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Buried electricity cables ‘4.5 times more expensive than overhead lines’

29 Apr 2025 4 minute read
Photo Gareth Fuller/PA Wire

Underground electricity cables are on average 4.5 times more expensive than overhead lines, an independent group of experts has found.

The report, overseen by the Institution of Engineering and Technology (IET), explored the cost of the different technologies that may be deployed to transport electricity across Britain in the next decade, such as underground cables, subsea cables, overhead lines carried by different types of pylons and emerging technologies.

The country needs to roll out thousands of miles of new cables in the coming years to meet growing demand, upgrade ageing lines and decarbonise the electricity grid as part of efforts to tackle climate change.

But public opposition to new overhead lines and pylons is strong, especially among potentially affected communities, with many campaigning for the transmission network to be buried underground.

Cost ratio

The group of experts behind the report, released on Tuesday, found that the cost ratio comparing overhead lines and underground lines has not changed significantly since a similar IET report published in 2012.

Underground cables were found to be on average around 4.5 times more expensive than overhead lines and undersea cables were found to be on average five times more expensive than overhead lines.

Amid recent debates over the comparative expense, Professor Keith Bell, from the University of Strathclyde, said the team aimed “to get some objective truths on the costs and what’s really involved”.

“There’s a lot of people campaigning for the transmission network to be undergrounded,” he said.

“What we’re trying to do in this report is to provide some truth actually around what the cost is of undergrounding but also… to shine a light on the range of impacts.”

Environmental impact

As such, the researchers looked into other “non-cost” factors of different options, such as environmental impact, carbon impact and local impact on communities – and how these may differ during construction versus operation and maintenance.

Even with evolving technology, the team said all of the options still come with downsides and trade-offs.

For example, while underground cables have a lower visual impact than overhead lines, they can cost more and have their own adverse environmental impacts, especially during construction.

Meanwhile, the development of transmission capacity using subsea cables off Britain’s coast might reduce the need for either onshore overhead lines or underground cables but would also have cost and environmental impacts.

Andrew Lovett, professor of geography at the University of East Anglia, said the team has tried to provide “as authoritative of a statement as we can of the average relative cost between different technologies”.

Specifics

But he added that costs and benefits depend heavily on the specifics of individual transmission projects, their locations, and their desired outcomes.

“If you’re thinking about the options to select in particular circumstances, you’ve got to think about the cost, you’ve got to think about the various non-cost factors as well,” Prof Lovett said.

“What you might do in one set of circumstances and one location is not necessarily what would be the best choice in another set of circumstances but we tried in this report to set out what those different sorts of characteristics are now.”

Energy specialist Katherine Jackson, who is a project board member for the report, said the paper is also not intended to be used to make choices over individual projects but instead act as an independent source of information that can provide “a detailed evidence base” for those weighing up the best options.

“It’s to inform the public and individuals and Government and to help inform the decision-making that goes on,” she said.

From their research, the experts also found “major supply chain bottlenecks” that could affect the rollout of new transmission infrastructure, particularly with cables.

The main manufacturers reported that their order books are full and they have difficulties keeping up with delivery timescales on existing contracts.

“The ratios and relative comparisons are broadly in line with what we would have expected,” David Reid, global practice leader for integrated electricity networks at Mott MacDonald, said.

“But the extent of the pressure on the supply chain is very clear as a result of the work that needs to be done.”


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Jeff
Jeff
15 days ago

Gotta wonder at the origin of the complaints.

Gareth Cemlyn Jones
Gareth Cemlyn Jones
15 days ago

There are other factors to be considered other than the relative cost difference between undergrounding and pylons There are social impacts and effects on the well being of the communities to be considered. The impact on property values and potential health effects of overhead power lines also needs to be taken into account. Pylons are a 20th century solution which is still being rolled out as the preferred option despite technological advances which allows other options to be utilised.

PeterC
PeterC
15 days ago

What is not clear from this article is are the costs the initial installation costs or the lifetime costs.

Baxter
Baxter
15 days ago

And buried cables are cheaper than no cables.

Baxter
Baxter
14 days ago
Reply to  Baxter

For anyone confused by this comment, they’re losing money by not being able to move the electricity that needs moving. Of course they want to do it as cheaply as possible but a more expensive option is better than no option. Less profit is better than no profit.

Dai Ponty
Dai Ponty
15 days ago

They would not put up with it in the Prosperous parts of England should why should Wales

John Young
John Young
15 days ago

I can’t stand this sort of thing. Why can we not have honesty up front. This group of ‘experts’ say it will cost as much as 4.5 times more to go underground. On Politics Live yesterday they interviewed a farmer from Landovery who was arguing that the cost was comparable. They can’t both be right and each was presumably using stats that suited their viewpoint. Now we’ll have enormous arguments to and fro and the truth will be hidden somewhere out of sight.

John
John
15 days ago
Reply to  John Young

Oh – Deary me!
The IET report (publicly available online by the way) was led by Prof. Keith Bell FRSE, FHEA, CEng, BEng (Hons), PhD, MIET  – one of the preeminent electrical engineers and smart grid experts in the UK. It had had membership from IET, industry consultants, Past presidents of the IET.
I saw ‘farmer from Llandovery’ on TV yesterday as well. The BBC should have called out his nonsense there and then. Same as the Brexit debate a few years back – we shouldn’t have people propagating unbacked nonsense like he did.

PeterC
PeterC
15 days ago
Reply to  John

Just because he is an expert does not mean he is right. He can (and probably is) subject to the same sorts of blind spots and prejudice as the rest of us. In fact, he is possibly so expert, that he takes certain things as given without questioning the relevance to a particular circumstance. Remember; the definition of an expert – “A has-been who spouts”.

John
John
15 days ago
Reply to  PeterC

Well firstly, it’s not a single expert, it’s a panel of experts. In addition, if you bothered to read the report, you’ll see the IET produced a 150 page report with data backing up their claims.
“Farmer from llandovery” doesn’t even back anything up with data, has no experience in electrical power distribution, and is allowed to spout whatever nonsense he wants – which should have been called out for the lie it was. He was an embarrassment to his cause

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