Attitudes Towards Photovoltaic Systems on Listed Buildings
An assessment of the attitudes of different stakeholders regarding the use of photovoltaic systems on listed buildings in England
A research paper submitted towards the degree of Master of Architecture at the University of Bath, Department of Architecture and Civil Engineering, 2022-23
Tom Ellis
Candidate Number: 10957
Tutor: Stephen Emmitt
Word Count: 5396
Acknowledgements
I would like to thank Professor Stephen Emmitt, my tutor at the University of Bath, for his continued knowledge, insight and support throughout this research project. I am also grateful for Dr Robert Proctor’s advice given during the interim presentation.
I also wish to express my gratitude to those within the built environment sector who generously gave their time to take part in interviews. There were a number of enjoyable conversations and each was vital to the writing of this research.
Word Count: 5396
Excluding abstract, captions, tables, bibliography and appendices
3 Contents Abstract Introduction Literature Review Research Methodology Results Discussion Conclusion References Illustrations Appendices 04 06 09 14 16 19 21 22 25 26
The built environment sector is one of the key emitters of energy-related global carbon emissions, with 73% of the sector’s emissions attributed to the operation of buildings. Therefore, the retrofit of existing building stock is becoming increasingly important. Photovoltaic systems offer one retrofit strategy for the reduction of carbon emissions. England has a very old building stock which is found to be energy intensive. However, retrofitting of many of these buildings is restricted due to listed building statuses.
The research presented in this paper investigates stakeholders’ attitudes towards the use of photovoltaic systems on listed buildings as a retrofit strategy. This encompasses an exploration of perceptions towards the suitability of photovoltaics and the legislative context that governs their use on listed buildings. Interviews with four stakeholders are utilised alongside the analysis of 10 local planning authority databases.
The paper finds that all participants identified positive perceptions towards the reversibility of photovoltaic systems and their minimal interference with historic building fabric. Conversely, most participants identified visual impact as a minor perception barrier to the use of photovoltaic systems on listed buildings. It is identified that conservation officers and listed building owners have a preference for the use of photovoltaic systems when compared to fabric energy efficiency improvements. Alternatively, architectural professionals are found to prefer fabric alterations. The paper establishes a number of negative perceptions towards the current legislation and guidance that governs the use of photovoltaics on listed buildings. Therefore, this paper suggests that the widespread use of local listed building consent orders across English planning authorities would enable greater use of photovoltaic systems on listed buildings.
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Abstract
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Figure 1: A photovoltaic panel array installed to the roof of Grade I listed Gloucester Cathedral
Public debate concerning the future of the planet has never been greater. A rise in global temperature first identified in 1938 is now universally recognised as ‘the climate emergency’. This emergency, instigated by extensive carbon emissions since the start of the industrial revolution, is predicted to expose humanity to unthinkable consequences (LETI, 2020). Nonetheless, global carbon emissions continue to rise drastically (IEA, 2022). Predictions show that this continuation will result in a +4.4⁰C temperature rise above pre-industrial times by 2100 (IPCC, 2021). However, it is stated that limiting the temperature rise to below +1.5⁰C is required to avert the worst impacts of the climate emergency (IPCC, 2018). Resultantly, the UK government has introduced legislation requiring the nation to be carbon net-zero by 2050 (HM Government, 2021).
According to the International Energy Agency (2018), the built environment sector is responsible for 42% of global energy-related carbon emissions. Furthermore, it is found that 73% of the sector’s emissions arise from the operation of buildings (IEA, 2018). Given that a predicted 80% of the UK’s building stock in 2050 has already been built (LETI, 2021), built environment bodies, such as RIBA and LETI, are vigorously promoting the retrofit of existing building stock.
The UK has the oldest building stock in Europe – over 20% of buildings were constructed before 1919 (CIH, 2022). There are over 400,000 listed buildings in England, many of which are historic buildings, due to listing criteria specified by the UK government (Historic England, 2022). Whilst Listed buildings represent only 2% of all buildings in England, they may play a significant
role in reducing future carbon emissions: The Office for National Statistics (2022) highlights that older dwellings typically have far inferior energy ratings (figure 4). Additionally, the protected status of listed buildings dictates that most will still be standing in 2050. Hence it can be viewed that reducing their operational carbon output is of great importance for achieving netzero carbon by 2050.
