Publication - Publication

Offshore wind energy - draft sectoral marine plan: strategic environmental assessment

Published: 18 Dec 2019
Marine Scotland Directorate
Part of:
Energy, Marine and fisheries

Strategic environmental assessment (SEA) identifies the likely significant environmental impacts of plans and policies and proposed reasonable alternatives to them.

305 page PDF

12.4 MB

305 page PDF

12.4 MB

Offshore wind energy - draft sectoral marine plan: strategic environmental assessment
6 Mitigation and Monitoring

305 page PDF

12.4 MB

6 Mitigation and Monitoring

6.1 Introduction

6.1.1 The assessment of the potential effects of development of offshore wind has identified a number of potential mitigation measures that can be applied at individual project level, regional DPO level and at a national (plan level) scale.

6.2 Project Level Mitigation

6.2.1 At an individual project level EIA will be required, this should identify specific mitigation (or potential enhancements) to reduce effects based on the local environment and project characteristics. This SEA assessment identifies potential mitigation measures within Appendix C which may be required at a project level, including:

  • Appropriate consultation with national and local statutory and public stakeholders;
  • Spatial planning within the DPO areas to avoid areas of higher environmental risk;
  • Surveys to develop comprehensive baselines for marine mammals in relevant regions, to inform assessment of potential risk and any project level mitigation required;
  • Measures relating to piling or soft start procedures in order to mitigate the risk of physiological damage from noise from piling activities, including consideration of sequential or concurrent piling depending on the individual site characteristics;
  • Implementation of noise abatement measures at source to reduce the input of anthropogenic noise into the environment;
  • Seasonal restrictions on specific construction activities, depending on particular sensitivities of species at a project level;
  • Developing a robust baseline and subsequent post construction monitoring for bird species present within or transiting through the development footprint, including potential surveys, tagging and radar studies;
  • Development of pollution management plans, to mitigate the effects of any pollution releases;
  • Development of biosecurity management plans to minimise the risk of introduction of INNS;
  • Survey of potential cable pathways and landfall areas to determine route of least environmental effect, including habitat and ecological surveys and Cultural heritage surveys;
  • Sediment testing and water quality monitoring to manage potential effects on water quality;
  • Development of a navigational risk assessment;
  • Coastal process assessments to confirm and validate effects on sediment dispersion and transport, wave and current regimes;
  • Management of cultural heritage through the development and application of a MARP and consideration of impacts on the setting of historical assets within project level assessment;
  • Assessment and management of night-time lighting effects through the application of SNH guidance[252];
  • Development of, and adherence to Vessel Management Plans;
  • Preparation of a decommissioning programme, detailing how a developer intends to remove the installation when it comes to the end of its useful life and how the costs of doing so will be funded. This programme should include a base case of all infrastructure being removed, alongside any alternatives that the operator proposes, backed up by evidence and reasoning for the preferred option.
  • Cable burial or, where this is not possible, suitable cable protection measures to minimise safety risk to fishing vessels; and
  • Project specific array or turbine design.

6.3 Plan Level Mitigation

6.3.1 Within each individual Draft Plan Option and within the overarching plan assessment, mitigation is focused on the use of spatial planning to avoid areas of highest effect. At a plan level, there are a number of measures which can be implemented to either reduce the effect associated with development under the plan or offset any significant effects. Proposed plan level mitigations identified through the SEA process are summarised below:

  • Limiting the scale of development under the plan to a maximum of 10 GW nationally;
  • Requiring spatial planning of DPOs to reduce, so far as is reasonably practicable, effects on environmental receptors;
  • Implementation of temporal mitigation in DPOs where it cannot be concluded with certainty that there will be no adverse effect on site integrity of any European marine site or European site. Specifically relating to potential effects on bird populations in sites NE2, NE3, NE4, NE5, NE6 and E3.
  • Iterative Plan Review /adaptive management of the sectoral plan, in order to allow for changes in the evidence base and outcomes of research or monitoring programmes;
  • Project level EIA, the development of which will identify areas of concern with regard to specific projects, and identify mitigation required at a project level;
  • Collaboration between governmental bodies, non-governmental Organisations and industry on research issues to determine a consistent and comprehensive evidence baseline;
  • Requiring appropriate temporal planning so that sites within the same region are not developed at the same time in order to reduce the potential for cumulative effects associated with construction;
  • Potential for consideration of environmental enhancement schemes at a plan level. A strategic view of large scale or multi-stage potentially significant enhancements, supported by developers, may deliver more significant benefits than the undertaking of multiple small discrete projects designed to offset any significant effects at individual development level. Such interventions might include predator control at (island) bird colonies, or measures to enhance abundance of prey stocks (e.g. sandeel, sprat, herring). However, the location and scale of development under the plan is currently considered to be too uncertain to be able to meaningfully define such enhancement measures.

