Householder permitted development rights: guidance - updated 2021

6. Installing Microgeneration Equipment

6.1 The relevant permitted development rights for the main types of microgeneration equipment are explained within this section.

6.2 This guidance replaces:

• Planning Circular 2/2009:The Town and Country Planning (General Permitted Development) (Domestic Microgeneration) (Scotland) Amendment Order 2009; and
• Planning Circular 2/2010: The Town and Country Planning (General Permitted Development) (Domestic Microgeneration) (Scotland) Amendment Order 2010.

6.3 Classes 6A and 6B have been removed since Classes 2B and 4A now apply for installation of solar PV and solar thermal equipment that would be attached to a wall or roof of a dwellinghouse or a flat. Class 3B permits the installation of free-standing solar PV and solar thermal equipment for a dwellinghouse.

6.4 All the limitations and restrictions within a class will need to be complied with. Where a proposal would involve a combination of classes, then the development would have to comply with the limitations and restrictions of all the relevant classes to be permitted development.

6.5 There are many types of microgeneration equipment. The following 6 classes, along with Classes 2B, 3B and 4A, cover the installation of the most common types of domestic microgeneration, ensuring appropriate controls are applied to the specific type of development.

Flues for Biomass Heating System

Class 6C - The installation, alteration or replacement of a flue, forming part of a biomass heating system, on a dwellinghouse or building containing a flat.

Flues for Combined Heat and Power System

Class 6F - The installation, alteration or replacement of a flue, forming part of a combined heat and power system, on a dwellinghouse or building containing a flat.

Ground and Water Source Heat Pumps

Class 6D - The installation, alteration or replacement of a ground source heat pump within the curtilage of a dwellinghouse or building containing a flat.

Class 6E - The installation, alteration or replacement of a water source heat pump within the curtilage of a dwellinghouse or building containing a flat.

Free-standing Wind Turbines and Air Source Heat Pumps

Class 6G - The installation, alteration or replacement of a free-standing wind turbine within the curtilage of a dwelling.

Class 6H - The installation, alteration or replacement of an air source heat pump on a dwelling or within the curtilage of a dwelling.

Flues for Biomass Heating System

6.6 Permitted development rights allow the installation, alteration or replacement of a flue, forming part of a biomass heating system, on a dwellinghouse or building containing a flat.

6.7 If the flue exceeds any of the following limitations then an application for planning permission is required.

6.8 A planning permission is needed for flues for dwellinghouses or flats within an Air Quality Management Area. Air Quality Management Area has the meaning given in section 83(1) of the Environment Act 1995.

6.9 Planning permission is required if the flue is to be attached to the principal elevation of a dwellinghouse or flat within a conservation area or World Heritage Site. The identification of the principal elevation is discussed in paragraphs 3.2 - 3.6.

Legislation

Class 6C.-

(1) The installation, alteration or replacement of a flue, forming part of a biomass heating system, on a dwellinghouse or building containing a flat.

(2) Development is not permitted by this class if-

(a) the height of the flue would protrude more than one metre above the highest part of the roof (excluding any chimney) on which the flue is fixed;

(b) in the case of land within a conservation area or a World Heritage Site, the flue would be installed on the principal elevation of the dwellinghouse or building containing a flat; or

(c) the flue would be within an Air Quality Management Area.

Flues for Combined Heat and Power System

6.10 Flues for Combined Heat and Power System permitted development rights allow the installation, alteration or replacement of a flue for combined heat and power system, on a dwellinghouse or building containing a flat.

6.11 If the flue exceeds any of the following limitations then an application for planning permission is required.

6.12 A planning permission is needed for flues for dwellinghouses or flats within an Air Quality Management Area. Air Quality Management Area has the meaning given in section 83(1) of the Environment Act 1995.

6.13 Planning permission is required if the flue is to be attached to the principal elevation of a dwellinghouse or flat within a conservation area or World Heritage Site. The identification of the principal elevation is discussed in paragraphs 3.2 - 3.6.

Legislation

Class 6F.-

(1) The installation, alteration or replacement of a flue, forming part of a combined heat and power system, on a dwellinghouse or building containing a flat.

