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Because of their non-flammability, chemical stability and electrical insulating properties, polychlorinated biphenyls (PCBs) are used in a variety of commercial applications. There have long been concerns about health issues associated with PCBs and thus their manufacture was banned in 1979. Because the U.S. Environmental Protection Agency (EPA) authorized their continued use in certain enclosed applications, PCBs may still be present in older electrical equipment, such as transformers and capacitors.
Thirty years ago, EPA determined that the use of PCBs in electrical equipment as authorized under its regulations does not present an unreasonable risk of injury to human health or the environment. EPA has not provided any evidence that the toxicity of PCBs is greater than was thought at the time of the original use authorization. However, EPA is expected to issue a notice of proposed rulemaking in the fourth quarter of 2017 to reassess whether certain PCB use authorizations should be ended or phased out. This reassessment, related to liquid PCBs in equipment, will focus on large capacitors, transformers and other electrical equipment. A revised rule may amend the use authorizations for electrical equipment so that, by a yet-to-be-determined date-certain, “known” PCB and, potentially, PCB-contaminated transformers can no longer be used. EPA is also considering a phase-out date for other types of PCB electrical equipment.
PCBs can be found in some equipment on the Great River Energy system, such as transformers, capacitors and circuit breakers. While it is not known exactly what equipment and end date will be targeted, Great River Energy has been planning for the eventual PCB phase-out for some time. Great River Energy has a policy to remove equipment that is found to contain PCBs, however the full extent to which PCBs are present in equipment is not entirely known. Some equipment is untestable and cannot be identified without the potential to cause significant damage to PCB and non-PCB equipment. In many cases, the process required to identify whether PCBs are present would necessitate widespread service disruptions, create possible North American Electric Reliability Corporation (NERC) violations, damage or destroy equipment, and present real and immediate risk to worker safety. All PCB-containing equipment has been removed from Great River Energy’s high-voltage direct current system. All testable equipment containing PCBs has been removed from Great River Energy’s substations. The only other known pieces of PCB equipment are 103 transformers associated with electrostatic precipitators at Coal Creek Station; these transformers are scheduled to be removed during scheduled maintenance of the precipitators in 2019 and 2020.
Great River Energy continues to monitor the status of rule development.
June 12, 2017