Analysis of Bonneville Power Administration's Estimate To Bury Segments of Transmission Line in Montana

EMD-82-80: Published: May 7, 1982. Publicly Released: Jun 7, 1982.

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GAO was requested to review the Bonneville Power Administration's (BPA) cost estimates to bury segments of high voltage transmission lines in Montana. Specifically, GAO was asked to: (1) evaluate the validity of the BPA cost data for burying portions of a "twin" 500 KV transmission line; and (2) analyze the general engineering reliability and safety considerations of burying such lines.

GAO found that the BPA estimates of $7.1 to $7.4 million per mile to bury the transmission lines are reasonable. However, because this type of installation is not common, uncertainties exist which could make the actual costs higher or lower. For this reason, little is known about the engineering, reliability, and safety considerations of underground installation for lines of this size.

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    Priority Open Recommendations:

    Department of Energy
    GAO-20-285PR: Published: Apr 22, 2020. Publicly Released: Apr 29, 2020.

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