(2) Development is not permitted by this class if-

(a) the height of the flue would protrude more than 1 metre above the highest part of the roof (excluding any chimney) on which the flue is fixed;

(b) in the case of land within a conservation area or World Heritage Site, the flue would be installed on the principal elevation of the dwellinghouse, or building containing a flat; or

(c) in the case of a combined heat and power system fuelled by biomass sources, the flue would be within an Air Quality Management Area.

Ground and Water Source Heat Pumps

6.14 Permitted development rights allow the installation, alteration or replacement of a Ground Source Heat pump or Water Source Heat pump within the curtilage of a dwellinghouse or a building containing a flat.

6.15 There are no restrictions on those permitted development rights.

Legislation

Class 6D.- The installation, alteration or replacement of a ground source heat pump within the curtilage of a dwellinghouse or building containing a flat.

Class 6E.- The installation, alteration or replacement of a water source heat pump within the curtilage of a dwellinghouse or building containing a flat.

Free-standing Wind Turbines and Air Source Heat Pumps

6.16 Class 6G permits the installation, alteration or replacement of a free-standing micro wind turbine (MWT) within the curtilage of a dwelling, and Class 6H permits the installation, alteration or replacement of an air source heat pump (ASHP) on a dwelling or within the curtilage of a dwelling. In both cases, this means a dwellinghouse, a building containing one or more flats or a flat contained within such a building.

6.17 The aim of these provisions is to manage adverse impacts on neighbours and amenity generally (e.g. noise and visual impact) set against the wider environmental, social and economic benefits of microgeneration. They do this by means of limitations and conditions.

Limitations

6.18 For MWT, the limitations are that:

• the installation of a MWT must be not less than 100 metres from the curtilage of another dwelling
• development is not permitted if it would result in more than one MWT within the curtilage of a dwelling
• development is not permitted within a conservation area, a World Heritage Site, a site of special scientific interest, a site of archaeological interest, or within the curtilage of a listed building

6.19

For ASHP, the limitations are that:

• an ASHP must comply with MCS Planning Standards or equivalent standards
• development is not permitted if it would result in more than one ASHP on the same building or within the curtilage of a building
• development is not permitted if it would result in the protrusion of an ASHP by more than 1 metre from the outer surface of an external wall, roof plane, roof ridge or chimney of a dwelling
• development is not permitted on a dwelling within a Conservation Area unless the ASHP is located at ground floor level and on the rear elevation of the dwelling
• development is not permitted within the curtilage of a building if any part of the installation would be forward of a wall forming part of the principal or side elevation of a building where that elevation fronts a road, or if any resulting ASHP structure would exceed 3 metres in height
• development is not permitted in a World Heritage Site or within the curtilage of a listed building

Conditions

6.20 One ASHP is permitted on a building or within the curtilage of a building. A building in this context includes a terraced house, semidetached house or a block of flats.

6.21 This provides potential opportunities for one MWT and one ASHP within the same curtilage, but not more than one of each using permitted development rights. For example, this would allow for a wind turbine to provide the electricity to power a heat pump.

6.22 The conditions require that MWT/ASHP microgeneration equipment only be used for domestic microgeneration purposes, and that an ASHP only be used for the purpose of providing domestic heating or hot water. MWT and ASHP equipment must be removed as soon as reasonably practicable where it is no longer needed for, or capable of, being used for these purposes.

6.23 MWT installations are subject to prior notification and/or prior approval procedure, and are to be sited to minimise effects on the amenity of the area so far as reasonably practicable. ASHP are not subject to prior notification and/or approval but must comply with MCS Planning Standards or equivalent standards.

The prior notification and prior approval condition

6.24 The purpose of prior approval for micro-wind turbines is to allow the planning authority to consider any matter it may deem relevant in respect of the design and size of the proposed wind turbine. However, it is intended principally to provide a safeguard for aerodromes, radar technical sites, radio and television networks and National Scenic Areas (NSAs) that could be affected by wind turbine installations.

6.25 The consultation process which the planning authority should undertake is the same as that for a planning application.

