8.12Cumulative Effects Assessment
Overview
8.12.1 The general approach to the cumulative effects assessment is described in Volume 1, Chapter 4: EIA Methodology and in further detail in the LVIA Methodology in Section 8.8.
8.12.2 GLVIA3 and NatureScot guidance provide the basis for the methodology for the cumulative assessment appropriate to the LVIA.
8.12.3 The NatureScot (2021) guidance defines:
- ‘Cumulative effects as the additional changes caused by a proposed development in conjunction with other similar developments or as the combined effect of a set of developments taken together;
- Cumulative landscape effects are those effects that ‘can impact on either the physical fabric or character of the landscape, or any special values attached to it’; and
- Cumulative visual effects are those effects that can be caused by combined visibility, which occurs where the observer (visual receptor) is able to see two or more developments from one viewpoint and/or sequential effects which occur when the observer has to move to another viewpoint to see different developments.’
Approach
8.12.4 The two-tiered approach which has been applied within the LVIA CEA employs the following stages:
- Stage 1: Operational/under construction/consented scenario – the Proposed Development in addition to the operational/under construction and consented developments; and
- Stage 2: Application scenario - the Proposed Development in addition to the operational/under construction/consented and application stage developments.
8.12.5 Both scenarios provide an understanding of the different levels of cumulative effects around how cumulative developments are brought forward.
8.12.6 Stage 1 scenario with operational Spittal Substation and consented West of Orkney Substation, has been considered as part of the baseline and effects upon landscape and visual resource have been assessed on this basis in Section 8.10 above.
8.12.7 Stage 2 scenario of cumulative effects arising from the addition of the Proposed Development to other operational/consented developments plus cumulative developments, which are the subject of a valid planning application, are assessed in this section below.
8.12.8 Both scenarios have been assessed in the Viewpoint Assessment in Appendix 8.1: LVIA Viewpoint Assessment.
8.12.9 The locations of cumulative developments considered in the EIA are shown on Figure 8.8 Open ▸ .
8.12.10 The LVIA Study Area has been defined on the basis of where significant effects attributable to the Proposed Development are expected, and therefore the LVIA CEA includes only developments which are located within the 5 km Substation Study Area ( Figure 8.1 Open ▸ ).
8.12.11 The specific projects scoped into the LVIA CEA are outlined in Table 8.21 Open ▸ .
Cumulative Future Baseline
Developments in Scoping
8.12.12 NatureScot guidance suggests not including developments which have been refused on appeal, have been withdrawn, or are at the scoping stage in the LVIA. Due to the lack of data for developments in scoping stage, these developments cannot be visualised. As LVIA deals with perceptual qualities describing landscape and visual change, it should not make speculative assumptions in relation to these cumulative developments, also these projects have not been subject to a request by THC in their Scoping Opinion.
Ouglassy Parks Wind Farm
8.12.13 Ouglassy Parks Wind Farm, which is in scoping stage, is proposed approximately 2 km to the south-east of the proposed Substation, to the east of Spittal Hill. The proposed Ouglassy Parks Wind Farm of eight wind turbines, with a blade tip height of up to 180 m, would introduce a large-scale change into the landscape when located next to the local landmark hill, taking over the skyline. If the development should be approved, then the proposed Substation would appear as a subsidiary low-lying element without the potential to generate any additional large scale cumulative effects. Based on this, and due to the lack of project details, the likely cumulative effects with the Ouglassy Parks Wind Farm have not been further assessed.
Spittal to Beauly overhead transmission line
8.12.14 The 400 kV Spittal to Beauly OHL entered scoping in October 2024. The proposed OHL would span a distance of approximately 167 km between new proposed substations at Spittal (Banniskirk), Loch Buidhe (Carnaig) and Beauly (Fanellan). The OHL will be supported by steel lattice towers which are 57 m above ground level in height on average, with a maximum extension height of up to 70 m. Taking into account the prominence of the towers, the particular siting of the towers in relation to Spittal Hill would broadly determine potential landscape and visual effects within the area. However, it is expected that the Substation would appear as a subsidiary low-lying element without the potential to generate any considerable cumulative effects in addition to the Spittal to Beauly OHL. Based on this, and due to the lack of Spittal to Beauly OHL project details, the likely cumulative effects with the Spittal to Beauly OHL are not further assessed.
