Management Measures Tool for Marine Renewable 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. 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.

A workshop was held in May 2017 with researchers, regulators, and developers to create the basis for the tool shown here. More information on the workshop and input for the tool can be found here.

In addition to the searchable tool below, the information below 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.

^{Last updated July 2022}

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Technology	Project Phase	Receptor	Stressor/Interaction	Management Measure	Implications of Measure	Advantages	Challenges	Project Documents
Wave, Tidal	Decommissioning	Birds Birds	Vessel disturbance Potential for disturbance from project vessels.	Mitigation Limit use of vessels, e.g. one vessel present with regular use of thrusters to maintain position.	Reduces potential disturbance effects			Low 2012, MeyGen 2012
Tidal	Operation & Maintenance	Birds Diving birds	Collision risk Potential for collision with turbine blades.	Mitigation Reduce maximum blade tip speed.		This could reduce the likelihood/consequence of potential collision events	Potential impacts on power production. Control mechanism of turbine blade speed unclear. May cause increased fatigue.
Wave, Tidal	Operation & Maintenance	Fish Demersal fish	EMF Impacts of electromagnetic fields from landfall cables on sensitive species.	Design feature Use of 3-phase cables instead of DC cables.	n/a
Wave, Tidal	Operation & Maintenance	Fish Basking shark, large fish	Entanglement Potential for marine animals to become entangled in device mooring lines and cables.	Design feature Cable design with maximum bend radius.	Would remove/reduce risk of entanglement, however cable design driven by technical and commercial consideration. Entanglement records are a useful way to track events.	Remove/reduce risk of entanglement	Mooring design driven by technical and commercial consideration.	Foubister 2005
Wave, Tidal	Installation, Operation & Maintenance, Decommissioning	Fish All receptors	Marine Non-Native Species (MNNS) Potential for introduction of MNNS which can have an adverse impact on the native species at the site.	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.	Reduce/remove risk of transfer and settlement of non-native species.	N/A	McPherson 2015, MeyGen 2012, Royal Haskoning and Sea Generation (Kyle Rhea) Ltd. 2013, Federal Energy Regulatory Commission (FERC) 2020
Wave, Tidal	Installation, Decommissioning	Habitat All receptors	Changes in sediment dynamics Reduced visibility impacting prey detection and obstruction avoidance.	Mitigation Best practice methodologies to reduce resuspension of sediment during cable burial or device foundation / mooring installation.	n/a	N/A	N/A	Orbital Marine Power 2014, Foubister 2005, ScottishPower Renewables 2010, Royal Haskoning and Sea Generation (Kyle Rhea) Ltd. 2013, Sustainable Energy Authority of Ireland (SEAI) 2011, The Marine Institute 2016
Wave, Tidal	Installation	Habitat All receptors	Contamination Accidental release of contaminants during installation including diesel fuel, oil hydraulic fluids, etc.	Mitigation Best practice methodologies to reduce risk of accidental release of contaminants.	Reduces risk of contamination escaping from structure.			DP Energy Ltd. 2013
Tidal	Operation & Maintenance	Habitat All receptors	Marine Non-Native Species (MNNS) Potential for introduction of MNNS which can have an adverse impact on the native species at the site.	Mitigation, Design feature Antifouling application on components such as the pile and rodos blades.	To prevent colonisation of the device and prevent the structure forming a stepping stone for non-native species.			Royal Haskoning and Sea Generation (Kyle Rhea) Ltd. 2013, Orbital Marine Power 2018
Tidal	Operation & Maintenance	Marine Mammals Marine Mammals	Collision risk Potential for collision with turbine blades.	Monitoring Environmental monitoring to better understand near-field behaviour and avoidance.	This will help reduce scientific uncertainty, however monitoring can be costly.	This will help reduce scientific uncertainty	Can be a high cost associated with this. Unclear how much monitoring will be required to fully understand this risk. Practicalities of monitoring; technology is not advanced enough yet to do this efficiently. Data mortgage. 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.	GlaxoSmithKlineMontrose 2012, Minesto 2016, Davison and Mallows 2005, Xodus Group 2019, McGrath 2013, MeyGen 2012, Orbital Marine Power 2018
Wave, Tidal	Installation, Operation & Maintenance, Decommissioning	Reptiles All receptors	Barrier to movement Potential barrier to movement due to the physical presence of devices and associated moorings / support structures, cables and electrical equipment.	Mitigation Adherence to vessel management plan.		Minimises the potential interaction between animals and construction or maintenance vessels.	N/A
Wave, Tidal	Operation & Maintenance	Marine Mammals Cetaceans	Entanglement Potential for marine animals to become entangled in device mooring lines and cables.	Design feature, Monitoring Routine inspections of mooring lines. Implement features into existing control systems to detect entanglement events.	Removes/reduces risk of entanglement and is a low cost monitoring capability.	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	Argyll Tidal Limited 2013, Federal Energy Regulatory Commission (FERC) 2020, Orbital Marine Power 2018
Wave, Tidal	Installation, Operation & Maintenance, Decommissioning	Habitat All receptors	Barrier to movement Potential barrier to movement due to the physical presence of devices and associated moorings / support structures, cables and electrical equipment.	Mitigation Adherence to vessel management plan.		Minimises the potential interaction between animals and construction or maintenance vessels.	N/A	OpenHydro and SSE Group 2013, Aquatera 2017, ScottishPower Renewables 2010
Wave, Tidal	Installation, Decommissioning	Reptiles All receptors	Changes in sediment dynamics Sediment disturbance disrupting water clarity that results in smothering of fish spawning grounds.	Mitigation Best practice methodologies to reduce resuspension of sediment during cable burial or device foundation / mooring installation.	n/a	N/A	N/A
Wave, Tidal	Installation, Decommissioning	Habitat Benthic invertebrates, demersal fish	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.	Design feature Minimise footprint of anchors / foundations.	This could reduce effects on sensitive habitats, however the size of anchors/foundations likely to be that which is suitable for the safe and optimal operation of devices.	This could reduce effects on sensitive habitats	May impact technical considerations.