6.26 Aerodromes and radar technical sites are safeguarded by the Town and Country Planning (Safeguarded Aerodromes, Technical Sites and Military Explosive Storage Areas) (Scotland) Direction 2003. Circular 2/2003^[1] contains the Direction and explains what consultation is required by planning authorities when a planning application for development is made which could affect such a site. Certain military technical sites owned by the Secretary of State for Defence are also safeguarded under a similar process.

6.27 The operators of safeguarded aerodromes, technical sites and military explosives storage areas are also likely to need to examine specific proposals with particular reference to matters such as siting, design (including height), external appearance and type of construction when planning authorities consider applications for approval required by conditions attached to a grant of planning permission in principle. Although these are not applications for planning permission, and are therefore not covered by the Direction, Circular 2/2003 explains that planning authorities should as a matter of good practice consult the relevant consultees when they receive such applications and allow the consultees sufficient time to consider the implications for their operations before taking decisions on them.

6.28 It is considered therefore that as a conclusion of that good practice the same consultation procedure should apply where the planning authority's prior approval of a micro-wind turbine installation is sought.

6.29 Any response from the aviation safeguarding or other consultee to the planning authority would allow the authority to: issue their approval; issue it subject to conditions, or; refuse the application for approval. Where conditions are attached to an approval or the authority decides to refuse the application for approval, the developer can challenge the decision.

6.30 In considering a prior notification and/or application for prior approval, authorities must also have regard to the requirements of the EIA regulations. Further guidance on EIA and permitted development is contained in Circular 3/2011 The Town and Country Planning (Environmental Impact Assessment) (Scotland) Regulations 2011^[2].

Consultation - Further guidance

6.31 Additional guidance on aerodrome and technical sites safeguarding from obstacles including wind turbines is provided by the Civil Aviation Authority in CAP 168: Licensing of Aerodromes^[3], CAP 670: ATS Safety Requirements^[4], CAP 738 - Safeguarding of Aerodromes^[5] and CAP 764 - CAA Policy and Guidelines on Wind Turbines^[6].

6.32 For terrestrial radio and television networks the planning authority may consider it necessary to consult with the electronic communications provider or OFCOM to safeguard signal broadcasts from main sites or from relay sites typical of rural settings. OFCOM has provided guidance on the impact of tall structures on broadcast and other wireless services^[7].

6.33 In relation to NSAs, the same prior approval process consultations may be conducted with Scottish Natural Heritage. It is good practice to follow guidance in Circular 9/1987 - Development Control in National Scenic Areas, which requires notification of applications to SNH for all buildings or structures over 12 metres high (including agricultural and forestry developments). For micro-wind turbines, SNH regards 12 metres as being to the blade tip height. Further information is contained in SNH's Micro Renewables and the Natural Heritage Guidance Note^[8].

6.34 It would also be open to the planning authority and prospective developer to negotiate away any issues of concern, including submitting revised proposals as opposed to appeals or local reviews being pursued.

General amenity condition

6.35 When MWT equipment is installed on domestic properties under permitted development rights, consideration should be given to the siting and layout of the equipment in relation to the design of the building and its visual appearance; to those in the neighbouring area to which the equipment will be visible; as well as to the optimal orientation for energy purposes.

Purpose condition

6.36 The Purpose condition is intended to guide developers towards installations that are fit for purpose and scalable to domestic situations. Accredited installers will usually provide that advice. The Energy Act 2004 defines "microgeneration" as the use for the generation of electricity or the production of heat of any plant where its capacity is:

(a) in relation to the generation of electricity, 50 kilowatts;

(b) in relation to the production of heat, 45 kilowatts thermal.

6.37 However there is no threshold between domestic and non-domestic generation. Indicative guidance may be provided by suppliers of the products. Non-domestic scale microgeneration equipment will generally require planning permission meantime.

Removal condition

6.38 In instances where existing MWT or ASHP equipment is no longer intended to be used, for example if other technologies are installed, or the equipment becomes incapable of being used, for example through breakdown that cannot be or is not repaired, the condition requires that it must be removed as soon as reasonably practicable. The removal condition is otherwise self-explanatory.

Inability to comply with conditions and limitations

6.39 Where a prospective developer is unable to comply with the conditions and limitations above, then a full application for planning permission would be required.

