HC Deb 06 May 1957 vol 569 cc38-9W
26. Mr. Nabarro

asked the Paymaster-General the comparative costs of laying main transmission and main distribution lines for electricity underground as compared with the costs of placing them overhead.

Mr. Maudling:

The figures are given below. Generally speaking underground lines cost from four to eight times as much as overhead but the difference would be much greater in the case of the super-grid.

The following is the information:

COMPARATIVE COSTS OF PLACING OVERHEAD LINES AND LAYING UNDERGROUND CABLES
Type of main (1) Overhead costs per mile (see below) (2) Underground cable cost per mile (3)
£ £
(a) 275 kV standard super-grid … … … … 25,000 300,000–400,000
(b) 132 kV standard grid line … … … … 10,000 50 000– 80 000
(c) 33 kV … … … … 2,000–3,000 10,000– 15,000
(d)11 kV … … … … 800–1,900 3,000— 9,000
Note:
(i) Costs vary according to the sizes of conductors and types of construction used. Underground cable laying costs are particularly affected by different local conditions. In the case of the super-grid where the cost shown is an estimate, undergrounding would also present serious technical problems.
(ii) Substation costs are not included.