Wave, Tidal	Operation & Maintenance	Benthic Benthic invertebrates, demersal fish	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.	Monitoring Periodic visual monitoring through the use of divers or drop down video, static cameras / remote sensing techniques, benthic grab surveys, geophysical survey to identify scour pits, turbidity measurements.	Implementation of this measure would generate data to quantify level and spatial extent of effect, however there are technical and health and safety risks associated with periodic monitoring in close vicinity of infrastructure. This measure may also require power shut down. Additionally, the associated subsea static monitoring options require O&M which has potential time and cost implications.	Generation of data to quantify level and spatial extent of effect.	Technical and Health and Safety risks associated with periodic monitoring operation in close vicinity of infrastructure. Power shut down potential. Subsea static monitoring options require O&M.	Tidal Energy Ltd 2008, OpenHydro and SSE Group 2013, Foubister 2005, European Marine Energy Centre (EMEC) 2011, ScottishPower Renewables 2010, Davison and Mallows 2005, SSE Group 2011, Federal Energy Regulatory Commission (FERC) 2020, Xodus Group 2012
Wave, Tidal	Installation, Operation & Maintenance, Decommissioning	Benthic All receptors	Displacement Potential displacement of essential activities due to the presence of devices and associated moorings / support structures.	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 Group 2013, Aquatera Ltd 2011, Foubister 2005, Royal Haskoning and Sea Generation (Kyle Rhea) Ltd. 2013, SSE Group 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
Wave, Tidal	Operation & Maintenance	Benthic Benthic invertebrates	EMF Impacts of electromagnetic fields from landfall cables on sensitive species.	Design feature Strategic use of rock placement/other cable protection.	n/a
Wave, Tidal	Installation	Benthic All receptors	Marine Non-Native Species (MNNS) Potential for introduction of MNNS which can have an adverse impact on the native species at the site.	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.
Tidal	Operation & Maintenance	Birds Diving birds	Changes in water flow Modifications to prey distribution and abundance (to include for other receptors) resulting in changes to foraging behaviour.	Design feature Site selection.		Minimises significance of interaction	N/A	Argyll Tidal Limited 2013, ScottishPower Renewables 2012
Wave, Tidal	Operation & Maintenance	Birds All receptors	Displacement Potential displacement of essential activities due to the presence of devices and associated moorings / support structures.	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	N/A	Argyll Tidal Limited 2013, Orbital Marine Power 2014, ScottishPower Renewables 2012
Wave, Tidal	Installation	Birds Seabirds	Lighting Potential for light from installation vessels to adversely affect nocturnal and migratory species.	Mitigation Limit lighting on installation vessels to that safe for navigational purposes only.	Reduce impact on sensitive species. A lot of the light on navigational vessels is superflous so would not detract from their safe operation.			Xodus Group 2019
Wave, Tidal	Installation, Operation & Maintenance, Decommissioning	Fish Fish	Changes in sediment dynamics Reduced visibility impacting prey detection and obstruction avoidance.	Design feature Minimise the amount of structure on the seabed.		Minimises 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 Group 2013
Tidal	Operation & Maintenance	Birds Diving birds	Collision risk Potential for collision with turbine blades.	Mitigation Design proportion of swept area to structure area to minimise collision risk.		This could reduce the likelihood/consequence of potential collision events.	Can be a high cost associated with this. Can present financial/ logistical/ design challenges to technology developer to alter design of device.
