OES-Environmental distributes metadata forms (questionnaires) to solicit information from developers involved in environmental monitoring around marine renewable energy project sites around the world. This page provides project descriptions, baseline assessment, post-installation monitoring, and links to available data and reports. Content is updated on an annual basis.

MeyGen Tidal Energy Project

Description

The MeyGen tidal stream energy project is owned by SAE Renewables (SAE) previously known as SIMEC Atlantis Energy Ltd, a global developer of sustainable development projects. MeyGen was awarded an Agreement for Lease for the Inner Sound tidal development site on 21 October 2010 by The Crown Estate. The Inner Sound Agreement for Lease is for 398MW of installed tidal stream energy capacity and will be consented in a phased approach. Phase 1 is currently operational while Phase 2 and 3 have been awarded at this stage.

Phase 1 is an operational 6MW demonstration array, which comprises four 1.5MW turbines installed as part of MeyGen’s “deploy and monitor strategy” and entered into the 25-year operational phase in April 2018. All the turbines are upstream, three-bladed, horizontal-axis machines, fully submerged and mounted on gravity-base foundations resting on the seabed:

  • 1 x Atlantis Resources Limited AR1500: with a rated capacity of 1.5MW at 3.0 m/s, a rotor diameter of 18 m, and is designed to withstand the extreme environmental conditions expected to be encountered in the Pentland Firth in Scotland and the Bay of Fundy in Canada. The detailed design of this cutting-edge turbine was completed by Lockheed Martin Corporation during 2014. The AR1500 system has pitching blades and full nacelle yaw rotation capability to facilitate operation in highly energetic deployment locations.
  • 3 x Andritz Hydro Hammerfest HS1500: consisting of a horizontal axis rotor (18 m rotor diameter), pitched blades and yaw feeding a variable speed conventional generator via a gearbox and reaches rated power at current speeds of 3 m/s. Automatic control software governing a sensor-driven monitoring system adjusts the leading edge to capture optimum output from a given tidal environment. It is designed to handle flows between 1 and well above 4 m/s, in water depths down to 100m.

Another milestone of Phase 1 is   Project Stroma which comprises a subsea hub installed in September 2020. This allows multiple turbines to be connected to a single power export cable. This will significantly reduce the costs associated with grid connection. The length of power export cable as well as the amount of onshore conversion equipment required for grid connection will be significantly reduced, as will the amount of horizontal directional drilling and the amount of vessel time required for cable installation. Project Stroma will connect two additional Atlantis AR2000 turbines via the new subsea hub to a single power export cable which will then be connected via the MeyGen substation to the National Grid. 

Phase 2 has recently been awarded a total of 59MW from the three latest allocation rounds for Contracts for Difference (CfD) (Allocation Rounds 4,5 and 6) with a target commissioning date of 2027, 2028 and 2029 respectively. Overall, the Meygen lease and site resource allows for a capacity out to 398MW, therefore future phases of the project would seek to expand the consents and build out the remainder of this capacity.

SAE are also exploring the opportunity to collocate the tidal stream project alongside storage solutions, based upon prior experience at Uskmouth Energy Park. This is called the Meygen Sustainable Energy Park.

Export Cables: Each turbine requires its own cable to shore. Each cable was brought to shore via horizontal directional drilled (HDD) bores through the bedrock which terminate in a Power Conversion Centre (PCC). This subsea cable installation was carried out in September 2015 (see below).

Onshore Infrastructure: MeyGen requires an onshore PCC, cable landfall and cable routes from the PCC to the grid connection location.  At the PCC, the electricity is transformed up to higher voltages for export to the national transmission grid.  A further connection to the high voltage transmission network with Scottish Hydro Electric Transmission Ltd. has been secured, providing enough capacity to cover a large proportion of the remainder of the Project. The onshore infrastructure for the project was completed in early 2016 (see below).

Vessel Spread: The following vessels were utilised during construction and operation:
 

Vessel type

Activity

Comment

DP installation vessel

Installation of  turbine support structures

Smaller vessels were present for support services.

