Permitted Development Rights review - phase 3: consultation

3. Non-Domestic Renewables

3.1 Non-Domestic Solar Panels

Current PDR for non-domestic solar

3.1.1 Class 6J of the GPDO allows the installation, alteration or replacement of solar panels (or solar thermal equipment) on any non-domestic building. Panels installed under these PDR must be mounted on the building itself and there are specific restrictions regarding the placement of the panels depending on whether they are mounted on a pitched or a flat roof or on external walls. Specifically, development is not permitted under this class if:

• In the case of equipment installed on a pitched roof:
  • any part of the equipment would protrude more than 200mm beyond the roof plane.
  • any part of the equipment would project higher than the roof ridge.
  • Any part of the equipment would protrude outwith any of the edges of the roof.
• In the case of equipment installed on a flat roof:
  • the flat roof does not have a parapet wall.
  • the equipment would exceed the height of the parapet wall, or any part of the equipment would protrude outwith the edges of the roof.
• In the case of wall-mounted equipment:
  • any part of the equipment would protrude 200mm beyond the outer surface of the wall.
  • any part of the equipment would extend beyond the curtilage of the building.
  • Any part of the equipment would be situated within 200mm of any edge of the wall.

3.1.2 Additional restrictions apply to any installation under class 6J, whether on a wall or a roof. The PDR do not apply if installed on buildings in certain designated areas, namely: sites of archaeological interest; National Scenic Areas; historic gardens and designed landscapes; conservation areas, National Parks and within the curtilage of a listed building. Class 6J is also restricted within 3km of an aerodrome or technical site associated with civilian and military air traffic services. This 3km restriction also applies to solar canopies permitted under class 9M: this consultation also proposes to amend those PDR (see Question 11 and section 3.2).

3.1.3 The final restriction relates to the total energy output of equipment installed on a building. This is limited to 50 kW in relation to electricity generation, or 45 kW thermal if used to produce heat. There are currently no specific PDR for free-standing solar panels within the curtilage of non-domestic buildings.

Context for change: non-domestic solar

3.1.4 The current restriction on energy output limits the amount of energy that can be produced and does not necessarily reflect the energy requirements of any business occupying the building. It also fails to maximise potential for energy generation utilising available roof and wall space – particularly on larger premises. We are therefore minded to remove this output limit.

3.1.5 To give businesses greater flexibility to install small-scale solar equipment other than attached to buildings, we are also considering the introduction of a new PDR for free-standing solar panels within the curtilage of non-domestic buildings. This would be subject to restrictions on the maximum size of installations allowed, to avoid this proposed PDR being used to develop solar farms.

3.1.6 We are also considering the potential to amend the 3km exclusion zone around airports and technical sites associated with civilian and military air traffic services – with regard to PDR for both non-domestic buildings (class 6J) and solar canopies in parking areas (class 9M). The importance of aviation safety and the role that safeguarding plays in ensuring this is recognised, however, we note that large-scale solar installations are planned or have been developed close to airports, including by airport operators themselves. In this context, we are interested in whether there may be some scope to allow solar panels on non-domestic buildings closer to airports (and the abovementioned technical sites) under PDR. This could potentially be achieved by reducing the size of the 3km exclusion zone, allowing limited installations and/or allowing installations only on certain elevations.

Proposals: non-domestic solar

3.1.7 In light of the considerations above, we propose to amend class 6J PDR for non-domestic solar panels by:

• Removing the output restrictions of 50Kw and 45Kw respectively
• Removing the requirement for wall mounted panels to be not less than 200mm from the edge of the wall, allowing installations to extend to the edge and to 'wrap around' corners.
• Retaining the 200mm limit on protrusion from wall or pitched roof and allowing 500mm protrusion from surface of flat roof (in line with proposal at section 2.1).
• Enabling solar panels to be attached to non-domestic buildings which are located in conservation areas – subject to conditions that they are not permitted on a principal elevation or side elevation fronting a road or within the curtilage of a listed building.
• Stipulating that solar panels must be removed as soon as is practical should they become inoperative, or are no longer in use.

3.1.8 Additionally, we would welcome respondents' views on the potential to:

• Remove or reduce the current 3km exclusion zone around airports and aviation or defence installations to 2km; or
• Retain the 3km distance but allow limited installation of solar panels within that area in certain circumstances.