Wave, Tidal	Operation & Maintenance	Fish Demersal fish	EMF Impacts of electromagnetic fields from landfall cables on sensitive species.	Design feature Lay cables in natural crevices.	n/a			MeyGen 2012
Wave, Tidal	Operation & Maintenance	Fish Basking shark, large fish	Entanglement Potential for marine animals to become entangled in device mooring lines and cables.	Design feature, Monitoring Install tension sensors on mooring lines.	Informs of problem with mooring lines allowing rectification, however their implementation would come at an additional cost and would require control system integration.	Informs of problem with mooring lines allowing rectification. Cost per unit.	Additional cost and control system integration requirement. Load from entangled animal is likely to be smaller than the device loading on the moorings. Uncertainty of the efficacy of this measure.	Laminaria 2018
Wave, Tidal	Installation, Operation & Maintenance, Decommissioning	Fish All receptors	Marine Non-Native Species (MNNS) Potential for introduction of MNNS which can have an adverse impact on the native species at the site.	Mitigation Establish and implement a Biofouling Management Plan.	Reduce/removes risk of transfer of non-native species.	Reduce/remove risk of transfer of non-native species.	Lack of industry specific guidance.	European Marine Energy Centre (EMEC) 2014
Wave, Tidal	Installation, Decommissioning	Habitat All receptors	Changes in sediment dynamics Sediment disturbance disrupting water clarity that results in smothering of fish spawning grounds.	Mitigation Best practice methodologies to reduce resuspension of sediment during cable burial or device foundation / mooring installation.	n/a	N/A	N/A	Orbital Marine Power 2014, ScottishPower Renewables 2010, Royal Haskoning and Sea Generation (Kyle Rhea) Ltd. 2013, Sustainable Energy Authority of Ireland (SEAI) 2011, The Marine Institute 2016
Tidal	Operation & Maintenance	Marine Mammals Diving birds	Collision risk Potential for collision with turbine blades.	Mitigation Reduce maximum blade tip speed.		This could reduce the likelihood/consequence of potential collision events	Potential impacts on power production. Control mechanism of turbine blade speed unclear. May cause increased fatigue.
Wave, Tidal	Installation, Decommissioning	Marine Mammals Marine Mammals	Airborne noise The potential effects from airborne noise generated during installation/construction (excluding piling).	Mitigation Avoid/limit 'noisy works' within close proximity to sensitive sites i.e. known seal haul outs and important cliff nesting sites, during sensitive periods, defining appropriate clearance distances where necessary.	This could reduce potential effects on sensitive species during sensitive periods, however may could increase project construction timescales e.g. if continuous drilling time is restricted or specific periods need to be avoided.	This could reduce potential effects on sensitive species during sensitive periods.	This could increase project construction timescales e.g. if continuous drilling time is restricted or specific periods need to be avoided.	Foubister 2005, SSE Group 2011, ScottishPower Renewables 2012, McGrath 2013, SIMEC Atlantis Energy Ltd 2011, Aquatera 2017, The Marine Institute 2016, Federal Energy Regulatory Commission (FERC) 2020, McGrath 2013, DP Energy Ltd. 2017
Tidal	Operation & Maintenance	Marine Mammals Marine Mammals	Collision risk Potential for collision with turbine blades.	Mitigation Selective structural and blade coatings i.e. colours to aide detection.	Unknown - it is possible that this will aid detection of subsea structures and help reduce risk. It can be captured in early project design for a small one-off cost, however further research is needed as there is potential for an increased collision risk through 'attraction'.	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
Wave, Tidal	Installation, Operation & Maintenance, Decommissioning	Reptiles All receptors	Barrier to movement Potential barrier to movement due to the physical presence of devices and associated moorings / support structures, cables and electrical equipment.	Monitoring Monitoring of existing developments.		Reduces scientific uncertainty.	Can be complex and costly.
Wave, Tidal	Operation & Maintenance	Marine Mammals Cetaceans	Entanglement Potential for marine animals to become entangled in lost fishing gear or other equipment trapped on infrastructure.	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
Wave, Tidal	Installation, Operation & Maintenance, Decommissioning	Marine Mammals Marine Mammals	Underwater noise The potential effects from airborne noise from support vessel activity	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
Wave, Tidal	Operation & Maintenance	Habitat All receptors	Displacement Potential displacement of essential activities due to the presence of devices and associated moorings / support structures.	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	N/A
Wave, Tidal	Installation, Decommissioning	Habitat Benthic invertebrates, demersal fish	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.	Design feature Cable protection management measures to ensure that any rock placement that is required will be kept to a minimum to reduce seabed disturbance.	This could reduce effects on sensitive habitats.	This could reduce effects on sensitive habitats	Additional cost.
Wave, Tidal	Installation, Operation & Maintenance	Benthic Benthic invertebrates, demersal fish	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.	Design feature Micrositing of export cables and infrastructure to minimise the impact on sensitive habitats and species. Best practice techniques for cable installation, burial and protection.	Reduces, limits or offsets potential impacts on sensitive habitats and species.	N/A	N/A	Project Management Support Services 2006, Tidal Energy Ltd 2008, Foubister 2005, Royal Haskoning and Sea Generation (Kyle Rhea) Ltd. 2013, RSK Group 2012, South West of England Regional Development Agency (SWDRA) 2006, SSE Group 2011, ScottishPower Renewables 2012, DP Energy Ltd. 2017, Laminaria 2018, Sustainable Energy Authority of Ireland (SEAI) 2011, Tidal Lagoon Power 2017, THETIS Energy 2009, Royal Haskoning 2019, Aquamarine Power Ltd 2011
Wave, Tidal	Installation, Operation & Maintenance, Decommissioning	Benthic All receptors	Displacement Potential displacement of essential activities due to the presence of devices and associated moorings / support structures.	Design feature Array/ mooring configuration designed to avoid migratory routes or other important sites		Minimises 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
Wave, Tidal	Operation & Maintenance	Benthic All receptors	Entrapment Potential risk of entrapment within device chambers and mooring arrays.	Mitigation Regular ROV/ drop down camera surveys to establish occurrence of entrapment		Early detection of entrapment	Additional cost.
