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Wind power off the UK

Equinor’s biggest offshore wind power investment is in the UK – the largest market for this energy source in the world. The commitment covers both fixed and floating turbines. The British government’s target, set with the industry, is to meet 30 per cent of electricity consumption from offshore by 2030. This market is therefore growing.
By Kristin Øye Gjerde, Norwegian Petroleum Museum
- Crew transfer vessel at an offshore substation. Source: Sheringham Shoal

More wind is available at sea than on land, making it appropriate to base energy generation offshore. While a fixed turbine stands on the seabed, the floating type is attached with mooring lines.

Wind power is a renewable source where the kinetic energy in moving air rotates turbines to generate electricity. Modern wind turbines generate lift on their curved rotor blades, like an aircraft wing, to provide the energy for rotating the turbine. This rotary movement is then converted to electricity by a generator inside the nacelle (or housing) on the turbine support shaft. Exploiting the lift allows modern wind turbines to utilise more than half the available wind energy, giving an efficiency of about 50 per cent – very good compared with other types of renewable energy.[REMOVE]Fotnote:

Conditions on the relatively shallow UK continental shelf (UKCS) are very suitable for fixed wind turbines, and it was this technology which first brought oil companies from Norway into the market.

Fixed wind power – Sheringham Shoal

Statoil’s major commitment to clean energy in the UK began with the wind power projects acquired when it merged with the oil and energy division of Norway’s Norsk Hydro group in 2007.

Hydro was the first Norwegian oil company to gain a foothold in the British market for renewables, after securing 50 per cent of Scira Offshore Energy Ltd on 28 June 2005. This UK joint venture was licensed to build the Sheringham Shoal wind farm off the Norfolk coast of England. The plans were based on existing technology – in other words, fixed turbines to generate electricity.[REMOVE]Fotnote:

Since energy production would take place offshore, this activity was regarded after the merger as a natural business for an oil company operating offshore. At a time when questions were being asked about the petroleum industry’s greenhouse gas emissions, it offered a specific result for the company’s renewables strategy.

In 2008, Scira and StatoilHydro ­– as the company was called until it reverted to Statoil in 2009 – secured project approval from the British government. Responsibility for development and operation of the wind farm rested with Scira. This represented StatoilHydro’s first major renewables commitment.

At that point, the company was established in the UK market as a gas supplier from the Troll and Ormen Lange fields via the Langeled pipeline. That was far more profitable than wind power. But earnings were only one of the short-term considerations with the Sheringham Shoal commitment. Another was to secure experience with renewable energy.

In order to spread the financial risk, Statoil sold half its shares in the wind farm to Norwegian state-owned electricity generator Statkraft. The latter thereby became involved in the offshore wind power market, but withdrew later to leave Equinor as operator in 2022.

Wind Farm Place marine coordination centre. Photo: Campbell MacCallum

Development did not progress without a hitch. The wind farm covers 35 square kilometres, with water depths ranging from 17 to 22 metres. Difficulties with installing the foundations led to expensive delays, but the shafts for all 88 turbines were in place by September 2011. Installing the actual turbines took rather longer, and was not completed until the following summer.[REMOVE]Fotnote: The farm is connected to land by two cables.[REMOVE]Fotnote: Its official inauguration was conducted by Crown Prince Haakon of Norway on 27 June 2012.

On the basis of their experience in developing Sheringham Shoal, Statoil and Statkraft also acquired the neighbouring licence, Dudgeon, in 2012. Operating both wind farms meant their capacity could be utilised even more efficiently.

Renewable sources accounted for 33 per cent of UK electricity supply in 2018, with offshore wind power providing 6.6 per cent. At that time, Hywind Scotland – another bold new project run by Statoil – had become operational.[REMOVE]Fotnote: TU, 8 March 2019,

Floating wind power – Hywind Scotland

Learning lessons and continued development were among the main goals for Statoil’s Hywind Scotland floating wind power project in 2015. It lies 29 kilometres east of Peterhead, in water depths of 95-120 metres.

Statoil wanted to apply its expertise with offshore energy production to innovation and to building the world’s first floating wind power farm. It secured a licence for the project on condition that costs were to be reduced by 60-70 per cent from the Hywind Demo research project off Norway.

The development was bold both technologically and financially. Statoil was initially the sole owner of Hywind Scotland but, in order to reduce the financial risk, sold a 25 per cent stake to the Abu Dhabi Future Energy Company (Masdar) in 2017.

