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Overhead pylons still the cheapest

A cost study on installing new high-voltage transmission lines by the Institution of Engineering and Technology (IET) has showed they are still five times cheaper than burying the cables underground.

The research, carried out by engineering consultant Parsons Brinckerhoff and funded by power firm National Grid, show that the cost of installing overhead wires is between £2.2M to £4.2M per km, compared to an underground cable cost of between £10.2M to £24.1M per km.

However, the report focussed solely on the engineering costs, and not the human, environmental and planning costs.

The comparative cost between under-ground cables and overhead lines has been reduced from between 10 and 25 times more expensive, as previously estimated by National Grid, to between 4.7 and 5 times more expensive in the latest study.

The charity the Campaign to Protect Rural England (CPRE) said these findings “vindicate” its arguments questioning the previous costs estimates by National Grid. It is calling for increased use of under-ground power cables instead of overhead wires in National Parks and Areas of Outstanding Natural Beauty (AONBs).

“The company has no inherent preference between these different technologies, and issues such as the balance between cost and visual impactare ones that must ultimately be decided by society on a case by case basis through the planning process,” said a statement from the National Grid.

Many new high-voltage transmission lines are expected to be constructed across the country over the next decade to cater for electricity produced from offshore wind farms and new nuclear power stations.

Main findings are as follows

  1. The cost of new power infrastructure varies considerably but installing new power circuits underground is always more expensive than installing overhead lines
  2. The study also identifies factors that have an impact on costs - such as terrain, distances and energy loss
  3. The study’s remit purely relates to engineering costs, although it does acknowledge the aesthetic, human and environmental impacts, it makes no analysis of these areas

 

Readers' comments (3)

  • Michael Paul

    A shame that the study doesn't appear to consider the "whole lifecycle" costs. I would think that maintenance costs for overhead lines are higher than for buried ones, considering such things as storm damage, ice and snow etc. - and what about the effective service life? If overhead lines require replacement after a shorter life, then the difference in cost is further reduced.
    More information?

    Mike Paul, Stuttgart, Germany

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  • It's interesting to note that Tioga Pass in Yosemite Park is winterised in late October when it closes till the next May. This includes taking the roofs off some buildings and removing the lines from overhead powerlines. Presumably the cost of these measures is less than that of the repairs that would be needed if not done.
    Archie

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  • Though the visual importance and electromagnetic effect of overhead power transmission line matters a lot to the general public, nevertheless the cost of erecting an overhead power transmission line will be much less and lifetime maintenance much easier in particular for Extra High Voltage & multi-circuit power lines.

    Partha Bose, Kolkata, India

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