6.3.2 In addition, it is recognised that the process for the development of the DPOs assessed within this SEA represents an embedded mitigation measure. This includes, for example, initial avoidance of all designated areas in developing the early AoS and where AoS initially included have subsequently been excluded or modified to reduce plan level effects on navigational safety.

6.3.3 Further mitigation measures are likely to be identified as part of other assessments, including the HRA and SEIA, which may be similar to those identified above. However, the variation in assessment methodologies may identify different issues requiring mitigation and hence identify distinct mitigation measures.

6.4 Current and Ongoing Research

6.4.1 The Scottish Marine Science Strategy 2010-2015 and the UK Marine Science Strategy 2010-2025 identify three high level priorities for science research in the marine environment:

1. Understanding how the marine ecosystem functions;

2. Responding to climate change and its interaction with the marine environment; and

3. Sustaining and increasing ecosystem benefits.

6.4.2 Within these three priority areas there remain data limitations which introduce uncertainty in the current environmental baseline, however many of these areas of uncertainty are the focus of current or planned research projects promoted through the Scottish Marine Energy Research (ScotMER), Scottish Marine Renewables Research Group (SMRRG), and undertaken by organisations including SNH, the Joint Nature Conservation Committee (JNCC), Offshore Wind Developer Groups and the Crown Estate, amongst others.

6.4.3 In addition, Marine Scotland, in collaboration with industry, environmental NGOs, statutory nature conservation bodies and other stakeholders (collaboratively forming ScotMER), have developed evidence maps to highlight knowledge gaps when assessing environmental and socio-economic impacts of offshore renewable developments.

6.4.4 These evidence maps, available online[253], are broken down into seven topics and prioritise knowledge gaps in each specialist area to provide a framework to guide ScotMER research projects:

  • Ornithology;
  • Marine mammals;
  • Fish and fisheries;
  • Diadromous fish;
  • Benthic;
  • Physical processes; and
  • Socio-economic.

6.4.5 As research is undertaken against these knowledge gaps, it will serve to inform development through providing evidence at a project level, as well as guiding future developmental iterations of sectoral marine plans.

6.4.6 Additionally, a number of related research activities and frameworks are already in place, including: the Marine Mammal Scientific Support Research Programme managed by the Sea Mammal Research Unit (SMRU) and focused on filling gaps in knowledge between marine mammal distribution and interactions with renewable energy and the Co-ordinated Agenda for Marine, Environment and Rural Affairs Science (CAMERAS) which provides an overall framework for marine science in Scotland.

6.4.7 Within the large array of research activities ongoing there are a number of projects that will help to add greater certainty to future assessment and iterations of marine planning. Studies such as the replacement for the Joint Cetacean Protocol and tagging projects for Atlantic salmon are aimed at delivering greater understanding of species distributions and migratory routes.

6.5 Proposed Monitoring

6.5.1 It is expected that the further development of the baseline may be required to support the implementation and review of the temporal mitigation proposed at the NE and E inshore sites for the protection of bird species. This may include some survey of bird species (particularly Kittiwake, Razorbill and Gannet), such as the aerial surveys historically commissioned by Marine Scotland. In addition, current SPA monitoring will inform the baseline; and the collation of data from monitoring at current and proposed offshore wind developments should further support the Iterative Plan Review process, discussed further below.

6.5.2 However, it is expected that the majority of environmental monitoring under the sectoral marine plan be undertaken by developers as part of pre-construction, construction, and post construction monitoring as part of the planning and licensing process. Monitoring requirements are outlined within the draft plan.

6.5.3 As offshore renewable energy projects are put in place there will be the completion, collation and dissemination of project-level monitoring which should be managed as part of the plan. This will include monitoring work on the initial projects undertaken in response to the sectoral marine plan but also other relevant projects (in UK and Europe). It is envisaged that there will be collaboration between developers and regulators and that, as often as possible, there would be integrated work undertaken across sectors and between projects. Mechanisms and initiatives for such collaborations already exist such as the Offshore Renewables Joint Industry Programmes (ORJIP); the Knowledge Transfer Network (KTN) for offshore renewables (e.g. Offshore Wind Innovation Hub (including Offshore Wind Innovation Exchange (OWiX)); the Partnership for Research in Marine Renewable Energy (PRIMaRE); the Habitats Directive Implementation Review (England); and Marine Scotland's ongoing strategic research.

6.5.4 This developing evidence base can be used to inform Iterative Plan Review as part of an adaptive management process.