SNH’s draft guidance on Assessing the impact of repowered wind farms on nature was published this month following its launch at the Scottish Renewables Onshore conference. The consultation period closes on 31 August.

SNH are running a seminar to discuss their proposals with developers on Monday 25 June. While the discussion should be interesting, the key issues and arguments are already well known (see our previous discussion paper).


Unsurprisingly, the draft guidance confirms the SNH view that the baseline adopted for EIA purposes should ignore the existing scheme.

Anticipating the inevitable resistance to this position, Annex A of the draft sets out their reasoning –

The temporary nature of most consents is highlighted, yet EIA of the existing scheme will have treated the impacts as permanent, and in any event the number of years left to run on the existing consent will vary.

The alternative approach to baseline – categorised as GAP assessment – which focusses only on the additional effects of the repowered scheme risks underestimating effects, while limiting the potential for appropriate mitigations. However a similar approach is already taken to extensions, and SNH’s concerns about successive incremental changes don’t seem particularly realistic.

More generally, an assessment process which starts from a hypothetical/imagined baseline (restored greenfield site) is far from ideal. Amongst other things, it ignores the desensitising effect of the original scheme on human receptors.

Despite their views on baseline, SNH still want to see comparative information showing the existing scheme as against the repowered scheme included, given the materiality of the planning history. While arguably such information should be part of the wider planning submission rather than the EIA Report – applicants will no doubt be keen to put such information in front of the planning authority in any event.


Regardless of views on the baseline question, consistency of approach is generally desirable, and is one of the main drivers for the guidance. However the draft repeatedly refers to the need for case specific advice and the possibility of exceptions. While some flexibility is required, this should not be at the expense of a fair playing field.


While the industry can be expected to maintain its opposition on this issue, the guidance may have relatively limited application in the short term given the current industry focus on life extensions. Nor will it make a difference to schemes which are varied before first implementation. However a more significant shift towards repowering is likely at some stage, and so the importance of establishing robust guidance with industry support should not be underestimated.

Karen Hamilton
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