Windfarms planned for the UK sector of the North Sea in the relatively shallow waters of Dogger Bank could be among the first use a new generation of extremely large offshore wind turbines
In mid-April 2019 the companies behind the Dogger Bank Creyke Beck A and B projects confirmed they had secured consent from the Department of Business, Energy & Industrial Strategy (BEIS) to use much larger turbines than they originally envisaged on the first stage of developing the Dogger Bank Zone. Weeks later, innogy confirmed it had secured consent to use turbines of similar capacity on its Sofia project, formerly known as Dogger Bank Teeside B.
BEIS agreed to allow Doggerbank Offshore Wind Farm Project 1 Projco Limited and Doggerbank Offshore Wind Farm Project 2 Projco Limited to install turbines with a rotor diameter of up to 280 m should one be available in the timeframe for the project and should they wish to do so. The companies behind the consortia, SSE and Equinor, originally sought permission to install turbines with a diameter of 215 m.
The companies also sought changes to allow for using larger 12-m diameter monopile foundations rather than the 10-m foundations originally proposed. They also sought to use more powerful pile-driving equipment for the foundations, including equipment of up to 4,000 kJ during installation rather than the consented 3,000 kJ, but withdrew the hammer energy and monopile increase elements in a letter to BEIS on 22 February 2019.
No increase was sought in generating capacity for the projects and the number of larger turbines per project would therefore be constrained by the originally consented maximum capacity. The application indicates that for turbines with a maximum rotor diameter of 280 m, the maximum number of turbines would in effect be 70 per windfarm. Installing fewer, larger turbines would provide significant cost savings.
Consent for using turbines with a rotor diameter of up to 280 m will enable the project developers to use much larger turbines, potentially of up to 20 MW.
In a letter to the lead consent manager for the Dogger Bank projects, BEIS Secretary of State Greg Clark noted that since granting the 2015 order for the project there have been advancements in technology that would make the projects more efficient and cost effective. “These advances are based on the size of wind turbine generators available or likely to be available during the construction development programme,” he said.
“The Secretary of State has considered the ongoing need for the project… and notes that the Overarching National Policy Statement for Energy (EN-1) and the National Policy Statement for Renewable Energy (EN-3) both set out that, for the UK to meet its energy and climate change objectives, there is an urgent need for new electricity generation plants such as offshore windfarms. The Secretary of State considers, therefore, that the ongoing need for the project is established.”
At the end of April, innogy confirmed that the government and the Marine Management Organisation (MMO) had agreed to expand the capacity of the company’s Sofia offshore windfarm by 15%. Sofia is the largest project in innogy’s development portfolio and has been granted approval to increase its maximum installed capacity by 200 MW from 1.2 GW to 1.4 GW.
The MMO recently approved amendments to the marine licences for the project, which correspond to changes to the development consent order decided by Secretary of State for BEIS in late March 2019.
The additional 15% will provide enough power for approximately 150,000 average UK homes, which means the total amount of power Sofia could generate would be enough to provide almost 1.2M average UK homes with their electricity needs each year.
As well as the increase in overall installed capacity, the approvals allow innogy to use larger turbines with a maximum rotor diameter of 288 m, up from the 215 m in the original consent. That would put the turbines that could be used on the project in the 20-MW category, like those approved for the Dogger Bank Creyke Beck A and B projects.
The Sofia project is being developed 165 km off the UK’s northeast coast on a site of 593 km2. It has an agreed connection point at an existing National Grid substation in Lackenby, Teesside.
Sofia is one of the four Dogger Bank projects awarded consent in 2015. Formerly known as Dogger Bank Teesside B, the project was taken over by innogy in August 2017 and subsequently renamed.
The project is currently progressing through the latter stages of development and design, working closely with potential suppliers, stakeholders, statutory bodies and the authorities.
Like the other Dogger Bank projects, the sheer scale and size of Sofia will offer significant economic opportunities for the UK with potential supply chain benefits, infrastructure and associated jobs and contracts. Construction timelines will depend on a successful outcome in the next contracts for difference auction and a positive final investment decision. The current indicative timeline states that onshore construction could start by Q3 2022.
Sofia project director David Few said the increase was requested by innogy in applications submitted to the Planning Inspectorate and the MMO in June 2018.
“We applied to change the project’s development consent order and marine licences to ensure that Sofia would be able to employ the latest generation of larger, more efficient and technologically advanced wind turbines,” he explained.
“The approval decisions are clearly excellent news and now mean that Sofia will be able to make an even bigger contribution towards achieving the UK’s carbon emission reduction targets”.
The windfarm site covers an area of almost 600 km2 and is located 165 km off the UK’s northeast coast. Electricity generated by Sofia will feed into the national grid at an existing substation located in Lackenby, Teesside.
The project was granted its development consent order in August 2015 and is due to take part in the government’s next contracts for difference allocation round, expected in May this year.
In recent weeks, developers in other countries in Europe are understood to have also sought consent for using offshore wind turbines of up to 20 MW in upcoming projects.
The first developer to seek permission to use huge next-generation turbines on a project in the UK was Vattenfall. In 2017, the developer of the proposed Norfolk Vanguard offshore windfarm, confirmed it was considering using turbines of up to 20 MW for the project. Kicking off the consultation process for Norfolk Vanguard, Vattenfall said it was considering using between 90 and 257 turbines with a generating capacity of 7-20 MW each for the project.
By way of comparison, GE’s Haliade-X 12 MW turbine – which is currently in development and soon to be tested in the Netherlands – has 107 m long blades, a rotor diameter of 220 m and an overall height of 260 m.
Turbine manufacturers have previously described developing offshore wind turbines that could be far larger than existing marques and said they see few technical barriers to developing units as large as 20 MW, with rotors of up to 240 m in diameter.
None of the leading turbine manufacturers has confirmed development of turbines as big as those now being proposed for use on Dogger Bank, but there is clearly an ongoing dialogue between manufacturers and developers that has led the latter to anticipate the potential availability of huge machines of this size by the time they commit to actually building the windfarms.