Description
The Westray Tidal Array Project aims to install around 70 Orbital O2 style tidal turbine devices at Westray Firth, Orkney, with a total generating capacity of 170 MW. To ensure station-keeping, each device will be attached via four mooring lines connected to either rock drilled or gravity anchors and there will be four anchors per device, or anchor sharing if deemed technically achievable following detailed design.
There would be up to five 33 kV electrical export cables. These would pass through the EMEC Fall of Warness tidal demonstration site with the cable landfall and grid connection at EMEC’s onshore connection point.
The Project completed a geophysical survey of approximately 35% of the Westray Firth area in June 2023 and commenced marine wildlife surveys in April 2023 which comprises of boat-based ESAS and marine mammal observations at approximately monthly intervals covering the Westray Firth and Fall of Warness site.
Location
The planned project is located in the Westray Firth off the coast of Eday, Egilsay and Rousay. It is approximately 22 km northeast of Kirkwall.
Licensing Information
The Westray Tidal Array Project has been awarded an Option Agreement from the Crown Estate Scotland and the Orbital team are in the process of applying for a Marine License under the Marine (Scotland) Act 2010. Currently, Orbital have submitted a pre-application Scoping Request and are awaiting feedback.
Project Progress
In 2010, SSE Renewables was awarded an Agreement for Lease (AfL) from The Crown Estate for development rights to support a 200 MW tidal array in the Westray Firth, Orkney. This was transferred to DP Energy in 2014 and now Orbital Marine Power Ltd in March 2023. The original project can be found here: https://tethys.pnnl.gov/project-sites/westray-south-tidal-project.
The new lease is now a superset of the previous leases and was awarded an Option Agreement from Crown Estate Scotland for a 30 MW tidal array with an aim to increase the generating capacity to 170 MW through the Fall of Warness site. The export cable route through the EMEC site will be consented as part of EMEC’s planned consent application to expand the capacity of the site to 50 MW.
To get to this 170 MW target, Orbital will be applying for Contract for Differences (CfD) application allocation round 8 in Quarter 1 2026 and pending a successful CfD award, a final investment decision will be completed by Quarter 1 2028 to ensure installation in 2030.
Key Environmental Issues
Within the Scoping Report, key potential environmental issues that will be considered in the EIA include habitat change, disturbance, underwater noise, electromagnetic fields (EMF), collision risk, entanglement, and displacement.
Within the Scoping Report, five methods were mentioned to survey the project area. These include ROV, sonar, ACDP measurements, grab sampling and core sampling. These methods will help with project design activities such as micro-siting, identifying potential obstacles, assessing seafloor conditions and provide information to inform the EIA e.g. by identifying any sensitive habitats or protected areas.