Management Measures Tool for Marine Energy

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Accessing Management Measures that Support Deployment of Wave and Tidal Energy Devices

As the marine renewable energy (MRE) industry moves beyond deployment of individual wave and tidal energy devices towards arrays, certain risks of MRE devices on the marine environment are not well understood and have led to onerous monitoring requirements placed on device developers.

A workshop was held in May 2017 with researchers, regulators, and developers to create the basis for the tool shown below. In consultation with the research and regulatory communities, it was agreed that applying a set of robust management measures could act as safeguards for marine animals and habitats until available monitoring data allows for determining the level of risk from MRE devices. At that point, measures could be dialed back or removed, if warranted. More information on the workshop and input for the tool can be found here.

The Management Measures Tool for Marine Energy shows management (or mitigation) measures from past or current MRE projects as a reference to help manage potential risks from future projects and allow them to move forward in the face of uncertainty, or until a risk can be retired. Additional management measures are regularly added by the OES-Environmental team. In addition to the searchable tool below, the information can be downloaded here. The download file includes additional details not shown below, including comments from stakeholders on past experience, cost of management measures, and when a management measure is needed.

View the instructions document for more in-depth details and examples on how to use the Management Measure Tool for Marine Energy or check out this webinar for an overview and demonstration of the tool. 

*Information in advantages and challenges comes from a SEA Wave report, and may also include information from the listed project documents.

Last updated June 2024

Displaying 101 - 200 of 339 management measures
Technology Project Phase Stressor Receptor Management Measure Advantages Challenges Project Documents
Wave, Tidal Operation & Maintenance EMF

Impacts of electromagnetic fields from subsea cables on sensitive species.

Fish
Migratory fish
Design feature

Bundle cables together to reduce field vectors.

Reduce the level of EMF to surrounding water column and therefore any potential effects.

Less redundancy in system.

Potential commercial and technical feasibility issues.

Greater costs associated with not laying direct cable paths.

MeyGen 2012, MeyGen Tidal Energy Project
Wave, Tidal Installation, Operation & Maintenance, Decommissioning Underwater noise

The potential effects from airborne noise from support vessel activity.

Fish
Mitigation

Adherence to Scottish Marine Wildlife Watching Code (SMWWC).

None identified

None identified

European Marine Energy Centre (EMEC) 2014, Magallanes Renovables 2020, Xodus Group 2019, European Marine Energy Centre (EMEC) 2020, Aquatera 2017, Laminaria 2018, Orbital Marine Power 2018, EMEC Fall of Warness Grid-Connected Tidal Test Site, Magallanes Renovables ATIR at EMEC, EMEC Billia Croo Grid-Connected Wave Test Site, EMEC Scapa Flow Scale Wave Test Site, Tocardo InToTidal at EMEC, Orbital Marine Power O2 at EMEC, Mocean Wave Energy Converter: Blue Horizon
Wave, Tidal Operation & Maintenance Habitat Creation

The introduction of infrastructure and artificial substrates will provide habitat and artificial refuges.

Habitat
Monitoring

Monitor near-field behaviors.

Reduces scientific uncertainty around collision risk, displacement, and other impacts.

Increased value/fecundity of commercially important species.

Can be expensive and difficult to deliver in practice.

May require additional licensing (e.g., echosounders).

Tidal Operation & Maintenance Collision risk

Potential for collision with turbine blades.

Marine Mammals
Mitigation

Install propeller guards.

None identified

None identified

McGrath 2013, Fair Head Tidal Array
Wave, Tidal Operation & Maintenance Entanglement

Potential for marine animals to become entangled in device mooring lines and cables.

Marine Mammals
Cetaceans
Mitigation

Install strain gauges on the device

Alerts the operator in the event of an entanglement event.

Magallanes Renovables 2020, Magallanes Renovables ATIR at EMEC
Tidal Operation & Maintenance Changes in water flow

The potential wider or secondary effects on protected or sensitive sub-littoral seabed due to removal or alteration of energy flow arising from devices and moorings or support structures.

Reptiles
Monitoring

Modelling to predict the interaction between changes in tidal flow, flux, and turbulence structure and animals.

Reduces scientific uncertainty so appropriate management measures can be employed

Limited management measures available to minimize interaction despite modelling to fully predict interaction

Wave, Tidal Installation, Operation & Maintenance, Decommissioning Changes in sediment dynamics

The potential wider or secondary effects (siltation changes or smothering) on protected or sensitive sub-littoral seabed due to scour or siltation around devices and associated moorings, support structures, and export cables.

Benthic
Design feature

Minimize the amount of structure on the seabed.

Minimizes the changes in sediment dynamics due to presence of structure on the seabed.

Can present financial/ logistical/ design challenges to technology developer to alter design of device/moorings.

OpenHydro and SSE Renewables 2013, Fox 2019
Wave, Tidal Operation & Maintenance Habitat Creation

The introduction of infrastructure and artificial substrates may generate additional habitat diversity.

Benthic
Benthic species
Monitoring

Structure colonization and biofouling surveys.

Informs understanding of potential for increased prey availability and ecological diversity.

Cost associated with monitoring.

Magallanes Renovables 2020, Orbital Marine Power 2018, Magallanes Renovables ATIR at EMEC, Orbital Marine Power O2 at EMEC
Tidal Operation & Maintenance Collision risk

Potential for collision with turbine blades.

Birds
Diving birds
Monitoring

Environmental monitoring to better understand near-field behaviour and avoidance.

Help reduce scientific uncertainty.

Can be a high cost associated with this.

Unclear how much monitoring will be required to fully understand this risk.

Technology is not advanced enough yet to do this efficiently.

Data mortgage (data generated more quickly than it can be analysed).

...Read more

Can be a high cost associated with this.

Unclear how much monitoring will be required to fully understand this risk.

Technology is not advanced enough yet to do this efficiently.

Data mortgage (data generated more quickly than it can be analysed).

Power supply availability - hard-wired vs. battery; power is required for monitoring and power availability can present logistical, financial, and technical challenges.

Interaction between equipment - e.g., multibeam sonar/ADCP/echosounder; there can be interaction between monitoring equipment which can present challenges in monitoring.

Certain equipment used such as PAM may actually effect behaviour themselves.

Read less
Aquamarine Power Ltd 2011, OpenHydro and SSE Renewables 2013, Minesto 2016, SSE Renewables 2011, Xodus Group 2012, GlaxoSmithKlineMontrose 2012, Orbital Marine Power 2018, AECOM 2009, Oyster 800 at EMEC, Minesto Holyhead Deep - Non-grid connected DG500, Westray South Tidal Project, Costa Head Wave Farm, GSK Montrose Tidal Array, Orbital Marine Power O2 at EMEC, Fundy Ocean Research Center for Energy (FORCE) Test Site
Wave, Tidal Installation, Operation & Maintenance, Decommissioning Marine Non-Native Species (MNNS)

Potential for introduction of MNNS which can have an adverse impact on the native species at the site.

Birds
Mitigation

Source vessels locally.

Reduce/remove risk of transfer and settlement of non-native species.

None identified

McPherson 2015, Nova Innovation - Shetland Tidal Array, Mocean Wave Energy Converter: Blue Horizon
Tidal Operation & Maintenance Collision risk

Potential for collision with turbine blades.

Birds
Diving birds
Mitigation

Design proportion of swept area to structure area to minimize collision risk.

Could reduce the likelihood/consequence of potential collision events.

Can be a high cost associated with this.

Can present financial, logistical, or design challenges to technology developer to alter design of device.

Wave, Tidal Operation & Maintenance Entanglement

Potential for marine animals to become entangled in device mooring lines and cables.

Fish
Elasmobranch, large fish
Design feature, Monitoring

Routine inspections of mooring lines. Implement features into existing control systems to detect entanglement events.

Remove/reduce risk of entanglement.

Likely to be required as part of the technical monitoring of the device and therefore not an additional cost

Could be a costly measure for technology developers if not required as part of technical monitoring of device.

