Permitted Development Rights review - phase 3: consultation analysis

2. Domestic Renewables

2.1 Domestic solar energy equipment

The consultation paper outlines current PDR that allow relatively unrestricted installation of solar panels on domestic properties outside conservation areas. Greater flexibility to install solar panels inside conservation areas is now being considered, while still recognising the importance of heritage protection and protecting a location’s character. It is therefore proposed that PDR should be extended to allow the installation of solar panels on domestic properties in conservation areas in some – but not all – circumstances.

It is proposed that new PDR should enable solar panels to be attached to dwellinghouses and buildings containing flats which are located in conservation areas – subject to conditions that:

(i) Solar panels installed under this PDR are not permitted:

• On a principal elevation or a side elevation where that side elevation fronts a road.
• If any part of the solar panel, including associated mountings, protrude more than 1 metre from the outer surface of the wall or roof.
• Within the curtilage of a listed building.

(ii) Solar panels are to be removed as soon as is practical should they become inoperative, or are no longer in use.

An additional PDR is proposed for the installation of solar panels on outbuildings ancillary to, and within the curtilage of, a dwellinghouse – subject to conditions that:

(iii) Solar panels installed under this PDR may not protrude more than 200mm from a wall or pitched roof of an outbuilding, or more than 500mm from the surface of a flat roof.

(iv) The PDR would only apply to outbuildings that are located:

• Within the rear curtilage or side curtilage not facing a road.
• Within the rear curtilage in a conservation area.

The intention is that this specific PDR for solar panels attached to domestic outbuildings would provide greater flexibility than is currently offered by class 3A.

Question 1: Do you agree with the proposed PDR for solar panels attached to domestic properties in conservation areas?

Responses to Question 1 by respondent type are set out in Table 2 below.

Table 2

	Yes	No	Don't know	Total
Organisations:
Planning authority	11	4	1	16
Public body or corporation
Professional or representative body	9	3		12
Private sector - energy/renewables	4			4
Private sector - thermal efficiency/heating		1		1
Private sector - other	1		1	2
Third sector - built environment/conservation	2	3		5
Third sector - shooting			3	3
Third sector - community councils/representative groups	3			3
Third sector - other	3			3
Total organisations	33	11	5	49
% of organisations	67%	22%	10%
Individuals	45	31	31	107
% of individuals	42%	29%	29%
All respondents	78	42	36	156
% of all respondents	50%	27%	23%
% excluding “don’t know” responses	65%	35%

Percentages may not sum to 100% due to rounding

Half of respondents who answered the question – 50% – agreed with the proposed PDR for solar panels attached to domestic properties in conservation areas, while 27% disagreed and 23% did not know. Excluding those who answered “don’t know”, 65% agreed and 35% disagreed. Among organisations, 67% agreed.

Please add any comment in support of your answer

Around 85 respondents provided a comment at Question 1.

Reasons for supporting new PDR

Some respondents saw the need to generate sustainable energy as the main reason that the new PDR should be introduced, with related suggestions that:

• The proposals strike a reasonable balance between climate and heritage considerations or that solar panels in the permitted locations would have limited visual impact.
• The proposed PDR will make it easier for those living in conservation areas – where properties are often ‘hard to treat’ – to install solar panels, improving the energy efficiency of their homes, reducing electricity bills and supporting a just transition to net zero.
• Ensuring a just transition to net-zero is also an imperative for homeowners in rural areas where renewable sources can off-set the higher costs of energy linked to rurality and where farmers and crofters can benefit from the PDR.
• Overall, concerns with respect to potential impacts on visual amenity or the character of conservation areas are outweighed by the benefits.

However, some respondents who expressed support for the proposals went on to add caveats to their approval and others to argue that the PDR should actually go further than currently envisaged.

Reasons for opposing new PDR

The most frequent reason for opposing the proposed PDR was concern for the cumulative impact of solar panels on the appearance and character of conservation areas. The proposed exclusion with respect to solar panels ‘on a principal elevation or a side elevation where that side elevation fronts a road’ was considered inadequate since solar panels may still be visible from many other vantage points, including areas with public access. Respondents also emphasised the duty set out in legislation to preserve or enhance the character and appearance of conservation areas.

At a more personal scale, an Individual respondent queried why neighbours who face the side or rear of a building in a conservation area should be given less consideration than those passing on a road.

Some respondents expressed a view that a requirement for planning permission should be retained. It was also argued that the proposed approach will make it difficult to follow either Planning Advice Note (PAN) 71 on Conservation Area Management or Historic Environment Scotland guidance: ‘Managing Change in the Historic Environment: Micro-renewables’. Specific issues were also raised with respect to the World Heritage Site status of Edinburgh’s Old and New Towns and it was argued that, in addition to concerns for preserving the historic environment, relaxing planning controls with impacts on the visual appearance of conservation areas could be harmful to tourism and therefore to the local economy.

However, while some respondents who disagreed with proposed PDR thought it goes too far, others argued that provisions should be extended further, including that solar panels should be allowed wherever practical or that all restrictions on roof-mounted panels should be removed.

Comments on the proposed limitations

The analysis below considers each of the limitations proposed in the consultation paper in turn, followed by various additional conditions or additional permissions that were suggested.

Solar panels are not permitted on a principal elevation or a side elevation where that side elevation fronts a road

Although this exclusion was welcomed by some it was, as noted above, a major concern for others. General issues were raised regarding what is the ‘principal elevation’ in conservation areas and it was noted that all elevations of a building may be important in a conservation area. Specifically, respondents argued that:

• Some conservation areas are on sloping ground such that many roofs, rear and side elevations are visible from elsewhere.
• Roof areas of side curtilages (or side elevations) can be very visible from the road.
• Elevations and hence solar panels may also be widely visible in coastal towns and in conservation areas where buildings are at lower density.
• Conservation areas may also be viewed from the sea.

Some respondents argued that the PDR should not be implemented for conservation areas or, more specifically, should not apply to World Heritage Sites. Others suggested that the PDR should not apply to any ‘principal elevation’ (as defined by the planning authority) of any building within a conservation area, or should not apply to side elevations.

Alternative suggestions included that, in conservation areas, PDR should only apply:

• To side and rear elevations where these do not face on to public places, including streets and parks.
• To rear elevations if these do not front a road.
• To solar panels on roofs.
• To elevations, roofs or panels that are not visible from the public realm.

Solar panels are not permitted if any part of the solar panel, including associated mountings, protrude more than 1 metre from the outer surface of the wall or roof

Few respondents commented on this exclusion, but most who did argued that panels should not be allowed to protrude by as much as 1m, including because this is unnecessary would and create visual clutter. Specific suggestions were that:

• There should be separate thresholds of 200mm for a wall or pitched roof and 500mm for a flat roof, as per the proposals for outbuildings.
• A flush/inset design should be specified for conservation areas.

A very different perspective was that the limit on height should be removed in view of pitch requirements – the need for panels to be angled at between 20 - 50° in order to function as efficiently as possible.

Solar panels are not permitted within the curtilage of a listed building

Again, there were few comments with respect to the exclusion of curtilage of listed buildings, although the views expressed were mixed, including both that the restriction is welcome and that it is unnecessary because Listed Building Consent would be required. A very different perspective was that, subject to meeting criteria deemed acceptable by the Scottish Government, listed buildings should be included under the PDR. The Third sector – other respondent making this point argued that inhabitants of listed buildings are facing the same energy bills as other households and should be allowed to install solar panels without seeking planning permission.

Solar panels are to be removed as soon as is practical should they become inoperative, or are no longer in use

Comments on the stipulation regarding removal of inoperative panels included that this is impractical or that it is not clear how it could be policed.

Concerns were also expressed with respect to the absence of any safeguards to prevent poor or inappropriate roof repairs using the wrong materials after panels are removed, and it was suggested that the text be amended to require that, when panels are removed, any associated works should also be reversed using like for like materials.

Suggestions for clarification, additional restrictions or wider PDR

Other suggestions were that there should be:

• Acknowledgement of the importance of a fabric-first approach to energy efficiency, for example highlighting the importance of improving insulation before other measures.
• Additional specifications with respect to the design of panels (for example materials and colours) to minimise their visual impact within conservation areas.
• A distinction between flatted and non-flatted properties in view of additional issues, including amenity of other residents, associated with installation of solar panels on the walls of tenements and other buildings containing flats.
• A limit on the extent of coverage of an elevation or roof since it was suggested that, as drafted, it would be possible to cover the rear and side roof pitches or elevations with what would look like a new roof or newly clad elevation of a different colour and texture.
• Considerations that would apply on flat roofs, such as a condition that panels are at least 1m from the edge of the roof.
• Additional requirements with respect to roof coverings and insulation materials in order to address potential fire safety concerns.

