How they’re building world’s biggest offshore windfarm off Yorkshire’s coast

Dong Energy's Walney windfarm in the Irish Sea, off the Cumbrian coast.
Dong Energy's Walney windfarm in the Irish Sea, off the Cumbrian coast.
  • Energy: Plans for the world’s biggest offshore windfarm off the coast of Yorkshire are forging ahead. Lizzie Murphy reports.
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It’s a hive of activity on the Yorkshire coast with construction well underway for the onshore elements of Hornsea Project One.

Workers from Balfour Beatty are building the substation where the windfarm will connect into the National Grid, while work on the subsea power cables is also taking place.

Duncan Clark, programme director for Hornsea Project One, with site support Naomi Casey.

Duncan Clark, programme director for Hornsea Project One, with site support Naomi Casey.

At the same time, the foundations for the turbines and cables are in the process of being laid.

“It’s an active construction project at the moment with lots of things going on,” says programme director Duncan Clark.

Dong Energy’s £4bn offshore windfarm is part of a £6bn investment to transform Yorkshire into a hub for the UK’s renewable energy sector.

Project One will consist of 174 wind turbines, each producing 7 megawatts (MW) of power, located 120km off the Yorkshire coast, covering approximately 157 square miles. They will not be visible from the shore.

At 1.2 gigawatts (GW), the project will be the first to have more than 1GW of capacity.

Onshore construction of Project One started in early 2016, with offshore construction due to begin in 2018. The site is expected to start operating in 2020.

The project is already providing a huge boost to East Yorkshire’s economy and is expected to create 2,000 employment opportunities during the construction phase, as well as 300 additional jobs during its operational phase.

Danish-owned Dong has already awarded a number of contracts for the project. The turbine blades will be manufactured by Siemens from their recently opened factory in Hull. They will be taken from the factory to the wind farm on vessels where the turbines will be built in modules, like Lego.

Other suppliers include Leeds-based onshore cable installation firm J Murphy & Sons. The firm will lay over 350,000m of cable along a 38km route, which will cross agricultural farmland, roads, rail crossings, canal, river crossings and ditches, overhead and underground services.

Scunthorpe-based company AMS No-Dig will design, supply and install cable ducts under the sea defence at Horseshoe Bay, south of Grimsby. The offshore export cables, which transmit the electricity generated by the windfarm back to shore, will be pulled through these ducts and then connected to the onshore cable to provide a connection into the National Grid.

JDR Cables, a Hartlepool business, will provide the cables for each of the turbines, and Bladt Industries on Teesside will supply 96 transition pieces which will link the foundations of the turbines with the towers.

​Rochdale-based Granada Material Handling will assemble and test all 174 davit cranes required for each of the turbines.

Meanwhile, British multinational Babcock is building a substation for the project, which will be deployed mid-way between shore and the turbine site to enable a high-voltage transmission system to work on longer cable lengths.

“There are lots of companies, big and small as part of the supply chain,” says Mr Clark.

When plans for Project One were announced last year, opinion was divided. Dong Energy was keen to point out the economic benefits and the project’s green energy credentials, but critics feared the project could add at least £4.2bn to household energy bills.

Project One secured a contract three years ago under which it is paid four times the market price for every unit of electricity it generates.

This costs an estimated £280m per year in subsidies, which could be funded by households and businesses through green levies on their energy bills.

The Government could cut this subsidy after the contract ends in 2029.

In January, ministers revealed in their new industrial strategy that they want to “minimise” the cost and rely instead on “competitive markets” to deliver green energy.

“Offshore wind is at a tipping point. We have to show we can do it cost effectively,” says Mr Clark. “We haven’t got better options and there is a lot of seabed out there which is suitable for offshore wind power.”

Plans for Hornsea Project Two and Project Three are also in the pipeline. Dong received planning permission for the 300-turbine Hornsea Project Two, which will sit to the west of Project One, last August.

Meanwhile, plans for Hornsea Project Three are in the pre-application phase. Project Three, which will sit to the east of Project One, could be twice as big as the first scheme, generating 2.4GW of electricity.

Three will be the maximum number of windfarms in that area. “We won’t be rolling out another one there,” he adds.

“We don’t know what type of turbine projects two and three will take. Turbines have been getting bigger and bigger and that trend will continue. Bigger turbines produce more energy, which lowers the cost of electricity.”

As each turbine gets bigger and produces more energy, the cost of building that turbine will be easier to offset by the power it produces.

An immense amount of research and preparation work has gone into reaching the point Project One is at today.

After it was given the go-ahead in 2008, a number of surveys and investigations were done to find out which areas of the seabed could withstand the turbines.

He adds: “It will have taken more than 10 years to build this project but that is quite good for an offshore windfarm. It is a long-term business.”

Compared with Germany, Denmark, Spain and France, the UK is still behind in wind power. But the country now has an opportunity to meet its energy needs through offshore wind.

Dong is also creating the UK’s largest offshore wind operations and maintenance hub in Grimsby, where it already employs 78 people.

The company already uses the port to operate the Westermost Rough and Race Bank windfarms.

“Taking on all these projects has given us a chance to take a greater responsibility for the whole area,” says Mr Clark. “Because we have got a number of projects, we should be able to do it more effectively.”