More than 80 Norfolk towns and villages have joined forces in a plea to the Energy Secretary to refuse planning consent for what would be the largest offshore wind farm in the world.

Their intervention comes just days before a decision on the first of the wind farms is due.

Swedish energy giant Vattenfall plans to build two vast offshore wind farms off the Norfolk coast, Boreas and Vanguard, which between them will provide enough renewable electricity for almost four million homes.

However, connecting the power generated by the turbines to the National Grid will require 60 kilometres of underground cables dug into a trenche up to 80 metres wide, running from Happisburgh on the coast to a new substation at Necton.

Further complicating the picture for the thousands of residents who will be affected by the works, are plans for a north-south cable corridor to bring power onshore from another wind farm called Hornsea Three. Those power lines will start at Weybourne in north Norfolk and run south to Swardeston.

But in a letter, the Norfolk Parish Movement for an Offshore Transmission Network (OTN) calls on the government to move beyond "stone-age" technology which necessitates miles of on-shore trenches and cables and instead connect the wind farms off the coast, something which the wind farm firms say is not yet possible and would take years to implement.

Vattenfall says it will "minimise" impacts to residents and wildlife and says the technology to connect offshore is not yet viable. It also points out the farms will bring investment to the region with a £15m pot for community projects announced last week.

It also says that an offshore grid would be impossible for its Vanguard project as the technology is in too early a stage of conception for a project which has been in the works for ten years.

Head of stakeholder management at Vattenfall, Dr Catrin Ellis Jones, said: "The Vanguard and Boreas wind farms will use the most innovative technology available to bring the electricity ashore and minimise the impact on the surrounding environment.

“We’re very confident about our proposals. We’ve gone above and beyond the requirements laid out in the consenting process and we also have a clear plan in place for maximising the benefits of the projects for the local area.

"Vattenfall’s Norfolk Zone will be the largest offshore zone in the world when constructed, providing renewable electricity to nearly four million homes."

In a letter to the Secretary of State for Business, Energy and Industrial Strategy, Kwasi Kwarteng, the Norfolk Parish Movement for an OTN wrote: “There are many cumulative impacts of these two sister projects [Vanguard and Boreas] that remain to this day unresolved, including … the punishing construction traffic impacts over many years … unpredictable effects on the eroding cliffs at the landfall site … and the massive intrusion into the rural landscape of the enormous converter halls and associated infrastructure at Necton.”

The letter, written by Oulton Parish Councillor and Convenor of the Norfolk Parish Movement Alison Shaw, also cites a lack of effort to mitigate impacts on on-shore bird life.

The towns and parishes insist they are not objecting to wind farms but to the disruption onshore.

The letter said: “The difficulty arises with... the hundreds of miles of cross-crossing cable trenches, the endless years of heavy goods vehicle traffic along country lanes often not wide enough for the school bus to pass a bicycle … and a totally unnecessary legacy of more than 1,000 acres of drain-damaged farmland."

The group wants the energy cables to be connected at sea, joined up with other offshore projects, to minimise disruption on land.

A decision from the Planning Inspectorate on Boreas is due by December 10, while the ruling on Vanguard is expected later this month, after a surprise delay in February when campaigner Raymond Pearce of Reepham won a High Court case challenging the planning process.

The judge ruled that the cumulative impacts of the schemes had not been properly assessed.

The letter urges the Secretary of State to refuse development consent to both the Boreas and the Vanguard project in their current form.

Alternatively, they propose the Secretary of State could green-light the offshore construction but defer a decision about onshore works, or postpone the whole decision.

The 85 Signatories

Eastern Daily Press: Decisions on new Vattenfall wind farms off the Norfolk coast could be made by the end of the year.Decisions on new Vattenfall wind farms off the Norfolk coast could be made by the end of the year. (Image: Rasmus Kortegaard Photography)

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and the Independent Group of 15 councillors on West Norfolk & King’s Lynn Borough Council