There were also requests to:

• Reference latest Microgeneration Certification Scheme (MCS) standards for solar installations to ensure that the PDR supports good design, safe installation and is kept up to date with changing technologies.
• Provide guidance on bird proofing or bird proof design to ensure nuisance conditions (noise, bird droppings, insects) are not caused to neighbouring properties.
• Advise against a presumption that associated tree removal required to obtain adequate gain from solar panels is permitted.
• Ensure the PDR regime is simple and easily understandable for the broader public, so regulatory complexity does deter those who might be willing to deploy renewable energy sources.
• Consider issues relating to the waste stream for solar panels.

With respect to potentially widening the PDR beyond what is currently proposed, suggestions included:

• That since solar installations are best when south facing, further consideration should be given to including PDR on roof elevations to the front of properties where the panels will not be visible from the road, for example flat roofs or roofs with a parapet at the front.
• That solar panels should be permitted on all elevations, including those facing a road and, specifically, that it is not clear why there should be a blanket exclusion on the front face of a property.
• That where no material adverse visual impact arises, PDR should apply in conservation areas and within the curtilage of a listed building.
• That the PDR could be extended to include Category C listed buildings since panels are an addition to the building rather than requiring removal of historic fabric.
• That restrictions on flat roofs seem disproportionately onerous compared to other restrictions.
• That use of solar PV tile replacements should be considered.

There were also references to planning costs for owners of properties in conservation areas, with one suggestion that greater use should be made of prior notification and approval procedures in relation to installation of solar panels on elevations that are excluded, in order to allow panels to be located in the most advantageous places for energy generation and mitigate costs and delays associated with applying for planning permission.

An alternative suggestion was that there should be no PDR for solar panels in conservation areas but that a low-cost Green Energy planning application could be formulated. A Planning authority respondent suggested that there may be a case for further reduction of application fees for developments in conservations areas that would be covered by PDR outside conservation areas.

Question 2: Do you agree with the proposed PDR for the installation of solar panels on outbuildings ancillary to, and within the curtilage of, a dwellinghouse?

Responses to Question 2 by respondent type are set out in Table 3 below.

Table 3

	Yes	No	Don't know	Total
Organisations:
Planning authority	15	1	2	18
Public body or corporation
Professional or representative body	8	1	3	12
Private sector - energy/renewables	3	1		4
Private sector - thermal efficiency/heating		1		1
Private sector - other	1		1	2
Third sector - built environment/conservation	3	2		5
Third sector - shooting			3	3
Third sector - community councils/representative groups	3			3
Third sector - other	3			3
Total organisations	36	6	9	51
% of organisations	71%	12%	18%
Individuals	49	24	33	106
% of individuals	46%	23%	31%
All respondents	85	30	42	157
% of all respondents	54%	19%	27%
% excluding “don’t know” responses	74%	26%

Percentages may not sum to 100% due to rounding

A small majority – 54% of those who answered the question – agreed with the proposed PDR for solar panels on outbuildings ancillary to, and within the curtilage of, a dwellinghouse while 19% disagreed and 27% did not know. Excluding those who answered “don’t know”, 74% agreed and 26% disagreed. Organisations were more likely to agree than individual respondents at 71% and 46% respectively.

Please add any comment in support of your answer

Around 70 respondents provided a comment at Question 2, with some referring back to their answer at Question 1.

Reasons for supporting new PDR

General reasons given in support of the new PDR also reflected points made at Question 1, including that this is a reasonable or logical approach, particularly in light of increased energy prices, and will allow more flexible deployment of solar panels. It was suggested that the proposed conditions should limit impact or that positive effects outweigh any negative impacts. Some respondents argued that proposed limitations should be amended or removed.

It was also suggested that ancillary buildings can be well suited to solar PV providing an economically viable but inobtrusive option, and can allow the main building to benefit without directly hosting the panels. However, it was noted that outbuildings may be in more shaded situations.

Reasons for opposing new PDR

Reflecting responses at Question 1, reasons that the new PDR should not be introduced included both that current requirements to obtain planning permission should remain and that it should be made even easier to generate solar energy, with some or all of the proposed limitations removed.

Comments on the proposed limitations

The analysis below considers each of the limitations proposed in the consultation paper in turn, followed by various additional conditions or additional permissions that were suggested.

Solar panels installed under this PDR may not protrude more than 200mm from a wall or pitched roof of an outbuilding, or more than 500mm from the surface of a flat roof

There was a query as to why panels should not be allowed to protrude by up to 1m, in line with the restriction for the dwelling, and a suggestion that the proposed limits should be increased. Inconsistencies with height limits in PDR for free standing solar were also noted.

Pitch requirements were cited as a specific reason for increasing the proposed limits, since standard sized (2m length) panels at an optimal panel pitch of 20-50° would not be permitted under the proposed PDR.

However, there was also a view that panels protruding by up to 1m could be very harmful and that 200mm from a wall or pitched roof and 500mm from a flat roof is appropriate.

The PDR would only apply:

to outbuildings that are located within the rear curtilage or side curtilage not facing a road

A limitation to rear curtilages or side curtilages not facing a road was seen as reasonable and not likely to have adverse visual impact, although with a caveat in respect of potential glare impacting neighbouring residential amenity. Concerns were also raised with respect to potential for glint and glare to impact train drivers and hence affect the safety of operational railway lines.

Other views covered a number of differing perspectives, including that there should be further relaxation so there are no restrictions on solar panels on outbuildings within either side or front curtilages or that, outside of conservation areas or the curtilage of listed buildings, PDR should cover solar panels for public facing elevations. It was also argued that:

• Outside of conservation areas, the restriction on side curtilages fronting a road is unnecessary, provided that panels are mounted on outbuildings and are not free standing.
• It may be appropriate to exclude the rear curtilage where it fronts a road.
• PDR should only apply where elevations do not face onto public spaces.

There was also a query with respect to what is meant by ‘facing a road’ – for example how far an isolated property would need to be from a road before this restriction would cease to apply.

to outbuildings within the rear curtilage in a conservation area

Although some respondents agreed with limitation to a rear curtilage or saw the proposed restriction as being appropriate to limit potential impacts, there was also a view that the PDR should not apply at all in conservation areas, where planning permission should still be required. Points raised included that:

• Even minor change can have a significant effect on the overall character and appearance of conservation areas, and this can happen incrementally without effective controls.
• A rear curtilage in a conservation area will be difficult to define, some properties may not have a defined curtilage, or that gardens may be separated from the houses.

Proposed amendments were suggested such that:

• PDR should apply only to installations that are not visible from the public realm.
• For an outbuilding positioned to the side of the main house, solar panels facing towards the front curtilage should not benefit from PDR.
• World Heritage Sites should be excluded.

From an alternative perspective, it was suggested that greater flexibility would be welcome with respect to front and side elevations and curtilages that front onto a road, and that prior notification and approval procedures could provide this flexibility in conservation areas.

Suggestions for clarification, additional restrictions or wider PDR

One respondent made a general point on drafting, that it should be made clear that the PDR would only apply to outbuildings that are sited within the curtilage and not just within the curtilage. There were also suggestions that the PDR should be extended to cover installation of freestanding solar panels or that greater use should be made of prior notification and approval procedures.

It was also noted that, in contrast to the text in relation to dwellinghouses, the additional PDR proposed for outbuildings makes no reference to listed buildings, with related concerns that this could allow installation of solar panels within the curtilage of a listed building. An alternative view was that there is scope to extend PDR to listed buildings on a similar basis as conservation areas, allowing cultural heritage impacts to be considered and safeguarded through the separate requirement to obtain Listed Building Consent.

Other suggestions included that:

• To minimise impact there should be a requirement for solar panels to be black with black frames, or to be frameless.
• PDR should only apply to permanent buildings not temporary structures such as sheds or carports.
• There should be a requirement to restore buildings to their original state after panels are removed.
• As in respect of panels attached to dwellings, there should be consideration of potential fire safety issues and guidance on bird proofing or bird proof design to prevent nuisance to neighbouring properties.

2.2 Domestic Air Source Heat Pumps

The consultation paper outlines current class 6H PDR that permit the installation, alteration or replacement of an air source heat pump (ASHP) on a dwelling or within the curtilage of a dwelling. It is proposed that class 6H should be amended for domestic ASHPs by:

(i) Providing that one ASHP per dwelling is permitted under the PDR, rather than the current restriction of one per building.