Developments at Application Stage
The Spittal Mains and Spittal Quarry BESS
8.12.15 The Spittal Mains and Spittal Quarry BESSs, both low lying developments (max 3.2 m in height), which are located to the south of the existing Spittal Substation, appear to lie outside of the ZTV of the proposed Substation. There would not be any cumulative effects which could be attributable to the Substation in addition to the Spittal Mains and Spittal Quarry BESSs.
Banniskirk Hub
8.12.16 In terms of the cumulative context, the main development would potentially be the Banniskirk Hub, 1.1 km to the south-west of the proposed Substation.
8.12.17 The Banniskirk Development would consist of two main components, outdoor Alternating Current 400 kV substation infrastructure up to 15 m in height, and two HVDC converter station buildings of 26 m in height. The substation would connect into the new proposed Spittal – Loch Buidhe – Beauly OHL, whilst the Banniskirk convertor station would connect the Spittal (Banniskirk) to Peterhead HVDC Link which is an offshore connection.
8.12.18 The Banniskirk Hub mitigation proposal includes several linear screening mounds along the alignment of the A9 which are up to 7 m in height and 30 m wide. The mounds will be planted by a mixture of native woodland trees and scrub with some evergreen species. The LVIA of Banniskirk points out that due to a number of known services connection corridors and unknown but required overhead cable connections entering and leaving the site, the placing and location of the mound and planting would be limited, especially along the most northerly site boundary with the A9 and the north-eastern boundary.
Assessment of Cumulative Landscape and Visual Effects
8.12.19 The assessment of the likely cumulative significance of the landscape and visual effects attributable to the Proposed Development considers the likely effects during the construction, operational and decommissioning phases.
8.12.20 Based on the analysis of the future cumulative baseline the Proposed Development is assessed in addition to or in conjunction with Banniskirk Hub, consented West of Orkney Substation and operational Spittal Substation.
8.12.21 The LCTs are described in Section 8.6 and shown in Figure 8.5.
Construction Cumulative Impacts
8.12.22 The residual effects arising as a result of the construction of the Proposed Development are assessed as being of the same magnitude and significance on all landscape receptors as those arising due to their operation and maintenance, however the residual effects arising as a result of the construction are assessed as being temporary, occurring during the length of the construction phase, and differing in nature from the operational effects mainly due to the influence of the various construction machinery, earthworks, construction compound(s), that will not be present or result in effects during the operational phase.
8.12.23 Therefore, the effects attributable to the construction stage of the Proposed Development are not assessed further.
Operational Cumulative Impacts
8.12.24 The above-described cumulative future baseline developments, alongside Banniskirk Hub, are located within the Farmed Lowland Plain LCT and therefore retain a certain direct impact upon its landscape fabric. For this assessment the potential cumulative impact is considered in relation to perceptual qualities of the Farmed Lowland Plain LCT.
Farmed Lowland Plain LCT
8.12.25 Due to the large scale of the Banniskirk Hub convertor station buildings, the proposed mitigation (including green colouring of buildings) would not achieve screening of the development, however, these measures would help to soften the appearance of the development, enabling a more effective integration of the development into the wider landscape.
Sensitivity
8.12.26 The Farmed Lowland Plain LCT is not subject to any landscape designations within the LVIA Study Area. This is a landscape that is actively used and subject to alteration by humankind. It is not a landscape that can be considered particularly susceptible to the type of the development proposed. It is identified as the ‘East Coast Connectivity and Tourism Corridor’ and the ‘Area for Energy Business Expansion’ on the CaSPlan Strategy Map. The landscape is valued for its openness, which allows for spectacular views of the surrounding complex landscape pattern, these open vistas generally being edged by the distant horizon of the sea or distinctive profiles of the faraway hills.
8.12.27 Based on this, the Farmed Lowland Plain LCT is evaluated as having a Medium-low sensitivity to the type of development proposed.
Magnitude of change
8.12.28 The proposed Substation, existing cumulative schemes and Banniskirk Hub, are located within the Farmland Lowland Plain LCT. Therefore, additional direct effects/changes to landscape character are anticipated as a result of the proposed Substation.
