Full Blown: Building the world’s largest offshore wind farm in the North Sea

Dogger Bank, a large sandbank around 130km off the North East coast of England, used to be known primarily for its plentiful fish. It derived its name from dogge, an ancient Dutch word for cod, which were caught in huge numbers by the small fishing vessels that once plied its shallow waters.¹

But soon Dogger Bank will be known for a different, yet equally sustaining, natural resource. It will be home to the world’s largest offshore wind farm, capable of producing 3.6GW of electricity, enough to power five million homes.

“Dogger Bank has opened up new horizons for how large an offshore wind farm can be”, says Alex Grant, UK Country Manager at Equinor, which will operate the €10bn wind farm over its lifetime of up to 35 years.

The project, a 50:50 joint venture between Equinor and SSE Renewables, is being built in three equal phases, with Italy’s Eni taking a 20 per cent stake in the first two phases. When the first 13MW turbines start to turn in 2023, a single sweep of their 220-metre rotors will produce enough electricity to power a home for two days. The project will be the first to use these turbines, the largest moving machines in the world. It’s a sign of how far offshore wind has come over the past decade, confounding the expectations of even its most ardent proponents.

13MW turbines

A single sweep of their 220-metre rotors will produce enough electricity to power the average UK home for two days

Five to six years ago, the cost of offshore wind was €207 per MWh. Now, it is well below the wholesale price

Megan Smith, head of offshore wind advisory

“Five to six years ago, the cost of offshore wind was €207 per Mwh. Now, it is well below the wholesale price,” says Megan Smith, Head Head of Offshore Wind Advisory at the Carbon Trust, which runs the Offshore Wind Accelerator, an initiative to cut costs in the sector. “One of the main drivers in cost reduction is the increase in the size of the turbines.”

Dogger Bank won contracts at record-low prices in 2019, which means that when it starts generating electricity in 2023 it will be essentially subsidy-free.

Because it is sited so far from shore, the project will use high voltage DC (HVDC) cables to transport the power back inland — the first UK offshore wind farm to do so. Too much power would be lost if AC cables were used.

The 1,700km2 project, covering an area larger than Greater London, is set to make a significant contribution to the UK economy.

When Equinor got involved in Dogger Bank a decade ago, the UK’s entire offshore wind capacity was 1.3GW, around the same as a single phase of this project. “Bear in mind that our initial business case was for 2000 turbines. With the speed of development increasing all the time, we’ll end up with the same capacity using just 15 per cent of the original 2000 turbines,” Equinor’s Grant said. “This shows how far the industry has come but also how we had to adapt our plan based on anticipated future technologies rather than those that existed at the time”


“Dogger Bank is a huge step forward in both our ambitions to become global offshore wind major and increase our renewables capacity from 0.6GW, as it is today, to 12-16GW by 2030.” Grant adds.

Our initial business case was for 2000 turbines. With the speed of development increasing all the time, we’ll end up with the same capacity using just 15 per cent of the original 2000 turbines

Alex Grant, UK Country Manager, Equinor

Cable ducting on the onshore construction site for Dogger Bank A and B. Image Source: Dogger Bank Wind Farm by SSE Renewables and Equinor

Europe installed 3.6 GW of offshore wind capacity in 2019, which set a new record. But the EU’s Offshore Renewable Energy Strategy, announced last November, sets a target of generating a whopping 300 GW from offshore wind by 2050 in order to help achieve climate neutrality. That will mean a 25-fold increase on current capacity, requiring major investment in infrastructure and a huge increase in installation rates.2


If that is to be achieved it will mean building up regional clusters, like in the North Sea. The region is the epicentre of offshore wind because it is shallow enough to allow turbines to be fixed to the seabed. But many other countries with plentiful wind resources, such as France, South Korea and Japan, have much deeper coastlines, which are unsuitable for bottom-fixed turbines.

Taking our existing strengths in oil and gas and our robust portfolio in fixed-bottom offshore wind, we have a unique advantage as developing floating offshore wind requires many of the same skills

Alex Grant, UK Country Manager, Equinor

Floating turbines can be placed almost anywhere where the water is deeper than 60 metres enabling these areas to generate renewable power and meet their emissions targets. Equinor, which was the first to build a floating turbine platform with its Hywind concept, believes floating wind could potentially power 12 million homes in Europe by 2030. The technology unlocks new renewable energy potential because average wind speeds are higher and more consistent in deeper water further from shore.³

“We have decades of experience in offshore energy, and it’s this that has enabled us to become the leading developer in floating offshore wind. Taking our existing strengths in oil and gas and our robust portfolio in fixed-bottom offshore wind, we have a unique advantage as developing floating offshore wind requires many of the same skills. It’s our people that are really driving the energy transition.” says Grant.

Following in the footsteps of the North Sea, other European regions are set to become offshore wind hubs. Equinor has recently announced that it will develop 3GW of offshore wind capacity in the Polish Baltic Sea.

3D visualization of a floating turbine. Source: Equinor ASA

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