Wave, Tidal	Installation, Operation & Maintenance, Decommissioning	Benthic All receptors	Marine Non-Native Species (MNNS) Potential for introduction of MNNS which can have an adverse impact on the native species at the site.	Monitoring, Compliance Monitoring and reporting of MNNS.	Reduce/removes risk of transfer of non-native species.			Orbital Marine Power 2014, Xodus Group 2019, Magallanes Renovables 2020
Wave, Tidal	Installation, Decommissioning	Birds All receptors	Changes in sediment dynamics Sediment disturbance disrupting water clarity that results in smothering of fish spawning grounds.	Mitigation Best practice methodologies to reduce resuspension of sediment during cable burial or device foundation / mooring installation.	n/a	N/A	N/A	Sustainable Energy Authority of Ireland (SEAI) 2011, The Marine Institute 2016, Federal Energy Regulatory Commission (FERC) 2020
Wave, Tidal	Installation, Operation & Maintenance, Decommissioning	Birds All receptors	Displacement Potential displacement of essential activities due to the presence of devices and associated moorings / support structures.	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 Group 2013, Aquatera Ltd 2011, Foubister 2005, Royal Haskoning and Sea Generation (Kyle Rhea) Ltd. 2013, SSE Group 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
Wave, Tidal	Installation, Operation & Maintenance, Decommissioning	Birds All receptors	Marine Non-Native Species (MNNS) Potential for introduction of MNNS which can have an adverse impact on the native species at the site.	Compliance Compliance with all relevant guidance (including IMO guidelines) regarding ballast water management and transfer of non-native species.	Would remove/reduce risk of transfer and settlement of non-native species.	Reduce/remove risk of transfer and settlement of non-native species.	N/A	MeyGen 2012, Magallanes Renovables 2020, Royal Haskoning and Sea Generation (Kyle Rhea) Ltd. 2013, Federal Energy Regulatory Commission (FERC) 2020
Wave, Tidal	Installation, Operation & Maintenance, Decommissioning	Fish Fish	Changes in sediment dynamics Sediment disturbance disrupting water clarity that results in smothering of fish spawning grounds.	Design feature Minimise the amount of structure on the seabed.		Minimises 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 Group 2013
Tidal	Operation & Maintenance	Fish Fish	Collision risk Potential for collision with turbine blades.	Monitoring Environmental monitoring to better understand near-field behaviour and avoidance.	This will help reduce scientific uncertainty, however this type of monitoring can be expensive and there are difficulties associated with storing and analysing the data produced.	This will help reduce scientific uncertainty	Can be a high cost associated with this. Unclear how much monitoring will be required to fully understand this risk. Practicalities of monitoring; technology is not advanced enough yet to do this efficiently. Data mortgage. 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.	Xodus Group 2019, Magallanes Renovables 2020
Wave, Tidal	Operation & Maintenance	Fish Demersal fish	EMF Impacts of electromagnetic fields from landfall cables on sensitive species.	Design feature Maximise length of any drilled boreholes.	n/a			MeyGen 2012
Wave, Tidal	Operation & Maintenance	Fish Basking shark, large fish	Entanglement Potential for marine animals to become entangled in device mooring lines and cables.	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	Fish All receptors	Marine Non-Native Species (MNNS) Potential for introduction of MNNS which can have an adverse impact on the native species at the site.	Mitigation, Compliance Adhere to appropriate measures when jettisoning ballast water.	Reduce/removes risk of transfer of non-native species.	Reduce/remove risk of transfer of non-native species.	N/A	Sustainable Energy Authority of Ireland (SEAI) 2011
Tidal	Operation & Maintenance	Marine Mammals All receptors	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.	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	N/A	Tidal Energy Ltd 2008, Aquatera 2017
Tidal	Operation & Maintenance	Marine Mammals Diving birds	Collision risk Potential for collision with turbine blades.	Mitigation Design proportion of swept area to structure area to minimise collision risk.		This could reduce the likelihood/consequence of potential collision events.	Can be a high cost associated with this. Can present financial/ logistical/ design challenges to technology developer to alter design of device.
