Wind turbine consents: aviation objections and associated negative conditions

Guidance on dealing with aviation objections and associated negative conditions in wind turbine consents.

Given the complexities involved in achieving the agreements and technical arrangements required to mitigate the effects of wind turbines on radar, planning authorities should recognise that the existence of a theoretical or potential technical mitigation will not represent a solution to an aviation objection if it cannot be realised.  It is recognised that planning authorities are under no obligation to apply a “reasonable prospect” test before applying negative conditions [1][2].

However the use of such conditions where there is no identified mitigation to deal with an aviation objection, could have an impact on the likelihood of other developments being consented owing to cumulative effects related to both radar and landscape. Planning authorities should consider the views of relevant consultees on the matter and, where applicable, evidence confirming the technical existence of mitigation already identified in theory. Evidence of the likelihood of a technical solution being realised within a reasonable timeframe will therefore be a relevant consideration in deciding whether or not to give consent with negative conditions to address aviation issues. 

The fact that a Feasibility Study undertaken by the Scottish Government and published in 2010 identified substantial potential for mitigation should not in itself influence planning authorities’ consideration of specific applications. Developers should engage with air navigation service providers from the earliest possible stage in order to establish if radar issues exist which should be considered in the submission of a planning application and, where there are issues, should initiate the process of identifying or developing a solution.

The Scottish Government recognises the advantages, in terms of meeting published renewable energy targets, of maximising the potential generated power released by the available mitigation where this is an option. However, it should be noted that the availability of a mitigation solution does not over-ride other planning considerations, including spatial planning factors.  Planning authorities should balance all the material considerations in the normal manner in coming to a view on a proposed development.

Background note

The Scottish Government is committed to working, both within Scotland and UK-wide, to help develop effective radar solutions which can be implemented to safeguard operational air safety whilst mitigating what is a very a significant barrier to renewable energy deployment. Large scale wind farm proposals can impact significantly on both Primary Radar and Secondary Radar systems as they appear as clutter, potentially obscuring visibility of aircraft in the same air space. This raises operational safety risks related to the development of large scale wind farms depending on their location. 

Discussions within the South West Scotland Aviation Solution Group highlighted the issue of the use, or otherwise, of negative, or “suspensive”, conditions within consents for wind farms. There was a lack of coherent planning advice on the issue and pressure from various parties for the Scottish Government to provide formal guidance on the use of suspensive conditions for dealing with aviation objections to wind development.

The Scottish Government provided a suggested “form of words” for this advice in an initial draft which was sent out for consultation to a wide range of stakeholders for feedback and made open to consultation through the SG website. Various iterations were produced following that consultation to take account of views expressed, before the advice above was finalised.


1. ‘Negative conditions’, also sometimes referred to as ‘Grampian condition’ or ‘suspensive conditions’, require something to happen off-site before the development can proceed.

2. See paragraph 38 of Circular 4/1998 - the use of conditions in planning permissions 


Email: Central Enquiries Unit

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