8.12.29 The existing Spittal substation is well screened by the intervening topography and vegetation, and the consented West of Orkney substation would be shielded behind bunds and therefore difficult to distinguish within the wider landscape. Although the Banniskirk Hub would assume a more prominent position on the north-west extending shallow shoulder of Spittal Hill, it would appear on the backdrop of the landform of Spittal Hill within the wider landscape.
8.12.30 The addition of the Substation would be perceivable simultaneously with the other cumulative substations within a limited area to the north-west and to the west of the A9, around Halkirk and Harpsdale. This change to the landscape is presented by VP7B and VP8 (Volume 2, Appendix 8.1 and Volume 3), showing the upper sections of the GIS buildings above the intervening forestry plantation and vegetation. The landform of Spittal Hill forms a local prominent landmark and also provides a backdrop to the Banniskirk Hub development, which would not protrude or compete in scale with the profile of Spittal Hill.
8.12.31 Due to the location of the proposed Substation on the lower slope of the north-eastern shoulder of Spittal Hill, the impact upon the perceivable character of the landscape, attributable to the proposed Substation, would also occur within the area around the basin of Loch Scarmclate, on the slopes of the surrounding shallow hills, such as Sordale Hill to the north and Corsback Hill to the north-east. This change to the landscape is presented by VP1, VP2 and VP3 (Appendix 8.1 and Volume 3), showing the upper section of the Banniskirk Hub convertor station buildings on the backdrop of the landform of Spittal Hill, and against the skyline in the view from VP2. The addition of the proposed Substation to the underlying cumulative context would increase the extent of the energy infrastructure within this Farmed Lowland Plain LCT. However, the proposed Embedded Mitigation (Section 8.9) would soften views and allow the landscape to absorb the Proposed Development.
8.12.32 Farmed Lowland Plain LCT is a large-scale landscape, which has the capacity to accommodate electricity infrastructure, also the area is allocated for Energy Business Expansion and these types of cumulative developments are not notably discordant in nature within this busy agricultural landscape of ‘a confusion of characteristics – physical, cultural and experiential.’ The proposed Substation is surrounded by large scale forestry plantations which are due to be harvested in 2057. It is well distanced and buffered from the Banniskirk Hub, which is located on the north-western slope of Spittal Hill, whereas the proposed Substation is located on the lower slope of its north-eastern shoulder. Due to this subtle topographical parting, the developments would be seen simultaneously in more distant and elevated views. Therefore, the addition of the proposed Substation would result in direct overall Low magnitude of cumulative change, to the Farmed Lowland Plain LCT within the LVIA Study Area.
Significance of Effect
Year 1
8.12.33 The low magnitude of change upon medium-low sensitive landscape would result in Minor and not significant effects at year 1. The nature of these effects would be direct, long-term (reversible), localised and adverse.
Year 15
8.12.34 It is expected that the magnitude of change/impact would reduce over time as the proposed mitigation planting and surrounding forestry matures, resulting in Minor/negligible and not significant effects at year 15.
Cumulative Decommissioning Impacts of the Proposed Development on landscape resource
8.12.35 In the absence of detailed information regarding decommissioning works, the impacts during the decommissioning of the Proposed Development are considered to be likely less than, or at least analogous with, those of the construction stage.
Cumulative Visual Effects
Construction Cumulative Impacts
8.12.36 The residual effects arising as a result of the construction of the Proposed Development are assessed as being of the same magnitude and significance on all visual receptors as those arising due to their operation and maintenance, however the residual effects arising as a result of the construction are assessed as being temporary, occurring during the length of the construction phase, and differing in nature from the operational effects mainly due to the influence of the various construction machinery, earthworks, construction compound(s), that will not be present or result in effects during the operational phase.
8.12.37 Therefore, the effects attributable to the construction stage of the Proposed Development are not assessed further.
Operational Cumulative Impacts
Settlements and residential properties
8.12.38 The addition of the Banniskirk Hub to the existing landscape context, as described above, would introduce a more prominent development on the north-west extending shallow shoulder of Spittal Hill, which provides a backdrop and shield it in views within the wider landscape.
8.12.39 Table 8.19 Open ▸ describes the likely significant effects potentially attributable to the proposed Substation on settlements and residential properties when considered as an addition to the existing cumulative baseline context with the existing SHET-L Spittal substation and the consented West of Orkney substation.
