Plans for an £83M tunnel linking the island of Whalsay to the mainland of Shetland will be scrapped unless costs can be significantly reduced or a subsidy can be found by Shetland Island Council.
A report by the council’s head of finance Graham Johnston today went before its Special Infrastructure Committee, which stated that the prohibitive costs meant that the best value for money option would be to continue relying on the existing ferry service.
The council wants to build a 6.3km long drill and blast tunnel, which it had hoped would cost only £35M. However, a study by its Infrastructure Services Department has concluded that this would be “entirely unrealistic”.
It believes the tunnel would cost between £10,000 and £11,000 per metre based on a comparison with costs of tunnelling in Norway, which commonly uses drill and blast tunnelling and spends an average of £9,500 per metre on the technique.
This estimation puts the cost of building the Whalsay tunnel alone at between £64M and £70M. Connecting roads would cost an extra £8M with site investigations and design fees adding another £5M.
The scheme had been seen as a potential cost-effective alternative to the existing ferry link which is due to retire from service in five years.
It is the second low-cost tunnel being proposed to link mainland Shetland with outlying islands – a 1.2km drill and blast tunnel to link to the Isle of Bressay was estimated to cost as little as £34M (NCE 21 January).