Renewable technologies have become a critical focus for reducing the operational carbon emissions of existing buildings – photovoltaic (PV) systems are among the most familiar options (EDF Energy, 2022). PV systems are assemblies of photovoltaic solar cells that generate electrical energy from solar radiation (Jelley, 2020). This electricity generation does not emit any operational carbon emissions, unlike the carbon-intensive national grid. Moran et al. (2014) highlight that PV systems can significantly reduce the carbon emissions of listed buildings. Ginks et al. (2017) recommend that research is required to identify stakeholders’ attitudes towards the use of renewable energy systems on listed buildings.
This paper will investigate the attitudes of stakeholders towards the use of PV systems on listed buildings. This will offer insight into perceptions regarding the suitability of PV systems for listed buildings and the legislative context that governs their use. Past studies have identified a requirement for further research into user perceptions towards the energy efficiency strategies of historic buildings: Fouseki & Cassar (2014) and Gram-Hanssen (2017) determine that this research is necessary as policy and legislation should be informed by stakeholders for best implementation.
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Introduction
Environmental Heritage
1938
Global temperature rise was first identified by Guy Callendar. His research showed that the global temperature had risen 0.3°C in the previous 50 years.
1958
Charles David Keeling was able to prove that CO2 levels in the atmosphere were rising and that this was directly attributed to the use of fossil fuels.
2003
Professor Pete Scott publishes a paper showing a direct link between climate change and extreme weather events for the first time. This followed the deaths of 20,000 people in a European heatwave.
2018
The IPCC publish a report stating that the global temperature must be limited to +1.5°C by 2100 in order to avert the most serious effects of climate change.
2025
The year by which LETI states the UK must begin to upgrade existing building stock at a rate of 3,750 per day.
2033
Predicted year that the +1.5°C global temperature increase will be reached
2035
Commitment made by the UK government for the National Grid to be decarbonised by 2035.
1940-43
The widespread destruction of UK cities during the Second World War prompted ‘Salvage Lists’. These lists determined which buildings should be protected from demolition following bomb damage.
1947
The Town and Country Planning Acts of 1944 and 1947 established the listing of buildings of special architectural or historical interest.
1990
The Town and Country Planning Act 1990 consolidated previous legislation for listed buildings and create a segregation of general planning legislation and conservation legislation.
2010
Historic England (formerly English Heritage) first publish guidance on the use of solar panels on listed buildings. This guidance states the visual impact of solar panels will be a key consideration for approval.
2022
The Royal Borough of Kensington and Chelsea introduce a planning order that allows for the use of solar panels on grade II and II* listed buildings without planning consent.
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Figure 2: A timeline of critical moments for environmental and heritage conservation.
8 Pre1900 19001929 19301982 19832011 2021 Onwards All dwellings 0 20 40 60 80 100
Figure 4: Median energy efficiency score by property age (ONS, 2022) 1945 - 1964 17.7%
Figure 3: Age of housing stock in England (CIH, 2022) 1919-1944 11.0%
Pre-1919 21.8% Post 1980 29.6% 1965-1980 19.9%
Literature Review
The legislative context
Listed buildings form an important part of England’s building stock, with the nation ranked 5th globally on an index for the richness of heritage buildings (Historic England, 2014). Mynors (2006) highlights that the protection of listed buildings is essential for the preservation of the country’s cultural heritage. Historic England is a public body that maintains the national heritage list (Historic England, 2022), making recommendations for listings using criteria established by the Department for Digital, Culture, Media and Sport (DDCMS, 2018).
The Planning Act (1990) stipulates that all works to listed buildings that affect their character require authorisation from the local planning authority (LPA) in the form of listed building consent (LBC). Resultantly, many energy efficiency improvements classified as permitted development on unprotected buildings require authorisation for use on listed buildings. Within most LPAs, conservation officers are delegated with the role of case officer to LBC applications. In this role, they have the duty to determine application outcomes (Mynors, 2006).
Davies et al. (2018) identify that conservation officers rely on the National Planning Policy Framework (NPPF) and Historic England guidance documents when determining LBC applications. The NPPF is a document that provides a consolidated set of government policies based on all planning legislation. Davies et al. (2018) highlight a lack of specificity in the NPPF regarding energy efficiency improvements to listed buildings. For example, section 10 of the NPPF explains that “plans and decisions should apply a presumption in favour of
sustainable development”. However, section 16, titled ‘conserving the historic environment’, states that “great weight should be given to the asset’s heritage conservation” (HM Government, 2021a). These statements can be considered contradictory in the context of energy efficiency retrofit measures.
Historic England guidance advocates a minimum intervention approach for modern technologies on listed buildings (Historic England, 2018a). The organisation provides specific guidance on using PV systems in ‘Energy Efficiency and Historic Buildings: Solar Electrics’. Historic England (2018b) states that reversibility, visual impact and building setting are critical factors in determining the acceptability of PV systems. However, again, this guidance offers little specificity or metrics for the determination of applications.