Wave, Tidal	Installation, Decommissioning	Marine Mammals All receptors	Changes in sediment dynamics Reduced visibility impacting prey detection and obstruction avoidance.	Mitigation Best practice methodologies to reduce resuspension of sediment during cable burial or device foundation / mooring installation.	n/a	None identified.	N/A	Foubister 2005, Sustainable Energy Authority of Ireland (SEAI) 2011, The Marine Institute 2016, Federal Energy Regulatory Commission (FERC) 2020
Wave, Tidal	Operation & Maintenance	Marine Mammals All receptors	Collision risk Pontential risk of collision with device giving size and character of structure	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
Wave, Tidal	Operation & Maintenance	Marine Mammals Marine Mammals	Displacement Potential displacement of essential activities due to the presence of devices and associated moorings / support structures.	None identified None identified.	n/a
Wave, Tidal	Operation & Maintenance	Marine Mammals Cetaceans	Entanglement Potential for marine animals to become entangled in device mooring lines and cables.	Mitigation Install strain gauges on the device	It allows alerting the operator of an entanglement event			Magallanes Renovables 2020
Wave, Tidal	Installation, Operation & Maintenance, Decommissioning	Marine Mammals Cetaceans	Vessel collision Potential for collision with project vessels.	Mitigation Adhere to minimum approach distances for vessels on approach.	Reduces potential effects and is a relatively low cost measure.	Reduces potential effects. Relatively low-cost measure.	N/A	Aquamarine Power Ltd 2011, Xodus Group 2019, European Marine Energy Centre (EMEC) 2020, Aquatera 2017, Federal Energy Regulatory Commission (FERC) 2020, Orbital Marine Power 2018
Wave, Tidal	Installation, Operation & Maintenance, Decommissioning	Habitat All receptors	Displacement Potential displacement of essential activities due to the presence of devices and associated moorings / support structures.	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 Group 2013, Aquatera Ltd 2011, Foubister 2005, ScottishPower Renewables 2012, Royal Haskoning and Sea Generation (Kyle Rhea) Ltd. 2013, SSE Group 2011, ScottishPower Renewables 2012, McGrath 2013, Orbital Marine Power 2014, The Marine Institute 2016, Federal Energy Regulatory Commission (FERC) 2020, THETIS Energy 2009
Wave, Tidal	Installation, Decommissioning	Habitat Benthic invertebrates, demersal fish	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.	Mitigation Use of locally sourced materials, for cable protection, of the same type as the habitat to be disturbed by cable installation.	Minimize impact on biodiversity/ ecosystem.	Lost seabed is replaced with same material. Minimises habitat loss.	N/A
Wave, Tidal	Installation, Decommissioning	Benthic All receptors	Changes in sediment dynamics Reduced visibility from altered water clarity associated with sediment mixing that can impact prey detection and obstruction avoidance.	Mitigation Best practice methodologies to reduce resuspension of sediment during cable burial or device foundation / mooring installation.	n/a	N/A	N/A	Foubister 2005, ScottishPower Renewables 2010, Royal Haskoning and Sea Generation (Kyle Rhea) Ltd. 2013, South West of England Regional Development Agency (SWDRA) 2006, Sustainable Energy Authority of Ireland (SEAI) 2011, Tidal Lagoon Power 2017, The Marine Institute 2016, Federal Energy Regulatory Commission (FERC) 2020
Wave, Tidal	Installation, Operation & Maintenance, Decommissioning	Benthic All receptors	Contamination Potential for oil spill incident resulting from the influence of unfavourable weather conditions.	Mitigation Vessel activities to occur in suitable weather conditions	Reduces the chance for oil spill to the environment			MeyGen 2012, Aquamarine Power Ltd 2011, ScottishPower Renewables 2012
Wave, Tidal	Operation & Maintenance	Benthic Benthic invertebrates	EMF Impacts of electromagnetic fields from landfall cables on sensitive species.	Design feature Bundle cables together to reduce field vectors.	n/a			MeyGen 2012
Tidal	Operation & Maintenance	Benthic All receptors	Marine Non-Native Species (MNNS) Potential for introduction of MNNS which can have an adverse impact on the native species at the site.	Mitigation, Design feature Antifouling application on components such as the pile and rodos blades.	To prevent colonisation of the device and prevent the structure forming a stepping stone for non-native species.			Royal Haskoning and Sea Generation (Kyle Rhea) Ltd. 2013, Magallanes Renovables 2020, McGrath 2013
Tidal	Operation & Maintenance	Birds Diving birds	Changes in water flow Modifications to tidal flows affect prey distribution and abundance resulting in changes to foraging behaviour.	Monitoring Observational surveys (including remote sensing) of species (prey availability linked to benthic community).	Reduces scientific uncertainty.	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 Group 2011, Xodus Group 2012, MeyGen 2012, Aquamarine Power Ltd 2011, ScottishPower Renewables 2012, Xodus Group 2012
Wave, Tidal	Installation, Operation & Maintenance, Decommissioning	Birds All receptors	Displacement Potential displacement of essential activities due to the presence of devices and associated moorings / support structures.	Design feature Array/ mooring configuration designed to avoid migratory routes or other important sites		Minimises 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
Wave, Tidal	Installation, Operation & Maintenance, Decommissioning	Birds All receptors	Marine Non-Native Species (MNNS) Potential for introduction of MNNS which can have an adverse impact on the native species at the site.	Mitigation Establish and implement a Biofouling Management Plan.	Reduce/remove risk of transfer of non-native species.	Reduce/remove risk of transfer of non-native species.	Lack of industry specific guidance.	European Marine Energy Centre (EMEC) 2014
Wave, Tidal	Installation, Operation & Maintenance, Decommissioning	Fish Fish	Changes in sediment dynamics Reduced visibility impacting prey detection and obstruction avoidance.	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
Tidal	Operation & Maintenance	Fish Fish	Collision risk Potential for collision with turbine blades.	Mitigation Selective structural and blade coatings i.e. colours to aide detection.	Unknown - it is possible that this will aid detection of subsea structures and help reduce risk although further research is needed - certain colours may serve to attract fish and lead to an increase in collision risk. A small one off cost that can be easily planned for at the design stage.	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
Wave, Tidal	Operation & Maintenance	Fish Demersal fish	EMF Impacts of electromagnetic fields from landfall cables on sensitive species.	Design feature Strategic use of rock placement/other cable protection.	n/a
Wave, Tidal	Operation & Maintenance	Fish All receptors	Entrapment Potential risk of entrapment within device chambers and mooring arrays.	Mitigation Regular ROV/ drop down camera surveys to establish occurrence of entrapment		Early detection of entrapment	Additional cost.