Argyll Tidal Limited 2013, European Marine Energy Centre (EMEC) 2014, Xodus Group 2019, Federal Energy Regulatory Commission (FERC) 2020, Argyll Tidal Demonstrator Project, EMEC Fall of Warness Grid-Connected Tidal Test Site, EMEC Billia Croo Grid-Connected Wave Test Site, PacWave South Test Site
Tidal Operation & Maintenance Changes in water flow

The potential wider or secondary effects (siltation changes or smothering) on protected or sensitive littoral habitat due to changes in tidal flow around devices and associated moorings, support structures, or landfall cables.

Habitat
Benthic invertebrates
Monitoring

Pre and post installation monitoring of sensitive benthic communities, based on visual surveys.

Reduce scientific uncertainty.

Interpretation of data for statistical purposes may not have power to detect change generated by impact.

May require correlation with detailed Computational Fluid Dynamics studies and physical flow measurements.

Orbital Marine Power 2014, European Marine Energy Centre (EMEC) 2011, Davison and Mallows 2005, ScottishPower Renewables 2010, The Marine Institute 2016, Orbital Marine Power 2018, EMEC Shapinsay Sound Scale Tidal Test Site, Strangford Lough - MCT (SeaGen), Sound of Islay Demonstration Tidal Array, Galway Bay Test Site, Orbital Marine Power O2 at EMEC
Wave, Tidal Installation, Operation & Maintenance, Decommissioning Marine Non-Native Species (MNNS)

Potential for introduction of MNNS which can have an adverse impact on the native species at the site.

Habitat
Mitigation

Establish and implement a Biofouling Management Plan.

Reduce/remove risk of transfer of non-native species.

Lack of industry specific guidance.

European Marine Energy Centre (EMEC) 2014, Xodus Group 2019, Orbital Marine Power 2018, EMEC Fall of Warness Grid-Connected Tidal Test Site, EMEC Billia Croo Grid-Connected Wave Test Site, Orbital Marine Power O2 at EMEC
Wave, Tidal Installation, Operation & Maintenance, Decommissioning Contamination

Potential for accidental or unplanned events which could lead to contamination of the marine environment.

Marine Mammals
Design feature

Physical Containment systems including bulk heads, closed circuit systems, pressure relief systems.

Reduces risk of contamination/pollution escaping from structure.

None identified

Foubister 2005, MeyGen 2012, Royal Haskoning and Sea Generation (Kyle Rhea) Ltd. 2013, Sustainable Energy Authority of Ireland (SEAI) 2011, The Marine Institute 2016, THETIS Energy 2009, EMEC Fall of Warness Grid-Connected Tidal Test Site, MeyGen Tidal Energy Project, Kyle Rhea Tidal Stream Array Project, Atlantic Marine Energy Test Site (AMETS), Galway Bay Test Site, Torr Head Project
Wave, Tidal Installation, Decommissioning Underwater noise

The potential effects from underwater noise generated during installation/construction (excluding piling).

Marine Mammals
Mitigation

Avoid/limit 'noisy works' within close proximity to sensitive sites (e.g., known seal haul outs during sensitive periods, defining appropriate clearance distances where necessary).

Could reduce potential effects on sensitive species during sensitive periods.

Could increase project construction timescales (e.g., if continuous drilling time is restricted or specific periods need to be avoided).

Orbital Marine Power 2014, Xodus AURORA 2010, Aquatera Ltd 2011, European Marine Energy Centre (EMEC) 2014, Davison and Mallows 2005, Xodus Group 2019, ScottishPower Renewables 2012, McGrath 2013, Aquatera 2017, The Marine Institute 2016, Federal Energy Regulatory Commission (FERC) 2020, DP Energy Ltd. 2017, HS1000 at EMEC, Wello Penguin at EMEC, EMEC Fall of Warness Grid-Connected Tidal Test Site, Strangford Lough - MCT (SeaGen), EMEC Billia Croo Grid-Connected Wave Test Site, Fair Head Tidal Array, Tocardo InToTidal at EMEC, Galway Bay Test Site, PacWave South Test Site, Fair Head Tidal Array
Wave, Tidal Operation & Maintenance Entanglement

Potential for marine animals to become entangled in lost fishing gear or other equipment trapped on infrastructure.

Reptiles
Sea turtles
Monitoring

Ensure standard notifications of loss of fishing gear in region notified to operators. Reporting of entanglement events.

Good practice for emergency preparedness.

Chances of lost fishing gear being reported is reportedly low.

Wave, Tidal Installation, Operation & Maintenance, Decommissioning Contamination

Potential for oil spill incident resulting from the influence of unfavorable weather conditions.

Benthic
Mitigation

Vessel activities to occur in suitable weather conditions.

Reduces the chance of oil spill to the environment.

None identified

MeyGen 2012, Aquamarine Power Ltd 2011, ScottishPower Renewables 2012, Naval Facilities Engineering Command (NAVFAC) 2014, MeyGen Tidal Energy Project, Oyster 800 at EMEC, Pelamis Wave Power P2 Demonstration at EMEC, U.S. Navy Wave Energy Test Site (WETS)
Wave, Tidal Installation, Operation & Maintenance, Decommissioning Marine Non-Native Species (MNNS)

Potential for introduction of MNNS which can have an adverse impact on the native species at the site.

Benthic
Compliance

Compliance with all relevant guidance (including IMO guidelines) regarding ballast water management and transfer of non-native species.

Reduce/remove risk of transfer and settlement of non-native species.

None identified

MeyGen 2012, McPherson 2015, OpenHydro and SSE Renewables 2013, European Marine Energy Centre (EMEC) 2014, Xodus Group 2019, Magallanes Renovables 2020, Royal Haskoning and Sea Generation (Kyle Rhea) Ltd. 2013, SSE Renewables 2011, Tidal Lagoon Power 2017, Federal Energy Regulatory Commission (FERC) 2020, MeyGen Tidal Energy Project, Nova Innovation - Shetland Tidal Array, EMEC Fall of Warness Grid-Connected Tidal Test Site, EMEC Billia Croo Grid-Connected Wave Test Site, Magallanes Renovables ATIR at EMEC, Kyle Rhea Tidal Stream Array Project, Westray South Tidal Project, Swansea Bay Tidal Lagoon (SBTL), PacWave South Test Site
Wave, Tidal Operation & Maintenance Contamination

Potential for oil/hydraulic spill incident resulting from the maintenance activities.

Fish
Mitigation

All maintenance activities involving oil/hydraulic fluid treatments will be carried out on-shore.

Reduces the chance for oil spill to the environment.

None identified

Foubister 2005, EMEC Fall of Warness Grid-Connected Tidal Test Site
Wave, Tidal Installation Barrier to movement

Potential barrier to movement due to the physical presence of devices and associated moorings/support structures, cables and electrical equipment.

Fish
Design feature

Array/mooring configuration designed to avoid migratory routes or other important sites

Minimizes risk of development acting as a barrier to movement by avoiding migratory routes or other important sites.

May be inconsistent with optimal layout of the development for exploitation of the energy source.

Can be a costly measure when scaling up to larger arrays.

Aquamarine Power Ltd 2011, Davison and Mallows 2005, Fox 2019, Oyster 800 at EMEC, Strangford Lough - MCT (SeaGen)
Wave, Tidal Operation & Maintenance EMF

Impacts of electromagnetic fields from subsea cables on sensitive species.

Fish
Migratory fish, elasmobranchs
Design feature

Install cable protection, armor, rock placement, or other cable protection.

Reduce the level of EMF to surrounding water column and therefore any potential effects.

Reduces 'snagging risk' for vessels.

Creation of artificial habitat.

May have an impact on surrounding benthic habitats and sensitive species e.g smothering

Creation of artificial habitat may cause aggregation effect causing greater impact of EMF.

Increased cost to project.

Reduced possibilities for decommissioning in future.