The Planning Act (1990) makes provision for LPAs to create local listed building consent orders (LLBCO). This legislation allows LPAs to remove the need for LBC for prescribed works, provided that the works are carried out in accordance with conditions detailed in the LLBCO (Historic England, 2015). In 2022, the Royal Borough of Kensington and Chelsea (RBKC) Council took unprecedented action by introducing an LLBCO for PV systems – the first in England. This LLBCO permits the use of PV systems on most grade II/II* listed properties (RBKC Council, 2022). The LLBCO’s conditions (figure 5) offer great specificity regarding when PV systems are permissible. The council hoped that it would encourage more listed building owners to install PV systems, helping the council reach its 2040 net-zero target (RBKC Council, 2022).
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3.2 Consent is granted subject to the following conditions: -
i) the solar PV panels are to be installed on a roof structure;
ii) the solar PV panels are not to be placed on any roof slope facing a highway;
iii) the solar PV panels would protrude no more than 0.2 metres beyond the plane of the roof when measured from the perpendicular with the external surface of the roof;
iv) no part of the solar PV panels would be higher than the highest part of the roof, excluding chimneys;
v) the solar PV array is, so far as practicable, sited so as to minimise its effect on the external appearance of the building;
vi) the solar PV array is, so far as practicable, sited so as to minimise its effect on the amenity of the area;
vii) details of the position, size, fixing, colour and finish of the solar PV array and associated equipment shall be submitted to and approved in writing by the Local Planning Authority before works commence;
viii) the solar PV equipment is removed as soon as reasonably practicablewhen no longer needed.
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Figure 5: conditions of RBKC Council’s local listed building consent order for PV systems (RBKC Council, 2022)
Energy Efficiency and Listed Buildings
The UK government is committed to decarbonising the national grid by 2035 (BEIS, 2021). However, the IPCC (2021) predicts that a +1.5⁰C rise in global temperature will be reached by the early 2030s. As a result of an imminent climate threat, Architects Declare (2019) called for the rapid upgrade of existing buildings to reduce operational carbon emissions. LETI (2020) and RIBA (2021) both support Architects Declare (2019) by stating that retrofit of existing buildings is necessary to reach net-zero carbon targets. Additionally, Historic England (2018a) has acknowledged a need to improve the energy efficiency of historic buildings to meet net-zero targets.
LETI’s (2021) guidance for the retrofit of existing buildings states that best practice retrofit utilises a fabric-first approach – “improving fabric energy efficiency before introducing low carbon technologies”. LETI (2021) reasons that this approach has greater benefits to the internal building environment and the comfort of occupants. RIBA (2021) supports this by also highlighting a preference for a fabric-first approach to retrofit. LETI (2021) offer two sets of best-practice retrofit targets (figure 6). Listed buildings are classified as a constrained retrofit; therefore, there is no target for using PV systems on them. Instead, the LETI (2021) targets focus predominantly on fabric improvements.
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Figure 6: LETI best-practice retrofit targets (LETI, 2021)
Barriers to fabric-first Retrofit
Stuart (2014) offers one of the first UK-focused evaluations of listed building owners’ perceptions towards energy efficiency improvements. Stuart (2014) identifies that many owners have negative attitudes towards improving the insulation of listed buildings. It is found that the negative perceptions of many were fuelled by concern for unintended damage to the building resulting from improved insulation. Stuart (2014) states that fear of condensation and subsequent mould resulting from the reduced breathability of the building were critical concerns. Sunikka-Blank & Galvin (2015) support this by also highlighting that many listed building owners have negative perceptions of insulation improvements due to concerns about building damage resulting from condensation and mould.
Yarrow (2016) considers the perceptions of a range of stakeholders towards energy efficiency improvements in listed buildings. The study identifies that a fundamental perception barrier for conservation officers, owners and architects is a loss of original fabric. The study identifies that many listed building owners feel a sense of ethical responsibility to their buildings and that this directly limits their desire to replace or alter original elements of building fabric. It is observed that owners feel that the removal of a building element results in the loss of historical value. Consequently, Yarrow (2016) highlights that this forms negative perceptions towards the replacement or alteration of original windows with double-glazed units.