(ii) Providing that where an ASHP is installed on a building containing flats:

• The outdoor compressor unit must not exceed 1.5 cubic metres.
• The external parts of the ASHP (including any housing etc.) must not be within 1 metre of any window of a habitable room, or door, of another flat in the same building.

(iii) Removing the requirement that an ASHP installation in a conservation area must be at ground level.

Question 3: Do you agree with the proposed amendments to PDR for ASHPs?

Responses to Question 3 by respondent type are set out in Table 4 below.

Table 4

	Yes	No	Don't know	Total
Organisations:
Planning authority	10	7		17
Public body or corporation	1			1
Professional or representative body	8	5	1	14
Private sector - energy/renewables	3			3
Private sector - thermal efficiency/heating
Private sector - other	1		1	2
Third sector - built environment/conservation	2	3		5
Third sector - shooting			3	3
Third sector - community councils/representative groups	1		2	3
Third sector – other	4		1	5
Total organisations	30	15	8	53
% of organisations	57%	28%	15%
Individuals	36	31	32	99
% of individuals	36%	31%	32%
All respondents	66	46	40	152
% of all respondents	43%	30%	26%
% excluding “don’t know” responses	59%	41%

Percentages may not sum to 100% due to rounding

Respondents were most likely to agree with the proposed amendments to PDR for ASHPs; 43% of those answering the question were of this view. Of the remaining respondents to the question, 30% disagreed with the proposed amendments, and 26% did not know. Excluding those who answered “don’t know”, 59% agreed and 41% disagreed. The balance of opinion was different amongst organisations, with a small majority – 57% of those answering the question – agreeing with proposals, compared with 36% of individual respondents.

Please add any comment in support of your answer

Around 85 respondents provided a comment at Question 3.

Reasons for supporting the proposals

Comments in support of the proposed amendments to PDR for ASHPs included recognition of the potential role of heat pumps as a key technology for delivery of net zero policy targets. Respondents agreed with the need for expansion of PDR to support wider roll out of ASHPs and suggested that restrictive planning rules are limiting heat pump deployment. The importance of effective communication with installers was also highlighted as a means to raise awareness of changes to PDR, and to ensure these can support wider roll out of ASHPs.

However, as discussed below, some of those expressing general support for proposals highlighted concerns and suggested caveats to their approval.

Reasons for opposing the proposals

General concerns raised around proposed changes were most commonly related to noise impacts. Respondents supported the retention of current standards for maximum noise levels, but also noted potential for cumulative noise impacts associated with multiple installations in close proximity. It was suggested that planning authorities have already observed cumulative noise impacts associated with multiple installations, and there was concern that this will worsen given the planned increase in deployment and the proposal to allow multiple installations to a single building. There was also a view that regulation and guidance on noise emissions are inconsistently applied across planning authorities and noise consultants.

Concerns were also raised around the current MCS 020 methodology for the assessment of noise impacts,^[1] including that the scheme is based on an assumption that there should be no more than one ASHP per building, such that the proposed amendment to PDR would invalidate the methodology. Specific aspects of MCS 020 methodology highlighted included that it does not:

• Make allowance for varying levels of background noise including low noise environments.
• Consider the characteristics of noise nor noise rating levels (rather than simply the decibel level).
• Consider structure borne vibration.
• Take account of cumulative impacts of multiple ASHPs.

Further, MCS 020 only assesses noise impacts on the nearest habitable room rather than on the householder. There was also concern that the scheme can create confusion for installers. It was suggested that, as a result of these deficiencies, compliance of individual units with MCS 020 does not provide confidence that the installation will not result in noise disturbance. In this context, respondents suggested alternative noise assessment methodologies, such as BS4142 (Methods for rating and assessing industrial and commercial sound). There was also reference to advice on noise impact assessment produced by the Institute of Acoustics and the Chartered Institute of Environmental Health, and to ongoing UK Government research on noise impacts.

Other concerns raised by respondents included reference to potential vibration issues dependent on how ASHPs are installed and isolated from buildings, and to the risk of visual clutter where multiple units are installed in a small area. The importance of long-term maintenance of units was also highlighted, including concerns that inappropriately maintained units could have a significant impact on visual amenity and lead to increased noise impacts. Respondents saw this as a potential long-term monitoring and enforcement issue for the planning system.

Comments on specific amendments

Comments specifically in relation to each of the proposed changes to current PDR are summarised below.

One ASHP per dwelling is permitted under the PDR, rather than the current restriction of one per building

There was specific support for the proposal to permit one ASHP per dwelling rather than per building, which was seen as being consistent with the aims of the Heat in Buildings Strategy and having potential to encourage wider roll out of heat pumps. This included reference to the proportion of tenement and other flatted properties across Scotland, with these seen as essential in meeting net zero targets.

The issue of cumulative noise impacts was seen as particularly significant in relation to potential for multiple ASHPs to be installed to a single building. This included concerns that cumulative noise impacts can contribute to health issues. Potential cumulative noise impacts were seen as a reason for caution in expanding PDR in relation to installation to flatted properties.

Other comments in relation to this proposed amendment included views that:

• Encouraging a shared low carbon heating system may be preferable to permitting multiple ASHPs.
• Multiple ASHPs may be required for larger properties, especially older properties with poorer energy efficiency, and that PDR should allow for this. This was linked to a view that neighbouring residents are likely to be more concerned with noise impacts rather than the number of units installed.
• The proposed amendment has potential to erode civil rights of communal ownership for tenement properties.

Where an ASHP is installed on a building containing flats the outdoor compressor unit must not exceed 1.5m³ and the external parts must not be within 1m of any window of a habitable room, or door, of another flat

Support for proposed limits on ASHP installations included specific reference to the importance of separation from neighbouring doors and windows in protecting residential amenity. This was seen as a key factor in limiting the noise impacts of ASHPs.

However, there was also concern that the proposed limits on the physical size and positioning of ASHP units are related primarily to aesthetic considerations rather than noise impacts. As such, it was suggested that these conditions will not be sufficient to limit noise impacts, dependent on the character of the installation. In this context, there was a view that limits on the placement of ASHP should not be used to mitigate noise impacts, but that the main focus should be on the level and nature of noise emissions. This approach was seen as having potential benefits in terms of incentivising the industry to develop quieter solutions.

Respondents also specifically questioned the need for the proposed restriction on the physical volume of the outdoor unit. While some did not see the proposed 1.5m³ limit as a significant concern, there was reference to the proposal as an ‘arbitrary limitation’ and concern that this could be too restrictive as the technology and design of ASHPs continues to develop. This was linked to a view that the risk of adverse impacts associated with ASHP relates to the overall character of the installation, rather than the size of individual components. It was also suggested that the limitation could prevent residents from selecting the most suitable and efficient option for their circumstances, for example if a larger ASHP unit would result in lower noise emissions. Others were of the view that the proposed limit of 1.5m³ is too large, and there was particular concern around the potential for cumulative visual impact in conservation areas. It was also noted that similar size limits are not imposed on other heating technologies such as oil tanks.

Specific concerns were highlighted around the proposed limit on external parts being within 1m of any window of a habitable room of another flat. For example, it was suggested that this may be too restrictive for dense building types and there was a wider view that the proposed conditions may be difficult to meet for flatted properties with limited curtilage. There was also concern that the proposed restriction on positioning of ASHPs could have unintended consequences in inhibiting innovation and limiting future uptake, for example if technological development results in larger ASHP units.

Removing the requirement that an ASHP installation in a conservation area must be at ground level

A number of respondents expressed specific support for the proposed change to PDR in conservation areas. This included reference to the proportion of buildings across Scotland located in conservation areas, and the need for change to support deployment of low carbon heating across these areas to meet net zero targets. Respondents suggested that ASHPs are likely to have an especially important role in off-gas areas and areas with high levels of fuel poverty, which often applies to conservation areas. In this context, the proposal was seen as particularly relevant. It was also noted that permitting installations above ground level is consistent with the incidence of air conditioning units and flues at this level on the rear elevation of buildings within conservation areas.

Opposition to removing the requirement was most commonly linked to concerns regarding the potential impact on the character and appearance of conservation areas. It was suggested that ASHP installation above ground level is likely to have a significant visual impact even where this is limited to rear elevations. This included concern around the potential cumulative visual impact of multiple ASHPs being installed to the rear elevation of flatted properties, given the proposal to permit multiple installations per building. It was also suggested that a lack of PDR in these areas has not been a significant barrier to delivery of net zero policy objectives.

