Manager will provide overall guidance and recommendations in support of Process Safety Management Program and emergency response support personnel. Table 1-1 Risk Management System Organization Accidental Release Prevention Program (40 CFR (68)) o Station Director o Environmental Health & Safety (EH&S) Manager Off-Site Hazard Assessment o RMPlan: E H & S Manager o LEPC: Indiana County Emergency Management Agency PSM Program o Plant Administrative Manager o Manager, Plant Operations o Manager, Plant Maintenance o E H & S Engineer Emergency Response Program o Station Director o Manager, Plant Operations o E H & S Manager 2.0 PROCESS AND SUBSTANCE SUBJECT TO 40 CFR PART 68 The Homer City generating station includes three coal-fired electrical generating units with a total capacity of 1,884 megawatts. An air pollution control project has been undertaken to install Selective Catalytic Reduction (SCR) for oxides of nitrogen (NOx) control. The SCR system will be capable of reducing NOx emissions by approximately 6,000 tons per year during the ozone season (May through September). This NOx reduction will provide a substantial benefit to the ambient air quality in terms of reduced ground level ozone concentrations. An integral part of the SCR system is th e storage and transfer of anhydrous ammonia used as a reagent that reduces NOx emissions. Anhydrous ammonia is regulated under U.S. EPA's Accident Release Prevention Program (40 CFR Part 68). Because anhydrous ammonia will be present in the SCR process in quantities well in excess of the 10,000 lb. threshold, the SCR process is subject to ARP regulations. The Homer City generating station already utilizes relatively small quantities of anhydrous ammonia in the electrostatic precipitators (ESP) to enhance the control of particulate matter. However, because 1) less than 10,000 lbs. of ammonia is present in the ESP process at any time, 2) the ESP process is not connected to the SCR process, and 3) ESP ammonia storage is separated from SCR storage by nearly 500 ft, the ESP process is not subject to the risk management regulation. Even though it is not subject to regulation, EME Homer City Generation L. P. has taken steps to ensure the safe handling and use of ammonia in the ESP area. Anhydrous ammonia is a colorless liquid or gas which is readily detectable by its extremely pungent odor. In sufficient concentrations, anhydrous ammonia is an eye, skin, and/or inhalation irritant. For this reason, anhydrous ammonia is regulated under the Occupational Safety and Health Administration (OSHA) Process Safety Management Standard at 29 CFR Part 1910.119 and the U.S. EPA risk management rule at 40 CFR Part 68. For ammonia processes, the threshold quantity for coverage under 40 CFR Part 68 is 10,000 lbs. Anhydrous ammonia is delivered to the site via tank truck and stored above-ground in three horizontally oriented cylindrical pressure vessels, with a combined storage capacity of 663,000 lbs. Shipping and transfer of ammonia to the pressure vessels is carried out by trained qualified personnel provided by the vendor, using standard operating procedures that have been thoroughly reviewed for safety. The unloading process is monitored from the boiler control rooms an d plant security facility via video cameras. The procedures minimize routine release of residual ammonia in the transfer hose by purging ammonia from the transfer hose back into the transport trailer. Ammonia is pumped from the storage area to the SCR area where it is vaporized, mixed with heated air and injected into the flue gas, which is then immediately passed through a catalyst material. The reaction in the presence of the catalyst reduces the nitrogen oxide (NOx) and ammonia (NH3) mixture to nitrogen (N2) and water vapor (H2O) . The U.S. EPA Risk Management Regulation identifies three levels of requirements for industrial processes. Program 1 can be applied to any process which has not had a "significant" release of a regulated substance over the five year period prior to the RMPlan submittal date and for which the worst-case release does not affect "public receptors" (e.g., residences, parks and recreation areas, commercial/industrial facilities, hospitals). Given that th e SCR process contains substantial quantities of ammonia that if released could affect public receptors, it does not qualify for Program 1. Program 2 applies to any process that is ineligible for Program 1 and is not subject to Program 3. Program 3 applies to processes, such as those present at the Homer City facility, that are subject to the OSHA PSM. Because the accident prevention elements of Program 3 are virtually identical to PSM, compliance with U.S. EPA Risk Management regulations also constitute compliance with PSM. 3.0 RELEASE SCENARIOS For the