Orbital Marine Power 2014, Foubister 2005, McGrath 2013, Federal Energy Regulatory Commission (FERC) 2020, EMEC Fall of Warness Grid-Connected Tidal Test Site, Fair Head Tidal Array, PacWave South Test Site
Wave, Tidal Operation & Maintenance Lighting

Potential for lighting to adversely affect nocturnal and migratory species.

Fish
Design feature

Consider type, color and use of lighting during design and consultation with navigational stakeholders.

Could reduce impacts on sensitive species if they are known to use or migrate near to the project site.

A targeted lighting plan may have the potential to reduce impacts on sensitive species but navigational interests need to be considered at all times

Navigational safety need to be considered at all times and may take precedent over ecological needs.

DP Energy Ltd. 2013, European Marine Energy Centre (EMEC) 2014, Tidal Lagoon Power 2017, AECOM 2009, West Islay Tidal Project Energy Park, EMEC Fall of Warness Grid-Connected Tidal Test Site, Swansea Bay Tidal Lagoon (SBTL), Fundy Ocean Research Center for Energy (FORCE) Test Site
Wave, Tidal Operation & Maintenance Contamination

Potential for oil/hydraulic spill incident resulting from the maintenance activities.

Habitat
Mitigation

All maintenance activities involving oil/hydraulic fluid treatments will be carried out on-shore.

Reduces the chance for oil spill to the environment.

None identified

Foubister 2005, EMEC Fall of Warness Grid-Connected Tidal Test Site
Tidal Operation & Maintenance Changes in water flow

Modifications to prey distribution and abundance (to include for other receptors) resulting in changes to foraging behaviour.

Marine Mammals
Monitoring

Observational surveys (including remote sensing) of bird and marine mammals (prey availability linked to benthic community).

Reduces scientific uncertainty.

Statistical power of studies can be low. Can be difficult to distinguish between natural variation and direct effects of energy removal from the system.

Monitoring may be expensive.

Aquamarine Power Ltd 2011, GlaxoSmithKlineMontrose 2012, Orbital Marine Power 2014, Tidal Energy Ltd 2008, Xodus AURORA 2010, European Marine Energy Centre (EMEC) 2011, Davison and Mallows 2005, McGrath 2013, Xodus Group 2012, Orbital Marine Power 2018, AECOM 2009, Oyster 800 at EMEC, GSK Montrose Tidal Array, Ramsey Sound, HS1000 at EMEC, EMEC Shapinsay Sound Scale Tidal Test Site, Strangford Lough - MCT (SeaGen), Fair Head Tidal Array, Orbital Marine Power O2 at EMEC, Fundy Ocean Research Center for Energy (FORCE) Test Site
Wave, Tidal Installation, Operation & Maintenance, Decommissioning Displacement

Potential displacement of essential activities due to the presence of devices and associated moorings/support structures.

Marine Mammals
Design feature

Array/mooring configuration designed to avoid migratory routes or other important sites.

Minimizes risk of development creating displacement by avoiding migratory routes or other important sites.

May be inconsistent with optimal layout of the development for exploitation of the energy source.

Can be a costly measure when scaling up to larger arrays.

Aquamarine Power Ltd 2011, Davison and Mallows 2005, Fox 2019, Oyster 800 at EMEC, Strangford Lough - MCT (SeaGen)
Wave, Tidal Decommissioning Vessel disturbance

Potential for disturbance from project vessels.

Marine Mammals
Cetaceans, seals
Mitigation

Limit use of vessels, e.g. one vessel present with regular use of thrusters to maintain position.

Reduces potential disturbance effects.

None identified

Low 2012, MeyGen 2012, Atlantis Resources Corporation at EMEC, MeyGen Tidal Energy Project
Wave, Tidal Installation, Operation & Maintenance, Decommissioning Marine Non-Native Species (MNNS)

Potential for introduction of MNNS which can have an adverse impact on the native species at the site.

Reptiles
Monitoring

Monitoring and reporting of MNNS.

Reduces/removes risk of transfer of non-native species.

None identified

Wave, Tidal Operation & Maintenance EMF

Impacts of electromagnetic fields from subsea cables on sensitive species.

Benthic
Benthic invertebrates
Design feature

Bundle cables together to reduce field vectors.

Reduce the level of EMF to surrounding water column and therefore any potential effects

Less redundancy in system.

Potential commercial and technical feasibility issues.

MeyGen 2012, MeyGen Tidal Energy Project
Wave, Tidal Installation, Decommissioning Changes in sediment dynamics

Sediment disturbance disrupting water clarity that results in smothering of fish spawning grounds.

Birds
Mitigation

Best practice methodologies to reduce resuspension of sediment during cable burial or device foundation/mooring installation.

None identified

None identified

Sustainable Energy Authority of Ireland (SEAI) 2011, The Marine Institute 2016, Federal Energy Regulatory Commission (FERC) 2020, Atlantic Marine Energy Test Site (AMETS), Galway Bay Test Site, PacWave South Test Site
Wave, Tidal Operation & Maintenance Entanglement

Potential for marine animals to become entangled in device mooring lines and cables.

Birds
Diving birds
Design feature

Minimize the number of mooring lines.

Reduce risk of entanglement.

Could be a costly measure for technology developers.

Tidal Operation & Maintenance Changes in water flow

The potential wider or secondary effects on protected or sensitive sub-littoral seabed due to removal or alteration of energy flow arising from devices and moorings or support structures.

Fish
Monitoring

Modelling to predict the interaction between changes in tidal flow, flux, and turbulence structure and animals.

Reduces scientific uncertainty so appropriate management measures can be employed.

Limited management measures available to minimize interaction despite modelling to fully predict interaction.

Wave, Tidal Operation & Maintenance EMF

Impacts of electromagnetic fields from subsea cables on sensitive species.

Fish
Elasmobranchs
Design feature

Bundle cables together to reduce field vectors.

Reduce the level of EMF to surrounding water column and therefore any potential effects.

Less redundancy in system.

Potential commercial and technical feasibility issues.

Greater costs associated with not laying direct cable paths.

MeyGen 2012, MeyGen Tidal Energy Project
Wave, Tidal Installation, Operation & Maintenance, Decommissioning Vessel disturbance

Potential for disturbance from project vessels.

Fish
Elasmobranch, large fish
Mitigation

Reduce speed and maintain steady course when animal is sighted.

Reduces potential effects and is a relatively low cost measure.

None identified

Aquatera Ltd 2011, Magallanes Renovables 2020, European Marine Energy Centre (EMEC) 2020, SSE Renewables 2011, Magallanes Renovables 2020, Royal Haskoning 2012, Aquatera 2017, Federal Energy Regulatory Commission (FERC) 2020, Wello Penguin at EMEC, Magallanes Renovables ATIR at EMEC, EMEC Scapa Flow Scale Wave Test Site, Westray South Tidal Project, Oyster 800 at EMEC, Tocardo InToTidal at EMEC, PacWave South Test Site
Wave, Tidal Operation & Maintenance Habitat Creation

The introduction of infrastructure and artificial substrates will provide potential roosting habitat.

Habitat
Roosting birds
Monitoring

Monitor use of device as a roosting platform.

Reduces scientific uncertainty around collision risk, displacement, and other impacts.

Monitoring is relatively inexpensive to carry out.

Data mortgage (data gathered more quickly than it can be analyzed).

Tidal Operation & Maintenance Collision risk

Potential for collision with turbine blades.

Marine Mammals
Mitigation, Design feature

Install a 'detect and deter' system using a combination of active sonar and acoustic deterrent device (ADD).

Could reduce likelihood of collision with moving blades and enable a route through the consenting process.

Would rely on well proven and reliable system - efficacy of ADDs is unknown in these environments and unknown if deterrent systems will help reduce risk.

Expensive to implement.

Questions around the effects of ADDs (e.g., added noise) on sensitive species.

...Read more

Would rely on well proven and reliable system - efficacy of ADDs is unknown in these environments and unknown if deterrent systems will help reduce risk.

Expensive to implement.

