Description
The first three Nova M100 devices (installed capacity 300 kW) were deployed in 2016 and 2017. This was the world’s first offshore tidal array to supply electricity to the grid with greater than 17,000 generating hours reached in 2019.
In 2018 licences were granted to extend the array to six turbines (increase capacity to 600 kW). In 2018, Nova Innovation worked with Tesla to add energy storage to their tidal technology. This created the world’s first grid connected tidal power station with the ability to deliver baseload (constant, steady state) power and deliver energy on demand to meet consumer needs.
In August 2020 a fourth 100 kW turbine was added to the array. This was the M100-D, next generation of Nova's M100 turbine, with no gearbox (direct drive). A further two 100 kW M100-D turbines were installed in January 2023, taking the total number of turbines to six. An offshore hub was also installed, enabling a single export cable to take the power from the fifth and sixth turbines to shore.
In 2023 licences were granted to partially decommission the array by removing the three original M100 turbines and associated offshore infrastructure. This was carried out as part of the EnFAIT project to gather information on the full end-to-end lifetime of an operational tidal array. Decommissioning the three M100 devices was completed in October 2023. The three M100-D turbines continue to generate and export electricity to the grid.
A comprehensive environmental monitoring programme has gathered data from the operational array since the installation of the first turbine in Bluemull Sound and is ongoing. The primary objective of the monitoring programme is to gather data on nearfield interactions between marine wildlife and the operational turbines, with a focus on marine mammals and diving seabirds. Over time the environmental monitoring programme has evolved, in line with the principles of adaptive management, to ensure it remains fit for purpose. All previous monitoring reports, along with other licensing information and documentation, are available online via the Marine Scotland Information website .
The environmental monitoring programme is now based on the use of turbine-mounted high-definition cameras to gather data on nearfield interactions between marine wildlife and the operational turbines. Other methods, including land-based bird and mammal surveys were previously employed, but have since been retired, having demonstrated that the risk of adverse effects to birds and mammals is very low.
Location
The Shetland Tidal Array is located in the Bluemull Sound, Shetland off the far north-east coast of mainland UK, between the islands of Yell and Unst.
Licensing Information
Marine Licence required from Marine Directorate Licensing Operations Team for construction and operation of the project.
Marine Licence required from Marine Directorate Licensing Operations Team for decommissioning the three original turbines.
Offshore Works Licence required from Shetland Islands Council.
Onshore Works licence required from Shetland Islands Council.
Licence to disturb European Protected Species (EPS) required from Marine Directorate Licensing Operations Team.
Project Progress
First three geared M100 turbines installed 2016-17. Fourth direct drive M100-D turbine installed 2020. Two more direct drive M100-D turbines and an offshore hub installed 2023. Three original geared turbines decommissioned in 2023.
Key Environmental Issues
Collision risk and disturbance to EPS. See https://marine.gov.scot/ml/marine-licence-shetland-tidal-array-extended-bluemull-sound-shetland-0664200009110 and https://marine.gov.scot/node/23874
Papers, Reports, Research Studies
Licence application document:
Monitoring reports:
- Subsea Monitoring Report – Shetland Tidal Array
- Vantage Point Survey Report – Shetland Tidal Array
- Enabling Future Arrays in Tidal: Y1 Environmental Monitoring Report
- Automated detection of wildlife in proximity to marine renewable energy infrastructure using machine learning of underwater imagery
- Environmental Monitoring and Mitigation Plan: Shetland Tidal Array, Bluemull Sound
- Appropriate Assessment for Nova Innovations Ltd, Extended Shetland Tidal Array, March 2018
- European Protected Species Application – Shetland Tidal Array
- European Protected Species Licence Decommissioning of Tidal Turbines – Shetland Tidal Array
- Marine Licence - Alteration of constructed works (removal of turbines), Shetland Tidal Array
Baseline Assessment: Nova Innovation - Shetland Tidal Array
Receptor | Study Description | Design and Methods | Results | Status |
---|---|---|---|---|
Marine Mammals | Encounter Rate Modelling (ERM) to inform collision risk | Use of computer models to determine the potential for sensitive species to collide with turbine blades. A 98% avoidance rate was assumed. | The following calculations are based on the assumption that the devices are operating for 73% of the time as estimated by Nova. All year predicted encounter rate – 3.96 Breeding season parameters based on seals-at-sea density figure – 4.00 | Encounter Rate Modelling (ERM) to inform collision risk |
Birds | Encounter Rate Modelling (ERM) to inform collision risk | Use of computer models to determine the potential for sensitive species to collide with turbine blades. A 98% avoidance rate was assumed. | Atlantic puffin (Breeding season ERM: 1.45; All year ERM: 1.36) Red-throated diver (Breeding season ERM: 0.13; All year ERM: 0.15) Northern gannet (Breeding season ERM: 0.00; All year ERM: 0.00) Common guillemot (Breeding season ERM: 0.37; All year ERM: 0.36) European shag (Breeding season ERM: 4.87; All year ERM: 11.25) | Complete |
Post-Installation Monitoring: Nova Innovation - Shetland Tidal Array
Stressor | Receptor | Study Description | Design and Methods | Results | Status |
---|---|---|---|---|---|
Collision | Birds, Fish, Marine Mammals | Underwater video monitoring | Nova Innovation has carried out extensive video monitoring of the turbines currently deployed in the area to assess the potential impact on marine wildlife. Each turbine is fitted with cameras that are triggered by the presence of wildlife. | There have been no observations of any marine wildlife colliding with the blades. Fish, birds and seals have been observed on the cameras, however, both the fish and their predators were observed to leave the region of the turbines while tide was flowing (and blades were rotating), with fish moving to areas of lower flow on the seabed. | Ongoing |