Two giant trenches and up to 11 years of construction work - what the world's biggest offshore wind farms mean for Norfolk
PUBLISHED: 07:53 14 December 2017 | UPDATED: 08:11 15 December 2017
Archant Norfolk 2017
Almost 11 years of construction work, the destruction of wildlife, billions of pounds of investment and the creation of hundreds of jobs - what is the impact on Norfolk of building the world’s biggest offshore wind farms?
Three wind farms with enough energy to power more than four million homes – the equivalent of five Sizewell nuclear power stations – are planned off the Norfolk coast.
They will be the biggest offshore wind farms in the world and need two trenches up to 60 kilometres long to be carved through the county’s countryside.
New electrical substations will also need to be built on farmland.
The work will affect more than 200 landowners and the effects on communities, businesses and the environment will be huge. But are those impacted, aware of the likely scale of disruption?
Today we start a series revealing the major impact these schemes will have on swathes of Norfolk – both positive and negative.
Our findings include:
• Construction disruption in numerous communities, starting in 2020 and potentially lasting for up to 11 years;
• A huge increase in number of HGVs on some country roads;
• Concerns about the impact on tourism, the environment and farming;
• The creation of hundreds of high-skilled jobs;
• Billions of pounds of investment in Norfolk, with each scheme costing more than £2 billion;
• Around 2,500 acres of land will be needed for the projects.
One wind farm, called Hornsea Three, will be built 120km north of the Norfolk coast by Danish energy firm Orsted.
To get its 2.4 Gigawatts of electricity to the National Grid, a cable corridor 55km long and around 80 metres wide will be dug from Weybourne on the coast to a new electrical substation south of Norwich at Swardeston.
A second cable corridor, up to 100 metres wide, will need to be dug for wind farms being built by Swedish energy company Vattenfall.
That trench will be dug from Happisburgh to Necton where two new substations up to 19 metres high will spring up.
It will take electricity from two wind farms being built 50km east of Happisburgh called Vanguard and Boreas.
The energy companies said the effects of digging the trenches will be temporary, with land returned to how it looked before the work. And there is a huge long-term gain in providing renewable energy for millions of homes and businesses.
But campaigners point out that thousands of HGVs will be needed to carve the two cable corridors through Norfolk. Three new electrical substations will need to be built, and three relay stations to boost the electricity being taken to the National Grid may also be needed, meaning further farmland is lost.
From Happisburgh to Necton, Weybourne to Swardeston, those living near the massive infrastructure projects are worried.
The news has been greeted in Happisburgh with astonishment.
The cliffs which Vattenfall will need to drill through are soft and eroding fast. Vattenfall said it took erosion into account when choosing Happisburgh as the place where its cables will make landfall.
But the parish council remains unconvinced. Chairman Glenn Berry said weakening the cliffs is their main concern. On Saturday a large section of the coastal footpath fell away.
And in a letter to Vattenfall, the parish council said the firm, which is owned by the Swedish Government, “does not seem to understand that one metre of beach can be lost during a storm - that is the depth at which the cable would be buried” (under one proposed method).
But Happisburgh Parish councillor Denise Burke said the village should use this chance push Vattenfall for compensation which could be used for coastal defences against erosion.
A report about the impact of the project, produced by consultants Royal Haskoning for Vattenfall, said there would be “significant effects” at Happisburgh during construction, which could take six years, but these effects would mostly be “temporary”.
Penelope Malby, who set up a group opposing the project called Happisburgh REACTS in June, criticised Vattenfall for allegedly misleading people in its consultation about the scale of the project and not being open about the full impacts which may include closing the beach and coastal footpath.
“It feels like it is out of our control and you don’t really have any say,” Ms Malby said. “I don’t think people yet realise the impact of how many villages it will go through.”
After reaching Happisburgh, the cables then need to join to an electrical substation to connect to the National Grid.
Vattenfall was offered several connection options by the National Grid and chose Necton. That means a 60km-long cable trench needs to be dug through Norfolk, with a construction area 100 metres wide.
The electricity can either be carried through AC (Alternating Current) cables or DC (Direct Current) cables.
Both Vattenfall and Orsted are seeking permission from the Planning Inspectorate to use both options and said it will then decide later which option to use.
But the impacts on Norfolk of choosing either DC or AC are vastly different. The AC option will need more cables and therefore a potentially wider cable corridor.
The AC option will also need two relay stations covering around six acres of land each and eight metres high to be built near Happisburgh. The relay stations would boost the power being carried to the National Grid and would need to be built near East Ruston hall or Ridlington.
Beverley Wigg, who lives at East Ruston and is part of a campaign group called No 2 Relay Stations in open countryside (N2RS), said: “Either East Ruston or Ridlington face permanent impact on the landscape which will blight an otherwise unspoilt area that is devoid of similar development.”
N2RS is lobbying Vattenfall to pick the DC option which will mean no relay stations are needed and the cable route will be narrower.
They are also concerned about the noise the stations would make.
The environment information report for Vattenfall said the relay stations would have “significant effects” on the landscape but after 15 years, growth of trees would mean this would be “largely” reduced by blocking out the station.
The report also said they would use “noise reduction technology” around the relay stations.
•The towns and villages on the cable routes
Two sets of trenches will be dug to put the transmission cables from the wind farms underground.
The cable corridor for the Hornsea Three wind farm runs north to south for 55km beginning at Weybourne. It will then go around Holt and may cut through Kelling under one option.
It will then pass by: High Kelling, Hempstead, Corpusty, Heydon, Reepham, Little Witchingham, Morton, Weston Longville, between Marlingford and Bawburgh, close to Hethersett and connect to a new substation at Swardeston.
The second cable corridor for two wind farms being built by Vattenfall makes landfall at Happisburgh. The cables then run 60km south-west to Necton passing by: Ridlington, Bacton Wood, North Walsham, Banningham, Aylsham, Cawston, Reepham, then south near Sparham, Swanton Morley, north of Dereham, Scarning and finally Necton.
•What the energy companies say
Vattenfall and Orsted said they were regularly speaking to one another to reduce the disruption of building the two underground cable corridors.
Particular disruption is expected near Reepham where they cross.
A Vattenfall spokesman said: “The UK is facing a looming energy gap, and offshore wind, as one of the cheapest forms of large scale energy generation has consistently delivered on time and on budget, and of course addresses another UK legal obligation – to reduce carbon emissions, we can all appreciate why the drive is on.
“As the project takes shape, there will be more we can do to work with Norfolk to ensure project delivery works for and with Norfolk.”
An Orsted spokesman said: “The offshore wind farm has the potential to deliver significant benefits to Norfolk and beyond in terms of the clean energy generated and economic activity associated with such a large project.”
•TOMORROW: In the crosshairs of the wind farm cable corridors at Reepham