Hermiston Generating Plant - Executive Summary |
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Hermiston Generating Plant is owned by Hermiston Generating Company, LP and PacifiCorp. Hermiston Generating Company, LP is a subsidiary of PG&E Generating, the competitive electric generation business of San Francisco-based PG&E Corporation. The facility is operated in strict accordance with stringent policies and protocols designed to protect the health and safety of our employees and neighbors, as well as the environment. Responsibility for safety and environmental performance at the plant is shared by every employee. This message is communicated through ongoing training programs designed to raise awareness and build necessary on-the-job skills. Performance in these areas is regularly evaluated through audits, assessments and other mechanisms, with the goal of measuring progress and identifying areas for continued improvement. As is the case for many facilities, Hermiston Generating Plant's participation in the RMP program is triggered by the use of only one substance (aqueous ammonia) on-site in quantities that exceed a threshold amount. At this and other PG&E Generating facilities, ammonia is a key ingredient in the facilities' air pollution control systems. In both the design and operation of our plants, among the most important priorities is the minimization of air emissions, including nitrogen oxides (NOx). Nitrogen oxides are a primary contributor to smog. The U.S. Environmental protection Agency and state regulators have identified NOx emission reductions as one of the most important keys to achieving national air quality improvement goals. In order to help achieve this objective, the Hermiston facility employs advanced emissions control technology that uses ammonia to reduce nitrogen oxides emissions. This technology enables the plant to achieve NOx emission rates that are among the lowest for any facility of its kind. Hermiston Generating Plant is pleased to share the information in this document. As the operators of this facility, PG&E Gen erating takes seriously its commitment to accident prevention and effective emergency response. While no industrial site is entirely free from risk, it is our goal, through continuous improvement, to manage risks as effectively as possible. This plan demonstrates that the company has the programs in place both to minimize the possibility of a release and to respond to one in the unlikely event that it occurs. The worst-case release scenario assumes that the contents of the ammonia storage tank is released in a ten minute period. The tank is surrounded by a dike that would contain the spill. The offsite release impact distance for a worst-case release is 0.1 miles. This distance was determined using EPA's "Risk management Program Guidance for Offsite Consequence Analysis". A worst-case release of the entire tank contents is very unlikely because the facility is staffed 24 hours/day and a leak would be identified and repaired in a timely manner. The facility was placed in commerc ial operation in July, 1996 and it is very unlikely that the tank would fail. Also, the dike around the tank makes the possibility of an accident that would puncture the tank very unlikely. The alternative release scenario is based on the failure of a fill line to the tank. It is estimated that the maximum amount of ammonia that would be released in this scenario would be 7,000 gallons (54,000 pounds). This release would result in an offsite impact area of 0.1 miles. This distance was determined using RMPComp. For either the worst-case or alternative release scenarios there are no schools, residences, hospitals, prisons/corrections facilities, or recreation areas inside of the offsite consequence area. There are no environmental receptors inside of the offsite consequence area. The neighboring industrial business is within the worst-case and alternative consequence area. There have been no accidents involving ammonia at this facility. The facility complies with all Federa l and State emergency response planning rules and guidelines. Employees are trained to identify spills and take immediate action to stop the leak and/or call for emergency assistance. Ammonia spill prevention steps include written operating procedures for tank filling and ammonia handling operations. The ammonia tank has gages and alarms to monitor tank pressure and level. The ammonia tank is diked and bermed to contain any leak that might occur. The existing ammonia storage system was put into commercial operation in July, 1996. It was designed with consideration for industry standards and regulatory requirements. The facility will review safety and operating procedures on an annual basis to identify potential improvements. |