A contrary view was that the proposal could unduly restrict deployment of ASHPs, given their potential role in delivery of climate objectives. This included a view that the Scottish Government should consider removing the restriction on ASHPs on front and side elevations in conservation areas.

Additions and amendment to proposals

Respondents suggested a range of additions and amendments to the proposals as set out in the consultation paper.

Suggestions in relation to the proposed limit of one ASHP per dwelling included that:

• Proposals should permit more than one ASHP per dwelling, providing the installation is within noise limits.
• A clear distinction between ‘dwelling’ and ‘building should be made.

In relation to the proposed limits on the size and positioning of external parts for Installation to buildings containing flats suggestions included that:

• Conditions should focus on noise impacts as the primary driver of design of ASHP installation, rather than on the size and location of units.
• Installation on buildings containing flats should be restricted to ground floor level locations only.
• Further research is required into the average available wall space and distances between windows before proposed changes are implemented.
• A clear definition of ‘habitable room’ is required.
• Clarity is required around whether the compressor housing is included in the maximum size threshold.

With respect to criteria for installation in conservation areas suggestions included that:

• Additional conditions should apply to the appearance of ASHP units to minimise impacts in conservation areas, for example colour and branding.
• PDR should limit ASHPs to elevations not visible from public places.
• The Scottish Government should consider removing the restriction on ASHPs on front and side elevations in conservation areas, noting that these may be the only available elevations for some buildings.
• Language should be clearer around scope to allow ASHPs above ground level to ensure consistent application.

Respondents also suggested various additions and amendments to the proposals including that alternative approaches to the assessment of noise in relation to ASHPs, such as BS4142 should be considered. It was proposed that this should make reference to relevant research and guidance, including guidance produced by the Institute of Acoustics, take account of the results of forthcoming UK Government research, and incorporate discussion with relevant bodies such as the Royal Environmental Health Institute of Scotland and heads of Environmental Health across Scottish local authorities. It was argued that the approach to the assessment of noise should recognise the overall aim of enabling wider deployment of ASHP.

Other suggestions included that:

• If MCS 020 is retained as the basis for noise assessment in relation to ASHPs, the standard should be owned by an independent standards authority.
• PDR restrictions around noise levels and size and positioning of installations should be applied equally across other domestic heating and cooling equipment, for example including oil tanks, heat pumps, external boilers and air conditioning.
• The Scottish Government should seek to ensure coordination with the rest of the UK for PDR in relation to ASHPs, where possible.
• PDR for ASHPs should be extended to include listed buildings, noting that this would be consistent with PDR for solar panels and that the requirement for Listed Building Consent would still apply. PDR could also allow appropriate installations in World Heritage Sites.
• PDR should be restricted where the ASHP unit would encroach onto a footpath or right of way.
• Clarification is required on whether proposals would apply to air-air in addition to air-water heat pumps.

2.3 Domestic Ground Source and Water Source Heat Pumps

Classes 6D and 6E permit the installation, alteration or replacement of a ground source heat pump (class 6D) or a water source heat pump (class 6E) within the curtilage of a dwellinghouse or a building containing a flat. However, there is currently no reference to associated pipes so it is proposed that classes 6D and 6E should be amended to clarify that, in addition to the ground/water source pump itself, the PDR also cover the associated underground pipework and any above-ground connections to the pump. The pipework would need to be wholly within the curtilage of the dwellinghouse or flatted building.

Question 4: Do you agree that classes 6D and 6E should be amended to include reference to the installation etc. of pipework and associated connections required to operate a ground or water source heat pump?

Responses to Question 4 by respondent type are set out in Table 5 below.

Table 5

	Yes	No	Don't know	Total
Organisations:
Planning authority	15	3		18
Public body or corporation
Professional or representative body	9	2	2	13
Private sector - energy/renewables	3			3
Private sector - thermal efficiency/heating
Private sector - other	1		1	2
Third sector - built environment/conservation	1	2		3
Third sector - shooting			3	3
Third sector - community councils/representative groups	2			2
Third sector - other	5		1	6
Total organisations	36	7	7	50
% of organisations	72%	14%	14%
Individuals	43	20	31	94
% of individuals	46%	21%	33%
All respondents	79	27	38	144
% of all respondents	55%	19%	26%
% excluding “don’t know” responses	75%	25%

A small majority of respondents agreed with the proposed amendments to classes 6D and 6E PDR; 55% of those answering the question were of this view while 19% disagreed. The remaining 26% did not know. Excluding those who answered “don’t know”, 75% agreed and 25% disagreed. This balance of opinion varied across respondent types, with 72% of organisations agreeing with proposals compared with 46% of individual respondents.

Please add any comment in support of your answer

Around 50 respondents provided a comment at Question 4.

Reasons for supporting the proposals

Those expressing support for the proposed change to classes 6D and 6E PDR agreed that the lack of reference to associated pipes and connections could cause confusion around the scope of PDR for domestic ground source and water source heat pumps. It was suggested that proposed changes will provide clarification, and are a logical proposal.

Respondents also noted that proposed amendments would bring existing PDR in line with those relating to non-domestic heat pumps, and there was support for restricting installation to the curtilage of buildings as a means of limiting potential for adverse visual and other impacts It was also noted that existing consent requirements would remain, for example in relation to development within the curtilage of scheduled monuments.

Reasons for opposing the proposals

Concerns and issues raised in relation to proposals were most commonly linked to a view that PDR should continue to be restricted in areas of archaeological interest and within the curtilage of historic sites. This included reference to the scale of groundworks associated with pipework and connections for ground source and water source heat pump installation, although it was noted that the size of trench required for these installations is likely to constrain use of PDR within the typical curtilage of residential properties.

It was also suggested that the proposed limitation of pipework to the curtilage of properties could prevent installers from choosing the most appropriate solution for each circumstance. For example, it was noted that there may be a need to extend underground piping to a water body outside the curtilage of the building but within the property boundary. However, concerns were also raised around the potential for proposed changes to allow for installation of underground piping without proper consideration of potential ground pollution issues. This was seen as a particular issue where heat pumps are retrofitted to existing properties, where there may be less awareness of existing remedial works, and on brownfield sites or areas impacted by mining.

Concerns were also raised around the potential noise impacts of the installation of piping and connections. This included reference to the risk of noise being transferred within the building as a result of poorly designed pipework. It was noted that neither the existing PDR, nor the proposed amendment, make reference to potential noise impacts.

Clarity was sought around specific aspects of the proposed change to PDR, including the definition of ‘curtilage’ (for example whether this is intended to be within the footprint of the building or property boundary) and. Specifically. which connections are to be allowed under PDR.

Additions and amendment to proposals

Respondents also suggested additions and amendments to the proposals including that:

• PDR should be restricted in areas of archaeological interest.
• PDR should include a requirement that surfacing is restored following installation in conservation areas and within the curtilage of listed buildings.
• PDR should allow pipework that extends beyond the curtilage of the dwellinghouse or flatted building.
• Installation of pipework and connections within the curtilage of flatted properties should require consent from all property owners.
• Consideration should be given to allowing the installation of ground arrays in the road, as is permitted for other shared network infrastructure.

2.4 Free-standing domestic wind turbines

Class 6G permits the installation of a free-standing wind turbine within the curtilage of a dwelling – in this context a dwellinghouse, a building containing one or more flats or a flat contained within such a building. The class is subject to a number of restrictions, including that the turbine must be situated no less than 100m from the curtilage of another dwelling, and that it cannot be located within a conservation area, the curtilage of a listed building, a World Heritage Site, a Site of Special Scientific Interest or a site of archaeological interest. Current PDR do not include any restriction on turbine height, but are subject to a prior notification and approval process.

It is proposed that class 6G should be amended by:

(i) Introducing a maximum turbine height of 15m, measured to the tip of the wing blades.

(ii) Providing that the distance between the lowest part of the turbine blade and the ground must be at least 5m.

(iii) Replacing the separation 100m distance between the turbine and curtilage boundary with a calculation of the turbine height plus a specified safety factor (e.g. height + 10%).

(iv) Adding a requirement to comply with the Microgeneration Certification Scheme (MCS) planning standards.

(v) Simplifying the prior notification and approval process so that a single procedure covers all aspects of design and siting.

(vi) Providing that the turbine and blades must be painted a uniform neutral colour and not bear any advertising.

Other elements of the current class 6G would be retained, including the requirement for prior notification and approval, to ensure that planning authorities can exercise some degree of control where a particular proposed development could have potentially unacceptable impact on amenity.