Yarrow (2016) also highlights visual impact as a perception barrier towards fabric energy efficiency improvements. It was observed that many listed building owners have concerns that externally visible fabric alterations, such as external wall insulation and double-glazed windows, would undermine the aesthetic quality of their properties. Wise et al. (2021) support
Yarrow (2016), highlighting that the visual appearance of fabric alterations is a significant perception barrier. Wise et al. (2021) identify that external wall insulation and window alterations are perceived to be unacceptable energy efficiency improvements due to the change in a building’s aesthetic character.
Ginks et al. (2017) provide further support for Yarrow (2016) by highlighting that two critical perception barriers of conservation officers towards fabric improvements are visual impact and loss of original fabric. The study assessed the perceptions towards the use of slim profile double glazing (SPDG) in listed buildings, finding that the details of glazing bars and the uniform reflection of modern glass were both contributing factors to negative perceptions of visual impact. Ginks et al. (2016) observe that conservation officers are more open to fitting SPDG in the original window frames than into new window frames. This suggests that the loss of heritage fabric is a critical perception barrier. The research also identifies a significant variation in the attitudes of conservation officers in England towards SPDG. Consequently, this leads to a variation in the determination of LBC applications, possibly resulting from a lack of specificity in current legislation and guidance.
Seifhashemi (2022) identifies that a further barrier to fabric alterations is a perceived impact on a building’s spatial qualities. This study of perceptions towards internal wall insulation in heritage buildings highlights that many owners feel negatively about floor area lost by the alteration. The study’s questionnaire reveals that many owners worried that internal wall insulation would significantly reduce internal floor area and, subsequently, their property’s value.
This existing literature has shown that perceived barriers towards fabric energy efficiency
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improvements from various stakeholder groups are building damage, loss of historic fabric, visual impact and spatial quality impact. Although built environment organisations suggest a fabric-first approach to retrofit, this may not be the most suitable approach when assessing the attitudes of the owners who will implement the changes.
The Opportunity for PV Systems
Wise et al. (2021) suggest that the perception barrier of visual impact identified for fabric improvements is not held for PV systems despite systems often being visible externally. The study found that most listed building owners would be open to using PV systems on their properties. Okutan et al. (2018) also suggest that PV systems may be viewed more favourably by members of the public when compared to specific fabric alterations. Participants in the quantitative study were asked to rank 15 energy-efficient retrofit measures in the context of a grade II listed property in Bath. Integrated PV roof tiles ranked as the 6th most acceptable measure, whilst roof-mounted PV panels ranked 9th. Okutan et al. (2019) highlight that both PV systems were preferred to internal and external wall insulation. However, it must be noted that SPDG was preferred to both PV systems.
Wise et al. (2021) indicate that the greater tolerance for the use of PV systems may be due to the greater reversibility of the systems. The study identifies that other reversible alterations, such as thermal curtains and interior shutters, were also positively perceived. Hence Wise et al. (2021) suggest that the permanency of energy efficiency alterations is a crucial determinant for listed building owners. PV panels fitted on top of an existing roof surface are held to the building using lag bolt connections that are drilled into the roof rafters – figure 7 (Energy Saving Trust, 2022). The mechanical nature of this connection allows for easy removal of the PV system and results in minimal roof damage.
Davies et al. (2018) assess the attitudes of conservation officers in England to PV roof tiling systems on listed buildings. The study finds that only 4% of conservation officers felt likely to permit this specific PV system. Integrated PV roof tile systems require the removal of the existing roof tiles, and then the PV tiles are each individually mechanically fastened to the roof –figure 8 (Energy Saving Trust, 2022). Whilst this system can be reversed and the original roof tiles replaced, it is a time and cost intensive process. Subsequently, Davies et al. (2018) highlight the lack of reversibility of PV roof tiles as a critical perception barrier. Additionally, the research identifies that very few LBC applications have been made for PV tile systems, but the reasons for this are unidentified.
There is very little existing literature regarding stakeholders’ perceptions towards the use of PV systems. Davies et al. (2018) focus specifically on PV roof tiles which have specific perception barriers. Meanwhile, findings identified by Okutan et al. (2019) and Wise et al. (2021) are part of broader studies. Therefore, this paper seeks to understand the perceptions of a range of stakeholder groups towards the use of all PV systems on listed buildings.
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Figure 7: PV panel fixing (Solar Power World, 2014)
Figure 8: PV roof tiles fixing (Tesla, 2022)
Results
Trends in Planning Data
28,661 listed building entries are located within the 10 authorities surveyed in this study (British Listed Buildings, 2023). Figure 12 illustrates that there were 222 LBC applications for PV systems within the LPAs - <0.77% of all listed buildings. Less than 0.77% is assumed because there were cases identified where multiple applications were associated with a single property.
