Question to the Department for Energy Security & Net Zero:

To ask His Majesty's Government what is the relative cost of installing National Grid electricity cables that are (1) suspended from pylons and (2) buried underground.

The relative costs of overhead lines and burying underground electricity cables are assessed by National Grid at a project-specific level, with costs varying depending on factors such as the terrain and other site conditions. The Institute of Engineering and Technology Study, 2012, found that the lifetime costs for overhead lines range from £2.2m to £4.2m per kilometre, while direct burial underground cables range from £10.2m to £24.1m per kilometre, meaning that undergrounding can cost between 5-10 times more than overhead lines.