Sensitivity
8.12.40 The sensitivity of visual receptors (people) from/on settlements and recreational routes has been considered as high.
Halkirk and Scattered Properties next to C1018
Magnitude of Change
8.12.41 Views from and around the settlement of Halkirk and the scattered properties along the local road are presented by VP7A VP7B and VP8 (see Viewpoints Assessment in Appendix 8.1 and Viewpoint Visualisations in Volume 3).
8.12.42 The large scale Banniskirk Hub development would be seen on the backdrop of Spittal Hill. Although the convertor station buildings of 26.4 m in height cannot be screened, the large buildings do not protrude or compete in scale with the profile of Spittal Hill and are therefore well sited on this landscape which is influenced by existing large scale energy infrastructure.
8.12.43 With the addition of the proposed Substation, only the upper sections of its GIS buildings would be perceivable above or through the intervening large scale young forestry plantations or tree belts. Also, the proposed Substation location is away from the Banniskirk Hub. The eye is drawn towards the peak of Spittal Hill, to which the Banniskirk Hub sits closer.
8.12.44 The magnitude of change attributable to the addition of the proposed Substation is considered Low-Negligible.
Significance
8.12.45 Minor/Negligible and not significant cumulative adverse effects.
Properties Next to B874
Magnitude of Change
8.12.46 Stemster Mains and Beech Cottage are the properties which would have distant views of the Banniskirk Hub, as illustrated by VP2 (Appendix 8.1 and Volume 3), due to their elevated position above the basin of Loch Scarmclate, gaining open views to the south-east. Banniskirk Hub convertor station buildings would appear against the skyline. Surrounding forestry plantations lessen the effect of large-scale buildings.
8.12.47 The Substation would appear in front of the Banniskirk Hub, on a lower ground level. Although the addition of the Substation would extend the development in the view, the scale of both developments is reduced by the distance, the surrounding commercial forestry plantations, and the intervening large fields, as well as by the underlying large-scale landform. In addition, the introduction of the proposed mitigation mound would have an immediate effect, screening both the Substation and Banniskirk Hub. However, the mound itself would be noticeable as a new element within the landscape, therefore attributing the cumulative effect to the manmade landform. The proposed planting will be designed to integrate the mound into the wider landscape.
8.12.48 The magnitude of change attributable to the addition of the Substation is considered Low.
Significance
8.12.49 Moderate/minor and not significant cumulative adverse effects.
Properties Next to A882
Magnitude of Change
8.12.50 As illustrated by VP3, the proposed Banniskirk Hub buildings would likely be screened through a combination of the intervening topography, forestry plantations and tree belts. The magnitude of change attributable to the addition of the Substation is considered Low.
Significance of Effect
8.12.51 Moderate/minor and not significant cumulative neutral effects.
Properties Next to Banniskirk Road
Magnitude of Change
8.12.52 Most of the properties adjacent to Banniskirk Road at its northern end would not have views of the Banniskirk Hub, or of the Substation. Large scale forestry plantations also intervene towards the Banniskirk Hub. It is expected that Banniskirk Mains would have open views of Banniskirk Hub to the south-west.
8.12.53 The Substation would occur in sequential views to the north-east. Although these views from the curtilage of the property are screened by an intervening garage building, and the vegetation along the property’s perimeter, the proposed Substation would appear prominently in views from the access to the property (see VP5). The magnitude of change attributable to the addition of the Substation is therefore considered High-Medium.
Significance of Effect
Year 1
8.12.54 Major/Moderate and significant cumulative adverse effects.
8.12.55 It is expected that the magnitude of change/impact would reduce over time as the proposed mitigation planting next to Banniskirk Road and along the PPP Application Boundary at the Substation site matures. However, this would not provide more than a softening effect in elevated views, which are available from Banniskirk Mains, resulting in Moderate and significant adverse effects at year 15.
Recreational Routes
Sensitivity
8.12.56 The sensitivity of recreational routes has been considered as High.
Core Paths
Magnitude of change
8.12.57 Core Paths CA06.09, CA06.05 have a total length of 1 km and line the eastern perimeter of the settlement of Halkirk, passing the rear and front gardens of properties.
