Offshore Renewable Energy

Wind turbine

The Joint Nature Conservation Committee (JNCC) provides advice on nature conservation to government and industry on renewable energy proposals in the offshore environment. It is JNCC policy to support appropriately sited renewable energy developments because of the environmental benefits they can deliver through sustainable energy generation.


The UK is currently generating over 5.1GW of offshore renewable energy (around 5% of UK electricity requirements) with a further 4.5GW under construction. The Government is anticipating this will be delivered by 2020, thereby ensuring the UK achieves 15% of its energy needs from renewable sources. The majority of proposed windfarm development is located in offshore waters where JNCC has a role in providing environmental advice.  


JNCC is a member of the Offshore Wind Programme Board, which brings together senior representatives from industry, UK and Scottish government, The Crown Estate and Statutory Nature Conservation Bodies. The UK Government released an update to its UK Renewable Energy Roadmap in 2012, which sets out the potential for growth in offshore wind generation to 2020, with the sector potentially producing up to 18GW if costs come down.


With the increase in offshore renewables likely to continue, JNCC will have an ever increasing role in providing strategic environmental advice on offshore renewables and their potential interaction with marine life. JNCC co-ordinate with country conservation agencies on nature conservation issues related to marine renewables, such as the potential for disturbance of marine mammals arising from piling noise, and potential collision and displacement effects on seabirds.  


Offshore Renewable Energy and marine birds



Offshore wind development has the potential to impact UK and international seabird and marine bird populations in a number of ways, if not managed appropriately. Birds are at risk of direct mortality from collision with turbine blades as they forage or transit through sites.

'Open Tidal' device © EMEC

They are also potentially subject to displacement from their normal foraging habitat through disturbance. This can occur during the construction phase, but also after construction in some cases. Birds have also been observed to actively avoid offshore wind farms by flying around them (e.g. during migration). This is known as the barrier effect. 


The Statutory Nature Conservation Bodies have produced an updated Joint Interim Displacement Advice note to provide information on how to present assessment information on the extent and potential consequences of seabird displacement from offshore wind farm developments.


It updates the previous interim displacement advice note (Natural England and JNCC., 2012. Joint Natural England and JNCC Interim Advice Note – Presenting information to inform assessment of the potential magnitude and consequences of displacement of seabirds in relation of Offshore Wind Farm Developments) to take account of potential areas of disparity in approaches that have arisen in casework since the original note was issued. It also follows on from a Displacement Workshop (6-7 May 2015), run by JNCC and the Marine Renewables Ornithology Group (MROG) and funded by The Crown Estate, which sought to make progress towards developing a more refined best practice approach to assessing displacement impacts.



Offshore Renewable Energy and marine mammals


Offshore renewable energy installation has the potential to injure and disturb marine mammals as a result of the high levels of noise produced by pile-driving, i.e. hammering of the turbine foundations on the seabed. For example, there is some field evidence for short-term behavioural responses to the noise, such as displacement of harbour porpoises, however the long term consequences on individuals fitness and on population vital rates are less certain.


The assessment of the potential impacts on marine mammal populations from offshore industries has used, on occasions, some form of population modelling framework to ascertain the likelihood of a population level impact resulting from the disturbance. JNCC commissioned the guide below as an accessible reference on population models used to help practitioners dealing with such assessments.


Guide to population models used in marine mammal impact assessments – JNCC Report 607


JNCC also worked with Natural England in commissioning a report on the use of the iPCoD modelling framework to assess the aggregate/cumulative effects of the construction of offshore wind farms on the harbour porpoises in the North Sea.




JNCC piling guidelines

Windfarm turbine pile and transistion piece - Kentish Flats © Vattenfall


The installation of driven piles in the marine environment without mitigation is likely to produce noise levels capable of causing injury and disturbance to marine mammals. In association with DEFRA and the country agencies, JNCC has produced guidance on ‘the protection of marine European Protected Species from injury and disturbance’. The piling protocol forms part of that more general guidance and the recommendations should be considered as ‘best practice’ for piling operations.




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