Client: DECC


The offshore wind industry has expanded rapidly in the UK in recent years. It is acknowledged that both injury and disturbance of marine mammals caused by piling in the marine environment are important issues each requiring due consideration. However, addressing the (increasing) risk of injury offences has been identified as a primary consenting risk for offshore wind projects in UK waters. There are strict legislative provisions in place, via the EC Habitats Directive, which protect marine mammals and influence the mitigation required in order to protect them from noise activities during installation, such as piling, that can injure and / or effect their behaviour.

Consent conditions and the transposed environmental management measures must strike a careful balance, be appropriate and proportional to the risks posed by the development of the project, allow the delivery of offshore wind projects which are technically and economically viable, have acceptable levels of environmental impact, and ultimately comply with legal requirements to maintain populations of European Protected Species and Annex II species at a  favourable conservation status (effected through process such as EPS licensing and Habitats Regulations Appraisal). There is therefore a high level of interest from all parties to have the right marine mammal mitigation protocol in place.

Xodus Group Ltd, in partnership with SMRU Marine, were contracted by DECC on behalf of the Offshore Renewables Joint Industry Programme (ORJIP) to conduct Phase 1 of ORJIP Project 4.The Phase 1 study was a desktop review and advisory services regarding Acoustic Deterrent Device (ADD) use and improvements to standard mitigation measures currently used in the UK (marine mammals observers (MMO), passive acoustic monitoring (PAM) and soft starts) during piling. Phase 2 of the Project will include the field research to test and/ or develop ADDs or other deterrent devices.

  • Independent and balanced assessment of the challenges facing regulators, their advisors and industry in the implementation of effective marine mammal mitigation, particularly as development programmes for Round 3 OWFs gather pace
  • Desk based review of current and potential mitigation against direct and indirect injury to marine mammals during piling
  • Consultation with a wide range of stakeholders via one to one interviews and informal discussions
  • Two project workshops attended by a wide range of stakeholders and interactive review of initial findings, involving the ORJIP project steering group
  • Underwater noise modelling used to estimate radius of injury zones for different species (using Xodus in house modelling expertise) to inform the potential use of ADDs as a mitigation technique
  • Review of research project scopes proposed by ORJIP for Phase 2 of the project
Value Added
  • While there were site specific issues and uncertainties surrounding the efficacy of certain mitigation techniques used to date, it was possible to identify seven key generic drivers and supporting parameters important to interested parties (regulators, statutory advisors, offshore developers, non-government organisations (NGO), service providers and researchers) in the development of offshore wind projects.  These are listed below:
  • 1) Efficacy; 2) Unintended consequences; 3) Practicality; 4) Regulation & legislation; 5) Installation schedule; 6) Cost; 7) Heath and safety
  • Based on the noise modelling results, it was concluded that it was not possible at the time to recommend a “one size fits all” ADD mitigation protocol
  • Recommendations provided for consideration during the revision of UK piling mitigation guidance; JNCC 2010 guidance; encompassing site specific SNCB advice and the current marine mammal mitigation protocol (MMMP) 
  • Recognition of the challenge facing the next steps in the ORJIP Project 4 process to collaboratively develop a clear roadmap for achieving a site specific mitigation framework that is compliant with legislative requirements, achieves environmental protection, and positively enables sustainable development of offshore wind 
  • Identification that the ultimate end point of the ORJIP Project 4 should be a risk based project specific MMMP Framework, that enables developers to select and agree with regulators the best mitigation options based on their particular site characteristics (e.g. priority species present, water depth, pile size, hammer energy, substrate type, distance offshore, installation and support vessel set up)
  • Suggested research programmes, study sites and preliminary costings for research into ADD use as marine mammal mitigation
  • The key output was a research and recommendation roadmap that enabled ORJIP to focus its research and support efforts on topics that will make a material difference to the industry