Questions around the effects of ADDs (e.g., added noise) on sensitive species.

Detection systems are currently insufficient to detect animals (in particular at array scale).

Further research around ADDs which deter specific groups or species, is underway. This could be useful in deterring specific sensitive species or species groups, at a particular site. For example, University of St Andrews is developing an ADD which deter seals, but which don't effect cetaceans.

Read less
Harrison et al. 2015, Orbital Marine Power 2010, Keenan et al. 2011, Aquamarine Power Ltd 2011, THETIS Energy 2009, Churchill Barriers - Wave Overtopping and Tidal Flow Energy Capture, Pelamis Wave Power P2 Demonstration at EMEC, Strangford Lough - MCT (SeaGen), Oyster 800 at EMEC, Torr Head Project
Wave, Tidal Operation & Maintenance Entrapment

Potential risk of entrapment within device chambers and mooring arrays.

Marine Mammals
Mitigation

Release entrapped animal.

None identified

Animal may be deceased before they are able to be released.

Tidal Lagoon Power 2017, Swansea Bay Tidal Lagoon (SBTL)
Tidal Operation & Maintenance Changes in water flow

The potential wider or secondary effects on protected or sensitive sub-littoral seabed due to removal or alteration of energy flow arising from devices and moorings or support structures.

Reptiles
Design feature

Site selection.

Minimizes significance of interaction.

None identified

ScottishPower Renewables 2012, Fox 2019, Ness of Duncansby Tidal Array
Wave, Tidal Operation & Maintenance Changes in sediment dynamics

The potential wider or secondary effects (siltation changes or smothering) on protected or sensitive sub-littoral seabed due to scour or siltation around devices and associated moorings, support structures and export cables.

Benthic
Monitoring

Modelling to predict the interaction between changes in sediment dynamics and animals.

Reduces scientific uncertainty so appropriate management measures can be employed.

Limited management measures available to minimize interaction despite modelling to fully predict interaction.

Foubister 2005, MeyGen 2012, Project Management Support Services 2006, GlaxoSmithKlineMontrose 2012, Fox 2019, Orbital Marine Power SR250 at EMEC, MeyGen Tidal Energy Project, Anglesey Skerries Tidal Stream Array, GSK Montrose Tidal Array
Wave, Tidal Operation & Maintenance Habitat Creation

The introduction of infrastructure and artificial substrates will provide habitat and artificial refuges.

Benthic
Monitoring

Monitor near-field behaviors.

Reduces scientific uncertainty around collision risk, displacement, and other impacts.

Increased value/ fecundity of commercially important species.

Informs understanding of potential positive impacts from colonization and use of project infrastructure.

This type of monitoring can be expensive and difficult to deliver in practice.

May require additional licensing (e.g. echosounders).

Foubister 2005, Magallanes Renovables 2020, Orbital Marine Power 2018, EMEC Fall of Warness Grid-Connected Tidal Test Site, Magallanes Renovables ATIR at EMEC, Orbital Marine Power O2 at EMEC
Tidal Operation & Maintenance Collision risk

Potential for collision with turbine blades.

Birds
Diving birds
Mitigation

Selective structural and blade coatings (e.g., colors to aide detection.

Unknown - it is possible that this will aid detection of subsea structures and help reduce risk.

This could result in 'attraction', increasing risk of collision

Uncertainty around how animals use visual cues.

Other sensory organs are often more important for fish & seals

Use of such measures may be limited to conform with IALA standards

Xodus Group 2019, EMEC Billia Croo Grid-Connected Wave Test Site
Wave, Tidal Installation Marine Non-Native Species (MNNS)

Potential for introduction of MNNS which can have an adverse impact on the native species at the site.

Birds
Design feature

Avoid the introduction of hard bottom substrate into a soft bottom habitat.

Ensures the efficient recovery of species native to the surrounding habitat.

May have technical implications.

Wave, Tidal Operation & Maintenance Collision risk

Potential risk of collision with device giving size and character of structure.

Fish
Design feature

Device components (e.g., transformer and power conditioning equipment) are designed internally.

Reduces potential for collision with external moving parts.

None identified

The Marine Institute 2016, Galway Bay Test Site
Wave, Tidal Operation & Maintenance Entanglement

Potential for marine animals to become entangled in lost fishing gear or other equipment trapped on infrastructure.

Fish
Elasmobranch, large fish
Mitigation

Fisheries management: Agreement with fishermen not to fish near to the device, warning of the dangers of losing equipment.

Reduces potential for entanglement of fishing gear in mooring lines and thus potential for entanglement of marine animals.

None identified

Xodus Group 2019, EMEC Billia Croo Grid-Connected Wave Test Site
Tidal Operation & Maintenance Changes in water flow

The potential wider or secondary effects on protected or sensitive sub-littoral seabed due to removal or alteration of energy flow arising from devices and moorings or support structures.

Habitat
Monitoring

Installation of ADCPs and turbulence sensors to better understand the baseline tidal flow conditions and hence the change in tidal flow due to presence of the device(s).

Reduce scientific uncertainty.

None identified

Tidal Energy Ltd 2008, Aquatera 2017, Fox 2019, Ramsey Sound, Tocardo InToTidal at EMEC
Wave, Tidal Installation, Operation & Maintenance, Decommissioning Marine Non-Native Species (MNNS)

Potential for introduction of MNNS which can have an adverse impact on the native species at the site.

Habitat
Mitigation, Compliance

Adhere to appropriate measures when jettisoning ballast water.

Reduce/remove risk of transfer of non-native species.

None identified

Sustainable Energy Authority of Ireland (SEAI) 2011, Atlantic Marine Energy Test Site (AMETS)
Wave, Tidal Installation, Operation & Maintenance, Decommissioning Contamination

Potential for accidental or unplanned events which could lead to contamination of the marine environment.

Marine Mammals
Mitigation

Material selection - lubricants, coolants, hydraulic fluids etc. - selected with low ecotoxicity levels and biodegradable.

Reduces/removes risk of contamination/pollution from materials which may have escaped structure.

Use of lower toxicity materials may compromise performance, or impact other technical issues (e.g., fluid changes.)

Foubister 2005, MeyGen 2012, Xodus AURORA 2010, The Marine Institute 2016, THETIS Energy 2009, EMEC Fall of Warness Grid-Connected Tidal Test Site, MeyGen Tidal Energy Project, Galway Bay Test Site, Torr Head Project
Wave, Tidal Operation & Maintenance Underwater noise

The potential effects from underwater noise generated by wave and tidal energy converters.

Marine Mammals
Monitoring

Measure noise generated by device(s) during operation to better understand the potential effects on sensitive species.

Measured noise levels can be correlated with threshold values of relevant species and baseline noise levels of the site to determine impact and need for adaptive management measures.

Can be complex and costly to undertake this type of monitoring in high energy environments.

Data and analysis have requirement for acoustic experts.

SAE Renewables 2011, Aquamarine Power Ltd 2011, Orbital Marine Power 2014, Minesto 2016, Xodus AURORA 2010, European Marine Energy Centre (EMEC) 2019, ScottishPower Renewables 2010, Davison and Mallows 2005, McGrath 2013, Royal Haskoning 2012, Orbital Marine Power 2018, Atlantis Resources Corporation at EMEC, Oyster 800 at EMEC, Minesto Holyhead Deep - Non-grid connected DG500, HS1000 at EMEC, EMEC Billia Croo Grid-Connected Wave Test Site, Sound of Islay Demonstration Tidal Array, Strangford Lough - MCT (SeaGen), Fair Head Tidal Array, Oyster 800 at EMEC, Orbital Marine Power O2 at EMEC
Wave, Tidal Operation & Maintenance Entanglement

Potential for marine animals to become entangled in device mooring lines and cables.

Reptiles
Sea turtles
Design feature, Monitoring

Routine inspections of mooring lines. Implement features into existing control systems to detect entanglement events.

Remove/reduce risk of entanglement.

Likely to be required as part of the technical monitoring of the device and therefore not an additional cost.