8.12.58 Visibility of the Banniskirk Hub from the Core Path is represented by VP7B and VP78. Converter station buildings would appear on the backdrop of Spittal Hill and in the foreground context of large farm buildings, houses, OHL. Visibility of the Substation is limited to its upper sections above the intervening forestry/ vegetation at a distance of 3 km, resulting in Low-negligible magnitude of change.
Significance of Effect
8.12.59 The magnitude of change is considered low-negligible, resulting in minor and not significant cumulative adverse effects. These effects are expected to reduce, when the existing intervening forestry plantation has matured, down to Minor/ negligible, which is not significant in EIA terms.
Transport Routes
8.12.60 Table 8.19 describes the likely effects potentially attributable to the proposed Substation on users of transport routes such as A9, A882, B874 and C1018. In order to assess the additional effects attributable to the proposed Substation in combination with the cumulative context, the appearance of the Banniskirk Hub has been identified and described within the Substation LVIA Study Area.
Sensitivity
8.12.61 The transport routes (Figure 8.5) are considered as Medium sensitivity receptors.
A9
Magnitude of Change
8.12.62 Banniskirk Hub would be screened behind the mounds placed along the A9 boundary. Although the mounds themselves would provide a visual change by virtue of their size and proximity to the road, the addition of the Substation is considered with Negligible magnitude. Visibility of the Substation is restricted by the topography, roadside and intervening vegetation.
Significance of Effect
8.12.63 The magnitude of change is considered negligible, resulting in Negligible and not significant cumulative neutral effects.
A882
Magnitude of Change
8.12.64 Banniskirk Hub would be well screened in views from the A882, as illustrated by VP3. The available views from the road are orientated towards the shallow basin of Loch Scarmclate, which is in the opposite direction to the proposed Substation. The addition of the proposed Substation is considered with Low magnitude.
Significance
8.12.65 Minor and not significant cumulative adverse effects. These effects are expected to reduce, when the intervening forestry plantation has matured.
B874
Magnitude of Change
8.12.66 In views from the B874, the large converter buildings of Banniskirk Hub would be well screened, appearing on the backdrop of Spittal Hill (VP1). In views from the north-east Banniskirk Hub would appear against the skyline, as illustrated by VP2. However, these upper visible sections of the Banniskirk Hub buildings would appear within a large scale landscape. Therefore, the addition of the Substation is considered of Low magnitude, due to the transient nature of the views.,
Significance
8.12.67 Minor and not significant cumulative adverse effects. These effects are expected to reduce, when the intervening forestry plantation has matured.
Local road C1018
Magnitude of Change
8.12.68 Visibility of the Banniskirk Hub from the local road C1018, which extends to the south of Halkirk, is illustrated by VP7b. Banniskirk Hub buildings would appear on the backdrop of Spittal Hill and in the foreground context of large farm buildings, houses, OHL. Visibility of the Substation is limited to its upper sections above the intervening vegetations at a distance of 3 km. The magnitude of change is considered Low-negligible.
Significance of Effect
8.12.69 Minor/negligible and not significant cumulative adverse effects. These effects are expected to reduce, when the intervening forestry plantation has matured.
Cumulative Decommissioning Impacts of the Proposed Development on visual resource
8.12.70 In the absence of detailed information regarding decommissioning works, the impacts during the decommissioning of the Proposed Development are considered to be likely less than, or at least analogous with, those of the construction stage.
8.13Summary of Impacts, Mitigation and Likely Significant Effects
8.13.1 Information on landscape and visual resource within the LVIA Study Area was collected through baseline analysis, as laid out in Section 8.6.
8.13.2 Table 8.22 Open ▸ presents a summary of the potential impacts, Embedded Mitigation and the conclusion of likely significant landscape and visual effects in EIA terms.
8.13.3 It is anticipated that nine properties would experience temporary adverse and direct visual effects attributable to the construction of the Onshore Export Cable Corridor. However, if the final alignment of the route changes, then the magnitude of change upon these residential receptors, as provided in Table 8.18 Open ▸ , would change accordingly.
8.13.4 During the operational and maintenance phase significant adverse and direct visual effects attributable to the proposed Substation are considered in relation to five properties (depending on final layout and design). These effects are expected to be mitigated by year 15, with no significant residual effects.
8.13.6 Table 8.22 Open ▸ presents a summary of the potential impacts, Embedded Mitigation and the conclusion of likely significant cumulative landscape and visual effects in EIA terms.