During year 1 and 2 of installation, only one DP vessel was onsite at any one time.  During year 3, two DP vessels were on site during support structure installation. 

Installation of export cables

DP installation vessel (or tug)

Install turbines onto support structures

Location

Inner Sound, Pentland Firth, Scotland.

Licensing Information

Consent was granted in 2013 by the Scottish Ministers under Section 36 of the Electricity Act for the construction and operation of Phase 1, consisting of up to 61 turbines with a permitted capacity of up to 86MW.  The consent was conditional upon SAE deploying the turbines in stages, with Phase 1A limited to a maximum of 6 turbines (only 4 turbines were installed), with all subsequent stages of the development being subject to the prior written approval of the Scottish Ministers. 

A Marine Licence under the Marine (Scotland) Act 2010 was granted for Phase 1 in 2014. A Marine Licence Variation was issued in 2017 with a revised Turbine Deployment Area (to include an additional area to the north-west of the site and to remove a similar sized area from the eastern side of the site). Following this, in 2019 a Section 36 Consent Variation was granted to ensure that the Turbine Deployment Area specified in Annex 3 of the s.36 consent is consistent with the revised Phase 1 Marine Licence area shown in Part 4 of the Schedule to Marine Licence (ref: ML 04577/17/1).

Licencing documentation can be accessed on Marine Scotland Information: https://marine.gov.scot/ml/meygen-tidal-energy-project

Licence

Competent Authority

Reference

Date issued

Expiry date

Section 36 (Electricity Act) Consent

Scottish Ministers

 

9 October 2013

 

Section 36 Consent Variation

Scottish Ministers

 

29 August 2019

 

Marine Licence (Marine (Scotland) Act) Consent – Construction, Operation and Deposit of a Tidal Stream Electricity Generating Station

Marine Scotland

04577/14/0

31 January 2014

31 December 2020

Marine Licence (Marine (Scotland) Act) Consent (variation) – Construction, Operation and Deposit of a Tidal Stream Electricity Generating Station

Marine Scotland

04577/17/1

11 September 2017

1 January 2041

European Protected Species Licence

Marine Scotland

MS EPS 19/2016/00

4 November 2016

4 November 2018
Marine Licence Variation Marine Scotland 04577/15/0 17 September 2015 31 December 2020
Marine Licence Variation Marine Scotland 04577/16/0 29 July 2016 1 January 2041
Marine Licence - Seabed Preparation Marine Scotland 06045/16/0 29 July 2016 1 January 2041
Marine Licence - Cable stability measures for the 4 turbine subsea cables Marine Scotland 06234/17/0 18 January 2017 1 January 2041
MeyGen Tidal Energy Project - Marine Licence Marine Scotland 06978/19/0 1 October 2019 30 November 2036
Marine Licence Variation - Cable stability measures for the 4 turbine subsea cables Marine Scotland MS-00009804 6 May 2022 1 January 2041
Marine Licence Variation - Construction, Operation and Deposit of a Tidal Stream Electricity Generating Station Marine Scotland MS-00009802 6 May 2022 1 January 2041

Project Progress

MeyGen secured an Agreement for Lease (AfL) from the Crown Estate for the Inner Sound tidal development site in 2010.  This AfL is for a tidal stream development with an installed capacity of up to 398 MW.

In 2013, MeyGen was awarded consent from the Scottish Government for the installation and operation of Phase 1 (up to 86MW).  Phase 2 will take place following the ‘deploy and monitor strategy’ on Phase 1 turbines and will see the build out of the remainder of the project subject to a separate consent application .

Onshore construction of the development commenced in 2015, beginning with the creation of a 340 m access road to the onshore site in Caithness. Completion of the access route was expected to take three months, with all onshore construction work being finished by the end of 2015. A press release in spring 2016 confirmed that the foundations, steelwork and cladding for the onshore infrastructure were complete, and the onshore project was ready to start electrical ¬fit out works. Works on the building included installing power conversion equipment for the turbines, 33kV switchgear for grid connection and a control centre for controlling the tidal turbine array off shore, as well as an indoor substation for SSE grid connection equipment and offices for MeyGen project operations team.

