The expansion of two wind farms off the Norfolk coast could lead to years of construction work and the digging of another cable trench across the countryside.

Eastern Daily Press: Turbines at the Dudgeon offshore wind farm which will expand. Picture: Roar Lindefjeld/Woldcam - Statoil.Turbines at the Dudgeon offshore wind farm which will expand. Picture: Roar Lindefjeld/Woldcam - Statoil. (Image: Archant)

Norwegian energy firm Equinor is leading a project to build 34 new turbines at Dudgeon wind farm, 30km from Cromer, and 27 turbines at Sheringham Shoal wind farm. The turbines would be up to 326 metres high.

Each project will bring more than 100MW of renewable energy, according to a report by Equinor outlining the plans.

They also said the projects would reduce carbon emissions, provide energy security and bring economic benefits.

They are looking to bring the cables ashore either at Bacton or Weybourne and connect them to the National Grid south of Norwich at Swardeston.

But to do that they would need to dig a 60km-long cable trench from north Norfolk to Norwich which will lead to years of construction work and harm the environment, the report added.

Two possible routes have been put forward.

North Norfolk MP Norman Lamb called on the Government to stop allowing energy firms to dig up the countryside for every new offshore wind farm.

"I'm supportive of these plans but strictly on the condition that the government and National Grid sort out a deal on creating an offshore ring main," he said.

An offshore ring main would mean the wind farms could connect to the National Grid at the coast rather than needing cable trenches.

But Equinor ruled that out, stating it was "not an option at this time".

A spokesman said: "For our plans we need to take into account the timeline for our projects as well as the time expected for common infrastructure to be established."

Two other energy companies, Vattenfall and Orsted, are currently pushing ahead with plans to build three more offshore wind farms which will need two more cable trenches.

Eastern Daily Press: The Sheringham Shoal wind farm. Picture: MIKE PAGEThe Sheringham Shoal wind farm. Picture: MIKE PAGE (Image: Archant)

The trench would either come down from Weybourne, head south to Cawston and then head through the Wensum to Barford. It would loop east around Hethersett and join to the National Grid at Swardeston where an AC substation will be built.

The alternative route is to come ashore at Bacton, loop south around North Walsham and past Hevingham and then follow the same route.

The report said the projects would impact sites of marine conservation and fishing.

Onshore, agriculture land and habitats would be lost. A consultation begins next year.

Eastern Daily Press: The substation at Necton for the Dudgeon offshore wind farm. Photo: Ole Jorgen Bratland/StatoilThe substation at Necton for the Dudgeon offshore wind farm. Photo: Ole Jorgen Bratland/Statoil (Image: Archant)

See also: Wind energy firm scraps plans for relay stations in countryside

-'Another nail in the coffin'

Jenny Smedley, from the Necton Substations Action Group, which has been campaigning against the cable corridors, warned the plans were "another nail in the coffin" for the Norfolk countryside.

"We've been trying to warn villages and their MPs and Parish Councils that all of Norfolk is under industrial attack and this proves we are right," she said.

"Unless an offshore ringmain is adopted, it will only get worse and worse as more and more massive wind farm infrastructure is shoe-horned into Norfolk.

"Our roads can't take the construction traffic, and no village, however pretty, however historical, however precious to its inhabitants is safe from destruction.

"We urge people to read the documents and see if their village is safe. But even if it is today it might not be tomorrow because this is just the start."

-An earlier version of this article said there could be two cable corridors. There will in fact be one, with one of either of the two routes chosen for both cable trenches.