3.1.9 We also propose to introduce a new PDR for free-standing solar panels within the curtilage of non-domestic buildings. It is proposed that such a PDR would be subject to conditions and limitations specifying that:

• The surface area of the panels may not exceed 12 square metres.
• The installation must be wholly within the curtilage of the non-domestic building the solar panels provide power or heat to.
• No more than one installation within any particular curtilage.
• The PDR does not apply in national scenic areas, national parks or within the curtilage of a listed building.
• If the building is located in a conservation area, the PDR only permits installations in the rear curtilage.
• Equipment is to be removed if inoperable or no longer in use.

Question 10: Do you agree with the proposed amendments to class 6J PDR for solar panels attached to non-domestic buildings?

Please add any comment in support of your answer

Question 11: Do you have any comments on the potential to amend the current restrictions that apply to solar panels on non-domestic properties (class 6J) and solar canopies in parking areas (class 9M) within 3km of airports and technical sites associated with civilian and military air traffic services?

Please add any comment in support of your answer

Question 12: Do you agree with the proposed new PDR for solar panels within the curtilage of non-domestic buildings?

Please add any comment in support of your answer

3.2 Solar Canopies in Parking Areas

Current PDR for solar canopies

3.2.1 On 31 March 2023, new PDR for solar canopies in qualifying parking areas^[6] ("parking areas") were introduced in a new Class 9M of the GPDO. This followed the consultation on Phase 2 of the PDR review and formed part of a package of changes to PDR for electric vehicle ("EV") chargers. In line with the Phase 2 consultation, the purpose of such canopies was primarily to power EV chargers. The legislation does not rule out the use of any excess power generated for other purposes, but the primary purpose of the solar canopies must be to power EV chargers.

3.2.2 Class 9M PDR grant planning permission for a solar canopy, battery storage and equipment (including equipment housing) necessary for the operation of a solar canopy. This is limited to parking areas, but there is no limit on the number of solar canopies, and equipment necessary for its operation, which can be installed in a parking area.

3.2.3 A solar canopy in this context is defined as a canopy structure which:

a) is open on three or more sides;

b) supports solar photovoltaics for the purposes of the generation of electricity from solar energy;

c) has as its primary use the recharging of vehicles; and

d) is designed to allow one or more vehicles to be parked underneath it.

3.2.4 Class 9M PDR specify various limitations and conditions to the size, siting and illumination of these solar canopies^[7]. In particular, such development is not permitted within 3km of an aerodrome or technical site associated with civilian and military air traffic services.

Context for change: solar canopies

3.2.5 The requirement within class 9M that solar canopies installed under those PDR must primarily be used for recharging vehicles reflects the particular scope of Phase 2 of the review. The Phase 2 consultation was focussed on EV charging infrastructure and the proposals were framed accordingly. Given Phase 3 is looking at how existing PDR could be extended to support renewable energy generation more generally, we are minded to remove that requirement. That is to say, the PDR described in paragraphs 3.2.1 to 3.2.3 would apply in parking areas regardless of the purpose for which solar power is generated.

3.2.6 This would mean that solar canopies installed under class 9M PDR could, for example, be installed solely to supply power to the grid, or solely to supply power to a building associated with the parking area. This may result in more parking areas having such solar canopies and supporting equipment, or such development being more extensive in individual parking areas, regardless of the presence of electric vehicle chargers.

3.2.7 The definition of solar canopy for the purposes of Class 9M specifies that it is a structure which "supports solar photovoltaics for the purposes of the generation of electricity from solar energy". Consequently, these PDR do not include solar canopies with solar thermal equipment, which are associated with the heating of water, and would appear to be irrelevant to parking areas.

3.2.8 In line with paragraph 3.1.4 in section 3.1 on non-domestic solar panels, we also propose that no maximum output capacity in relation to electricity generation be attached to the amended PDR for such solar canopies. This will depend on the size of the parking area involved.

Proposals: solar canopies

3.2.9 The proposal is to remove the restriction that solar canopies installed under Class 9M must primarily be for the powering of EV chargers – that is, remove part (c) from the definition of "solar canopy" at Class 9M(5) (see paragraph 3.2.3). With this proposed change, and in line with the proposals for solar panels attached to non-domestic buildings, the proposal is that no new maximum output capacity for electricity generation would be introduced to Class 9M.

