Issues for Consideration
PD in Areas Designated for Their Natural and Built Heritage Value
21. Many areas are designated for their natural and built heritage qualities, for example Sites of Special Scientific Interest and Conservation Areas. Generally speaking, these are areas where development is very carefully controlled and therefore the granting of PD rights has to be carefully considered.
22. The PD proposals in this paper only concern existing houses and very specific limits are set on the location and scale of the equipment. For example, wind turbine blades of 1.1 metres in length. The question arises, bearing this in mind, whether PD for domestic microgeneration, equipment should be further constrained in areas designated for their landscape or recreational value. This is particularly the case for wind turbines which, due to their operational requirements, have to be located above roofs or on stand-alone masts. The national designations in this context are National Parks and National Scenic Areas; regional and local landscape designations include Areas of Great Landscape Value, regional parks and country parks, and also green belts, though in some cases not all parts of them will be of the highest landscape quality. There is clearly a balance to be struck between the wider environmental benefits of reducing our carbon footprint and of generating energy where it will be consumed, and on the other hand changing the appearance of existing domestic buildings and their grounds in the landscape. Cumulative impact will be a further consideration.
23. In areas designated to protect species and habitats, the PD proposals are only relevant where there are existing houses in, and in some cases adjacent to, the areas in question. For European sites (Special Protection Areas and Special Areas of Conservation), the existing protection provided by Article 3 of the GPDO (under regulations 60 - 63 of the Conservation (Natural Habitats &c) Regulations 1994) will continue and therefore the PD proposals will not have the effect of granting planning permission if a significant effect on the interests of such a site is likely. Similarly, operations potentially affecting a Site of Special Scientific Interest require an application for consent to be made to Scottish Natural Heritage under the Nature Conservation (Scotland) Act 2004. Elsewhere, including National Nature Reserves and local designations, the questions arise of whether domestic scale microgeneration equipment for existing domestic property will compromise the overall integrity of the area; and if there are adverse effects whether they are clearly outweighed by social or economic benefits of national importance?
24. The PD proposals will not override other provisions which are designed to protect the environment. For example, bats and other European Protected Species are protected under the Conservation (Natural Habitats, &c.) Regulations 1994, as amended, and the Controlled Activities Regulations (see below) regarding the water environment.
25. Given the small scale of microgeneration equipment compared to the scale of the protected landscapes and the other controls in place, and that the proposed PD rights only relate to existing property, it may be thought unlikely to have a significant impact on these designated areas even when cumulative effects are taken into account. We are therefore consulting on whether or not there are grounds for further restrictions on PD in these areas.
26. Due to the scale of the equipment vis-a-vis the scale of domestic buildings, uncontrolled installation of the equipment has more potential to have an adverse impact where it is installed on property in areas designated for their built heritage value; conservation areas, places where it would affect the setting of a listed building and in World Heritage Sites. The greatest impact would arise where they were on the main façade of the building facing a highway where they would be visible to the public. Due to their characteristics, even small wind turbines would be highly visible against the scale of the buildings and likely to affect the character of the area. For wind turbines it is therefore proposed that PD rights are not granted in World Heritage Sites and Conservation Areas so that each case can be assessed through a planning application. Listed buildings themselves are protected under separate legislation and it is therefore unnecessary to specifically exclude them from the PD proposals.
27. The planning system is however responsible for controlling the effects of development on the setting of listed buildings. Of the microgeneration equipment considered in this paper, and bearing in mind that there will be no PD in Conservation Areas, wind turbines are the technology most likely to be sited so as to affect the setting of a listed building. The general distance criteria for wind turbines suggested below would safeguard the setting of nearby listed buildings, but not the listed building within whose curtilage the turbine was sited. It is therefore proposed not to grant PD rights for wind turbines within the curtilage of listed buildings.
Question 1 - Are there sufficient grounds to further constrain the PD proposals for domestic microgeneration equipment, especially wind turbines, in areas designated for their landscape quality? Please provide justification or evidence for your answer.
Question 2 - Are there sufficient grounds to further constrain the PD proposals for domestic microgeneration equipment in areas designated for the protection of flora and fauna? Please provide justification or evidence for your answer.
