Pylons profit from new study

Research shows that it is five times more costly to have the power lines underground

Burying high-voltage electricity cables underground is 10 times more expensive than using overhead lines with pylons, a report has said.

The UK faces the prospect of hundreds of miles of new cables and hundreds more pylons across the countryside to connect new windfarms and nuclear power stations over the next decade.

Amid controversy over the use of overhead cables and pylons, which are typically 40 to 55m high, the Infrastructure Planning Commission requested a report into the costs of the different options for carrying electricity.

The independent study, by engineering consultancy Parsons Brinckerhoff, showed that over the lifetime of the infrastructure it was around five times more costly to have the power lines underground than overhead. Costs per kilometre to bury the cables in the ground run to between £10 million and £24 million for construction and maintenance, compared with £2.2 million to £4.2 million for overhead lines.

Putting the underground cables in tunnels was even more expensive, according to the report, which did not consider the environmental and social costs of the different technologies.

But the relative cost of burying cables has fallen since the 1960s when the construction of an underground system was estimated at 20 to 30 times more expensive than overhead cables.

Report author Mark Winfield said that laying the cables in trenches cuts a swathe across the countryside which “looks like a motorway” while it is being built.