3.2.10 In addition, in line with paragraph 3.1.6, we are interested in views on whether the current restriction relating to using these PDR within 3 km of an aerodrome or technical sites associated with civilian and military air traffic services could be amended – see Question 11.

Question 13: Do you agree with the proposal to extend the Class 9M PDR to allow these to apply to solar canopies generally, rather than only those for which the primary use is charging of electric vehicle?

Please add any comment in support of your answer

Question 14: Do you agree that any extension of Class 9M PDR to be for the purposes of producing electric power generally, should not have a maximum power generation capacity?

Please add any comment in support of your answer

3.3 Non-domestic air source heat pumps

Current PDR for non-domestic air source heat pumps

3.3.1 There are currently no specific PDR for ASHPs associated with non-domestic buildings.

Context for change: non-domestic air source heat pumps

3.3.2 The Heat in Buildings Strategy commits us to "develop and introduce strengthened regulation for non-domestic buildings, to ensure they reduce demand for heat where feasible and install a zero emissions heating supply". ASHPs are likely to play an important role in this.

3.3.3 We are considering introducing PDR along similar lines to the domestic ASHP provisions. It is anticipated that there would be similar restrictions on location and dimensions of equipment mounted externally, although we recognise that non-domestic buildings may require larger ASHPs. We would also need to consider some form of minimum separation from other buildings to address potential noise issues, not least because the MCS 020 standards which include noise assessment apply specifically to domestic installations.

Proposals: non-domestic air source heat pumps

3.3.4 We propose to introduce a new class of PDR which would apply to all non-domestic buildings and would allow the installation, alteration or replacement of an ASHP on the building or within its curtilage. The PDR would only apply:

• In the case of ASHPs attached to buildings: if it is attached to a rear or side elevation (or a rear elevation in a conservation area).
• In the case of ASHPs within the curtilage of buildings: if it is within the rear curtilage and not within 5m of a curtilage boundary.
• It is not located within a World Heritage Site or within the curtilage of a listed building.

3.3.5 We do not propose size limits on ASHPs installed under this new PDR. However, If installed on a building which also contains residential accommodation (for example ground floor shop in a tenement building), we propose that the outdoor compressor unit must not exceed 1.5 cubic metres; and the external parts of the ASHP (including any housing etc.) must not be within 1m of any window of a habitable room, or door of a flat in the same building. Additionally, the ASHP would need to be removed as soon as is reasonably practical where it is no longer needed or no longer capable of providing heating or hot water.

Question 15: Do you agree with the proposed PDR for air source heat pumps on non-domestic buildings?

Please add any comment in support of your answer

3.4 Non- Domestic Ground Source and Water Source Heat Pumps

Current PDR for non-domestic ground and water source heat pumps

3.4.1 Class 6I PDR permit the installation, alteration or replacement of underground pipes within the curtilage of a non-domestic building required in connection with a ground source heat pump or a water source heat pump or both. There are a number of restrictions:

• The surface area of the land under which the pipes are located must not exceed 0.5 hectares.
• Development is not permitted within a site of archaeological interest, the curtilage of a listed building, a World Heritage Site, or a historic garden or designed landscape.
• The total heat output of all microgeneration installed within the curtilage of a non-domestic building would exceed 45 kilowatts thermal.
• The surface of the land must be restored as soon as possible after the installation, alteration or replacement of pipes.

Context for change: non-domestic ground and water source heat pumps

3.4.2 Given that existing PDR for domestic ground and water heat pumps (classes 6D and 6E – see section 2.3.3) refer to the installation of the pumps specifically, we consider that the non-domestic PDR should also do so. In other words, we intend to clarify that class 6I PDR cover both the pump itself and the associated pipework.

3.4.3 We also consider that the restriction on the total output of microgeneration equipment in the curtilage of a non-domestic building is no longer relevant and could act as a barrier to improving energy efficiency.

Proposals: non-domestic ground and water source heat pumps

3.4.4 We propose to amend class 6I to:

• Clarify that in addition to the underground pipes, the PDR also cover the ground/water source pump and any above-ground connections to the pump.
• Remove the reference to maximum heat output.

Question 16: Do you agree with our proposed amendments to class 6I PDR for ground and water source heat pumps on non-domestic buildings?

Please add any comment in support of your answer