Scottish Hydro Electric Power Distribution Ltd. completed a 17km onshore cable installation campaign with the final section of cable brought into the MeyGen onshore building in February 2016. MeyGen is classifi¬ed as a Large Power Station by National Grid and hence has a requirement to satisfy the stringent UK grid code. This was the fi¬rst tidal energy project to go through this diligence process and demonstrates the scale of this project.

In September 2015, 11km of submarine cable was successfully installed at the MeyGen off¬shore site. A specifi¬c neap-tidal window was selected in September to provide enough time for the vessel to install one of the four turbine cables every 12 hours. While ambitious, this schedule was achieved, and the offshore operation took just 2.5 days. The next phase of the project’s offshore works carried out in summer 2016 involved the installation of the four Turbine Support Structures. Following this, the four Tidal Turbine Generators were installed in late 2016 and early 2017.

The project announced the completion of its construction phase and the start of its 25-year operational phase in April 2018.  During 2018, several MeyGen tidal power turbines were inspected and underwent maintenance.  All the turbines were redeployed and re-connected towards the end of 2018. 

By February 2019, the MeyGen tidal array had exported more than 12 GWh of tidal energy to the grid in Scotland.  During Phase 1A the tidal array generated 6GWh of energy and saw monthly production of 1,400 MWh a month of tidal energy.  This was quickly surpassed by a new record with MeyGen exporting more than 15 GWH to the grid in May 2019.

2020 saw Phase 1 of the Group’s flagship MeyGen tidal energy project continue to break records, delivering over 37GWh of clean and predictable electricity to the grid.

In March 2020, the MeyGen project was awarded £1.5 million in grant funding from the Scottish Government’s Saltire Tidal Energy Challenge Fund to develop a subsea tidal turbine connection hub for the next phase of development of the MeyGen tidal power array, Project Stroma. The subsea hub was successfully installed in September 2020 and is said to be a key part of the overall cost reduction strategy for tidal power generation.

A press release in August 2021 announced that both the AR1500 and the Andritz turbine number one have been retrieved for planned quarter-life maintenance at the company’s tidal turbine workshop at Nigg Energy Park. Whilst in the workshop, the turbines have undergone basic routine maintenance, including oil and filter changes, and will soon be ready for reinstallation at the MeyGen site in Caithness. Currently, there is very limited availability for suitable offshore vessels. The plan will be to install both turbines in one offshore operation, reducing overall costs when compared to two separate vessel hires.

In July 2022, SAE achieved the first contractual milestone in Phase 2 for the delivery of additional 28MW of tidal power capacity for the project. 

In October 2022, SAE deployed an acoustic Doppler current profiler (ADCP), a tidal flow measurement device, at the MeyGen site. 

To date, the site has two of four turbines fully operational and generated its first 50 GWh of renewable power in February 2023 and is now generating 68 GWh as of September 2024. 
In September 2023, MeyGen Phase 2 secured multiple CFDs totaling 22 MW during Allocation Round 5, at a significantly higher strike price compared to Allocation Round 4. This total was further increased by an additional 9 MW from Allocation Round 6 in September 2024, bringing the overall total for Phase 2 to 59 MW.

Key Environmental Issues

There were a number of potential impacts that have been identified in the Environmental Statement, however only the following were deemed to be potentially significant:

  • Collisions between marine mammals and installation vessels; and
  • Disturbance to fish due to EMFs from subsea cables.

The following mitigation and best practice measures were outlined in the Environmental Statement and Environmental Management Plan: 