Question 3 - Should PD rights for microgeneration equipment, except wind turbines, be granted in areas designated for their built heritage value providing that the principle elevation fronting a highway is unaffected?.
Question 4 - Are the separate controls for listed buildings sufficient to control the installation of microgeneration equipment? If not, what specific provisions are necessary?
Question 5 - Will the setting of listed buildings be adequately protected by not granting PD rights to wind turbines and solar arrays within their curtilage?
General conditions which rely on interpretation
28. We have considered whether all PD rights for microgeneration equipment should be subject to a condition on safeguarding visual impact and amenity generally. For example, 'the equipment shall be sited to minimise its impact on the amenity of the area'. The SE research said that changes to PD rights should simplify matters as far as possible to reduce the uncertainties associated with interpretation of criteria and terminology. In the case of microgeneration equipment it recommended that there should be a general condition that the development must comply with a design code. This would make the question of whether a proposal was or was not PD a matter of judgement, initially for the householder, then the installer and the planning authority and potentially for neighbours. We have therefore sought to set PD rights which avoid or minimise visual impacts and effects on amenity. This approach would also have the benefit of allowing guidance, including web based systems, to be clearer, thus reducing the need for developers to check with planning authorities. We do not therefore propose to use general conditions to safeguard potential adverse impacts.
Question 6 - Do you think that general conditions on amenity and other impacts could be applied to the PD rights for microgeneration equipment?
Solar Water Heating and Photo-Voltaics
29. There are 2 types of solar panel. Solar water heating panels use the sun's rays to heat water for washing etc or for space heating. Photo-voltaic panels use the sun's rays to generate electricity. Both systems share many characteristics that could have potential impacts and therefore the same approach is proposed for both. The panels come in a variety of sizes, frequently in the range 1 - 2 metres by 0.5 - 1.0 metres and about 120 mm thick, though they can be larger and several can be mounted together. They can have matt surfaces though shiny surfaces are usual, making them highly reflective. They can be mounted on roofs, walls or as free-standing arrays. They can also be moveable to track the sun but we propose to follow the research recommendation and grant PD rights only to fixed arrays. The issues for PD are primarily about the impact of the panels on amenity and the wider visual environment where cumulative impacts may arise.
Question 7 - Do you agree that the same PD rights should apply to solar water heating and photo-voltaic panels? If not, please say why.
30. The Scottish Executive research recommended that limits should be set in terms of protrusion (150 mm) above the plane of the roof or wall but no limit on surface coverage, subject to compliance with design guidance. With no limit on coverage it would be possible to completely cover a roof with what would look like a new roof of a different colour and texture. This could substantially alter the character of the whole building and the integrity of the design, with an adverse impact on visual amenity. Making it subject to compliance with a design guide would not provide clear PD rights and could make installations open to dispute and possibly enforcement action. The research for the other administrations recommended 60% coverage. In setting the PD limits the issues are projection above the plane and highest point of the roof, position, coverage and cumulative impact. Re-roofing a house in a way which materially affects its appearance would require planning permission and it seems equitable that complete coverage of solar panels should also, with PD limited to a proportion of the area such that the overall integrity of the roof shape and its reflective qualities are retained.
Question 8 - Do you consider that the proposed PD limits for solar panels on domestic buildings of 150 mm above the plane of a pitched roof or a wall, not higher than the highest point of a pitched roof and covering up to 60% of the roof or wall area are appropriate? If not, what should the limits be and why?
31. The installation of solar panels on the walls of tenements and other buildings containing flats raises additional issues compared to installations on houses. A multitude of different installations on the same façade would be likely to affect the amenity of other residents and destroy the unity of the design. There would be no neighbour notification and other residents in the same building would not be able to object.
Question 9 - Do you agree that there should be no PD for solar panels on the walls of buildings containing flats?
