Management Measures Tool for Marine Energy

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.

^{Last updated January 2023}

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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.	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.			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 Minimise 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 minimise 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.		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 seveloping 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.		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.		ScottishPower Renewables 2012, 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 minimise interaction despite modelling to fully predict interaction.	Foubister 2005, MeyGen 2012, Project Management Support Services 2006, GlaxoSmithKlineMontrose 2012, 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 behaviours.	Reduces scientific uncertainty around collision risk, displacement, and other impacts. Increased value/ fecundity of commercially important species. Informs understanding of potential positivie 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.	Uncertainty around how animals use visual cues, could. Could result in 'attraction', increasing risk of collision. 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 Pontential 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.		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.		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.		Tidal Energy Ltd 2008, Aquatera 2017, 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.		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.		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.		Argyll Tidal Limited 2013, Orbital Marine Power 2014, ScottishPower Renewables 2012, 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.		OpenHydro and SSE Renewables 2013, Aquatera 2017, ScottishPower Renewables 2010, Brims Tidal Array, 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.			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.		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.		Minesto 2016, SSE Renewables 2011, Aquatera 2011, 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.		Tidal Energy Ltd 2008, Aquatera 2017, 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.			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.		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.			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, EMEC Fall of Warness Grid-Connected Tidal Test Site, Orbital Marine Power SR250 at EMEC, Nova 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 minimise 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. 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.		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, 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, EMEC Fall of Warness Grid-Connected Tidal Test Site, Orbital Marine Power SR250 at EMEC, Nova 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.		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 minimise footprint.	Could reduce/remove effects on sensitive habitats. Low cost measure at single device or small-scale array.		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, 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
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, 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.
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 Ccontainment systems including bulk heads, closed circuit systems, pressure relief systems.	Reduces risk of contamination/pollution escaping from structure.		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 Minimise 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 minimise 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, 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.		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
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.		SAE Renewables 2011, 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.
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).	Minimises risk of development causing displacement by avoiding migratory routes or other important sites.		ScottishPower Renewables 2012, 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.		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, Brims Tidal Array, 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.			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.			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, Brims Tidal Array, 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 minimise 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, 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.
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		Tidal Energy Ltd 2008, Aquatera 2017, 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.		ScottishPower Renewables 2012, 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 minimise footprint.	Could reduce/remove effects on sensitive habitats. Relatively low cost measure.		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.		ScottishPower Renewables 2012, OpenHydro and SSE Renewables 2013, Ness of Duncansby Tidal Array, Brims 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 minimise the impact on sensitive habitats and species.			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 behaviours.	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