purposes of developing and maintaining adequate RMPlans, the U.S. EPA has defined in its governing rules and guidance a series of modeling methods and assumptions which are to be utilized as administrative guides for planning purposes. In order to standardize and simplify to a practical level the many factors that can potentially occur in an accidental release situation, some of these assumptions may not take into account the a vailable preventive measures or mitigation methods that would diminish or even eliminate the implied risks that are suggested by "worst-case" analyses. For that reason, both the results for the standardized "worst-case" defined by the U.S. EPA methods and an alternative case, which is considered by EME Homer City Generation L. P. to more realistically represent situations that may possibly, but rarely, occur within the lifetime of the facility, are presented and described. As noted, the EME Homer City Generation Station already uses anhydrous ammonia in the ESP. No accidental release of ammonia has resulted in reportable on-site injury, off-site injury, emergency response, or damage to property or the environment. To ensure that mitigation measures and emergency response plans are appropriate, potential release scenarios are considered. Thus, the sections of the RMPlan which discuss both the worst-case and the alternative case, believed to be somewhat more probable, are meant t o provide the data necessary to develop and evaluate possible improvements in the overall safety provided by the programs which constitute the EME Homer City ARP program. 3.1 Worst-Case Release As defined by 40 CFR Part 68, a worst-case release of a gas liquefied under pressure is a 10-minute ground-level release of the entire tank contents, taking into account passive and administrative controls that limit the maximum quantity. The worst-case release scenario for the Homer City facility is a gaseous release from the anhydrous ammonia storage tank dispersed under stable meteorological conditions (see Section 3.1.1, below). The worst-case scenario involves a quantity of 221,000 lbs. of liquefied ammonia stored under pressure. This corresponds to maximum volume of liquid ammonia that is expected to be present in the tank at any time. The amount of liquid ammonia in a tank is slightly less than the volume of the tank because procedures and safeguards are in place to ensure that t he ammonia storage tank is never filled to its total volume to allow for the volumetric expansion of ammonia. Administrative procedures and controls limit the quantity of ammonia in each tank. The standard operating procedure and alarms are set to allow the tank to be filled to no more than approximately 85% by volume. 3.1.1 Dispersion Conditions Meteorologists have defined six "atmospheric stability classes," A through F, each representing a decreasing degree of turbulence in the atmosphere. The most turbulent condition is stability A, which is associated with light winds and very strong solar heating. Stabilities B and C are characterized by progressively weaker solar heating and stronger winds. Neutral, or D, stability occurs when winds are strong or when the sky is overcast. At night the earth's surface cools, causing the lower atmosphere to stabilize and become less turbulent. Stability E (moderately stable) corresponds to partly cloudy conditions with moderate winds. S tability class F (very stable) represents a very low level of turbulence due to overnight radiational cooling and weak winds. U.S. EPA requires that worst-case analyses be conducted using stability class F and 1.5 m/sec wind speed. Analysis of meteorological data collected by the National Weather Service at Pittsburgh International Airport indicates that these dispersion conditions commonly occur at night during fair weather. To describe aerodynamic surface roughness for modeling purposes, U.S. EPA's regulation establishes two roughness categories based on land-use in the vicinity of the process. "Urban" surface roughness indicates areas where there are many obstacles to the flow, such as industrial buildings or trees. "Rural" indicates that there are no large buildings in the area and the terrain is generally flat and unobstructed. By this definition, the vicinity of the SCR process at the Homer City facility with its large buildings, stacks, coal piles and cooling towers is cla ssified as urban for purposes of modeling an accidental release. 