  • Where cables are not within boreholes they will be laid where possible within natural crevices and cracks within the seabed ensuring that the majority of the cable is below the seabed.
  • The length of the drilled boreholes for the cable will, as far as possible, increase the length of cable under the seabed.
  • Cables will be bundled into groups of 3 minimising the magnetic field by placing the cables close together, allowing the field vectors to cancel each other out. 
  • Ongoing research by Marine Scotland and their advisors will be monitored for further indications of successful mitigation strategies. 
  • MeyGen commit to undertaking frequent reviews of the literature regarding spiral injuries in seals and ducted propellers and to regularly discuss advances in understanding of this topic with relevant regulatory and advisory bodies. MeyGen will apply appropriate mitigation, as deemed necessary in consultation with Marine Scotland and SNH, should vessels with ducted propellers be used, to avoid any significant impacts[1].
  • The turbines have been subjected to engineering design and third-party verification to ensure they are suitable for deployment in the Inner Sound.
  • The Project will be using tried and tested equipment and techniques to minimise the risks associated with the high tidal flow environment.
  • Turbine nacelle designs that use buoyancy as part of the installation and maintenance strategy have failsafe locking systems for the connection between the nacelle and the Turbine Support Structures (TSSs) to prevent accidental release.
  • On-site monitoring via SCADA (Supervisory Control and Data Acquisition) will alert the 24-hour control room operations team of turbine failure or an object hitting the turbine.
  • An Emergency Response Cooperation Plan (ERCoP) will be prepared for the Project following the template provided by the MCA in Marine Guidance Note (MGN) 371. This will be submitted to the MCA for comment and approval. Emergency response would include informing HM Coastguard, Royal National Lifeboat Institution (RNLI), Harbours and local users (e.g., Pentland Ferries) so that vessels in the area are alerted to the potential hazard.
  • Multicat type vessels will be used for some of the activities to reduce ship strike and propeller collision due to the lack of ducted propellers and and a fixed seabed anchor system on these types of vessels.

[1]   A large majority of spiral injuries are now understood to be caused by aggressive interactions from other grey seals, based on observations of lethal attacks by adult male grey seals (Sea Mammal Research Unit, 2015): http://www.smru.st-andrews.ac.uk/files/2015/10/USD1and-6_addendum_repor…