Could be a costly measure for technology developers if not required as part of technical monitoring of device.

Wave, Tidal Operation & Maintenance Contamination

Potential for oil/hydraulic spill incident resulting from the maintenance activities.

Benthic
Mitigation

All maintenance activities involving oil/hydraulic fluid treatments will be carried out on-shore.

Reduces the chance of oil spill to the environment.

None identified

Foubister 2005, EMEC Fall of Warness Grid-Connected Tidal Test Site
Wave, Tidal Installation Marine Non-Native Species (MNNS)

Potential for introduction of MNNS which can have an adverse impact on the native species at the site.

Benthic
Design feature

Avoid the introduction of hard bottom substrate into a soft bottom habitat.

Ensures the efficient recovery of species native to the surrounding habitat.

May have technical implications.

Minesto 2016, Federal Energy Regulatory Commission (FERC) 2020, Minesto Holyhead Deep - Non-grid connected DG500, PacWave South Test Site
Wave, Tidal Operation & Maintenance Displacement

Potential displacement of essential activities due to the presence of devices and associated moorings/support structures.

Birds
Design feature

Site selection (taking into account cumulative impact of other developments).

Minimizes risk of development causing displacement by avoiding migratory routes or other important sites.

None identified

Argyll Tidal Limited 2013, Orbital Marine Power 2014, ScottishPower Renewables 2012, Fox 2019, Argyll Tidal Demonstrator Project, Ness of Duncansby Tidal Array
Wave, Tidal Installation, Operation & Maintenance, Decommissioning Barrier to movement

Potential barrier to movement due to the physical presence of devices and associated moorings/support structures, cables and electrical equipment.

Fish
Mitigation

Adherence to vessel management plan.

Minimizes the potential interaction between animals and construction or maintenance vessels.

None identified

OpenHydro and SSE Renewables 2013, Aquatera 2017, ScottishPower Renewables 2010, Xodus Group 2019, Fox 2019, Tocardo InToTidal at EMEC, Sound of Islay Demonstration Tidal Array
Wave, Tidal Operation & Maintenance EMF

Impacts of electromagnetic fields from landfall cables on sensitive species.

Fish
Demersal fish
Design feature

Use of 3-phase cables instead of DC cables.

None identified

None identified

Tidal Energy Ltd 2008, Ramsey Sound
Wave, Tidal Installation, Operation & Maintenance, Decommissioning Marine Non-Native Species (MNNS)

Potential for introduction of MNNS which can have an adverse impact on the native species at the site.

Fish
Compliance

Compliance with all relevant guidance (including IMO guidelines) regarding ballast water management and transfer of non-native species.

Reduce/remove risk of transfer and settlement of non-native species.

None identified

McPherson 2015, MeyGen 2012, Royal Haskoning and Sea Generation (Kyle Rhea) Ltd. 2013, Federal Energy Regulatory Commission (FERC) 2020, Nova Innovation - Shetland Tidal Array, MeyGen Tidal Energy Project, Kyle Rhea Tidal Stream Array Project, PacWave South Test Site
Wave, Tidal Operation & Maintenance Displacement

Potential displacement of essential activities due to the presence of devices and associated moorings/support structures.

Habitat
Design feature

Site selection (taking into account cumulative impact of other developments).

Minimizes s risk of development causing displacement by avoiding migratory routes or other important sites.

None identified

Minesto 2016, SSE Renewables 2011, Aquatera 2011, Fox 2019, Minesto Holyhead Deep - Non-grid connected DG500, Westray South Tidal Project, Farr Point Wave Array - Phase 1
Tidal Operation & Maintenance Changes in water flow

The potential wider or secondary effects on protected or sensitive sub-littoral seabed due to removal or alteration of energy flow arising from devices and moorings or support structures.

Marine Mammals
Monitoring

Installation of ADCPs and turbulence sensors to better understand the baseline tidal flow conditions and hence the change in tidal flow due to presence of the device(s)

Reduces scientific uncertainty.

None identified

Tidal Energy Ltd 2008, Aquatera 2017, Fox 2019, Ramsey Sound, Tocardo InToTidal at EMEC
Wave, Tidal Operation & Maintenance EMF

Impacts of electromagnetic fields from landfall cables on sensitive species.

Marine Mammals
Design feature

Bury cables where possible and viable.

None identified

None identified

McGrath 2013, Fair Head Tidal Array
Wave, Tidal Decommissioning Vessel disturbance

Potential for disturbance from project vessels.

Marine Mammals
Cetaceans, seals
Mitigation

Avoid sudden changes of speed.

Reduces likelihood of any further disturbance to marine animals in the vicinity.

None identified

Orbital Marine Power 2018, Orbital Marine Power O2 at EMEC
Wave, Tidal Operation & Maintenance EMF

Impacts of electromagnetic fields from landfall cables on sensitive species.

Benthic
Benthic invertebrates
Design feature

Use of 3-phase cables instead of DC cables.

None identified

None identified

Tidal Energy Ltd 2008, Ramsey Sound
Tidal Operation & Maintenance Changes in water flow

Modifications to tidal flows affect prey distribution and abundance resulting in changes to foraging behavior.

Birds
Diving birds
Monitoring

Observational surveys (including remote sensing) of species (prey availability linked to benthic community).

Reduce scientific uncertainty.

Statistical power of studies can be low. Can be difficult to distinguish between natural variation and direct effects of energy removal from the system.

Aquamarine Power Ltd 2011, Craig 2008, Tidal Energy Ltd 2008, Xodus AURORA 2010, European Marine Energy Centre (EMEC) 2014, Royal Haskoning and Sea Generation (Kyle Rhea) Ltd. 2013, SSE Renewables 2011, Xodus Group 2012, MeyGen 2012, Aquamarine Power Ltd 2011, ScottishPower Renewables 2012, Xodus Group 2012, Oyster 800 at EMEC, OpenHydro Alderney, Ramsey Sound, HS1000 at EMEC, EMEC Fall of Warness Grid-Connected Tidal Test Site, Kyle Rhea Tidal Stream Array Project, Westray South Tidal Project, Costa Head Wave Farm, MeyGen Tidal Energy Project, Pelamis Wave Power P2 Demonstration at EMEC
Wave, Tidal Operation & Maintenance Entrapment

Potential risk of entrapment within device chambers and mooring arrays.

Birds
Mitigation

Regular ROV/drop down camera surveys to establish occurrence of entrapment.

Early detection of entrapment.

Additional cost.

Foubister 2005, Orbital Marine Power 2010, McPherson 2015, Fox 2019, EMEC Fall of Warness Grid-Connected Tidal Test Site, Orbital Marine Power SR250 at EMEC, Nova Innovation - Canada Tidal Array
Tidal Operation & Maintenance Changes in water flow

Modifications to prey distribution and abundance (to include for other receptors) resulting in changes to foraging behaviour.

Fish
Monitoring

Modelling to predict the interaction between changes in tidal flow, flux, and turbulence structure and animals.

Reduces scientific uncertainty so appropriate management measures can be employed.

Limited management measures available to minimize interaction despite modelling to fully predict interaction.

Wave, Tidal Operation & Maintenance EMF

Impacts of electromagnetic fields from subsea cables on sensitive species.

Fish
Migratory fish
Design feature

Bury or HDD cables where possible and viable.

Reduce the level of EMF to surrounding water column and therefore any potential effects.

Reduces 'snagging risk' for vessels.

May have an impact on surrounding benthic habitats and sensitive species, e.g., from smothering

Can be very challenging or impossible at sites where seabed tends to be rocky.

Additional expense to the project.

Reduced possibility for decommissioning.

Sustainable Energy Authority of Ireland (SEAI) 2011, Tidal Lagoon Power 2017, Federal Energy Regulatory Commission (FERC) 2020, Atlantic Marine Energy Test Site (AMETS), Swansea Bay Tidal Lagoon (SBTL), PacWave South Test Site
Wave, Tidal Operation & Maintenance Vessel disturbance

Potential for disturbance from project vessels.