Wave, Tidal	Installation, Operation & Maintenance, Decommissioning	Fish All receptors	Marine Non-Native Species (MNNS) Potential for introduction of MNNS which can have an adverse impact on the native species at the site.	Mitigation Source vessels locally.	Reduce/removes risk of transfer of non-native species.	Reduce/remove risk of transfer and settlement of non-native species.	N/A	McPherson 2015
Tidal	Operation & Maintenance	Marine Mammals All receptors	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.	Design feature Design structures to minimise effect on turbulence structure.		Minimises change in turbulence structure and hence potential interaction	Can present financial/ logistical/ design challenges to technology developer to alter design of device/ moorings	Aquamarine Power Ltd 2011, Davison and Mallows 2005, Tidal Energy Ltd 2008
Wave, Tidal	Installation, Operation & Maintenance, Decommissioning	Habitat All receptors	Contamination Potential for oil spill incident resulting from the influence of unfavourable weather conditions.	Mitigation Vessel activities to occur in suitable weather conditions	Reduces the chance for oil spill to the environment			MeyGen 2012, The Marine Institute 2016, ScottishPower Renewables 2012
Wave, Tidal	Installation, Decommissioning	Marine Mammals All receptors	Changes in sediment dynamics Sediment disturbance disrupting water clarity that results in smothering of fish spawning grounds.	Mitigation Best practice methodologies to reduce resuspension of sediment during cable burial or device foundation / mooring installation.	n/a	None identified.	N/A	Craig 2008, Sustainable Energy Authority of Ireland (SEAI) 2011, The Marine Institute 2016, Federal Energy Regulatory Commission (FERC) 2020
Tidal	Operation & Maintenance	Marine Mammals All receptors	Collision risk Potential for collision with turbine blades.	Mitigation Minimise turbine standstill periods.
Wave, Tidal	Installation, Operation & Maintenance, Decommissioning	Marine Mammals Marine Mammals	Displacement Potential displacement of essential activities due to the presence of devices and associated moorings / support structures.	Mitigation Employ an MMO during periods when noisy operations are likely to cause disturbance i.e., all operations using a DP vessel				SIMEC Atlantis Energy Ltd 2011, Orbital Marine Power 2010, Minesto 2016, Foubister 2005, European Marine Energy Centre (EMEC) 2014, Xodus Group 2019, Magallanes Renovables 2020, McGrath 2013, MeyGen 2012, DP Energy Ltd. 2017, Royal Haskoning 2012, Sustainable Energy Authority of Ireland (SEAI) 2011, The Marine Institute 2016, THETIS Energy 2009, Davison and Mallows 2005
Wave, Tidal	Operation & Maintenance	Marine Mammals All receptors	Entrapment Potential risk of entrapment within device chambers and mooring arrays.	Mitigation Release entrapped animal.	Animal may be deceased before it is able to be released.			Tidal Lagoon Power 2017
Wave, Tidal	Installation, Operation & Maintenance, Decommissioning	Marine Mammals Marine Mammals	Vessel disturbance Potential for disturbance from project vessels.	Mitigation Reduce speed and maintain steady course when animal is sighted.	Reduces potential effects and is a relatively low cost measure.	Reduces potential effects. Relatively low-cost measure.	N/A	Aquamarine Power Ltd 2011, Xodus AURORA 2010, Aquatera Ltd 2011, European Marine Energy Centre (EMEC) 2020, Magallanes Renovables 2020, Royal Haskoning 2012, Aquatera 2017, Tidal Lagoon Power 2017, Federal Energy Regulatory Commission (FERC) 2020, Orbital Marine Power 2018
Wave, Tidal	Installation, Operation & Maintenance, Decommissioning	Habitat All receptors	Displacement Potential displacement of essential activities due to the presence of devices and associated moorings / support structures.	Design feature Array/ mooring configuration designed to avoid migratory routes or other important sites		Minimises 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
Wave, Tidal	Installation, Decommissioning	Habitat Benthic invertebrates, demersal fish	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.	Design feature Site selection to avoid sensitive or protected sub-littoral seabed communities.		This could reduce/remove effects on sensitive habitats.	N/A	ScottishPower Renewables 2012, OpenHydro and SSE Group 2013
