General pre-application and scoping advice for solar farms

Version: August 2022

This version replaces our previous guidance Natural heritage considerations for solar photovoltaic installations (November 2017).

Purpose

This guidance provides NatureScot’s standing advice on natural heritage considerations for large-scale, commercial solar photovoltaic (PV) proposals.  It aims to assist applicants, developers and consultants involved in preparing applications and Environmental Impact Assessment (EIA) reports (where these are required) for such developments.  It also provides advice on opportunities for mitigation and enhancement so that the approach to development delivers overall positive effects for biodiversity.  This guidance should be read in conjunction with any planning authority guidance on solar energy development.

The combination of the climate emergency, improving technology, reduced costs and in some cases the benefits of co-locating with other renewable energy developments appears likely to lead to an increased interest in solar farm proposals in Scotland.  We will continue to learn from case experience and update this guidance as required.

The service that NatureScot provides

Our Service Statement (Planning for Great Places) and related guidance set out the level of engagement you can expect from us during the planning process.  Our guide on the service that developers and consultants can expect is particularly relevant.

Our engagement with any specific solar proposal will depend on the nature, scale and importance of the potential impacts on the natural heritage.  At pre-application (including scoping) stage, our priority is to identify the potential impacts on nature and landscapes that could raise natural heritage issues of national interest.  The degree of national interest will determine our level of engagement in a proposal.  At application stage, we will only provide tailored advice for Planning Act cases where the impacts closely approach or exceed levels that raise issues of national interest.  We will however provide case-specific advice on issues that are not of national interest for section 36 (Electricity Act) cases, as stated in our Development Management and the Natural Heritage guidance.

Landscape and visual

Where there is potential for significant landscape and visual effects, an assessment will be required.  This should encompass the potential effects of any associated infrastructure such as access tracks, security fencing, lighting and substations.

Assessment should follow the Guidelines for Landscape and Visual Impact Assessment (GLVIA 3), and should include a Zone of Theoretical Visibility (ZTV) map to indicate where the arrays might be seen from, and a viewpoint analysis based on key viewpoints throughout the surrounding area.  The number of viewpoints will depend on the scale of the proposal and visibility within the surrounding area.  In some circumstances, where there is related potential for likely significant effects, the LVIA should include an assessment of the impact of glint and glare.  In keeping with GLVIA, cumulative effects should be considered.

The extent to which a landscape can accommodate development will often depend on its landscape character.  A Landscape Character Type dataset for all Scotland is available on our website at Landscape Character Assessment in Scotland.  Siting and design should take account of key aspects such as landscape scale, landform and land cover.  With appropriate siting and effective screening the visibility can often be minimised for ground-mounted panels. 

Paragraph 212 of Scottish Planning Policy outlines the key policy test for development that affects a National Scenic Area (NSA) or National Park (NP).  This should only be permitted where:

• the objectives of the designation and the overall integrity of area will not be compromised; or
• any significant adverse effects on the qualities for which the area has been designated are clearly outweighed by social, environmental or economic benefits of national importance.

Developers should refer to our policy and advice on NSAs.  We are also developing guidance on how to assess effects on NSA Special Qualities and can provide a draft copy of that guidance by request.  Our website also contains advice on National Parks.

Our advice and guidance on Wild Land Areas (WLAs) should be applied to proposals whose nature, siting, scale or design are likely to result in a significant effect on the qualities of a WLA.

Requirements relating to Local Landscape Areas (LLAs) will be available from planning authorities.  Our website also provides some helpful general information on Local Landscape Areas.

Birds

The main potential impacts are likely to arise through habitat loss, displacement and disturbance (during construction and operation), all of which may affect breeding, foraging and roosting birds.  Published evidence suggests the overall risk of collision is low for solar PV, and we advise there is no need for a collision risk assessment. 

We advise that some form of distribution and abundance surveys will typically be required, and that these should be undertaken following the methodologies detailed within Section 3.7 of our wind farm bird survey guidance.  The surveys should be proportionate to the scale and location of the development, recognising that in some circumstances the agreed extent of surveys might be less for a solar farm than they would be for a wind farm.  

During the breeding season, the type of distribution and abundance survey will vary according to the habitats at and within the vicinity of the proposed development and the species likely to be present.  It is expected that the most common surveys required might be for moorland birds using the Brown & Shepherd (1993) method (amended by Calladine et al., 2009), raptors and short-eared owl using the Hardey et al. (2009) method and lowland waders using the Gilbert et al. (1998) method.

Non-breeding season bird surveys may also need to be considered, for example, as noted at Section 3.7.2 of the survey guidance in relation to communal roosts for raptors, and at Section 3.7.8 in relation to wintering and migratory waterfowl. 