32. Different considerations apply on flat roofs where the panels could generally be expected to have less visual impact but where they need to be angled towards the sun, not laid flat, if they are to work most efficiently. The research recommended that further work be undertaken but nevertheless proposed a 'pragmatic' PD limit of 3m above the plane of the flat roof, or up to the threshold of visibility from the nearest public way. The 3 metre limit is considerable, and could be the equivalent of installing a pitched roof, with consequences for neighbours and affecting amenity generally. The visibility criteria is imprecise and could lead to enforcement problems. Having considered the issues, we propose instead measurable criteria based on minimising the potential visual impacts commensurate with the efficient operation of the panels.
33. As a basis for consultation, it is suggested that PD for solar panels on flat roofs should be subject to them being at least 1 metre from the edge of the roof, allowing them to be angled to the sun provided they don't exceed 1 metre in height so as to minimise visual impacts on neighbouring property, and the same 60% coverage as for pitched roofs.
Question 10 - For flat roofs do you agree or do you have alternatives to the suggestion that PD rights for panels should be set so that they are no closer than 1 metre to the edge of the roof, with the highest point of the panel not more than 1 metre above the plane of the roof and covering up to 60% of its area? If not, please suggest alternative provisions .
34. Solar panels can also be installed as free-standing features in gardens or elsewhere within the property boundary. The SE research recommended that these items were adequately covered in their general recommendations on residential PD and specific provisions were not needed under the microgeneration heading. In advance of those provisions it is proposed to consult on the same basis as the other administrations. That is, PD rights provided they are no higher than 4 metres, at least 5 metres from the boundary, with an overall area of 9 sq metres. and not within the curtilage of a listed building. The existing PD rights for extending dwellinghouses or adding buildings or oil tanks within the curtilage says that within 20 metres of a road they cannot be nearer to the road than the house itself. For some houses however the most efficient location for free-standing panels will be at the front of the house. We therefore do not propose to apply this rule to solar panels fixed to walls nor for panels installed within the curtilage of a dwellinghouse, where the proposal is to rely on the 5 metres distance
Question 11 - For free-standing arrays, should PD rights be set at less than
4 metres in height, at least 5 metres from the property boundary and with a maximum area of 9 sq metres?
Wind turbines
35. Small domestic scale wind turbines of about 2 metres in diameter can either be fixed on a pole attached to the building or on a free-standing mast. They differ in character from most existing domestic permitted developments, for example, satellite dishes or garden fences, because of their moving mechanical parts and potential for these to deteriorate over time due to wear and tear. There are concerns that they can generate a degree of noise, vibration and light flicker. Their impacts depend on their siting, the number of people in the area, the surrounding buildings/environments and ambient noise levels.
36. The research recommended that one way to deal with these impacts was by setting technical thresholds for noise when measured in nearby buildings, and that these would also protect amenity externally. The research for the other administrations recommended technical thresholds internally and externally and a universal condition requiring a turbine to 'minimise its effects on appearance and amenity'. This combination of complex thresholds and qualitative judgement would not however align with the principle of keeping PD rights straightforward so that it can be easily understood, including by the public. It is considered that this approach to PD would be unworkable in practice, as it would depend on noise measurements being taken. A specific difficulty would be its inability to control the cumulative effect of several turbines on noise levels in residential areas because PD would grant every house the right to a turbine. The noise from one turbine might be acceptable but not in combination with others. Vibrations can also travel through the structure of a building and be felt by neighbours.
37. The research also considered a simple distance criterion between the turbine and surrounding property, but thought that defining it in a reasonable way would result in complexity and therefore didn't suggest what it should be. In the longer term an alternative approach based on accreditation schemes for the equipment and installers may provide a basis for PD but it is too early to offer this option in this consultation paper.
38. We are mindful of the need to proceed with caution lest serious and irreversible adverse effects be imposed on residential areas. There is a need to gather more information about the effects of small scale wind turbines, including the nature of the noise and visual impacts. Experience and evidence will provide a basis for reconsidering the PD rights. Technical solutions may also emerge. In addition, while the performance of the equipment is a matter for those householders choosing to install it and is not a planning issue, a cautious approach is leant support by some recent research which indicates that the performance of micro-turbines is highly sensitive to a range of factors and in some locations, particularly parts of urban areas they perform poorly. (Micro-wind Turbines in Urban Environments - An assessment. Building Research Establishment Trust. 2007)
39. In the light of this and as a basis for seeking comments, we are suggesting that PD for building mounted or free-standing turbines applies to houses which are well separated from neighbours who might be adversely affected and limited to one turbine perhouse, including the curtilage. A simple distance criteria of at least 100 metres to the nearest residential property is put forward BUT we are very keen to hear of suggestions for an alternative distance, greater or lesser, and supporting evidence. It is appreciated that a distance criterion will mean that for most built-up areas and for flats a planning application will be required.