8.13.7 Significant cumulative visual effects are considered in relation to the property of Banniskirk Mains, which would have sequential views of both developments, the Banniskirk Hub and the Substation.
8.14References
Guidance
Countryside Agency and Scottish Natural Heritage (2004) Topic Paper 6: Techniques and Criteria for judging Capacity and Sensitivity. Landscape Character Assessment topic papers
Forestry and Land Scotland (2023). Caithness Land Management Plan. online at https://forestryandland.gov.scot/what-we-do/planning/active/caithnesslmp#:~: text=Caithness%20LMP%20was%20approved%20by,plan%20and%20maps%20linked%20below
Landscape Institute and Institute of Environmental Management and Assessment (IEMA) (2013). Guidelines for Landscape and Visual Impact Assessment: Third Edition (‘GLVIA3’). online at: https://www.landscapeinstitute.org/technical/glvia3-panel/
Landscape Institute (2024) Notes and Clarifications on aspects of the 3rd Edition Guidelines on Landscape and Visual Impact Assessment (GLVIA3) – LITGN-2024-01-GLVIA3-NC_Aug-2024.pdf
LI (2019a). Visual Representation of Development Proposals, Technical Information Note 06/19. online at: https://www.midsussex.gov.uk/media/6342/cd97-li_tgn-06-19_visual_representation.pdf
Landscape Institute (2021) Technical Guidance Note 02-21: Assessing landscape value outside national designations. online at: https://www.landscapeinstitute.org/publication/tgn-02-21-assessing-landscape-value-outside-national-designations/
NatureScot (2019). Scottish LCTs Map and Descriptions. online at: https://www.nature.scot/professionaladvice/landscape/landscape-character-assessment/scottish-landscape-character-types-map-and-descriptions
NatureScot (2022a). Landscape Sensitivity Assessment Guidance. online at: https://www.nature.scot/sites/default/files/2022-05/Landscape%20Sensitivity%20Assessment%20Guidance%20%28Methodology%29.pdf
NatureScot (2022). Assessing the Cumulative Landscape and Visual Impacts of Onshore Wind Energy Developments.
NatureScot (2022b). Landscape Character Assessment in Scotland. online at: https://www.nature.scot/professional-advice/landscape/landscape-character-assessment/landscape-characterassessment-scotland
NatureScot. (2023). European Landscape Convention. [online] Available at: https://www.nature.scot/professional-advice/landscape/framework-landscape-policy/european-landscape-convention [Accessed 3 Jun. 2025].
Sustrans (2023). The National Cycle Network. online at: https://www.sustrans.org.uk/national-cycle-network
The Highland Council (2012). Highland-wide Local Development Plan. April 2012. online at: https://www.highland.gov.uk/info/178/local_and_statutory_development_plans/199/highlandwide_local_development_plan
The Highland Council (2016). Visualisation Standards for Wind Energy Developments. July 2016. online at: https://www.highland.gov.uk/downloads/file/12880/visualisation_standards_for_wind_energy_developments
The Highland Council (2017). Onshore Wind Energy Supplementary Guidance. Supplementary Guidance published in November 2016 with Addendum published in December 2017. online at: https://www.highland.gov.uk/downloads/file/16949/onshore_wind_energy_supplementary_guidance-_nov_2016
The Highland Council (2023). Paths in the Highlands: Interactive Map of Our Core Paths. online at: https://www.highland.gov.uk/info/1225/countryside_farming_and_wildlife/161/outdoor_access/4
The Highland Council (2025). Renewable energy | Visualisation Standards for Wind Energy Developments. [online] Highland.gov.uk. Available at: https://www.highland.gov.uk/downloads/file/12880/visualisations.
Legislation
The Highland Council (2018). Caithness and Sutherland Local Development Plan. Adopted. August 2018. online at: https://www.highland.gov.uk/info/178/development_plans/283/caithness_and_sutherland_local_development_plan
Scottish Government (2023). National Planning Framework 4. Available online at: https://www.gov.scot/publications/national-planning-framework-4/documents/
Scottish Government (2011). Wildlife and Natural Environment (Scotland) Act 2011. online at: http://www.legislation.gov.uk/asp/2011/6/enacted