Circa 20-MW turbines cleared for use on Dogger Bank

The companies behind the Dogger Bank Creyke Beck A and B projects have secured consent from the Department of Business, Energy & Industrial Strategy to use much larger turbines than originally envisaged on the first stage of development in the Dogger Bank Zone.

The Department of Business, Energy & Industrial Strategy (BEIS) has 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 the use of larger 12-m diameter monopile foundations rather than the 10 m foundations that were originally proposed. They also sought the use of more powerful pile-driving equipment for the foundations, including the use equipment of up to 4,000kJ during installation rather than the consented 3,000kJ, but the subsequently withdrew the hammer energy and monopile increase elements by way of 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 to the use of 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 recent weeks other developers in other countries in Europe are understood to have also sought consent for the use of offshore wind turbines of up to 20 MW in upcoming projects. In 2017, the fast growth in the size of offshore wind turbines was highlighted by Vattenfall, the developer of the proposed Norfolk Vanguard offshore windfarm in the UK, which is 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 with next-generation offshore wind turbines, 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 the development of 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.

In a letter to the lead consent manager for the Dogger Bank projects, BEIS said Secretary of State Greg Clark noted that since the grant of 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 that are available or likely to be available during the course of the construction development programme,” it 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.”