Fish
Elasmobranch, large fish
Mitigation

Use smaller vessels for maintenance purposes.

Reduces potential effects and is a relatively low cost measure.

None identified

Aquatera Ltd 2011, Laminaria 2018, Wello Penguin at EMEC, EMEC Billia Croo Grid-Connected Wave Test Site
Wave, Tidal Operation & Maintenance Habitat Creation

The introduction of infrastructure and artificial substrates may generate additional habitat diversity.

Habitat
Benthic species
Monitoring

Structure colonization and biofouling surveys.

Informs understanding of potential for increased prey availability and ecological diversity.

Cost associated with monitoring.

Craig 2008, Fox 2019, OpenHydro Alderney
Tidal Operation & Maintenance Collision risk

Potential for collision with turbine blades.

Marine Mammals
Mitigation, Design feature

Install acoustic deterrent devices (ADDs).

Could reduce likelihood of collision with moving blades.

Simpler system than detect and deter.

Efficacy of ADDs in these environments is unknown.

Expensive to implement and it is unknown if deterrent systems will help reduce risk.

Questions around the effects of ADDs (e.g., added noise) on sensitive species and constant deterring means habituation is likely.

...Read more

Efficacy of ADDs in these environments is unknown.

Expensive to implement and it is unknown if deterrent systems will help reduce risk.

Questions around the effects of ADDs (e.g., added noise) on sensitive species and constant deterring means habituation is likely.

Detection systems are currently insufficient to detect animals (in particular at array scale).

Read less
Tidal Lagoon Power 2017, THETIS Energy 2009, Swansea Bay Tidal Lagoon (SBTL), Torr Head Project
Wave, Tidal Operation & Maintenance Entrapment

Potential risk of entrapment within device chambers and mooring arrays.

Marine Mammals
Mitigation

Regular ROV/drop down camera surveys to establish occurrence of entrapment

Early detection of entrapment .

Additional cost.

Foubister 2005, Orbital Marine Power 2010, McPherson 2015, Project Management Support Services 2006, Orbital Marine Power 2018, Fox 2019, EMEC Fall of Warness Grid-Connected Tidal Test Site, Orbital Marine Power SR250 at EMEC, Nova Innovation - Canada Tidal Array, Anglesey Skerries Tidal Stream Array, Orbital Marine Power O2 at EMEC
Wave, Tidal Installation, Operation & Maintenance, Decommissioning Contamination

Potential for accidental or unplanned events which could lead to contamination of the marine environment.

Reptiles
Design feature

Physical Containment systems including bulk heads, closed circuit systems, pressure relief systems.

Reduces risk of contamination/pollution escaping from structure.

None identified

Foubister 2005, MeyGen 2012, Sustainable Energy Authority of Ireland (SEAI) 2011, The Marine Institute 2016, EMEC Fall of Warness Grid-Connected Tidal Test Site, MeyGen Tidal Energy Project, Atlantic Marine Energy Test Site (AMETS), Galway Bay Test Site
Tidal Operation & Maintenance Changes in water flow

The potential wider or secondary effects on protected or sensitive sub-littoral seabed due to removal or alteration of energy flow arising from devices and moorings or support structures.

Benthic
Benthic invertebrates
Monitoring

Pre and post installation monitoring of sensitive benthic communities, based on diver, drop down, static visual surveys (camera), or grab sampling.

Reduce scientific uncertainty.

Interpretation of data for statistical purposes may not have power to detect change generated by impact.

May require correlation with detailed Computational Fluid Dynamics studies and physical flow measurements.

SAE Renewables 2011, Tidal Energy Ltd 2008, Foubister 2005, European Marine Energy Centre (EMEC) 2011, ScottishPower Renewables 2010, Davison and Mallows 2005, Laminaria 2018, Royal Haskoning 2012, The Marine Institute 2016, Royal Haskoning 2019, Orbital Marine Power 2018, Aquamarine Power Ltd 2011, Atlantis Resources Corporation at EMEC, Ramsey Sound, EMEC Fall of Warness Grid-Connected Tidal Test Site, EMEC Shapinsay Sound Scale Tidal Test Site, Sound of Islay Demonstration Tidal Array, Strangford Lough - MCT (SeaGen), EMEC Billia Croo Grid-Connected Wave Test Site, North West Lewis Wave Array, Galway Bay Test Site, Morlais Tidal Demonstration Zone, Orbital Marine Power O2 at EMEC, Oyster 800 at EMEC
Wave, Tidal Installation, Decommissioning Habitat Loss

Direct loss of protected or sensitive sub-littoral seabed communities due to the presence of devices and associated moorings or support structures on the seabed.

Benthic
Benthic invertebrates, demersal fish
Design feature

Micrositing of offshore infrastructure to avoid sensitive habitats and minimize footprint.

Could reduce/remove effects on sensitive habitats.

Low cost measure at single device or small-scale array.

None identified

Foubister 2005, Royal Haskoning and Sea Generation (Kyle Rhea) Ltd. 2013, RSK Group 2012, South West of England Regional Development Agency (SWDRA) 2006, Magallanes Renovables 2020, ScottishPower Renewables 2012, Laminaria 2018, The Marine Institute 2016, THETIS Energy 2009, Naval Facilities Engineering Command (NAVFAC) 2014, EMEC Fall of Warness Grid-Connected Tidal Test Site, Kyle Rhea Tidal Stream Array Project, West Orkney South Wave Energy Site, Wave Hub, Magallanes Renovables ATIR at EMEC, EMEC Billia Croo Grid-Connected Wave Test Site, Galway Bay Test Site, Torr Head Project, U.S. Navy Wave Energy Test Site (WETS)
Tidal Operation & Maintenance Collision risk

Potential for collision with turbine blades.

Birds
Diving birds
Mitigation

Implement a 'soft start' approach during cut-in.

Could reduce risk by allowing animals time to move away from the turbine.

Low cost option, adopted for other activities (e.g., piling)

Unclear if this offers additional mitigation as many devices power up gradually anyway.

Orbital Marine Power 2010, MeyGen 2012, South West of England Regional Development Agency (SWDRA) 2006, Tidal Lagoon Power 2017, Fox 2019, Orbital Marine Power SR250 at EMEC, MeyGen Tidal Energy Project, Swansea Bay Tidal Lagoon (SBTL)
Wave, Tidal Installation, Operation & Maintenance, Decommissioning Marine Non-Native Species (MNNS)

Potential for introduction of MNNS which can have an adverse impact on the native species at the site.

Birds
Monitoring

Monitoring and reporting of MNNS.

Reduce/removes risk of transfer of non-native species.

None identified

Wave, Tidal Installation, Operation & Maintenance, Decommissioning Contamination

Potential for accidental or unplanned events which could lead to contamination of the marine environment.

Fish
Design feature

Physical Containment systems including bulk heads, closed circuit systems, pressure relief systems.

Reduces risk of contamination/pollution escaping from structure.

None identified

Foubister 2005, MeyGen 2012, DP Energy Ltd. 2013, Royal Haskoning and Sea Generation (Kyle Rhea) Ltd. 2013, Magallanes Renovables 2020, Sustainable Energy Authority of Ireland (SEAI) 2011, The Marine Institute 2016, THETIS Energy 2009, EMEC Fall of Warness Grid-Connected Tidal Test Site, MeyGen Tidal Energy Project, West Islay Tidal Project Energy Park, Kyle Rhea Tidal Stream Array Project, Magallanes Renovables ATIR at EMEC, Atlantic Marine Energy Test Site (AMETS), Galway Bay Test Site, Torr Head Project
Wave, Tidal Operation & Maintenance Entanglement

Potential for marine animals to become entangled in device mooring lines and cables.

Fish
Elasmobranch, large fish
Design feature

Minimize the number of mooring lines.

Reduce risk of entanglement.

Could be a costly measure for technology developers.