Question 5: Do you agree with the proposed amendments to PDR for free-standing domestic wind turbines?

Responses to Question 5 by respondent type are set out in Table 6 below.

Table 6

	Yes	No	Don't know	Total
Organisations:
Planning authority	6	12		18
Public body or corporation	1			1
Professional or representative body	4	7	1	12
Private sector - energy/renewables	1			1
Private sector - thermal efficiency/heating
Private sector - other	1		2	3
Third sector - built environment/conservation	1	1	1	3
Third sector - shooting			3	3
Third sector - community councils/representative groups	2			2
Third sector - other	1	1	1	3
Total organisations	17	21	8	46
% of organisations	37%	46%	17%
Individuals	40	25	30	95
% of individuals	42%	26%	32%
All respondents	57	46	38	141
% of all respondents	40%	33%	27%
% excluding “don’t know” responses	55%	45%

Among respondents who answered the question, 40% agreed with the proposed amendments to PDR for free-standing domestic wind turbines, while 33% disagreed and 27% did not know. Excluding those who answered “don’t know”, 55% agreed and 45% disagreed. A majority of Planning authority and Professional or representative body respondents disagreed.

Please add any comment in support of your answer

Around 70 respondents provided a comment at Question 5.

Some respondents noted that they generally agreed or agreed in principle with the proposed approach, which was described as sensible or reasonable and as an effective way to encourage uptake. However, concerns were raised with respect to impacts on value and amenity of neighbouring properties.

There was also a view that erection of wind turbines should always require planning permission, particularly with respect to concerns over potential for a cumulative impact on neighbours. It was argued that a planning application enables neighbour notification and consideration of neighbours’ views. A Planning authority respondent noted their experience that very few planning applications are currently received for domestic wind turbines, arguing that the proposed PDR would be unlikely to benefit enough home owners to justify the potential harm that they believe could be caused.

Comments on the proposed limitations

Introducing a maximum turbine height of 15m, measured to the tip of the wing blades

Most of those respondents who commented specifically on turbine height supported the proposed 15m height limit including because it provides clarity, because of the potential for impact of turbines in domestic settings, and because of a requirement for taller turbines to go through the planning process to ensure aerodrome safeguarding assessments are carried out.

Among respondents who did not agree with the proposed height limit, some saw 15m as too restrictive, arguing that there may be situations – for example in rural areas or where a large area of land is available – where taller turbines could be acceptable and that it is not appropriate to set a single height. A specific proposal was for a maximum turbine height of 30m to the tip of the wing blades and a maximum swept area of 200m². It was also noted that turbine height will be accounted for by retaining prior notification and approval.

Different reasons for not seeing 15m as an appropriate limit for PDR included:

• The potential impact on neighbouring properties.
• That turbine height is a visual, aesthetic issue and that noise impacts on neighbouring properties are not properly considered.
• The greater importance of electrical output in respect of noise.
• A requirement in planning advice dating from 2014 that the Ministry of Defence (MOD) should be consulted where a proposed turbine would have a maximum blade tip height of, or exceeding, 11m or a rotor diameter of 2m or more.

Providing that the distance between the lowest part of the turbine blade and the ground must be at least 5m

Relatively few respondents commented on the required distance between the turbine blade and the ground, with those who did being divided between welcoming the proposal and arguing that a lower height would still be safe, and potentially safer for maintenance purposes. It was also suggested that by limiting turbines to only one per property, and specifying that no blade should be less than 5m above ground, the amendments may drive installation of larger turbines than are needed.

Replacing the separation 100m distance between the turbine and curtilage boundary with a calculation of the turbine height plus a specified safety factor (e.g. height + 10%)

This was the restriction attracting the greatest number of comments.

Some respondents supported use of the proposed calculation seeing it as sensible or more flexible for more rural settings, and it was suggested that the current 100m separation distance between turbine and curtilage boundary is too restrictive.

However, others argued that the 100m separation distance should remain, with the proposed reduction (potentially to 16.5m) seen as excessive, or as having the potential to allow turbines in large gardens in urban areas/semi urban areas. Potential impacts on amenity were identified including noise, shadow flicker, visual impact, and toxic debris if the turbine blade coating deteriorates. One respondent provided an example with respect to noise that, for a turbine with a sound power level of 85 decibels (dB), reducing the separation distance from 100m to 16.5m would increase the noise for the receiver from 34dB to around 50dB.

It was also suggested that the proposed methodology:

• Is likely to be inconsistent with the requirements of the MCS 020 calculation procedure in its current form.
• May be contrary to the intent of the Fourth National Planning Framework (NPF4) Policy 23 (Health and Safety) with respect to facilitating development that improves health and wellbeing.
• Is too complicated, and may cause time consuming debates (e.g. on curtilage distances).
• Will lead to conflict between neighbours.

A different perspective was that the Scottish Government should introduce greater flexibility than proposed including by:

• Reducing the separation distance to the length of the turbine blade.
• Allowing a turbine to be situated no less than 10m from the curtilage of another dwelling.
• Allowing the turbine to be located within the property boundary rather than within the curtilage, so that the location with the most suitable wind resource can be selected.

A number of other amendments or subjects for further consideration were proposed, including that the Scottish Government should:

• Give greater consideration to potential for impacts such as noise and shadow flicker.
• Consider turbine rotor size as a driver of noise and flicker.
• Increase the ‘safety factor’ distance.
• Require the separation distance to be at least one and a half times the ground to blade tip height.
• Ensure a reduced separation distance does not result in clustering of turbines.
• Incorporate impact on amenity of neighbouring properties into the calculation or introduce a minimum distance from neighbouring dwellings to reduce impact of noise.
• Carry out a full impact assessment before making any change.

Adding a requirement to comply with the Microgeneration Certification Scheme (MCS) planning standards

Relatively few respondents commented specifically on a requirement to comply with MCS planning standards, and among those who did there was both agreement and disagreement, the latter including because MCS 020 was conceived as a consumer protection measure, and that MCS installers will not necessarily be best suited to installing larger turbines that may be appropriate for rural properties.

Other issues raised with respect to the MCS standard included that:

• As noted above, the proposed calculation of a minimum separation distance is likely to be inconsistent with the requirements of the MCS 020 calculation procedure.
• MCS 020 applies a standard background noise level regardless of the actual noise environment and assumes a level higher than is typical of rural areas, and does not consider cumulative impact noise, tonal characteristics or background levels.
• Residential amenity issues that arise will need to be addressed by other regulatory functions, with the potential to create additional workload for the local authority.
• If subject to MCS 020 planning standards, then PDR should not be restricted to a single turbine.

Concerns were raised with respect to the mechanism for enforcement if an installation does not comply with MCS 020. It was noted that although non-compliance would mean that the turbine was not permitted development and would require a planning application, harm would have to be established in order to undertake planning enforcement action.

Simplifying the prior notification and approval process so that a single procedure covers all aspects of design and siting

Among those who commented, there was general approval for the proposed simplification. There was also a request for more information on what simplifying the process would involve and a suggestion that the process should be 8 weeks long.

Providing that the turbine and blades must be painted a uniform neutral colour and not bear any advertising

Although some of those who commented supported this provision, it was also suggested that a ‘neutral colour’ is very subjective and would need to be defined clearly. There was also a concern that neutral-coloured turbines could be less visible and hence more harmful to birds.

Other elements of the current class 6G would be retained, including the requirement for prior notification and approval

There was support for retention of a requirement for prior notification and approval because it allows:

• The planning authority to exercise some control where a proposed development could have potentially unacceptable impact on amenity.
• Consideration of impacts on landscape and on wildlife, particularly birds and bats.

However, there was also a view that the prior notification and approval process is complicated and confusing for customers and resource intensive for planning authorities and that it should be removed where there is scope to do so.

Suggestions for clarification, additional restrictions or wider PDR

There was a request to clarify which existing conditions from class 6G would be retained.

In terms of additional limitations there were requests to exclude turbines:

• Within an MOD statutory safeguarding zone.
• Within 20m of watercourses/open fresh water (especially with tree-lined banks/margins), hedges, or lines of trees in order to protect bats.
• In the setting of listed buildings and scheduled monuments, National Parks, National Scenic Areas and statutory protected sites, and consider impacts on heritage assets, including World Heritage Sites and conservation areas.