Further advice

6.40 Further advice on siting and design can be found in the Scottish Government's guidance "Planning for Micro Renewables", which is available on-line at www.scotland.gov.uk/ Resource/Doc/150324/0040009.pdf

6.41 It is a matter for the planning authority to consider enforcement action where they consider that microgeneration equipment does not meet the limitations or conditions.

6.42 The downloadable prior notification forms on the e-planning website have been updated. Councils should consider adopting these updated forms to ease the provisions for householders.

Legislation

Class 6G.-

(1) The installation, alteration or replacement of a free-standing wind turbine within the curtilage of adwelling.

(2) Development is not permitted by this class —

(a) if it would result in the presence within the curtilage of a dwelling of more than one free-standing wind turbine; or

(b) the wind turbine would be situated less than 100 metres from the curtilage of another dwelling.

(3) Development is not permitted by this class in the case of land within—

(a) a conservation area;

(b) a World Heritage Site;

(c) a site of special scientific interest; or

(d) a site of archaeological interest.

(4) Development is not permitted by this class if the wind turbine would be within the curtilage of a listed building.

(5) Development is permitted by this class subject to the following conditions—

(a) the developer must before beginning the development apply to the planning authority for—

(i) the approval of the authority in respect of the design and size of the proposed wind turbine; and

(ii) a determination as to whether the prior approval of the authority will be required in respect of the siting and external appearance of the proposed wind turbine;

(b) the application is to be accompanied by—

(i) a written description of the proposed development, including details of the design and size of the proposed wind turbine; and

(ii) a plan indicating the site;

(c) the development is not to be commenced before—

(i) the applicant has received written approval from the planning authority in respect of the size and design of the wind turbine; and

(ii) the occurrence of one of the following—

(aa) the receipt by the applicant from the planning authority of a written notice of their determination that prior approval in respect of the siting and external appearance of the proposed wind turbine is not required;

(bb) the expiry of a period of 28 days following the date on which the application was received by the planning authority without the planning authority giving notice of their determination that such approval is required; or

(cc) where the planning authority gives the applicant notice within a period of 28 days following the date of receiving the application of their determination that such prior approval is required, the giving of such approval;

(d) the development must, except to the extent that the planning authority otherwise agree in writing, be carried out—

(i) to the extent to which prior approval is required, in accordance with the details approved;

(ii) to the extent to which prior approval is not required, in accordance with the details submitted with the application;

(e) the development is to be carried out within a period of three years from the date on which all approvals required in accordance with this paragraph have been given.

(6) Development is permitted by this class subject to the conditions that a free-standing wind turbine—

(a) must, so far as reasonably practicable, be sited so as to minimise its effect on the amenity of the area; and

(b) is used only for the purposes of domestic microgeneration; and

(c) that is no longer needed for or capable of domestic microgeneration must be removed as soon as reasonably practicable.

Class 6H.-

(1) The installation, alteration or replacement of an air source heat pump on a dwelling or within the curtilage of a dwelling.

(2) Development is not permitted by this class—

(a) if it would result in the presence on the same building or within the curtilage of a building of more than one air source heat pump;

(b) in the case of an installation, alteration or replacement of an air source heat pump on a dwelling if—

(i) any part of the development would protrude more than 1 metre from the outer surface of an external wall, roof plane, roof ridge or chimney of the dwelling; or

(ii) the air source heat pump would be within a conservation area, unless the air source heat pump would be—

(aa) at ground floor level; and

(bb) on the rear elevation;

(c) in the case of the installation, alteration or replacement of an air source heat pump within the curtilage of a building if—

(i) any part of the development would be forward of a wall forming part of the principal elevation or side elevation where that elevation fronts a road; or

(ii) any resulting structure would exceed 3 metres in height; or

(d) the air source heat pump would be within—

(i) a World Heritage Site; or

(ii) the curtilage of a listed building.

(3) Development is permitted by this class subject to the following conditions—

(a) the air source heat pump must be used only for the purpose of providing domestic heating or hot water;

(b) where the air source heat pump is no longer needed for, or capable of, providing domestic heating or hot water it must be removed as soon as reasonably practicable;

(c) the air source heat pump must comply with MCS Planning Standards or equivalent standards.