Tidal Operation & Maintenance Changes in water flow

The potential wider or secondary effects on protected or sensitive sub-littoral seabed due to removal or alteration of energy flow arising from devices and moorings or support structures.

Habitat
Design feature

Design structures to minimize effect on turbulence structure.

Minimizes change in turbulence structure and hence potential interaction.

Can present financial, logistical, or design challenges to technology developer to alter design of device/moorings.

Aquamarine Power Ltd 2011, Davison and Mallows 2005, Tidal Energy Ltd 2008, Fox 2019, Oyster 800 at EMEC, Strangford Lough - MCT (SeaGen), Ramsey Sound
Wave, Tidal Installation, Operation & Maintenance, Decommissioning Marine Non-Native Species (MNNS)

Potential for introduction of MNNS which can have an adverse impact on the native species at the site.

Habitat
Mitigation

Source vessels locally.

Reduce/remove risk of transfer and settlement of non-native species.

None identified

Orbital Marine Power 2018, Orbital Marine Power O2 at EMEC, Mocean Wave Energy Converter: Blue Horizon
Wave, Tidal Installation, Operation & Maintenance, Decommissioning Contamination

Potential for accidental or unplanned events which could lead to contamination of the marine environment.

Marine Mammals
Mitigation

Where rock placement is used, ensure clean rock is used.

Reduces/removes risk of contamination/pollution from materials

None identified

Wave, Tidal Installation, Operation & Maintenance, Decommissioning Underwater noise

The potential effects from underwater noise generated during installation/ construction (excluding piling).

Marine Mammals
Mitigation

Limit vessel speed.

Reduces potential effects.

Relatively low-cost measure.

None identified

SAE Renewables 2011, Fox 2019, Atlantis Resources Corporation at EMEC
Wave, Tidal Operation & Maintenance Entanglement

Potential for marine animals to become entangled in lost fishing gear or other equipment trapped on infrastructure.

Reptiles
Sea turtles
Mitigation

Fisheries management: Agreement with fishermen not to fish near to the device, warning of the dangers of losing equipment.

Reduces potential for entanglement of fishing gear in mooring lines and thus potential for entanglement of sea turtles.

None identified

Wave, Tidal Operation & Maintenance Displacement

Potential displacement of essential activities due to the presence of devices and associated moorings/support structures.

Benthic
Design feature

Site selection (taking into account cumulative impact of other developments).

Minimizes risk of development causing displacement by avoiding migratory routes or other important sites.

None identified

ScottishPower Renewables 2012, Fox 2019, Ness of Duncansby Tidal Array
Wave, Tidal Installation, Operation & Maintenance, Decommissioning Marine Non-Native Species (MNNS)

Potential for introduction of MNNS which can have an adverse impact on the native species at the site.

Benthic
Monitoring, Compliance

Monitoring and reporting of MNNS.

Reduce/remove risk of transfer and settlement of non-native species.

None identified

Orbital Marine Power 2014, Xodus Group 2019, Magallanes Renovables 2020, EMEC Billia Croo Grid-Connected Wave Test Site, Magallanes Renovables ATIR at EMEC
Wave, Tidal Installation, Operation & Maintenance, Decommissioning Displacement

Potential displacement of essential activities due to the presence of devices and associated moorings/support structures.

Birds
Mitigation

Timing of installation and decommissioning & marine operations to avoid times of particular sensitivity (e.g. breeding).

Minimizes risk of development causing displacement by avoiding works during sensitive times.

Can be disruptive to installation/decommissioning and hence costly to developer.

OpenHydro and SSE Renewables 2013, Aquatera Ltd 2011, Foubister 2005, Royal Haskoning and Sea Generation (Kyle Rhea) Ltd. 2013, SSE Renewables 2011, ScottishPower Renewables 2012, McGrath 2013, Orbital Marine Power 2014, The Marine Institute 2016, Federal Energy Regulatory Commission (FERC) 2020, THETIS Energy 2009, ScottishPower Renewables 2012, Fox 2019, Wello Penguin at EMEC, EMEC Fall of Warness Grid-Connected Tidal Test Site, Kyle Rhea Tidal Stream Array Project, Westray South Tidal Project, Fair Head Tidal Array, Galway Bay Test Site, PacWave South Test Site, Torr Head Project, Ness of Duncansby Tidal Array
Wave, Tidal Installation, Operation & Maintenance, Decommissioning Changes in sediment dynamics

Reduced visibility impacting prey detection and obstruction avoidance.

Fish
Mitigation

Best practice methodologies to reduce resuspension of sediment during cable burial or device foundation/mooring installation.

None identified

None identified

Foubister 2005, Sustainable Energy Authority of Ireland (SEAI) 2011, Tidal Lagoon Power 2017, The Marine Institute 2016, Federal Energy Regulatory Commission (FERC) 2020, THETIS Energy 2009, EMEC Fall of Warness Grid-Connected Tidal Test Site, Atlantic Marine Energy Test Site (AMETS), Swansea Bay Tidal Lagoon (SBTL), Galway Bay Test Site, PacWave South Test Site, Torr Head Project
Wave, Tidal Operation & Maintenance EMF

Impacts of electromagnetic fields from landfall cables on sensitive species.

Fish
Demersal fish
Design feature

Lay cables in natural crevices.

None identified

None identified

MeyGen 2012, MeyGen Tidal Energy Project
Wave, Tidal Installation, Operation & Maintenance, Decommissioning Marine Non-Native Species (MNNS)

Potential for introduction of MNNS which can have an adverse impact on the native species at the site.

Fish
Mitigation

Establish and implement a Biofouling Management Plan.

Reduce/remove risk of transfer of non-native species.

Lack of industry specific guidance.

European Marine Energy Centre (EMEC) 2014, EMEC Fall of Warness Grid-Connected Tidal Test Site
Wave, Tidal Installation, Operation & Maintenance, Decommissioning Displacement

Potential displacement of essential activities due to the presence of devices and associated moorings/support structures.

Habitat
Mitigation

Timing of installation and decommissioning & marine operations to avoid times of particular sensitivity (e.g. breeding).

Minimizes risk of development causing displacement by avoiding works during sensitive times

Can be disruptive and hence costly to developer

OpenHydro and SSE Renewables 2013, Aquatera Ltd 2011, Foubister 2005, ScottishPower Renewables 2012, Royal Haskoning and Sea Generation (Kyle Rhea) Ltd. 2013, SSE Renewables 2011, ScottishPower Renewables 2012, McGrath 2013, Orbital Marine Power 2014, The Marine Institute 2016, Federal Energy Regulatory Commission (FERC) 2020, THETIS Energy 2009, Fox 2019, Wello Penguin at EMEC, EMEC Fall of Warness Grid-Connected Tidal Test Site, Ness of Duncansby Tidal Array, Kyle Rhea Tidal Stream Array Project, Westray South Tidal Project, Fair Head Tidal Array, Galway Bay Test Site, PacWave South Test Site, Torr Head Project
Tidal Operation & Maintenance Changes in water flow

The potential wider or secondary effects on protected or sensitive sub-littoral seabed due to removal or alteration of energy flow arising from devices and moorings or support structures.

Marine Mammals
Design feature

Design structures to minimize effect on turbulence structure.

Minimizes change in turbulence structure and hence potential interaction.

Can present financial, logistical, or design challenges to technology developer to alter design of device/moorings.

Aquamarine Power Ltd 2011, Davison and Mallows 2005, Tidal Energy Ltd 2008, Fox 2019, Oyster 800 at EMEC, Strangford Lough - MCT (SeaGen), Ramsey Sound
Wave, Tidal Operation & Maintenance Entanglement

Potential for marine animals to become entangled in device mooring lines and cables.

Marine Mammals
Cetaceans
Design feature

Maintain taut mooring lines.

Remove/reduce risk of entanglement.

Regular inspections can provide operational insight into condition.

Inspections help track interactions/events with marine animals.

Mooring design driven by technical and commercial consideration.

Regular ROV/dive or drop-down camera inspections required.

