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Research and analysis

Undergrounding transmission cables: study of costs of innovative methods

A study of innovative methods for undergrounding transmission cables with costs for two methods over distances of 20km and 50km.

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This research report, commissioned by DESNZ and carried out by Ramboll, examines innovative undergrounding methods and considers whether there is potential for them to reduce the costs for undergrounding high voltage transmission cables over distances of 20km and 50km by comparison with the conventional method of burial using ‘cut and cover’. The study also assesses aspects of cable technology that could influence undergrounding costs.

The report reviews innovative undergrounding methods and assesses the build costs for two methods (cable ploughing and horizontal directional drilling) for transmission voltages of 275 and 400 kilovolts in a rural location.

Updates to this page

Published 12 May 2026
Last updated 12 June 2026 Show all updates
  1. Published 'Undergrounding transmission cables: study of costs of innovative methods'.

  2. First published.

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