Have you seen trucks travelling through Norfolk with what appears to be an enormous wheel on the back and wondered what it’s for?

Why is it travelling through Norfolk’s bucolic roads with a police escort? And where is it headed?

The huge spool-like structures have a vital role to play in the green energy transition. They are cable drums that are critical to the renewable energy company Ørsted’s construction of Hornsea 3, the world’s single largest offshore wind farm.

Upon its completion, Hornsea 3 will have a generating capacity of 2.9 gigawatts – enough green energy to power over three million UK homes.

Cable drums

The cable drums are giant spools for the onshore export cables that are essential to the delivery of energy that will be produced offshore by Hornsea 3.

Once the renewable energy comes onshore near Weybourne, it needs to continue its journey via another 51km of onshore export cables buried underground to connect to the National Grid’s main substation near Norwich.

But first the export cables have their own lengthy journey to where they need to be installed.

This journey begins in Karlskrona, Sweden, where they are manufactured and then shipped to the Port of Boston.

Michael Creagh, Hornsea 3’s senior project lead, is responsible for organising the cable drums’ safe delivery from the Port of Boston to Ørsted’s Oulton supply compound on the site of an old Royal Air Force base that was decommissioned in 1949.

That’s a big job – because the cable drums are huge.

The largest drums, which can accommodate up to 1,200 metres of cable, are 4.7 metres high by three metres wide and weigh in at 50 tonnes. That’s the equivalent of four double-decker buses!

Hornsea 3’s senior project lead Michael CreaghHornsea 3’s senior project lead Michael Creagh (Image: Ørsted) The equipment is so big that transporting it requires specialised vehicles and police escorts. Their movements are known as ‘abnormal loads.’

Michael explained that every one of the transport movements from the Port of Boston requires weeks of advance logistical planning – particularly with the police whose assistance with traffic management while the trucks move through Norfolk’s small towns and villages is indispensable.

“We probably couldn’t do it without the police escorts,” said Michael. “They are really helpful and ensure that we make it a smooth transition every time.”

Working with the community

Ørsted works with parish councils, businesses and members of the public who may be impacted by the large transportation deliveries.

The company issues ‘advance work notices’ so communities are aware of the planned abnormal load movements and have a map of the approved route they will take.

“We do our very best to work with the local community to inform them about these movements so that people can plan their journeys ahead of time,” said Imran Nawaz, who leads Hornsea 3’s stakeholder and community relations team.

Advance work notices about all upcoming abnormal load movements are also posted on the Hornsea 3 website.

A cable drum arrives at the Port of Boston after being shipped from KarlskronaA cable drum arrives at the Port of Boston after being shipped from Karlskrona (Image: Ørsted) “Anytime people have a question, whether it’s about our advance work notices or the approved routes these vehicles can take, please call us, write to us or meet with us,” said Imran. “We are very happy to chat and answer questions.”

From Ørsted’s Oulton supply compound, the cable drums will be moved again to various construction sites as the onshore cable route is built.

Without the cables and the cable drums, there would be no offshore wind farm.

Ørsted appreciates the community support as it works to build the world’s single biggest offshore wind farm that will enhance UK energy security and contribute significantly toward the UK’s net-zero ambitions.

“Thank you for bearing with us as we deliver this important infrastructure needed for this critical project,” said Imran.

For more information, visit hornseaproject3.co.uk

Eastern Daily Press:

This article is part of LOCALiQ's Clean & Green campaign, which aims to promote our region as the biggest in the UK and Europe for all forms of renewable energy.