In was also suggested that there should be:

• A minimum required distance to protect public roads including verges against the collapse of a turbine and consideration of the proximity of turbines to footpaths.
• A limit on turbine area as well as height.
• A review of noise limits which may be too stringent, and a requirement that permitted decibel levels are specified over time intervals, since turbines are noisier in some conditions than others.
• PDR only for the first installation of a wind turbine and then only if there is no existing ASHP, due to the cumulative impact of noise from an ASHP and a wind turbine.
• A requirement for regular repair and maintenance to keep noise to acceptable levels.
• Provision to remove turbines on noise grounds.

Finally, it was suggested that the proposed PDR should consider the introduction of bladeless turbines.

Question 6: Do you agree with the current list of designated areas where the PDR do not apply, noting that the list does not currently include National Parks or National Scenic Areas?

Responses to Question 6 by respondent type are set out in Table 7 below.

Table 7

	Yes	No	Don't know	Total
Organisations:
Planning authority	10	6	2	18
Public body or corporation	1			1
Professional or representative body	4	4	3	11
Private sector - energy/renewables		1		1
Private sector - thermal efficiency/heating				0
Private sector - other	1	1	1	3
Third sector - built environment/conservation		2		2
Third sector - shooting			3	3
Third sector - community councils/representative groups	1	1		2
Third sector - other	2	1	1	4
Total organisations	19	16	10	45
% of organisations	42%	36%	22%
Individuals	29	29	36	94
% of individuals	31%	31%	38%
All respondents	48	45	46	139
% of all respondents	35%	32%	33%
% excluding “don’t know” responses	52%	48%

Respondents who answered the question were relatively evenly divided on this issue – 35% agreed with the current list of designated areas where the PDR do not apply, while 32% disagreed and 33% did not know. Excluding those who answered “don’t know”, 52% agreed and 48% disagreed. A small majority of Planning authority respondents agreed.

Please add any comment in support of your answer

Around 60 respondents provided a comment at Question 6.

The turbine cannot be located within a conservation area, the curtilage of a listed building, a World Heritage Site, a Site of Special Scientific Interest or a site of archaeological interest.

There was agreement with the exclusions currently set out, with some respondents taking a view that PDR should be restricted and that the controls are appropriate.

Reasons for allowing the PDR to apply in National Parks and National Scenic Areas included that:

• The proposed height restriction would provide an appropriate balance between protecting designated areas and generating higher levels of renewable energy and that excluding National Parks could disincentivise small-scale domestic renewables in rural and semi-rural areas.
• Smaller domestic turbines would be unlikely to have a significant impact and the requirement for prior approval should enable landscape or visual impacts to be minimised.
• It would be unreasonable to exclude residents in the many settlements within these areas from exercising PDR, and some who live within National Scenic Areas may not be aware that they do so.
• National Parks and National Scenic Areas may contain smaller, safeguarded designations within them.

It was also suggested that National Park Authorities should be consulted on impacts within the National Parks.

Caveats to agreement with the list of excluded areas included that this is subject to the proposed height restrictions being implemented and that turbines must be carefully sited to avoid impacts on nature. It was also suggested that smaller turbines could be specified in National Parks and National Scenic Areas or that, within these areas, there could be a requirement to place turbines within a specific distance of the property they are serving, to ensure they are visually part of an existing developed area rather than an additional item in the landscape.

Although most responses focused on the status of National Parks and National Scenic Areas, there was also specific support for retaining other excluded areas from the present list, including areas of archaeological interest and listed buildings.

Reasons for disagreeing with the current restrictions included both that there should be more excluded areas, and that there should be fewer.

Among respondents seeking wider restrictions, National Parks and National Scenic Areas were the most frequent suggestions for additional places that the PDR should not apply. Reasons given in support of this view included the need for greater protection for nationally important landscapes and a risk of visual, landscape and natural environment impacts, including disturbance to protected species.

It was also argued that the PDR should not apply to:

• Statutory protected areas.
• Scheduled ancient monuments and their setting.
• Battlefields.
• The setting of listed buildings.
• The Inventory of Gardens and Designed Landscapes.
• Regional Scenic Areas.
• National Nature Reserves.
• Locations within agglomerations adjacent to areas designated as Quiet Areas under the Environmental Noise (Scotland) Regulations 2006.
• Sites within 5km of an aerodrome or technical site.
• Any other site designated for its visual, conservation or biodiversity qualities.

Other respondents sought a reduction on current restrictions, including a suggestion that, rather than blanket exclusion of protected areas, there should be flexibility for PDR to apply where appropriate siting and generator designs are compatible with a local designation. It was noted that new turbine designs (including bladeless and cowled turbines) that are in development and may be available within the next few years could be more appropriate for currently restricted locations.

Specific locations where it was suggested the PDR should apply included:

• Conservation areas.
• Within the curtilage of a listed building property, providing that it is a specified distance away.
• World Heritage Sites where ‘invisible’ renewables can be hidden by the landscape.

2.5 Domestic wind turbines attached to a dwelling

At present there are no PDR for the installation of a wind turbine mounted on a domestic property. A new class of PDR for the installation, alteration or replacement of wind turbines mounted on the wall or roof of a dwellinghouse is proposed, whereby a turbine installed under the PDR would only be permitted if:

(i) Mounted on a detached dwellinghouse.

(ii) It is the only turbine on the same dwellinghouse.

(iii) It complies with MCS 020 planning standards.

(iv) No part of the turbine, including blade, would protrude more than 3m above the highest part of the roof.

(v) No part of the turbine, including blade tips, would be less than 5m from the ground.

(vi) It is located at least 5m from any curtilage boundary.

(vii) The swept area of the turbine is no more than 4 square metres.

(viii) It is a uniform neutral colour with no advertising or other designs.

(ix) It is not located in a conservation area, National Park, National Scenic Area, Site of Special Scientific Interest, World Heritage Site or within the curtilage of listed building.

(x) The turbine is removed as soon as is reasonably practical should it no longer be required or cease generating electricity.

The proposed PDR would not extend to wall- or roof-mounted turbines attached to outbuildings or structures that do not form part of the dwellinghouse itself.

Question 7: Do you agree with the proposed new PDR for wall or roof-mounted wind turbines attached to a dwellinghouse?

Responses to Question 7 by respondent type are set out in Table 8 below.

Table 8

	Yes	No	Don't know	Total
Organisations:
Planning authority	7	9	3	19
Public body or corporation	1			1
Professional or representative body	6	5		11
Private sector - energy/renewables	2			2
Private sector - thermal efficiency/heating
Private sector - other		1	1	2
Third sector - built environment/conservation	1	1		2
Third sector - shooting			3	3
Third sector - community councils/representative groups	2			2
Third sector - other	1	1	1	3
Total organisations	20	17	8	45
% of organisations	44%	38%	18%
Individuals	30	27	32	89
% of individuals	34%	30%	36%
All respondents	50	44	40	134
% of all respondents	37%	33%	30%
% excluding “don’t know” responses	53%	47%

Respondents who answered the question were relatively evenly divided on this issue – 37% agreed with the proposed new PDR for wall or roof-mounted wind turbines, while 33% disagreed and 30% did not know. Excluding those who answered “don’t know”, 53% agreed and 47% disagreed. Planning authority respondents were also divided.

Please add any comment in support of your answer

Around 60 respondents provided a comment at Question 7.

In some instances, reasons given in favour of the new PDR reflected those offered at Question 5, including that the proposals represent a reasonable compromise or provide greater flexibility, although also that appropriate controls are required. It was also noted that in urban situations with shared buildings, planning permission will still be expected. The potential for a range of new turbine designs that may be more appropriate on domestic buildings was also referenced.

Some respondents who disagreed with the proposed new PDR also referred back to arguments set out at Question 5. It was suggested that a requirement for planning permission should be retained to allow the planning authority to exercise control, and to assess individual and cumulative impacts and provide enforcement action if necessary. The importance of local democratic decision making and providing neighbours with the opportunity to object were also referenced. Individual and cumulative visual impact and flicker, noise, vibration, risk of malfunction and maintenance requirements were all cited as causes for concern with respect to local amenity.

Other reasons for disagreeing with PDR for turbines on dwelling houses included that:

• The number of restrictions being proposed suggests that PDR is not appropriate.
• Turbines could have adverse effects on the performance of flues serving fuel burning equipment.
• Turbulence reduces performance and turbine life and that turbines mounted on buildings are not efficient.

In relation to the last point, it was noted that this is not a recommended technology in relation to Home Energy Scotland grants and loans. Rather than introducing PDR for wall or roof-mounted turbines it was argued that the planning application process should require justification of the effectiveness of the system.

In contrast, some respondents argued that achieving net zero will require renewables to be accepted everywhere and that turbines should be available to those who do not have scope to deploy other renewables.

