United Kingdom

United Kingdom

Subsea transmission too expensive -- Minister seeks other solutions

A report into the feasibility of a sub-sea cable to connect renewable energy from the western seaboard of Britain into the electricity grid has concluded it would be too expensive. The cost of transmitting power over long distances is considerable -- and in some cases could even double the cost of electricity from renewables, says the report by consultants PB Power.

It goes on to recommend that renewable resources should be developed in areas where they can connect into the onshore grid to minimise overall costs. More distant resources should be developed when "local" resources and the existing onshore grid capability are fully utilised.

PB Power was commissioned by Energy Minister Brian Wilson to investigate whether a 400 mile sub-sea cable to tap the rich renewable resource in the north of Britain and along the west coast would be economically and technically viable (Windpower Monthly, December 2001). Wilson says that Scotland's capacity to be an exporter of renewable power is constrained by the inadequacy of the existing infrastructure. "The report ... points in the direction of considering land based options for strengthening the transmission capacity from north to south," says Wilson. "Indeed, it may well be that the optimum solution lies in some hybrid of the two -- sub-sea cable and land based strengthening."

The report points out that reinforcement of the onshore grid network using new overhead lines would be cheaper than a sub-sea cable, but it could be difficult to obtain the necessary consents. Therefore, in some cases using offshore high voltage direct current (HVDC) links to take renewable power from the north and west to elsewhere in the UK could be economically justified. The report greatly assists in informing the debate about the sub-sea option, claims Wilson. "It sustains the validity of the concept while being realistic about the costs and difficulties."

New tack

Looking next for an alternative solution to enable Scotland to realise its full renewable potential, Wilson has announced another study -- this time to look at options for strengthening the transmission system between Scotland and the rest of the UK. All involved parties will take part, including the Scottish Executive, National Grid Company and the office of energy regulation. "I will expect both conclusions and firm recommendations on the way forward to be available within six months. It will be a clear expectation of government that the final proposals will extend to the north and west of Scotland, including the islands," he says.

Any link to the Scottish isles would benefit plans by wind project developer AMEC and British Energy to build Europe's largest wind farm of up to 300 wind turbines totalling 600-1000 MW on the island of Lewis (Windpower Monthly, January 2002). David Still of AMEC Wind does not accept all the findings of the PB Power study. "It is an interesting report, but we do not agree with their costings," he says, adding that the study's costs were based on older more expensive HVDC technology. He claims it is economic to take power from the Western Isles into the transmission system in north Wales.

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