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	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.		Tidal Energy Ltd 2008, Aquatera 2017, Ramsey Sound, Tocardo InToTidal 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 Minimize footprint of anchors / foundations.	Could reduce effects on sensitive habitats.	May impact technical considerations, such as size of anchors/foundations that are safe and optimal for operation of device(s).	Aquamarine Power Ltd 2011, Aquatera Ltd 2011, Royal Haskoning and Sea Generation (Kyle Rhea) Ltd. 2013, RSK Group 2012, ScottishPower Renewables 2012, The Marine Institute 2016, Federal Energy Regulatory Commission (FERC) 2020, Oyster 800 at EMEC, Wello Penguin at EMEC, Kyle Rhea Tidal Stream Array Project, West Orkney South Wave Energy Site, Galway Bay Test Site, PacWave South Test Site
Wave, Tidal	Operation & Maintenance	Collision risk Pontential 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.		Aquatera Ltd 2011, The Marine Institute 2016, Wello Penguin at EMEC, Galway Bay Test Site
Wave, Tidal	Installation, Decommissioning	Underwater noise The potential effects from underwater noise generated during installation/ construction (excluding piling).	Birds Seabirds	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 and thus costs (e.g., if continuous drilling time is restricted or specific periods need to be avoided).	Aquatera Ltd 2011, Davison and Mallows 2005, ScottishPower Renewables 2012, McGrath 2013, Orbital Marine Power 2014, Aquatera 2017, Federal Energy Regulatory Commission (FERC) 2020, THETIS Energy 2009, Orbital Marine Power 2018, Wello Penguin at EMEC, Strangford Lough - MCT (SeaGen), Fair Head Tidal Array, Tocardo InToTidal at EMEC, PacWave South Test Site, Torr Head Project, 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.	Fish	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, Foubister 2005, MeyGen 2012, Xodus AURORA 2010, DP Energy Ltd. 2013, The Marine Institute 2016, THETIS Energy 2009, EMEC Fall of Warness Grid-Connected Tidal Test Site, MeyGen Tidal Energy Project , HS1000 at EMEC, West Islay Tidal Project Energy Park, Galway Bay Test Site, Torr Head Project
Wave, Tidal	Operation & Maintenance	Entanglement Potential for collision with turbine blades.	Fish Elasmobranch, large fish	Mitigation Install a 'detect and shut-down' system using active sonar and other appropriate monitoring equipment.	Could reduce/remove risk of collision with moving blades and enable a route through the consenting process, particulalrly at high sensitivity locations.	Could affect power production, is expensive to implement, and does not help to reduce scientific uncertainty regarding the risk....Read more Could affect power production, is expensive to implement, and does not help to reduce scientific uncertainty regarding the risk. The reductions in power production, although small, would bring about uncertainty in the investment process and there are questions around impacts of sonar on sensitive species. Read less	Xodus Group 2019, Davison and Mallows 2005, Magallanes Renovables 2020, Royal Haskoning and Sea Generation (Kyle Rhea) Ltd. 2013, Tidal Lagoon Power 2017, EMEC Billia Croo Grid-Connected Wave Test Site, Strangford Lough - MCT (SeaGen), Magallanes Renovables ATIR at EMEC, Kyle Rhea Tidal Stream Array 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.	Habitat	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 minimise interaction despite modelling to fully predict interaction	GlaxoSmithKlineMontrose 2012, Orbital Marine Power 2014, Craig 2008, GSK Montrose Tidal Array, OpenHydro Alderney
Tidal	Operation & Maintenance	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, Design feature Antifouling application on components such as the pile and rodos blades.	Prevents colonization of the device and structure, avoiding forming a stepping stone for non-native species.		Royal Haskoning and Sea Generation (Kyle Rhea) Ltd. 2013, Orbital Marine Power 2018, Kyle Rhea Tidal Stream Array Project, 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	Mitigation, Compliance Management: Establish and implement a Contamination Control Plan / Ship Oil Contamination Emergency Plans (SOPEPs). Compliance with International Maritime Organization (IMO) and Maritime Coastguard Agency (MCA) codes for the prevention of contamination.	Reduces risk of any contamination/pollution event and ensures that contingency plans are in place. Demonstrates compliance with environmental management systems.		Low 2012, Foubister 2005, GlaxoSmithKlineMontrose 2012, MeyGen 2012, Davison and Mallows 2005, Royal Haskoning and Sea Generation (Kyle Rhea) Ltd. 2013, Sustainable Energy Authority of Ireland (SEAI) 2011, The Marine Institute 2016, Federal Energy Regulatory Commission (FERC) 2020, Atlantis Resources Corporation at EMEC, EMEC Fall of Warness Grid-Connected Tidal Test Site, GSK Montrose Tidal Array, MeyGen Tidal Energy Project , Strangford Lough - MCT (SeaGen), Kyle Rhea Tidal Stream Array Project, Atlantic Marine Energy Test Site (AMETS), Galway Bay Test Site, PacWave South Test Site
Wave, Tidal	Installation, Operation & Maintenance, Decommissioning	Underwater noise The potential effects from airborne noise from support vessel activity.	Marine Mammals	Mitigation Adherence to Scotish Marine Wildlife Watching Code (SMWWC).			European Marine Energy Centre (EMEC) 2014, Xodus Group 2019, Magallanes Renovables 2020, European Marine Energy Centre (EMEC) 2020, Aquatera 2017, Laminaria 2018, Orbital Marine Power 2018, EMEC Fall of Warness Grid-Connected Tidal Test Site, EMEC Billia Croo Grid-Connected Wave Test Site, Magallanes Renovables ATIR at EMEC, EMEC Scapa Flow Scale Wave Test Site, Tocardo InToTidal at EMEC, EMEC Billia Croo Grid-Connected Wave Test Site, Orbital Marine Power O2 at EMEC, Mocean Wave Energy Converter: Blue Horizon
Wave, Tidal	Operation & Maintenance	Entanglement Potential for marine animals to become entangled in device mooring lines and cables.	Reptiles Sea turtles	Design feature Minimise the number of mooring lines.	Reduce risk of entanglement.	Could be a costly measure for technology developers.