Comments on the proposed limitations

Mounted on a detached dwellinghouse

There were few comments on the restriction to a detached dwellinghouse which, it was noted, would exclude many properties as well as flats, and there was a suggestion that PDR could be extended to terraced or semi-detached dwellings.

It is the only turbine on the same dwellinghouse

Again, there were few comments, although it was suggested that it is not clear why multiple turbines should require planning permission or that the restriction on size could allow more turbines to be installed.

It complies with MCS 020 planning standards

Some respondents noted that comments made at Question 5 also apply with respect to roof or wall mounted turbines. Other references to MCS 020 included concerns that noise issues in relation to small turbines may cause problems, even if the standard is complied with. It was reported that the tone of the noise generated by very small turbines can cause problems, and that the noise output information available is more limited than that available for freestanding domestic turbines, making them difficult to assess.

Other points with respect to MCS 020 included that guidance is not clear whether noise limits should be enforced for the building with the turbine attached, or the nearest residential property. The respondent making this point emphasised that limits should be enforced for all buildings, including the one to which the turbine is attached, noting that there would otherwise be a risk that a building owner could install a turbine that adversely impacts a tenant, without there being any protection for the tenant.

It was also argued that structure-borne noise is not controlled by MCS 020 and that an update to address this issue would be required before the PDR could be enacted.

One respondent disagreed with the requirement to comply with MCS 020 on the basis that the Scottish/UK market is unlikely to be large enough for manufacturers of innovative designs to obtain MCS certification just to sell in this country. Instead, it was argued that there should be specific decibel limits.

No part of the turbine, including the blade, would protrude more than 3m above the highest part of the roof

Again, few comments specifically addressed the proposed 3m above the highest part of the roof, although it was argued that this could have a significant cumulative impact on the visual amenity of residential areas if repeated.

A requirement that the MOD should be consulted where a proposed turbine would have a maximum blade tip height of, or exceeding, 11m or a rotor diameter of 2m or more was noted, and it was suggested that these limits should apply to any PDR outside MOD statutory safeguarding zones.

There was also a suggestion that the limit might be related to how high the roof is.

No part of the turbine, including blade tips, would be less than 5m from the ground

It was suggested that this restriction could exclude some single-storey dwellings, where the lowest part of the blade could easily be less than 5m from the ground, potentially disadvantaging rural dwellings that could otherwise be suited to this kind of installation.

It is located at least 5m from any curtilage boundary

Comments on the proposed distance to the curtilage boundary included both that it is too low and too high.

Respondents taking the first view argued that:

• It could allow turbines on many suburban properties with potential residential amenity and character concerns.
• It will not be sufficient to protect neighbours against noise, flicker or vibration issues, particularly where properties are close together.
• It may not be sufficient to protect neighbours if a turbine collapses.

It was also suggested that, in quiet areas, small turbines 5m away may still be noisier than the existing background noise.

A different perspective was that 5m may be overly restrictive or could mean that the best location structurally for a turbine – likely to be above a chimney on the end of the house – is not considered acceptable.

With respect to the text as drafted, it was suggested that ‘located at least 5m from any curtilage boundary’ could be difficult to define.

The swept area of the turbine is no more than 4 square metres

There was a view that this is more complicated than necessary, and a suggestion that a maximum radius/diameter might be more appropriate.

It was also argued that 4m² is arbitrary, may be inappropriate for new turbine designs and should be reconsidered.

It is a uniform neutral colour with no advertising or other designs

Comments on turbine colours reflected those at Question 5 with respect to the ambiguity of a ‘neutral colour’ and concerns for wildlife.

It is not located in a conservation area, National Park, National Scenic Area, Site of Special Scientific Interest, World Heritage Site or within the curtilage of listed building

Some respondents welcomed the proposed restrictions including with respect inclusion of National Parks and National Scenic Areas. It was also suggested that restricted areas should be the same as for free standing turbines.

Respondents also requested:

• Clarification that listed buildings themselves and not just buildings within their curtilage are excluded.
• Addition of battlefields, the Inventory of Gardens and Designed Landscapes, National Nature Reserves and Regional Scenic Areas.
• Consideration of the setting of heritage assets, including World Heritage Sites scheduled monuments, listed buildings, and conservation areas.

In relation to the last point, it was argued that it is important to distinguish between curtilage and setting, since impacts on the setting will typically be much wider than the curtilage.

Other respondents considered the proposed restrictions too wide or unfair, including because turbines currently in development may be suitable within currently protected areas. It was also argued that there is inconsistency with respect to listed buildings since PDR would allow for the attachment of a turbine to a listed building (subject to obtaining Listed Building Consent) but not installation of a turbine within the curtilage of a listed building.

The turbine is removed as soon as is reasonably practical should it no longer be required or cease generating electricity

This requirement was seen as impossible to monitor and impractical to enforce. It was noted, for example, that turbine blades could be turning but not generating electricity. There were queries with respect to who would remove turbines that fall into disrepair if the owner does not.

The proposed PDR would not extend to wall- or roof-mounted turbines attached to outbuildings or structures that do not form part of the dwellinghouse itself.

Several respondents questioned or disagreed with the exclusion of outbuildings, particularly as the intention is to allow solar panels on outbuildings. It was suggested that, as with respect to solar panels, outbuildings may be more suited to installation of renewable technology than the main dwellinghouse, and that the PDR could be extended to outbuildings or structures with the same restrictions on turbine size and distances from the curtilage.

Suggestions for clarification, additional restrictions or wider PDR

As noted above, there were concerns with respect to the noise that may be generated by roof- or wall-mounted turbines, and a view that this has not been adequately addressed. It was suggested that there should be additional noise restrictions including a maximum decibel reading at the curtilage, but also that wind strength and direction will determine noise impact to nearest neighbours.

Other suggested controls included:

• A stipulation that there will be no shadow flicker or shadow throw in neighbouring properties and provision for assessing this.
• Requirements with respect to repair and maintenance.
• Consideration of potential structural impacts on properties, with one view that all roof mounted turbines should be subject to Building Control.
• As for free standing turbines, that prior notification and approval should be required to ensure consideration of potential impacts on bats and birds, and to ensure that the MOD are consulted.

There was also a concern with respect to impacts on local authority resources in that the proposed PDR may result in complaints about noise or flicker, requiring Environmental Health investigation under nuisance regulations regardless of the status of the turbine under the planning process. Further, it was suggested that structural issues for older buildings caused by vibration and lack of ongoing maintenance may impact Building Standards.

With respect to additional areas that should be excluded from the PDR, suggestions included:

• Sites within 5km of an aerodrome or technical site.
• Sites falling within any MOD statutory safeguarding zone.

2.6 Flues for certain domestic heating systems

The Town and Country Planning (General Permitted Development) (Scotland) Order 1992 (GPDO) contains specific PDR for the installation, alteration or replacement of domestic flues for biomass heating systems (class 6C) and combined heat and power (CHP) systems (class 6F), which includes CHP fuelled by biomass sources. The term domestic in this context refers to existing dwellinghouses (terraced/semi-detached and detached) and existing buildings containing one or more flats. These PDR are subject to various limitations as set out in the consultation paper.

While classes 6C and 6F PDR are specific to particular types of flue, the majority of domestic flues are permitted under general PDR, which allow improvements, additions or alterations to the exterior of dwellinghouses (class 2B) and buildings containing flats (class 4A) within a ‘1 metre bubble’. Again, there are limitations.

However, the Cleaner Air for Scotland 2 (CAFS2) strategy has an action point for the Scottish Government to ‘consider with local government what changes are needed to the current PDR for flues for woodburning stoves and biomass boilers’. This relates to the PDR for flues for biomass heating systems (class 6C) and householder PDR in class 2B and class 4A that may grant permission for flues for wood burning stoves.

The consultation paper and draft business and regulatory impact assessment noted a number of issues with trying to control dispersal of pollutants/ nuisance and air quality matters through PDR, including: no effect retrospectively on existing flues; not all flues would necessarily constitute ‘development’ requiring planning permission; the need for a policy framework for considering and determining planning applications; and the resource implications for dealing with the potential increase in planning applications and enforcement implications.

Nevertheless, in the context of concerns about the adequate dispersal of pollutants and the impact of cumulative emissions on air quality, views were sought on the removal of PDR for flues for wood burning stoves and biomass boilers. Specifically, feedback was requested on:

(i) Removing class 6C PDR (flues for biomass heating systems).

(ii) Amending class 2B and class 4A PDR for dwellings to exclude flues for biomass heating systems and wood burning stoves.