40. For free-standing turbines the SE research recommended a maximum rotor diameter of 3.5 metres and a maximum hub height of 10 metres. In view of the cautious approach we have set out above we are proposing to limit the rotor size to the same 2.2 metres as for building mounted turbines. For safety reasons it is proposed, as recommended by the research, that a mast should be sited so that in the event of it structural failure, it would not reach to the property boundary.
Question 12 - Do you agree with the principle of applying a distance criteria for wind turbines to deal with the potentially adverse impacts?
Question 13 - If you agree with question 11 do you think it should be set at 100metres to the nearest domestic building or can you suggest and give evidence for another figure?
41. Criteria on the height, size and location of turbines are proposed to limit their impact on visual amenity and neighbours, including the risk of them blowing down or causing structural damage. The criteria have been set so that they can still apply if the distance criteria is reduced or replaced with an approach based on accreditation.
Question 14 - Do you agree with the following limits on the scale of building mounted wind turbines? (each turbine blade up to 1.1 metres in length, up to
3 metres above the highest part of the roof and one per building)
Question 15 - Do you agree with the following limits on the scale of
free-standing turbines? (each blade up to 1.1 metres in length and a maximum height including tower of 11.1 metres to the tip of the turbine blade, located at least 12 m from the boundary of the property and one per curtilage.)
42. For free standing turbines the masts may also have a visual impact. Planning Advice Note 45 (Annex) says that the colour should be appropriate to the setting and designed to minimise visual impact and reflection of light. It advises that the colour should minimise contrast with the predominant background e.g. if the main background is vegetation, a green/brown mast may be suitable. Clearly, the predominant background depends on the siting of the turbine and a specific 'one colour fits all' criteria for PD rights cannot be specified. While we have explained above why a general condition to deal with potential impacts is not thought to be necessary for the microgeneration equipment itself, a mast up to 10 metres high could have more of a visual impact than the turbine itself. One possibility would be to make PD subject to a condition such as 'provided the colour of the mast minimises its visual impact'. While this would be open to interpretation, it would provide a measure of control and a basis for enforcement. We are therefore seeking comments.
Question 16 - Should the visual impact of free-standing turbine masts be controlled by a condition on the PD rights such as 'provided the colour of the mast minimises its visual impact' or can you suggest an alternative formula?
Biomass
43. Biomass stoves and boilers burn wood, usually in the form of pellets or chips. They are deemed to be carbon neutral because the carbon emitted during burning is the same as that absorbed during growth. There are concerns that the very fine particles they emit may make it more difficult to achieve air quality objectives in urban areas. Research is underway to provide advice on the potential cumulative impacts of such emissions in urban smoke control areas compared to rural sites. If necessary the results can be taken into account in the final Order.
44. The planning issues concern flues and the storage/delivery of the wood. The SE research recommended that these items were adequately covered in their general recommendations on residential PD and specific provisions were not needed under the microgeneration heading. In advance of those provisions it is proposed that there are PD rights for the flues but the wood stores are treated under the existing PD provisions. The boilers and stoves would be internal and therefore not a matter for planning permission and hence for PD.
Question 17 - Do you agree that flues for biomass stoves should be permitted development up to 1 metre above the highest point of the roof but not on the principal elevation in conservation areas.
Question 18 - Do you agree that wood stores should be treated in the same way as any other residential alterations or ancillary development, so that depending on circumstances they may be PD.
Heat Pumps
45. Heat pumps collect low level heat from outside a building (from the ground, water or the air) and release it at a higher temperature inside the building. Ground and water source heat pumps require a closed loop of pipe in a large trench (typically 1 - 2 metres deep and many metres long) or submerged in water, or alternatively a vertical borehole where the pipe may be open and the water returned to the environment locally. For ground and water source heat pumps the equipment could be installed within the house so planning permission would only be needed for any trench or borehole, but air source equipment would normally be installed outside.