Aquatera Ltd 2011, Laminaria 2018, Federal Energy Regulatory Commission (FERC) 2020, Wello Penguin at EMEC, EMEC Billia Croo Grid-Connected Wave Test Site, PacWave South Test Site
Wave, Tidal Installation Barrier to movement

Potential barrier to movement due to the physical presence of devices and associated moorings/support structures, cables and electrical equipment.

Reptiles
Design feature

Site selection to avoid sensitive routes/areas.

Minimizes risk of development acting as a barrier to movement by avoiding migratory routes or other important sites.

None identified

Wave, Tidal Operation & Maintenance EMF

Impacts of electromagnetic fields from subsea cables on sensitive species.

Benthic
Benthic invertebrates
Design feature

Bury or HDD cables where possible and viable.

Reduce the level of EMF to surrounding water column and therefore any potential effects.

Reduces 'snagging risk' for vessels.

May have an impact on surrounding benthic habitats and sensitive species.

Uncertainty around the need for and efficacy of this measure.

Can be very challenging or impossible at sites where seabed tends to be rocky.

Additional cost to the project.

...Read more

May have an impact on surrounding benthic habitats and sensitive species.

Uncertainty around the need for and efficacy of this measure.

Can be very challenging or impossible at sites where seabed tends to be rocky.

Additional cost to the project.

Reduced possibility of decommissioning.

Read less
Sustainable Energy Authority of Ireland (SEAI) 2011, Federal Energy Regulatory Commission (FERC) 2020, Atlantic Marine Energy Test Site (AMETS), PacWave South Test Site
Tidal Operation & Maintenance Changes in water flow

The potential wider or secondary effects on protected or sensitive sub-littoral seabed due to removal or alteration of energy flow arising from devices and moorings or support structures.

Birds
Monitoring

Installation of ADCPs and turbulence sensors to better understand the baseline tidal flow conditions and hence the change in tidal flow due to presence of the device(s).

Reduce scientific uncertainty

None identified

Tidal Energy Ltd 2008, Aquatera 2017, Fox 2019, Ramsey Sound, Tocardo InToTidal at EMEC
Wave, Tidal Operation & Maintenance Habitat Creation

The introduction of infrastructure and artificial substrates will provide habitat and artificial refuges.

Birds
Monitoring

Monitor near-field behaviors.

Reduces scientific uncertainty around collision risk, displacement, and other impacts.

Increased value/fecundity of commercially important species.

Informs understanding of potential positive impacts from colonization and use of the project infrastructure.

This type of monitoring can be expensive and difficult to deliver in practice.

May require additional licensing (e.g., echosounders).

MeyGen 2012, Tidal Lagoon Power 2017, MeyGen Tidal Energy Project, Swansea Bay Tidal Lagoon (SBTL)
Tidal Operation & Maintenance Changes in water flow

The potential wider or secondary effects on protected or sensitive sub-littoral seabed due to removal or alteration of energy flow arising from devices and moorings or support structures.

Fish
Design feature

Site selection.

Minimizes significance of interaction.

None identified

ScottishPower Renewables 2012, Fox 2019, Ness of Duncansby Tidal Array
Wave, Tidal Installation EMF

Impacts of electromagnetic fields from subsea cables on sensitive species.

Fish
Migratory fish
Design feature

Micrositing of offshore infrastructure to avoid sensitive habitats and minimize footprint.

Could reduce/remove effects on sensitive habitats.

Relatively low cost measure.

None identified

DP Energy Ltd. 2013, ScottishPower Renewables 2012, Laminaria 2018, Tidal Lagoon Power 2017, The Marine Institute 2016, West Islay Tidal Project Energy Park, EMEC Billia Croo Grid-Connected Wave Test Site, Swansea Bay Tidal Lagoon (SBTL), Galway Bay Test Site
Wave, Tidal Installation Barrier to movement

Potential barrier to movement due to the physical presence of devices and associated moorings/support structures, cables and electrical equipment.

Habitat
Design feature

Site selection to avoid sensitive routes/areas.

Minimizes risk of development acting as a barrier to movement by avoiding migratory routes or other important sites.

None identified

ScottishPower Renewables 2012, OpenHydro and SSE Renewables 2013, Fox 2019, Ness of Duncansby Tidal Array
Wave Installation, Operation & Maintenance Habitat Loss

Direct loss of protected or sensitive intertidal communities from changes in hydrodynamics due to nearshore WECs.

Habitat
Intertidal ecology
Design feature

Micrositing of nearshore WECs to minimize the impact on sensitive habitats and species.

None identified

None identified

Foubister 2005, Royal Haskoning and Sea Generation (Kyle Rhea) Ltd. 2013, South West of England Regional Development Agency (SWDRA) 2006, SSE Renewables 2011, ScottishPower Renewables 2012, MeyGen 2012, Laminaria 2018, The Marine Institute 2016, EMEC Fall of Warness Grid-Connected Tidal Test Site, Kyle Rhea Tidal Stream Array Project, Wave Hub, Westray South Tidal Project, MeyGen Tidal Energy Project, EMEC Billia Croo Grid-Connected Wave Test Site, Galway Bay Test Site
Tidal Operation & Maintenance Collision risk

Potential for collision with turbine blades.

Marine Mammals
Monitoring

Environmental monitoring to detect collision events.

Understand avoidance behavior, nature of interactions, and outcome of collision events.

Can be a high cost associated with this.

Unclear how much monitoring will be required to fully understand this risk.

Technology is not advanced enough yet to do this efficiently.

Data mortgage (data gathered more quickly than it can be analysed).

...Read more

Can be a high cost associated with this.

Unclear how much monitoring will be required to fully understand this risk.

Technology is not advanced enough yet to do this efficiently.

Data mortgage (data gathered more quickly than it can be analysed).

Power supply availability - hard-wired vs. battery; power is required for monitoring and power availability can present logistical, financial, and technical challenges.

Interaction between equipment - e.g., multibeam sonar/ ADCP/echosounder; there can be interaction between monitoring equipment which can present challenges in monitoring.

Certain equipment used such as PAM may actually effect behaviour themselves.

Read less
SAE Renewables 2011, Aquamarine Power Ltd 2011, GlaxoSmithKlineMontrose 2012, Orbital Marine Power 2014, ScottishPower Renewables 2010, Davison and Mallows 2005, McGrath 2013, Tidal Lagoon Power 2017, Orbital Marine Power 2018, Atlantis Resources Corporation at EMEC, Oyster 800 at EMEC, GSK Montrose Tidal Array, Sound of Islay Demonstration Tidal Array, Strangford Lough - MCT (SeaGen), Fair Head Tidal Array, Swansea Bay Tidal Lagoon (SBTL), Orbital Marine Power O2 at EMEC
Wave, Tidal Operation & Maintenance Habitat Creation

The introduction of infrastructure and artificial substrates will provide habitat and artificial refuges.

Marine Mammals
Monitoring

Monitor near-field behaviors.

Informs understanding of potential positive impacts from colonization and use of the project infrastructure.

Reduces scientific uncertainty around collision risk, displacement, and other impacts.

Increased value/fecundity of commercially important species.

Can be expensive and difficult to deliver in practice.

May require additional licensing (e.g., echosounders).

Wave, Tidal Installation, Operation & Maintenance, Decommissioning Contamination

Potential for accidental or unplanned events which could lead to contamination of the marine environment.

Reptiles
Mitigation

Material selection - lubricants, coolants, hydraulic fluids etc., - selected with low ecotoxicity levels and biodegradable.

Reduces/removes risk of contamination/pollution from materials which may have escaped structure.

Use of lower toxicity materials may compromise performance, or impact other technical issues (e.g., fluid changes.)

Foubister 2005, MeyGen 2012, Xodus AURORA 2010, The Marine Institute 2016, THETIS Energy 2009, EMEC Fall of Warness Grid-Connected Tidal Test Site, MeyGen Tidal Energy Project, HS1000 at EMEC, Galway Bay Test Site, Torr Head Project