Mark Boon and Matthew Bramwell aboard the crew transfer vessel MCS Swath 1, on their way out to work at Hywind Scotland. Photo: Ole Jørgen Bratland

Work on constructing the installations began in 2016. Turbine supports for the farm were built in Spain, while all the components were assembled at Stord in western Norway. The floating structures comprise a steel cylinder ballasted with water and rock, which extends 78 metres beneath the sea surface and is attached to seabed with three mooring lines.[REMOVE]Fotnote: UK wind – The floating farm became operational in October 2017.

Despite the emphasis given to cost reductions, the offshore installations were three times more expensive than fixed wind turbines.[REMOVE]Fotnote: The potential of the technology was nevertheless so great that Statoil wanted to go further with it. Floating turbines gave the company an opportunity to exploit its existing offshore oil and gas expertise and to build on this. Everything beneath the waves on a wind turbine was the same as a moored oil and gas floater, and everything above represented renewable energy solutions. “It’s a perfect marriage between these two technologies,” Stephen Bull, Equinor’s former head of wind power, declared enthusiastically.[REMOVE]Fotnote:

The work has had spin-offs in Norway. In December 2017, the government announced a licensing round covering one-two areas in Norwegian waters for floating wind power in the form of a full-scale pilot farm. This is receiving support from Enova, a state-owned company which makes annual grants from a climate and energy fund. Its aim is to help reduce greenhouse gas emissions as a contribution to meeting Norway’s climate commitments for 2030, advancing innovation in energy and climate technology, and encouraging efficient power and energy consumption.[REMOVE]Fotnote: Enova was established in 2001 and was owned by the Ministry of Petroleum and Energy on behalf of the state until the first half of 2018, when it was transferred to the Ministry of Climate and the Environment. Source: Wikipedia.

One objective is to make floating wind turbines a profitable industry for Norway. Developing the technology and industrialising floater concepts would make it possible to exploit wind power in a number of ocean areas – not just shallow seas.[REMOVE]Fotnote: Dagbladet, 13 December 2017, “Flytende havvindkraft”. Almost 80 per cent of the global potential for offshore wind power lies in waters deeper than 60 metres.[REMOVE]Fotnote:

According to analyses in 2019 from the International Energy Agency (IEA), offshore wind power is set to expand substantially over the next two decades. As it becomes a growing part of electricity supply, it will help to decarbonise energy systems and reduce air pollution.[REMOVE]Fotnote: Offshore wind to become a $1 trillion industry – News – IEA.

Large-scale fixed wind power – Dogger Bank

Equinor’s next project in the UK is the Dogger Bank. The British government announced on 20 September 2019 that Equinor and SSE Renewables had been awarded contracts to develop three large wind farm projects in this part of the North Sea. Italy’s Eni has subsequently purchased a 20 per cent holding.

The first turbine is due to be operational in 2003, with the whole development scheduled for completion in 2026. Known historically as a rich fishing ground, the Dogger Bank will then be home to the world’s largest offshore wind farm area to date. Located 130 kilometres east of Yorkshire, it covers 1 700 square kilometres – larger than Greater London – with water depths of 20-35 metres. Due to have an operating life of up to 35 years, these projects are expected to cost GBP 9 billion and will be operated by Equinor.[REMOVE]Fotnote: They are set to deliver enough electricity to meet the needs of 4.5 million British homes.

Dogger Bank – one of Equinor’s biggest offshore wind projects. Illustration: Equinor

Technology for fixed offshore wind power has progressed since the initial projects. Turbines and rotor blades have increased in size and outputs are larger. When the first 13-megawatt turbines from General Electric start rotating in 2013, one sweep of their 220-metre rotors will generate enough electricity to operate an average UK home for two days, Equinor has said.

Because of the long distance from land, the project will be the first off Britain to use high-voltage direct current cables to transmit the electricity to land. Too much of the output would be lost if alternating current cables were used.[REMOVE]Fotnote:

The contracts awarded provide for a fixed price over the first 15 years in operation, which gives the projects a long and predictable income profile. “With very good wind conditions, shallow water and opportunities to make economies of scale, these projects are well positioned to deliver renewable energy at a low cost to British homes and companies,” Equinor CEO Eldar Sætre said in 2019.

Future in wind power

Equinor’s offshore wind power ambitions are not confined to the UK. The company has established itself in this field both off the north-western USA and in the Baltic. According to its management, the goal is to be a major global player in offshore wind power, and to increase its renewable capacity 30-fold from the 2019 level. Wind power at sea could be one of the world’s leading technologies for electricity generation. The projects in the UK have thereby been of great importance for Equinor’s future as an energy company.[REMOVE]Fotnote:

Sunset at Sheringham Shoal. Photo: Duncan Gomes


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