Up to one year of bird surveys will typically be appropriate for most solar PV farm developments, although developers and consultants must clearly demonstrate that the chosen duration is robust and appropriate to the specific proposal.  Additional survey work beyond one year may be required in some cases, for example:

• To potentially enable further detailed assessment of impacts of birds on, or connected to, protected areas, such as Special Protected Areas (SPAs); and
• In areas where bird sensitivity is expected or has been shown to be high, especially where activity varies significantly between years.

The ecological assessment should allow the identification of any significant cumulative impacts arising from the proposal in combination with other relevant developments.

Our standing advice note on planning consultations and birds should further help applicants submit proposals that minimise impacts.

Bats

Our standing advice for bats should be referred to inform survey, assessment, mitigation and any licensing requirements.  The risk of collision is low so bat activity surveys are not required.

Other protected species

The presence (or potential presence) of other legally protected species also needs to be factored into the planning and design of solar development proposals.  Any impacts on protected species must be fully considered prior to the determination of the application, and if there is evidence to suggest that a protected species is present on site or may be affected by the proposed development, steps must be taken to establish this.  Our standing advice for protected species helps set out survey (and mitigation) requirements for a range of species.

The assessment should include consideration of how construction works (e.g. piling), security fencing and lighting installations may affect local ecology.

Deer

If wild deer use the development site, you should assess the implications of the development on deer and the indirect impacts on other interests (e.g. habitats, neighbours, roads, etc.).  You should present the assessment as part of your EIA report or application, even if you conclude that impacts are unlikely.  The assessment may indicate the need for management to avoid adverse impacts.  If so, we advise the need for a deer management statement, either as part of a Habitat Management Plan or as a stand-alone document.  For some sites, the modification of an existing Deer Management Plan covering a wider area may be more appropriate.  We do not expect developers to exert control over land that they have no rights over.  However, we encourage a collaborative approach with neighbouring landowners and managers to avoid adverse impacts on the interests of all parties.  A deer management statement may be included amongst the EIA report’s submitted mitigation measures, or produced to comply with a planning condition.  See our guidance on what to consider and include in deer assessments and management at development sites.

Terrestrial habitats

Solar farm proposals, including any associated buildings and access tracks, may result in habitat loss, fragmentation and modification.  However, they also provide a good potential opportunity for habitat creation and improving nature networks. 

We advise that related habitat surveys should include:

• Either Phase 1 or EUNIS survey for all terrestrial habitats likely to be affected by the development. 
• National Vegetation Classification (NVC) survey of habitats listed on Annex 1 of the EC Habitats Directive and UK Biodiversity Action Plan (UKBAP) Priority Habitat. 
• Records of any rare and scarce plant species.

The habitat assessment should consider earthworks associated with construction compounds, access roads and cable trenching. 

Example opportunities for site-specific mitigation and enhancement measures are outlined in the Mitigation, compensation and enhancement section below. 

Peatland

In upland situations, potential peatland loss or damage will be a key issue. 

The Carbon and Peatland 2016 map is a high-level tool that provides some context to more detailed peat survey work.  The map is not a definitive account of where important carbon rich soils, deep peat and priority peatland habitat exist.  Development proposals on peat, whether in the mapped area or not, will always require a site-specific and detailed peat and vegetation survey to confirm the quality and distribution of peatland across the site.  This information will confirm the extent to which nationally-important peatland will actually be affected by the development, and inform design, micro-siting and mitigation.  Where the presence of peat may be a material issue for siting of infrastructure, peat survey is likely to be required, in line with Scottish Government peatland survey guidance. 

There is currently a lack of evidence about how installation and operation of a solar farm might affect peatland, however we know that peatland habitat can be easily disturbed, and a reduction in rainfall and sunlight below panels is likely to affect vegetation composition.  A sensitive approach will therefore be required, particularly minimising soil disturbance.  Thorough assessment will help ensure that risks are understood as far as possible, and we hope to learn more from developer monitoring of any early consents.  On a precautionary basis we advise that the area under solar panels is considered as permanent habitat loss, which, together with other direct and indirect peatland loss associated with the solar farm, would require compensation and additional enhancement to ensure overall positive effects for biodiversity.

In summary, we advise the following approach to development on peatlands:

• We encourage development to avoid carbon-rich soils, deep peat and priority peatland habitat and to minimise losses of the highest quality peatland habitat.  Besides protecting nature, avoidance will help reduce carbon release and the technical challenges of managing peat.
• Where avoidance is not possible, mitigate any impacts by, for example: adopting alternative construction techniques (such as floating roads or piling); carefully planning site drainage; and following good practice for handling, storing and reinstating peat materials.
• Restore and improve the condition of existing peatland habitat to compensate for unavoidable residual adverse effects.  Measures may involve, for example, blocking drains/installing dams to raise the water table and reducing grazing and trampling pressures.
• Habitat enhancement should go beyond compensation; it should provide overall positive effects or net benefit for peatland interest.