Papers, Reports, Research Studies

Baseline Assessment: MeyGen Tidal Energy Project

Receptor Study Description Design and Methods Results Status
Physical Environment Current profile of the water column by ERI ERI survey: Vessel mounted 300 kHz RDI ADCP to measure current speed and direction along transects. There are widespread and highly energetic tidal races, eddies and areas of general turbulence throughout the Pentland Firth. Just beyond the western end of the site off St John’s Point on the Scottish mainland, the Merry Men of Mey is one of the most significant oceanographic features in the Pentland Firth. This is an area of tidal racing that occurs on the west-going ebb, particularly when opposed by westerly wind or waves. Currents within the Inner Sound have a clear flood ebb pattern, while the island of Stroma generates extensive eddies on its downstream side during both flood and ebb flows. Completed 2011 (9 month survey beginning in October 2010 and finishing in July 2011)
Physical Environment Bathymetric and geophysical survey by Atlantis Multi-beam echo sounder, side scan sonar, pinger sub-bottom profiler and magnetometer used to determine water depths, seabed composition, bedform profiles, depth of seabed sediment type and presence of anomalies. Water depths within the turbine deployment area vary between approximately 31m to 49m below LAT. The majority of the area is relatively flat having a water depth between 31.5 and 38m, but fissures in the bedrock up to 10m deep occur in the site, particularly at the western end south of Mell Head. Completed 2009 (September)
Physical Environment Coastal geology field survey by Atlantis Visual survey Much of the coastal section around the project area is marked by cliffs between 5 to 10m high, with a platform of nearly flat-lying slabs exposed in the littoral zone at the cliff foot. Beyond the eastern end of the project area on the mainland are the sheer cliffs at Duncansby Head, which are cut in Old Red Sandstone and rise up to 70m in height. Similar cliffs are seen to the west of the site at Dunnet Head, which reach over 90m in height. In areas where cliff exposures are absent, the back wall of the beach is formed by a usually steep, vegetated bank of between 2 and 15m in height. Completed 2009 (November)
Physical Environment Seabed structure investigation by ERI Vessel mounted starfish 450F side scan sonar survey to gain an image of the seabed Within the Inner Sound survey area 70% (7.8km) of the seabed is current scoured bedrock exhibiting a sawtooth profile, comprising folded and tilted sedimentary sandstone, flagstone and siltstone. Areas of shell sand accumulation are present in the north-eastern regions of the survey area as well as a localised area in the north-west. These regions commonly exhibit mega-ripples, of lengths up to 20m and heights of between 0.2 and 0.5m. Completed 2011 (8 month survey beginning in November 2010 and ending in July 2011)
Physical Environment Current wave and turbulence survey by MeyGen Bottom mounted RDI 1200 kHz ADCP and bottom mounted Acoustic Wave and Current (AWAC) 600 kHz ADCP to measure current speed and direction throughout water column and provide some quantification of turbulence and wave heights. Wave conditions are most severe (i.e. the wave field contains the greatest energy) in the exposed coastal areas to the west of the site, but although the highest and most frequent waves approach the Inner Sound from the west (UKHO, 2005) , the coastal features and bathymetry of the Inner Sound are likely to cause these westerly waves to largely dissipate by the time they reach the Project site. Waves from the North Sea are less severe because a spit of shallower water extends north-east from Duncansby Head across the eastern end of the Inner Sound thus reducing their energy, but the open coastline on the eastern side of the Sound allows these waves to penetrate more Completed 2011 (July)
Physical Environment Seabed characterisation survey by MeyGen Grab samples, water samples and drop down video/photography to gain an idea of sediment bedload, particle size distribution and amount of suspended sediment. The Project area is generally devoid of superficial sediments, with the exception of the north-eastern and north-western regions of the site. Where found, sediments range from a coarse gravel veneer to larger mobile accumulations of coarse shell sand. At higher current speeds, and in coarser sediments, somewhat larger bed forms known as mega ripples are produced. Gravel waves are found where the currents are very strong, typically 1.5ms. Completed 2011 (July)
