Technical Data

This page is for historical interest only – SSE announced in January 2017 that this project is being wound down.

Undergrounding (why not put the line underground)?

National Grid data says that ‘under grounding’ is 10 times the cost of overhead cabling. And maintenance costs are higher that overground (reference needed to this data). [Our view is that the UK nationalised power distribution industry, one that has never been subject to normal commercial pressures and therefore not likely to be anywhere efficient, would say that wouldn’t they? This 400Kv technology is 50 years + old – we’ve gone to the moon and back and got computers since then – but this Grid technology is rooted in old and inefficient technology].

“For direct buried cables,  each cable needs to be well-spaced from others for good heat dissipation. To match overhead line thermal performance for a 400kV double circuit, as many as 12 separate cables in four separate trenches may be needed, resulting in a work area up to 65m wide”.  This extract from National Grid – “Undergrounding high voltage electricity transmission lines” (date needed).  [A 65m tranche of forest needs to be permanently cut down to route a 400 Kv line overhead line through it – so no difference there! In italics above is how the Grid want to confuse the issue by implying that ‘undergrounding’ is making a terribly wide gash – but it’s actually the same as their antique overhead technology.  Neanderthals!].