REGARDING you article on the National Grid pylon proposals, you quote the National Grid Project manager explaining that undersea cables do not carry enough power for this project and the undersea HVDC technology is not available.

REGARDING you article on the National Grid pylon proposals, you quote the National Grid Project manager explaining that undersea cables do not carry enough power for this project and the undersea HVDC technology is not available.

The Hinkley to Avonmouth cables are to carry 400kv. National Grid already has proposals, currently running two years ahead of these, to build a wind farm 30 miles off the north Devon coast with proposed cables of 500kv.

The National Grid report into off shore wind farms (http://www.thecrownestate.co.uk/round3_connection_study.pdf ) proposes/states the following:-

Extensive use of HVDC including in the Bristol Channel (P73)

That overhead power lines are currently planned at 800Kv, and non-overhead cables have a currently a restriction of 500kv (p21) due to cable insulation - the EDF Hinckley proposal is for just 400Kv.

Completion date for Hinckley C is 2017, well within time to meet supply of cable (p83).

In the ENSG report (Para 5.2.6) an Undersea HVDC is already proposed between Deeside and Hunterston with a target installation date of 2015. That means the Hinkley Point connection is likely to be two years behind initial use of undersea HVDC line by the national grid.

Regarding costs, the current proposals already plan for the use of five km of underground cabling over the Mendips on a sensitive part of the route. All this actually puts the costs of both routes (land and Bristol Channel) in the same area.

A spokesman has stated the offshore route was unsuitable due to dredging and the expansion of the deep sea terminal at Avonmouth. The Marine Fisheries Agency and The Environment Agency CPRE conclude if route considerations are taken into account then neither should be a problem.

MIKE BIRD

Goss Barton, Nailsea