Wave, Tidal	Installation, Decommissioning	Benthic All receptors	Changes in sediment dynamics Sediment disturbance disrupting water clarity that results in smothering of fish spawning grounds.	Mitigation Best practice methodologies to reduce resuspension of sediment during cable burial or device foundation / mooring installation.	n/a	N/A	N/A	ScottishPower Renewables 2010, Royal Haskoning and Sea Generation (Kyle Rhea) Ltd. 2013, South West of England Regional Development Agency (SWDRA) 2006, Sustainable Energy Authority of Ireland (SEAI) 2011, Tidal Lagoon Power 2017, The Marine Institute 2016, Federal Energy Regulatory Commission (FERC) 2020
Wave	Operation & Maintenance	Benthic Benthic invertebrates	Dissipation of wave energy 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.	Monitoring Modelling to predict the interaction between wave energy 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	Benthic Benthic invertebrates	EMF Impacts of electromagnetic fields from landfall cables on sensitive species.	Design feature Bury cables where possible and viable.	n/a			Sustainable Energy Authority of Ireland (SEAI) 2011, Federal Energy Regulatory Commission (FERC) 2020
Wave, Tidal	Installation, Decommissioning	Birds Seabirds	Airborne noise The potential effects from airborne noise generated during installation/construction (excluding piling).	Mitigation Avoid/limit 'noisy works' within close proximity to sensitive sites i.e. known seal haul outs and important cliff nesting sites, during sensitive periods, defining appropriate clearance distances where necessary.	This could reduce potential effects on sensitive species during sensitive periods, but could increase project construction timescales and thus costs e.g. if continuous drilling time is restricted or specific periods need to be avoided.	This could reduce potential effects on sensitive species during sensitive periods.	This could increase project construction timescales e.g. if continuous drilling time is restricted or specific periods need to be avoided.	OpenHydro and SSE Group 2013, Aquatera Ltd 2011, Foubister 2005, Royal Haskoning and Sea Generation (Kyle Rhea) Ltd. 2013, SSE Group 2011, ScottishPower Renewables 2012, McGrath 2013, Orbital Marine Power 2014, The Marine Institute 2016, Federal Energy Regulatory Commission (FERC) 2020, THETIS Energy 2009
Tidal	Operation & Maintenance	Birds Diving birds	Collision risk Potential for collision with turbine blades.	Monitoring Environmental monitoring to detect collision events.	Helps to develop an understanding of avoidance behaviour, nature of interactions and outcome of collision events. However, there are cost implications assocaited with this level of monitoring.	Understand avoidance behaviour, 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. Practicalities of monitoring; technology is not advanced enough yet to do this efficiently. Data mortgage (concept of generating data 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.	SIMEC Atlantis Energy Ltd 2011, Aquamarine Power Ltd 2011, Orbital Marine Power 2014, Minesto 2016, SSE Group 2011, Xodus Group 2012, McGrath 2013, GlaxoSmithKlineMontrose 2012
Wave, Tidal	Operation & Maintenance	Birds Diving birds	Entanglement Potential for marine animals to become entangled in device mooring lines and cables.	Design feature Maintain taut mooring lines.	Would remove/reduce risk of entanglement, however mooring design driven by technical and commercial consideration. Entanglement records are a useful way to track events.	Remove/reduce risk of entanglement. Regular inspections can provide operational insight into condition.	Mooring design driven by technical and commercial consideration. Regular ROV/ dive or drop-down cameras inspections required.	Aquatera Ltd 2011, Federal Energy Regulatory Commission (FERC) 2020
Wave, Tidal	Installation, Operation & Maintenance, Decommissioning	Birds All receptors	Marine Non-Native Species (MNNS) Potential for introduction of MNNS which can have an adverse impact on the native species at the site.	Mitigation, Compliance Adhere to appropriate measures when jettisoning ballast water.	Reduce/remove risk of transfer of non-native species.	Reduce/remove risk of transfer of non-native species.	N/A	Sustainable Energy Authority of Ireland (SEAI) 2011
Tidal	Operation & Maintenance	Fish All receptors	Changes in water flow Modifications to tidal flows affect prey distribution and abundance resulting in changes to foraging behaviour.	Monitoring Observational surveys (including remote sensing) of species (prey availability linked to benthic community).	Reduces scientific uncertainty.	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
Tidal	Operation & Maintenance	Fish Fish	Collision risk Potential for collision with turbine blades.	Mitigation Minimise turbine standstill periods.
