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California-Oregon Transmission Project

The California-Oregon Transmission Project (COTP) consists of 340-miles of 500-kV AC transmission line between Southern Oregon and Central California. From its northern end at the Bonneville Power Administration's Captain Jack Substation in Southern Oregon, the COTP continues south to the Western Area Power Administration's Tracy Substation and on towards the Tesla Substation owned and operated by Pacific Gas & Electric Company (PG&E).

Benefits of the COTP include:

  • Significant cost savings for Northern California electricity customers (between $50-$100 million annually)
  • Significant reduction in GHG emissions (approximately 2 million tons every year removing the equivalent of 300,000 cars from the road) through access to clean electric generation sources
  • Increased reliability of the overall electric grid to keep the lights on
  • Postponed development and acquisition of additional fossil-fueled generation in Northern California

The COTP was completed and became operational in March 1993. It is the "youngest" of the three major transmission lines that comprise the California-Oregon Intertie (COI) - the three major AC transmission lines that connect the electric systems of the Pacific Northwest to those in California. The two older Pacific AC Intertie lines became operational in the 1960s.

The COTP has a capacity of 1,600 megawatts, enough to provide power to more than one million homes at any given time. On a daily basis it serves electricity consumers throughout Central and Northern California.

One of the COTP's benefits is to provide California access to cheaper and cleaner energy supplies (e.g., hydroelectric and wind power from the Pacific Northwest). In doing so, it enables California-based energy providers to shift away from older, less efficient and less environmentally-friendly fossil fuel plants.

An important part of the COTP is its communication system. Essential to the operation of the COTP, it provides voice and data transmission for power flow monitoring, supervisory control and data acquisition (SCADA), relay protection, and remedial action. The system, comprised of both microwave radios and antennas and fiber optic technology, was designed with two geographically separate paths for increased reliability and availability during both scheduled and unplanned outages and to provide continuous operation during catastrophic events.

As the Project Manager for the COTP, TANC is responsible for day-to-day operation and maintenance of the line and facilities and upgrades to the line. Operations and maintenance services are contracted through the Western Area Power Administration (Western).

TANC is also responsible for maintaining a culture of compliance with local, state and federal regulatory obligations, examples of which are evident in TANCís Open Access Same-time Information System (OASIS) link on this website and TANCís Reliability Standards Compliance Program .



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