The Ayre and Bowdun Offshore Wind Farms in Scotland are planned to be developed using floating and fixed-foundation technologies, respectively.

Thistle Wind Partners (TWP), a consortium founded by DEME Concessions, Qair and Aspiravi, is developing the two projects.

In January 2022, TWP secured two option areas in ScotWind seabed leasing process to develop the two projects.

The development of Ayre and Bowdun Offshore Wind Farms, with individual capacities of 1GW each, are expected to support the energy transition in Scotland.

Currently, the two wind farms are in the environmental impact assessment development and planning phases.

The final investment decision (FID) for both the projects are expected to be taken in 2028, subject to receipt of necessary consent by 2025.

The construction period will begin in 2029 and the two wind farms are expected to be fully commissioned by 2033.

Once operational, Ayre and Bowdun will generate enough electricity to power 2.4 million households.

Ayre and Bowdun Wind Farms location details

The Ayre Offshore Wind Farm will be located 36km from Kirkwall and 33km from the nearest inhabited point on Orkney – Deerness in the E3 leasing zone, off the east coast of Scotland.

The floating wind farm will cover an area of 200km2.

The Bowdun Offshore Wind Farm will cover an area of 187km2 and will be located approximately 44km from the coast of Aberdeen. The project will lie on the same altitude as the town of Stonehaven and the historic clifftop castle of Dunnottar.

Ayre Wind Farm details

The Ayre wind farm is planned to be developed in two phases.

The first phase, consisting of 97km2 section area, is expected to enter commercial operations in 2031. The 103km2 Phase II area will be commissioned in 2033.

The wind farm will feature 40 - 60 turbines at a water depth of more than 70m. The turbines will have a capacity of 18MW each, which may be increased up to 25MW following further assessment.

The turbines will be on floating foundations based on semi-submersible (triangular platforms which are half-in and half-out of the water) or tension-legs (tied to the seabed by tight and vertical cables) concepts.

If made of steel, each foundation could weigh as much as 5,400 tonnes.

According to the design layout, the project will include a maximum of five turbines per string to minimise cable crossings, maritime disruption and environmental impact. The length of inter-array cables is expected to total 135km.

A 370km long export cable will transport the power generated by the wind farm onshore, with the project expected to make a landfall at Caithness.

Bowdun Wind Farm details

The Bowdun Fixed Offshore Wind Farm will feature fixed-foundation turbines, installed on jacket foundations.

The project will also have 40 - 60 turbines of individual capacities between 18MW and 25MW each.

The length of inter-array cables will be 140km and the export cable that will transport the power onshore will stretch 235km.

The construction works are expected to begin in 2029 and the commissioning is planned in 2032.

Contractors Involved

In January 2023, RPS secured the contract to provide consenting support services, Environmental Impact Assessments (EIA) and Habitats Regulation Assessments (HRA) for the two offshore projects. These assessments will be submitted for project consent applications in 2025.

APEM was selected for baseline survey, Digital Aerial Surveys (DAS) of mammals and seabirds, and LiDAR surveys of seabirds within and around the project site.

TWP will work with Glasgow-based specialist consultancy in land and marine project management Blackhall & Powis to ensure that the offshore wind developments harmonise with other maritime industries.

In April 2023, TWP commenced seabed surveys for Ayre and Bowdun Offshore Wind Farms. The first phase of the work will include the geophysical surveying of the seabed at both sites.

Specialised geophysical and GIS services provider G-tec leads the first phase of the survey, with GAC UK’s Aberdeen and Orkney offices providing support regarding vessel logistics and Cathie offering advisory services.