WECC rating process for TWE Project advances to Phase 2 status

Feb. 2, 2010 – WECC (Western Electricity Coordinating Council) has granted Phase 2 status to the TransWest Express Transmission Project, moving the 600kV project forward in the regional planning and rating process.

The Phase 2 confirmation supports a Planned Rating of 3,000 megawatts, the largest power line size in the West. The TWE Project is a high-voltage, direct-current transmission line that will connect to the existing WECC transmission grid in south-central Wyoming and southeastern Nevada. It is primarily designed to deliver Wyoming wind energy to markets in Arizona, California and Nevada. The proposed in-service date is late 2014-2015.

According to WECC, Phase 2 encompasses a review of the project’s plan of service by a Project Review Group of WECC members. During this phase, the  Planned Rating is validated and the impact of the project on neighboring transmission systems further assessed. The project sponsor and the Project Review Group must document all the studies and findings in a report called Project Review Group Phase 2 Rating Report. Phase 2 will be completed when the Phase 2 Rating Report is accepted and the project is granted an "Accepted Rating."

The three-phase WECC rating process ensures that new projects are properly integrated into the existing transmission grid to enhance the overall reliability of the grid.

WECC rating process milestones for the TWE Project include:

• Jan. 11, 2008: National Grid initiates the WECC Project Rating Process.
• Aug. 25, 2008: National Grid notifies WECC that TransWest Express LLC, an affiliate of The Anschutz Corporation, acquired the TWE Project and assumes responsibility for project development.
• April 21, 2009: TWE LLC notifies WECC's Planning Coordination Committee and Technical Studies Subcommittee that it is proceeding with Phase 1 of the Rating Process.
• Oct. 5, 2009: TWE LLC submits its Phase 1 Comprehensive Progress Report to PCC and TSS, which addresses all requirements to complete Phase 1.
• Oct. 19, 2009: TWE LLC holds a meeting/webinar to present the Progress Report; comments received by Dec. 4 are incorporated or will be addressed during Phase 2.
• Dec. 21, 2009: TWE LLC provides system modeling data for the TWE Project to WECC.
• Feb. 2, 2010: WECC grants Phase 2 status.

WECC regional planning process milestones for the TWE Project include:

• Sept. 7, 2007: National Grid initiates the WECC Regional Planning Review Process.
• March 28, 2008: National Grid submits the draft Regional Planning Project Report to WECC's Planning Coordination Committee and Technical Studies Subcommittee.
• June 3, 2008: WECC accepts the final Regional Planning Project Report.

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