3.1.2 Interpretation The risk management rule dictates that pressurized gases must be assumed to be released in the vapor state, regardless of whether an actual release would be in the gaseous or liquefied form. Thus, while the dike under the anhydrous ammonia tank provides mitigation, it cannot be considered to have an effect on the worst-case release rate. There are virtually no hypothetical events short of a sudden tank rupture that could result in a release of the entire contents of an ammonia pressure vessel in only 10 minutes. The possibility of a worst-case type of scenario is extremely remote and virtually prohibited, given the design of the ammonia storage system and inspection and maintenance measures that EME has taken as part of its accident prevention program. Even if such an event were to occur, only a fraction of the pressurized liquid ammonia would be released directly to the air as a gas because the liquid ammonia would be cooled by the loss of heat needed for vaporization to below its boiling point and would be contained in the dike, where it would be released to the air over a period of time. The dike would therefore substantially reduce the rate of release to the air and associated off-site migration of high concentrations. The dike would also isolate a liquefied ammonia release from the sewer lines to the wastewater treatment system and serve to protect any nearby workers from exposure. 3.1.3 Modeling Method Worst-case dispersion modeling to determine the distance to toxic endpoint was conducted using the U.S. EPA's RMP*COMP (Version 1.06) software. RMP*COMP implements the consequence analysis calculations set forth in the U.S. EPA's Off-site Consequence Analysis Guidance (OCAG). The toxic endpoint chosen by the U.S. EPA for ammonia is 200 parts per million (ppm). This level is the Emergency Response Planning Guideline, Level 2 (ERPG-2), which was developed by the American Industrial Hygiene Association. An ERPG-2 is "the maximum airborne concentration below which it is believed that nearly all individuals could be exposed for up to 1 hr without experiencing or developing irreversible or other serious health effects, or symptoms which could impair an individual's ability to take protective action." Within the toxic endpoint zone for ammonia, the outdoor concentration at a stationary receptor, averaged over 10 minutes, could exceed 200 ppm. Because this exposure level assumes a stationary receptor, it does not account for evasive or protective action. Actions that could reduce or eliminate exposure to ammonia include avoiding the plume transport path, relocating beyond the planning zone, or seeking shelter in a building. 3.1.4 Public and Environmental Receptors The worst-case endpoint distance extends substantially beyond the facility property including residences, public recreation areas, schools and commercial areas as well as sta te game lands. 3.2 Alternative Release for Anhydrous Ammonia The alternative release examined for anhydrous ammonia corresponds to a hose rupture or coupling failure occurring during transfer from a tanker truck. Liquefied ammonia from the leak could potentially spill into a secondary containment area outside of the tank dike area. The ammonia release rate has been estimated to be equal to the normal transfer rate of 400 lbs./min lasting for 10 minutes. According to the U.S. EPA's OCAG, this corresponds to a rupture of approximately 0.5 inches in diameter. Release of liquefied gas to the air was conservatively assumed to be at the same rate as the spill because the portion that does not initially flash to a gas upon release would rapidly spread out into a shallow pool until the spill rate equaled the evaporation rate. The spill is assumed to continue for 10 minutes before the truck operator or EME Homer City personnel are able to activate the transport trailer remote emergenc y shut-off valve. A complete break of the unloading hose was also examined as a possible alternative release scenario. A break of this type would result in a large pressure change in the ammonia delivery hose and a greater initial ammonia release rate. An emergency check valve located on the tanker truck is designed to sense the change in pressure due to this type of break and immediately shut down the flow of ammonia. The resulting ammonia spill would be limited to the amount of ammonia contained in the hose. Because the resulting distance to toxic endpoint is expected to be much smaller than the endpoint for the alternative release scenario discussed above, this release is not reported in the RMPlan. 