Marine Mammals Vessel and shore based visual surveys by RPS The boat-based surveys involved two approaches to data gathering; firstly, boat transect surveys based on modified European Seabird at Sea methods (Tasker et al., 1984) collected distributional data and secondly, stationary boat surveys at fixed locations were used to collect behavioural data. Land-based vantage point survey methods were adapted from approaches to terrestrial vantage point surveys; three vantage point locations on the Caithness coastline were selected and observations made during two to three visits each month over the same time period as the boat-based surveys. 10 cetacean species are either casual or regular visitors to the Pentland Firth; these are the mysticete (baleen whale) the common minke whale, the odontocetes (toothed whales and dolphins) sperm whale Physeter macrocephalus, killer whale Orcinus orca, long-finned pilot whale Globicephala melas, Risso’s dolphin, bottlenose dolphin, Atlantic white-sided dolphin Lagenorhynchus acutus, white-beaked dolphin Lagenorhynchus albirostris, short-beaked common dolphin and harbour porpoise and the two pinniped species the grey seal and the harbour seal. Completed 2011 (2 year survey beginning in October 2009 and ending in September 2011)
Physical Environment Geophysical survey by iXSurvey Limited Geophysical site survey to provide an indication of the seabed substratum present in the area. The Inner Sound is composed largely of exposed Devonian Old Red Sandstone bedrock. The majority of the seabed is comprised of current scoured bedrock with patches of sand, mega rippled sand and sandbanks with coarse gravel in isolated patches both directly south and southwest of Stroma. Completed 2009
Marine Mammals Acoustic detection survey by Ecologic UK Acoustic survey across the Inner Sound to trial the performance of PAM systems in the site conditions. Outputs used to qualitatively assess the likely efficiency of the visual surveys for harbour porpoise detection. PAM was deployed on the final 3 marine mammal surveys. The overall acoustic detection rate for harbour porpoise was higher than the visual detection rate. This could suggest that the visual sightings rates may not accurately reflect actual levels of harbour porpoise activity in the Inner Sound. Completed 2011 (between May and August 2011)
Human Dimensions, Navigation Radar survey by MeyGen 42 days of data from an existing radar scanner at Sandy Hill South Ronaldsay was gathered and analysed (along with other data sources such as AIS). Visual logs of small vessel activity were kept during other offshore and onshore projects surveys. Visible during all the periods are the tracks of the Pentalina ferry, operated by Pentland Ferries between Gills Bay and Saint Margaret’s Hope with three return trips per day. All the periods also showed consistently heavy east-west traffic via the Outer Sound between the islands of Stroma and Swona. The number of vessels using the Outer Sound averaged 14 per day, with around 11 per day heading east-west. The east-west traffic transiting the Inner Sound is low-to-moderate by comparison, averaging less than 1 vessel per day (approx. 4% of the Outer Sound traffic). The sizes of vessels in the Inner Sound also tended to be smaller. Completed 2011 (1 year survey beginning in June 2010 and ending in August 2011)
Birds Vessel and shore based visual surveys by RPS This survey was conducted in conjunction with the marine mammal survey. The same methods were used. During the 22 boat surveys, a total of 13,248 individuals comprising 19 species were recorded on the sea within the transect area. During land-based surveys a total of 21,568 individuals were recorded during distribution scans, comprising 24 species and 2 species groups. Completed 2011 (2 year survey beginning in October 2009 and ending in September 2011)
Invertebrates Benthic seabed survey by Aquatic Survey and Monitoring Ltd Drop down video and photographic survey was used to note seabed type and biotopes present. Grab sample survey to determine the infaunal community types in any sediment that exists in the area and to determine baseline sediment particle size distribution. Additional grabs taken to collect sediment for analysis of radioactivity. The largest biotope by area in the offshore Project development area is CR.HCR.FaT.BalTub (B. crenatus and T. indivisa on extremely tide-swept circalittoral rock), which is very similar to the CR.HCR.FaT.CTub (Tubularia indivisa and cushion sponges on tide-swept turbid circalittoral bedrock) biotope found in the area by the Marine Scotland surveys. CR.HCR.FaT.CTub (Tubularia indivisa and cushion sponges on tide-swept turbid circalittoral bedrock) was also recorded by the ASML survey. SML (2011) report that the observations made from the five Marine Scotland surveys by Moore & Roberts (2011) tallied very closely with those of the present survey. Completed 2011
Physical Environment Current profile of the water column by Atlantis Atlantis survey: 300kHz Acoustic Doppler Current Profiler (ADCP) and moving vessel current transects measured the current speed and direction at 1m bins throughout the water column. There are widespread and highly energetic tidal races, eddies and areas of general turbulence throughout the Pentland Firth. Just beyond the western end of the site off St John’s Point on the Scottish mainland, the Merry Men of Mey is one of the most significant oceanographic features in the Pentland Firth. This is an area of tidal racing that occurs on the west-going ebb, particularly when opposed by westerly wind or waves. Currents within the Inner Sound have a clear flood ebb pattern, while the island of Stroma generates extensive eddies on its downstream side during both flood and ebb flows. Completed 2009 (April)