(iii) Whether PDR for alteration and replacement of flues should be retained, even if the installation element of the PDR is removed.

Question 8: Do you have any comments on the potential removal of PDR for flues for wood burning stoves (including wood burners and log burners), biomass boilers and biomass heating systems?

Around 55 respondents provided a comment at Question 8.

Reasons for supporting proposals

Support for the removal of PDR for flues for biomass heating and wood burning stoves included a view that this would be consistent with national policy aims around climate impacts and air quality. These respondents recognised concerns around the adequate dispersal of air pollutants and the cumulative impact of emissions from biomass and wood burning, and noted that there is no known safe threshold for fine particulate matter. It was suggested that the removal of PDR for these flues could support improvement in national and local air quality.

It was also suggested that the change could lead to improved installation of suitable flues. This was linked to a view that the ‘1 metre bubble’ for class 2B and 4A PDR can encourage the inappropriate installation of smaller flues to avoid the need for planning permission. It was also suggested that the ‘1 metre bubble’ is not relevant to the mitigation of air quality issues associated with biomass heating systems and wood burning stoves.

In this context, respondents cited specific examples of poorly designed installation of flues as a result of unrestricted and unmonitored development, with this seen as a particular issue in affluent urban areas. There was concern that this kind of development can have an adverse impact on neighbouring properties and the health and amenity of the local area. It was suggested that the removal of PDR for these kinds of development would help to prevent installations in inappropriate locations.

There was also specific support for the assertion in the consultation paper that fine particulate matter emissions from biomass heating and wood burning stoves are an issue outside Air Quality Management Areas (AQMAs). Indeed, it was noted that many AQMAs are designated on the basis of nitrogen dioxide emissions primarily linked to transport rather than biomass heating.

A small number of respondents wished to see all new flues for biomass heating and wood burning stoves require planning permission. This included a suggestion that this change should be part of wider steps to discourage biomass heating, and eventually to eliminate all use of these appliances.

General concerns and issues raised

Respondents also highlighted a range of concerns around the potential for PDR to be removed for flues for biomass heating and wood burning stoves. This included a view that requiring planning permission for these flues would not deliver clear benefits. Some respondents suggested that biomass heating and wood burning stoves can offer significant benefits, including as a means to reduce heating load on the gas and electricity networks, and as part of a low carbon heating system. This included reference to improvements in appliances leading to a significant reduction in emissions of fine particulate matter. It was suggested that the planning system should encourage the replacement of older systems, rather than creating additional barriers to the installation of cleaner appliances. There was also concern that requiring planning permission for biomass heating could encourage households to choose less sustainable options such as oil or LPG, with potential to undermine any positive impact on emissions.

Removal of PDR was also seen as disproportionately impacting rural areas. Respondents noted that biomass forms an established part of heating systems across many rural areas and may still be the best option for some households, for example in rural off gas areas and/or those with a weak electricity network. It was also suggested that the potential cumulative air quality impacts from domestic biomass heating and wood burning stoves is of less concern in rural areas. Respondents also noted that domestic biomass heating and wood burning stoves are also subject to ongoing checks that help to minimise air quality impacts, for example annual safety checks and requirements on the types of fuel used.

In addition to these comments on the role and impact of biomass heating and wood burning stoves, there was a view that planning legislation is not the appropriate means to control emissions from these appliances. It was noted that planning permission is primarily concerned with visual amenity, and respondents highlighted the complexity of technical issues involved in assessing the potential impact of particulate matter and fume dispersal. It was also noted that planning authorities lack baseline air quality evidence against which to assess these impacts, and that factors beyond the scope of PDR – such as appliance specification and quality of fuel – can have a significant impact on emissions.

Some respondents referred to existing legislation and regulation that was seen as being more suited to addressing the air quality concerns identified in the consultation paper. This included specific reference to: public health legislation; the Environment Protection Act; powers to implement Smoke Control Zones; more effective enforcement of existing regulation (including proposals to make persistent offence a civil offence); regulation of appliances to promote the cleanest options; regulation of solid fuels (including reference to the UK Government’s regulation of domestic fuels); regulation of installation, for example through a Competent Person Scheme; ensuring the proper maintenance of servicing of appliances and flues; and consumer education, including potential use of biomass heating in historic buildings.

Concerns were also raised around impacts for planning authorities if the removal of PDR results in an increase in planning applications for biomass heating and wood burning stoves. This was highlighted both in terms of increasing workload for case officers, including concerns that this would require officers to engage with technical information around the design of heating systems, and increased demand on planning enforcement officers. It was also noted that there is little planning policy, guidance or advice to support the assessment of these applications, and that consideration of cumulative impacts would be particularly resource intensive, potentially requiring a register of appliances.

Additions and amendments to proposals

Reflecting some of the issues and concerns noted above, respondents suggested additions or amendments to the proposed removal of PDR including that:

• PDR should still apply for individual properties or clusters of rural properties that are a specified distance from the nearest neighbouring property.
• PDR should be retained for certain standards of biomass systems, with specific criteria added to make clear which systems are not permitted.
• Planning permission should be required for all new flues for biomass heating systems and wood burning stoves.
• References to wood burning stoves should be expanded to include all multi fuel appliances.
• The ‘1 metre bubble’ should be retained.
• Schemes such as the Home Energy Scotland Grant and Loan should be amended to ensure consistent messaging around biomass heating.

Question 9: Noting that current PDR cover the installation, alteration or replacement of flues, should any removal of these PDR be limited to installation of new flues, or also prevent existing flues being altered or replaced under PDR?

Around 90 respondents answered Question 9. A number of these respondents simply stated their support or opposition to preventing alteration or replacement of existing flues under PDR, including those who opposed any removal of PDR. Some also indicated that they did not have a clear view on the matter. The specific considerations highlighted in support of or opposition to removal of PDR for alteration or replacement are summarised below.

Support for preventing alteration or replacement of flues

Support for removal of PDR for the alteration or replacement of flues was most commonly linked to concerns around the potential for these works to have an adverse impact on visual amenity and air quality. Respondents repeated concerns noted at Question 8 around air quality issues associated with fine particulate matter, and suggested that flues can be integral to the efficient operation of biomass heating and wood burning stoves. There was also reference to potential for alteration or replacement of flues to have a visual impact.

Opposition to preventing alteration or replacement of flues

Most of those who commented highlighted concerns around the potential for removal of PDR for the alteration of replacement of flues for biomass heating and wood burning stoves. This included suggestions that alteration or replacement can be essential to the continued operation of flues, for example following storm damage and to ensure that flues continue to work efficiently to minimise pollutants. There was concern that such a change would prevent individuals from continuing to maintain and operate their heating system, and could act as a barrier to the installation of more efficient appliances.

Respondents also highlighted concerns that ‘retrospectively’ removing PDR for existing flues would unfairly penalise households who used existing PDR for the installation. It was noted that schemes such as the Renewable Heat Incentive have incentivised homeowners to install biomass heating systems.

Other concerns related to potential for preventing alteration and replacement to have unintended consequences for visual amenity and heritage, for example if this prevented the repair of a damaged chimney in a conservation area. Some also felt that is difficult to envisage circumstances where a planning authority would refuse permission to repair or replace an existing flue. In this context, there was a view that requiring planning permission for these works would be disproportionate, especially in rural areas. It was also noted that such a change would not be consistent with other PDR, which typically allow for replacement of existing domestic features.

Some respondents repeated concerns noted at Question 8 around the impact of removing PDR on the planning system. This included the additional administrative burden on planning authorities and the technical assessment required if alteration and replacement of flues are made subject to planning permission. It was also suggested that requiring planning permission on the basis of the type of boiler to which a flue is connected will cause confusion.

Some of those who supported the principle of removing PDR for the alteration and replacement of existing flues acknowledged that such a change could be very difficult to manage in practice. This included concerns around potential delays in circumstances where prompt action may be required, for example if alteration or replacement of a flue is required for continued operation of the heating system.

Specific suggestions from respondents

On the basis of the concerns and issues noted above, respondents made a number of specific proposals around PDR for alteration and replacement of flues including that:

• Replacement of a flue should require planning permission, but alteration should be permitted under PDR.
• The alteration or replacement of flues should be subject to other regulation to address potential air quality concerns, such as public health legislation and regulation of wood burning and multi fuel stoves.
• PDR should not apply where the replacement flue is of a greater height or diameter, and/or uses a different means of fixing to the building.
• PDR should only allow alteration or replacement of flues where this would improve the standard of particulate filtration, and/or the replacement flue meets minimum standards.