3.2.1 Dispersion Conditions U.S. EPA suggests that alternative release scenarios be analyzed using typical meteorological conditions of D stability, and a wind speed of 3 m/sec. Stability Class D represents conditions of neutral stability, or moderate atmospheric turbulence. A temperature of 77 degrees F and relative humidity of 50 percent were also used in accordance with the OCAG. Climatological data for Pittsburgh, PA indicate that these conditions are typical, with winds predominantly from the west. 3.2.2 Interpretation Alternative releases are intended to represent releases that generally have a greater likelihood than the worst-case release and that occur during typical rather than worst-case meteorological conditions. Unlike the worst-case release, alternative releases can account for both passive and active mitigation systems. In accordance with U.S. EPA Guidance, the alternative release does not necessarily represent the type of release that the PSM hazard analysis and/or accident history indicate is the most likely to occur, but rather a release that is somewhat more likely than the worst-case release and that generally still has the potential to affect off-site receptors. 3.2.3 Modeling Method Alternative dispersion modeling to determ ine the distance to toxic endpoint was conducted using the U.S. EPA's RMP*COMP (Version 1.06) software. As discussed in Section 3.1.1, the modeling was performed using urban surface roughness. 3.2.4 Public and Environmental Receptors The resulting endpoint distance extends off-site a small distance, encompassing a portion of a local roadway and reaching a nearby business. There are no residences, public recreation areas or environmental receptors within the endpoint distance from the unloading area. 4.0 ACCIDENT PREVENTION The processes subject to the Risk Management Regulation are also subject to the OSHA PSM Standard with which the EME Homer City facility is in compliance. PSM governs the same processes and regulated substances at the site that are subject to 40 CFR Part 68. EME Homer City has in-place specific operational programs to address PSM/RMP Prevention Program requirements. These include: * Process Safety Information * Process Hazards Analysis * Standard Operat ing Procedures * Training Programs for Operators and Risk Management Training for all Employees * Mechanical Integrity and Preventive Maintenance Program * Management of Change Program * Pre-startup Review Procedures * Incident Investigation and Follow-up Procedures * Safety Procedures for Contractors * Employee Participation Program * Hot Work Permits In addition to these programs, EME Homer City has designed and constructed the SCR system to meet stringent safety requirements. These include: * Continuous surveillance of tank truck unloading * Pressure relief devices to prevent catastrophic failure of lines and tanks * Alarms and interlocks to prevent operations outside of operating limits * Ammonia detection systems * Fogging nozzles at the outlets on the pressure vessels * Special liquid and vapor hose fittings to eliminate misconnection during unloading * System to eliminate fugitive emissions during unloading 5.0 FIVE-YEAR ACCIDENT HISTORY Since the SCR process has yet to start its operation there is no accident history to report. In conjunction with the current ARP and PSM programs in place at the EME Homer City facility, there is a standard management practice that requires immediate internal reporting of unusual events, including those in which any abnormal emission of regulated chemicals is observed or suspected. The incident information is reviewed by supervisory staff and a determination is made as to whether a reportable quantity on any chemical listed as requiring reports to regulatory authorities is involved. If so, the appropriate authorities are promptly notified. 6.0 EMERGENCY RESPONSE PROGRAM It is the policy of the EME Homer City to place the highest priority on employee safety and health and on protection of the community from all plant-induced environmental conditions. Experience has shown that proper planning and an organized approach will reduce the effects of emergency events. Prompt internal and external communications, emergency equipment, and trained personnel are the key ingredients of this plan. EME Homer City's policy provides for external communications with local and county-wide response agencies. The Indiana County HAZMAT Team has the lead responsibility in responding to major releases of ammonia that would have the potential to affect off-site locations. 7.0 PLANNED CHANGES TO IMPROVE SAFETY EME Homer City, under the recent RMP program, as well as its existing PSM and earlier Superfund Amendments and Reauthorization Act (SARA) Title III Community Right-to-Know Act compliance programs, has organized its management system to effectively address hazards and potential risks. Both the advanced planning aspects of process design, operating procedures, emergency preparedness, and the operational elements of system maintenance, safe operating practices and ongoing personnel training are necessary to support a continual improvement in facility safety. These programs are all documented so tha t needed information about the safe handling of all chemicals present at the facility is continuously available to employees. |