Post-Installation Monitoring: MeyGen Tidal Energy Project

Stressor Receptor Study Description Design and Methods Results Status
Changes in Flow Physical Environment Validation of hydrodynamic model Post installation deployment of an ADCP with the initial turbines to validate the hydrodynamic modelling undertaken to inform the EIA and to validate the erosion/deposition and bedload transport results. TBC Planned
Changes in Flow Physical Environment Monitor the dispersion of drill cuttings from potential TTS pile installation and HDD bore breakthrough Benthic monitoring will be primarily based on drop down video upstream / downstream of the project such that potential changes to the biotope mosaic in the area could be detected. Reference areas to either side of the turbine array and cable routes could also be sampled. TBC Planned
Changes in Flow Physical Environment Undertaken surveys (post-installation and post decommissioning) to detect any significant changes in habitats due to the presence of the turbines Benthic monitoring will be primarily based on drop down video upstream / downstream of the project such that potential changes to the biotope mosaic in the area could be detected. Reference areas to either side of the turbine array and cable routes could also be sampled. TBC Planned
Habitat Change Human Dimensions, Navigation Vessel traffic monitoring Vessel traffic behavior will be monitored on AIS during construction and operation to assess the effect the project has on passing traffic and the proportion of vessels that re-route within the Inner Sound or via the Outer Sound. TBC Planned
Habitat Change Human Dimensions, Fisheries Long term impacts upon local fisherman Consultation with local fishermen will be maintained throughout the project to aid the assessment of any long term impacts and to inform the decommissioning phase. TBC Planned
Collision Marine Mammals Collision / encounter interactions with the tidal turbines for diving birds, marine mammals and fish of conservation concern. Combined monitoring equipment, including, active acoustics, PAM, seal tagging, cameras and strain gauges. PAM data results for harbour porpoise (October 2017 – April 2019): echolocation clicks from 344 porpoise events were localised close to the turbine instrumented with a high frequency 12 hydrophone array. Porpoises were found to effectively avoid the turbine rotors, with only a single animal clearly passing through the rotor swept area while the rotors were stationary, and none passing through while rotating.
Ongoing
Collision Fish Collision monitoring Collision risk will be monitored by the installation of one or more active monitoring systems on one of more of the tidal devices. TBC Planned
Collision Fish Collision / encounter interactions with the tidal turbines for diving birds, marine mammals and fish of conservation concern. Combined monitoring equipment, including, active acoustics and cameras. TBC Planned
Collision, Noise Fish Collision monitoring Collection of underwater noise measurements of candidate prototype tidal turbines. Data collected will be used to validate the underwater noise modelling completed to inform the impact assessment. TBC Planned
Collision Birds Collision / encounter interactions with the tidal turbines for diving birds, marine mammals and fish of conservation concern. Combined monitoring equipment, including active acoustics and cameras. TBC Planned
Collision, Displacement Birds Monitoring of potential displacement and disturbance of birds Disturbance and displacement of birds at sea will be monitored from targeted land and boat based surveys to determine any behavioral changes. Collision risk will be monitored by the installation of one or more active monitoring systems on one of more of the tidal devices; this will assist in the understanding of near field bird interaction with devices. Birds will also be fitted with geo locators and dive loggers will provide information on any correlations between the site and breeding grounds. TBC Planned
Displacement Marine Mammals Disturbance and displacement of birds, marine mammals and fish during construction and operation. The seal tagging work will provide some information on potential disturbance and displacement of harbour seals, and information on seal behaviour in the wider area. Pentland Firth and Orkney were surveyed during the August moult by SMRU in 2013 and 2015 and 2016. Future monitoring plans of seal haulouts will be confirmed by the Special Committee on Seals (SCOS). The proposed monitoring equipment, such as active acoustics, PAM, and the cameras, may provide some information on the disturbance and displacement of marine mammals in close proximity to the turbines. Seal distribution is driven primarily by tidal dynamics. Distribution did not change with turbine installation but did change with operation of the turbines. Seals are actively avoiding the turbines when operating but continue to use the site during non-operational periods. Overall, movement behaviour does not appear to be hindered by the presence of turbines, suggesting that pre-installation foraging sites have not been significantly obstructed. Ongoing
Noise Marine Mammals Acoustic monitoring of operational noise Collection of underwater noise measurements of candidate prototype tidal turbines. Data collected will be used to validate the underwater noise modelling completed to inform the impact assessment. TBC Planned
Displacement Fish Disturbance and displacement of birds, marine mammals and fish during construction and operation. Atlantic salmon: The proposed monitoring equipment, such as active acoustics and cameras, may provide some information on the behaviour of Atlantic salmon in close proximity to the tidal array. It is considered, however, that the most appropriate way to improve our knowledge regarding the behaviour of migratory Atlantic salmon in the Pentland Firth and Orkney waters, would be through strategic research, which would benefit not just MeyGen but the marine renewables industry. TBC Planned
Displacement Marine Mammals Post deployment survey to assess possible displacement Targeted observation of marine mammals is proposed, as is acoustic monitoring of harbor porpoise using static loggers to with determining area use. TBC Planned
Changes in Flow Physical Environment Hydro dynamics / benthic surveys, export cable route and turbine locations and modelling to validate EIA predictions. Data from the Acoustic Doppler Current Profilers (ADCP) and Acoustic Doppler Velocimeter (ADV) will provide information on changes in flow around the array, which could be used to validate EIA predictions. TBC Planned