Woodland

If tree felling/woodland clearance will be required as part of the proposed development, we recommend that developers contact Scottish Forestry at as early a stage as possible to discuss the Control of Woodland Removal Policy and the implications it may have on the development.

Freshwater

We recommend that, as a minimum, all areas directly (e.g. watercourse crossings) or indirectly (e.g. sediment run off) affected by the development and appropriate buffers up and downstream should have a habitat survey.  This should inform the likelihood of the presence of salmonids, eels, freshwater pearl mussel and other protected/Biodiversity Action Plan (BAP) species and so the need or otherwise for species-specific surveys. 

Where there is connectivity to protected areas, e.g. river or loch Special Area of Conservation (SAC), then a higher level of targeted survey effort and assessment may be needed (e.g. to inform an appropriate assessment for a SAC).

Note that where there is suitable habitat for freshwater pearl mussel, and particularly where salmonids are present, we would expect survey following the method referenced in our standing guidance for freshwater pearl mussels.

Access and recreation

Consideration should be given to the existing and potential use of the area for recreation by the general public, with reference to Scottish access rights under the Land Reform (Scotland) Act 2003 and rights of way. 

Planning Authorities including National Park Authorities have a duty to uphold access rights within their areas.  These authorities have a lead role in advising on access management within the development site, including the effects of the development on existing access and opportunities for improved access provision.  We recommend that developers engage with Planning Authorities in the preparation of an access management plan, if required, on a case-by-case basis.  This plan should identify the current recreational activities in the area and any positive or negative impacts that may occur as a consequence of the development during both construction and operation.  

Developers are encouraged to design the layout of the site to ensure continued access, where possible, during construction and when operational.  Whilst access rights may be suspended while construction work is actively taking place, except for on core paths and rights of way, the suspension should be for the minimum area and time possible.  Interpretation and temporary diversions may be appropriate.

Avoidance, Mitigation, Compensation and Enhancement

Selection of the solar farm site will be important.  In addition, ‘mitigation by design’ can also help avoid and/or minimise effects on the more sensitive parts of a chosen site.  It will be important to follow the mitigation hierarchy to minimise impacts and provide additional benefits for biodiversity.

Solar farms should aim to maximise available opportunities to provide positive effects for biodiversity and to enhance the landscape.

Tailored, site-specific measures may include:

• ­Retaining, infilling and establishing native trees and hedges for the benefit of screening and biodiversity. 
• Minimising the use of security fencing and lighting where possible to reduce any adverse visual impacts or adverse effects on ecology and access/recreation.
• Considering the availability of natural features /defences such as steep gradients, hedging and rivers to help minimise the use of security fencing.
• Minimising the height and intrusive design of security fencing where possible, and considering potential for screening of fencing using existing hedges or landscaping.
• Marking fencing with deflectors to reduce risk of bird strikes in higher sensitivity locations.
• Incorporating mammal gates /gaps into fencing.
• Establishing and maintaining wildlife buffer strips between and around arrays.
• Directing security lighting away from areas of valued habitat, and using passive infra-red (PIR) technology.
• Minimising disruption and ground disturbance where possible particularly on sensitive habitats such as peatlands.  This might be achieved through sympathetic installation methods and maximising the use of existing infrastructure, for example new access and cabling adhering to the routes of existing tracks. 
• Installing using pile driven or screw foundations rather than trench foundations where possible, particularly on more sensitive habitats.  This will help reduce reliance on concrete, minimise ground disturbance and facilitate restoration.
• Where soil stripping or trenching is necessary, stripping, storing and replacing topsoil and subsoil separately in order to minimise soil damage and to provide optimal conditions for site restoration.
• Minimising potential for disturbance through a sympathetic maintenance regime.
• Minimising the use of chemicals to clean panels.  Plain water is preferable, especially over peatlands, where panel cleaning might also be done as infrequently as possible in order to minimise drainage and compaction impacts associated with maintenance.
• Employing vegetated roofs (in keeping with local habitats), where appropriate, on associated buildings and cladding or screening these to help reduce visual impacts.
• Maintaining appropriate grazing management in relation to proposals for habitat restoration/creation. 
• Installing heights of frames that allow effective sheep grazing where relevant.
• Incorporating wider biodiversity enhancements such as habitat, nesting and roosting boxes, and locally appropriate plant mixes for pollinator species.
• Considering invasive non-native species where appropriate.
• Facilitating enhancements to the local path network, where appropriate.

Developers should take account of our guidance on What to consider and include in Habitat Management Plans when draft or outline Habitat Management Plans are being presented.

Solar Energy UK’s Natural Capital Best Practice Guidance includes further useful information on mitigation and enhancement measures.