46. Ground source heat pumps which need trenches or boreholes could potentially affect archaeological sites. For those which are Scheduled Ancient Monuments the separate requirement to get Consent will remain and planning authorities will continue to have the option of using Article 4 Directions to control PD rights for them and for other areas provided there was sufficient justification. Advice on this is given in PAN 42 Archaeology. It is also the case that the size of garden required to dig a large trench within the curtilage of a dwelling house or flat will act as a constraint on the exercise of PD rights. In view of these factors it is not proposed to restrict PD rights generally for archaeological reasons.
47. Water source heat pumps could require a separate authorisation under the Controlled Activities Regulations to control effects on the water environment. Further information can be found at http://www.sepa.org.uk/wfd/index.htm
48. Air source heat pumps draw their air from just outside the building, are similar in appearance to large air conditioning units and are potentially a source of noise because of their fan(s) and compressor. Like wind turbines, there is a risk of cumulative impacts and changing performance over time, so there is the same need for a precautionary approach and the gathering of evidence to allow reconsideration. It is therefore proposed to consult on the basis of a 100 metre distance to the nearest residential building BUT to seek suggestions for alternative distances and the evidence to justify them. A distance criteria would have the effect of not granting PD rights to flats.
Question 19 - Do you agree with the proposal that ground and water source heat pumps, including the collectors and associated trenches or boreholes should be permitted development?
Question 20 - Do you agree that air source heat pumps should be permitted development with the proviso that they should not be located within 100 metres of a separate house or flat?
Question 21 - If you think the distance criteria should be different, please say what you suggest and give the evidence to justify it.
Combined Heat and Power
49. A combined heat and power device simultaneously generates electricity and heat for water and space heating. By recovering the heat from the power generation process the devices are highly efficient and in a domestic situation avoid the electrical losses over transmission lines. Units are available as replacements for domestic boilers. Being internal, they are not expected to give rise to planning issues unless they are biomass units, in which case the considerations described above would apply.
Question 22 - Do you agree that there are no PD issues for domestic combined heat and power devices except for flues, in which case the PD limit should be 1 metre above the highest point of the roof, and additionally in conservation areas or world heritage sites not on the principal elevation and visible from a road?
Hydro-electricity
50. Hydro schemes generate electricity by using water to turn a turbine connected to a generator. There are likely to be few opportunities for such schemes in domestic circumstances and the planning issues are likely to be specific to the land and property in question. A building to house the turbine might be needed and associated engineering and pipe work, some of which might already be PD. The Scottish Executive research recommended PD for projects of up to 50kW capacity if they used an 'existing engineered channel' but the justification for this and the implications are unclear. The research for the other administrations suggested that there was little scope to provide additional PD rights that would encourage the take up of hydro schemes. In the light of this uncertainty we are proceeding cautiously and consulting on the basis that hydro-electricity schemes should not be PD, BUT we are inviting views on the circumstances in which consideration should be given to making it PD.
Question 23 - Do you agree that there should be no additional PD rights for domestic scale hydro-electric generating schemes? If 'no' please see the next question:
Question 24 - If you have answered 'no' to the previous question please say in what circumstances and within what criteria you think that domestic scale hydro schemes should be permitted development?
PD Rights in combination - possible cumulative effects
51. The PD proposals above have been set on the basis of each individual technology. The question arises as to whether there should be an overall limit to the installation of microgeneration equipment under PD Rights. The purpose would be to control any cumulative impacts. The SE research recommended a limit of 50kW (or 45kW thermal) within the curtilage of a single house.
Question 25 - Do you think that an overall limit should be set for the combined microgeneration capacity which is permitted development, and if so what should it be? Please justify your answer.
Conclusion
52. Comments on the proposals for extending permitted development rights to domestic microgeneration equipment are invited. You may use the form at Annex 5. Comments need not be restricted to the specific questions above. Following consideration of the responses a final amendment Order will be prepared and laid in Parliament. It is intended that the amendment Order will be supported by guidance.