Wave, Tidal	Installation, Operation & Maintenance, Decommissioning	Displacement Potential displacement of essential activities due to the presence of devices and associated moorings/support structures.	Benthic	Mitigation Timing of installation and decommissioning & marine operations to avoid times of particular sensitivity (e.g., breeding).	Minimises 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, 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, Brims Tidal Array, 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
Tidal	Operation & Maintenance	Marine Non-Native Species (MNNS) Potential for introduction of MNNS which can have an adverse impact on the native species at the site.	Benthic	Mitigation, Design feature Antifouling application on components such as the pile and rotor blades.	Prevents colonization of the device and structure, avoiding forming a stepping stone for non-native species.		Royal Haskoning and Sea Generation (Kyle Rhea) Ltd. 2013, Magallanes Renovables 2020, McGrath 2013, Kyle Rhea Tidal Stream Array Project, Magallanes Renovables ATIR at EMEC, Fair Head Tidal Array
Wave, Tidal	Installation, Operation & Maintenance, Decommissioning	Displacement Potential displacement of essential activities due to the presence of devices and associated moorings/support structures.	Birds	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, Oyster 800 at EMEC, Strangford Lough - MCT (SeaGen)
Wave, Tidal	Installation, Operation & Maintenance, Decommissioning	Changes in sediment dynamics Sediment disturbance disrupting water clarity that results in smothering of fish spawning grounds.	Fish	Mitigation Best practice methodologies to reduce resuspension of sediment during cable burial or device foundation / mooring installation.			Sustainable Energy Authority of Ireland (SEAI) 2011, Tidal Lagoon Power 2017, The Marine Institute 2016, Federal Energy Regulatory Commission (FERC) 2020, THETIS Energy 2009, 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 Maximise length of any drilled boreholes.			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, Compliance Adhere to appropriate measures when jettisoning ballast water.	Reduce/remove risk of transfer of non-native species.		Sustainable Energy Authority of Ireland (SEAI) 2011, Atlantic Marine Energy Test Site (AMETS)
Wave, Tidal	Installation, Operation & Maintenance, Decommissioning	Displacement Potential displacement of essential activities due to the presence of devices and associated moorings/support structures.	Habitat	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, Oyster 800 at EMEC, Strangford Lough - MCT (SeaGen)
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	Design feature Design structures to minimise effect on turbulence structure.	Minimizeschange in turbulence structure and hence potential interaction.	Can present financial, logistical, or design challenges to technology developer to alter design of device/moorings.	Tidal Energy Ltd 2008, Aquamarine Power Ltd 2011, Davison and Mallows 2005, Ramsey Sound, Oyster 800 at EMEC, Strangford Lough - MCT (SeaGen)
Wave, Tidal	Operation & Maintenance	Entanglement Potential for marine animals to become entangled in device mooring lines and cables.	Marine Mammals Cetaceans	Design feature Cable design with maximum bend radius.	Remove/reduce risk of entanglement.	Mooring design driven by technical and commercial consideration.	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.	Reptiles	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, Oyster 800 at EMEC, Strangford Lough - MCT (SeaGen)
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.	Benthic	Design feature Site selection to avoid sensitive routes/areas.	Minimises risk of development acting as a barrier to movement by avoiding migratory routes or other important sites.		Argyll Tidal Limited 2013, OpenHydro and SSE Renewables 2013, Argyll Tidal Demonstrator Project, Brims Tidal Array
Wave, Tidal	Operation & Maintenance	EMF Impacts of electromagnetic fields from landfall cables on sensitive species.	Benthic Benthic invertebrates	Design feature Lay cables in natural crevices.			MeyGen 2012, MeyGen Tidal Energy 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.	Birds	Design feature Design structures to minimise effect on turbulence structure.	Minimises 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, Oyster 800 at EMEC, Strangford Lough - MCT (SeaGen), Ramsey Sound
Wave, Tidal	Operation & Maintenance	Habitat Creation The introduction of infrastructure and artificial substrates will provide potential roosting habitat.	Birds Roosting birds	Monitoring Monitor use of device as a roosting platform.	Reduces scientific uncertainty around collision risk, displacement, and other impacts.	Data mortgage (concept of generating data more quickly than it can be analysed). Could be expensive to monitor.	DP Energy Ltd. 2013, Orbital Marine Power 2018, West Islay Tidal Project Energy Park, Orbital Marine Power O2 at EMEC
Tidal	Operation & Maintenance	Changes in water flow Modifications to prey distribution and abundance (to include for other receptors) resulting in changes to foraging behavior.	Fish	Design feature Site selection.	Minimizes significance of interaction.		ScottishPower Renewables 2012, Ness of Duncansby Tidal Array
Wave, Tidal	Operation & Maintenance	EMF Impacts of electromagnetic fields from landfall cables on sensitive species.	Fish Demersal fish	Design feature Install cable protection/armour.	Higher levels of insulation reduces the level of EMF to surrounding water column and therefore any potential effects.		DP Energy Ltd. 2013, Foubister 2005, Federal Energy Regulatory Commission (FERC) 2020, West Islay Tidal Project Energy Park, EMEC Fall of Warness Grid-Connected Tidal 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.	Habitat	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, Oyster 800 at EMEC, Strangford Lough - MCT (SeaGen)