Wave, Tidal	Operation & Maintenance	Fish Demersal fish	EMF Impacts of electromagnetic fields from landfall cables on sensitive species.	Design feature Bundle cables together to reduce field vectors.	n/a			MeyGen 2012
Wave, Tidal	Operation & Maintenance	Fish Basking shark, large fish	Entanglement Potential for marine animals to become entangled in device mooring lines and cables.	Monitoring Fishing debris detected during routine inspections of mooring lines and cables will be removed.	Would remove/reduce risk of entanglement and is a low cost measure, implemented as part of standard O&M procedures.	Remove/reduce risk of entanglement Low cost measure, implemented as part of standard O&M procedures. Regular monitoring will benefit system performance in addition to addressing environmental risks (e.g. early detection of damage or failures in the system)	N/A
Wave, Tidal	Installation, Operation & Maintenance, Decommissioning	Fish Fish	Underwater noise The potential effects from underwater noise generated during installation/ construction (excluding piling).	Mitigation Limit vessel speed.		Reduces potential effects. Relatively low-cost measure.	N/A	SIMEC Atlantis Energy Ltd 2011
Tidal	Operation & Maintenance	Marine Mammals All receptors	Changes in water flow Modifications to prey distribution and abundance (to include for other receptors) resulting in changes to foraging behaviour.	Design feature Design structures to minimise effect on turbulence structure.		Minimises change in turbulence structure and hence potential interaction	Can present financial/ logistical/ design challenges to technology developer to alter design of device/ moorings	Tidal Energy Ltd 2008, Aquamarine Power Ltd 2011, Davison and Mallows 2005
Wave, Tidal	Operation & Maintenance	Habitat All receptors	Contamination Potential for oil/hydraulic spill incident resulting from the maintenance activities	Mitigation All maintenance activities involving oil/hydraulic fluid treatments will be carried out on-shore	Reduces the chance for oil spill to the environment			Foubister 2005
Wave, Tidal	Operation & Maintenance	Marine Mammals Marine Mammals	EMF Impacts of electromagnetic fields from landfall cables on sensitive species.	Design feature Bury cables where possible and viable.	n/a			McGrath 2013
Wave, Tidal	Installation, Operation & Maintenance, Decommissioning	Marine Mammals Marine Mammals	Underwater noise The potential effects from underwater noise generated during installation/ construction (excluding piling).	Mitigation Limit vessel speed.		Reduces potential effects. Relatively low-cost measure.	N/A	SIMEC Atlantis Energy Ltd 2011
Wave, Tidal	Operation & Maintenance	Marine Mammals Cetaceans	Entanglement Potential for marine animals to become entangled in device mooring lines and cables.	Design feature Maintain taut mooring lines.	Removes/reduces risk of entanglement, however mooring design tends to be driven by technical and commercial consideration. An entanglement record is a useful way to track events.	Remove/reduce risk of entanglement. Regular inspections can provide operational insight into condition.	Mooring design driven by technical and commercial consideration. Regular ROV/ dive or drop-down cameras inspections required.	Aquatera Ltd 2011, Laminaria 2018, Federal Energy Regulatory Commission (FERC) 2020
Wave, Tidal	Operation & Maintenance	Reptiles Sea turtles	Entanglement Potential for marine animals to become entangled in device mooring lines and cables.	Design feature Minimise the number of mooring lines.		Reduce risk of entanglement.	Could be a costly measure for technology developers
Wave, Tidal	Operation & Maintenance	Marine Mammals Marine Mammals	Vessel disturbance Potential for disturbance from project vessels.	Mitigation Use smaller vessels for maintenance purposes.	Reduces potential effects and is a relatively low cost measure.			Aquatera Ltd 2011, Laminaria 2018
Wave, Tidal	Installation, Operation & Maintenance, Decommissioning	Reptiles All receptors	Contamination Potential for accidental or unplanned events which could lead to contamination of the marine environment.	Design feature Physical Containment systems including bulk heads, closed circuit systems, pressure relief systems.	Reduces risk of contamination escaping from structure.	Reduces risk of pollution escaping from structure.	N/A	Foubister 2005, MeyGen 2012, Sustainable Energy Authority of Ireland (SEAI) 2011, The Marine Institute 2016
Wave, Tidal	Operation & Maintenance	Reptiles Sea turtles	Entanglement Potential for marine animals to become entangled in device mooring lines and cables.	Design feature Maintain taut mooring lines.	Removes/reduces risk of entanglement, however mooring design is driven by technical and economic consideration. An entanglement record is a good way to track events.	Remove/reduce risk of entanglement. Regular inspections can provide operational insight into condition.	Mooring design driven by technical and commercial consideration. Regular ROV/ dive or drop-down cameras inspections required.	Aquatera Ltd 2011
Wave, Tidal	Installation, Operation & Maintenance, Decommissioning	Benthic All receptors	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.	Design feature Minimise the amount of structure on the seabed.		Minimises 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 Group 2013
Wave, Tidal	Operation & Maintenance	Benthic All receptors	Contamination Potential for oil/hydraulic spill incident resulting from the maintenance activities	Mitigation All maintenance activities involving oil/hydraulic fluid treatments will be carried out on-shore	Reduces the chance for oil spill to the environment			Foubister 2005