The study identified that 153 applications were consented - a mean approval rate of 68.9% across all surveyed LPAs (figure 13). This indicates that <0.53% of listed buildings have consent from an LPA for the use of PV systems. The MCS Installation database (2023) highlights that 4.1% of all buildings in the UK have PV systems installed. Therefore, it can be assumed that the usage of PV systems on listed buildings is significantly lower than that on non-listed buildings.
Additionally, the study found a mean refusal rate of 16.3% across the 10 LPAs. However, there was a wide range of individual refusal rates of LPAs. Bath & North East Somerset had the highest rate at 27.1%, whilst RBKC Council had the lowest at 3.1%. This suggests a variation in attitude towards PV systems across different LPA conservation departments.
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Planning Authority Consented Refused Withdrawn Undecided Total BANES 34 13 1 0 48 Bedford 8 3 1 0 12 Birmingham 5 3 5 0 13 Cornwall 20 3 7 5 35 County Durham 21 3 4 1 29 Maidstone 19 3 2 1 25 Manchester 3 1 1 1 6 Redcar & Cleveland 4 1 0 0 5 RBKC 29 1 2 0 32 York 10 3 4 0 17 Totals 153 34 27 8 222
Figure 12: LBC applications for photovoltaic systems between 1st January 2000 - 5th January 2023. N.B. RBKC Council implemented the LLBCO in August 2022.
Consented Refused Withdrawn Undecided 68.9% 15.3% 12.2% 3.6%
Figure 13: Decisions of PV applications (All LPAs)
Background Attitudes
All interviewees shared strong concerns for the future climate of the planet. Climate concerns have a bearing on the personal decisions of participants, including living location and job choice (D:57; A:371). Thus, highlighting a significant degree of concern. The study identifies that all participants acknowledged that improving the energy efficiency of listed buildings is necessary. This aligns with the study by Davies et al. (2018) that determines 73% of conservation officers perceive it important to improve the energy efficiency of listed buildings. However, the present study finds interviewees to have varying degrees of support for improving the energy efficiency of listed buildings. Interviewee A felt that a loss of historic fabric is justified if it lessens a building’s environmental impact (A:53). Whilst the architect interviewed took a more conservative stance stating that improvements should be reserved for listed buildings with less historical significance (B:80).
Attitudes towards the suitability of PVs
All interviewees discussed the suitability of PV systems in relation to fabric alterations. The study finds a divide in which strategy is perceived as the most suitable for use on listed buildings. It was identified that both the listed building owner and conservation officer perceived PV panels to be advantageous, with minimal damage to the original building fabric cited as a reason (C:71; D:109). The conservation officer also suggests that their experience in an LPA has demonstrated that PV systems are preferred by owners (C:120). However, the study finds that those working in architectural practices have a preference for fabric improvements; this perception is driven by an understanding of environmental design, with interviewees A and B stating that fabric alterations are superior as they reduce energy demands (A:162, B:232). The longevity of fabric alterations in relation to PV systems was perceived as a further benefit by
these participants.
Some participants identified visual impact as a perception barrier to the use of PV systems, with one commenting that PV systems can “really destroy the aesthetic of a building” (A:113). Most participants have a shared preference for the placement of PVs in concealed locations on listed buildings (A:115, B:116, D:150). Interestingly, the study finds that the conservation officer has a more tolerant perception of visual impact. PV systems are likened to other pieces of rooftop service equipment. Resultantly, they are not seen to diminish the ability to understand the historic value of a building (C:271). Two interviewees also highlighted that the visual impact of PV systems could be utilised to raise awareness of climate change and the immediate need to retrofit further buildings. (A:274, C:126).
All interviewees perceived reversibility as a benefit of PV systems in the context of listed buildings, with one stating that “reversibility of PVs is paramount” (B:133). The ability to remove PVs and leave little to no damage to the building was widely acknowledged (B:160, C:301, D:108). Reversibility is highlighted to influence a preference for PV panels rather than integrated PV tiles. Whilst some participants felt that PV tile systems offer a better aesthetic, they are far harder to remove, which is a particular concern due to the limited lifespan of PV cells (A:263, B:176).
Attitudes towards legislation and guidance
Some interviewees perceive time and cost implications of LBC applications for PV systems to be a barrier to their use. For example, interviewee A describes the process as being “long-winded” (A:290). Meanwhile, the listed building owner highlights, from their experience, that the drawings and documentation required for the application necessitate consideration outlay of funds for professional fees (D:272).
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Additionally, an inability to get consent for PV systems is perceived to be a financial burden for owners due to the expensive running costs associated with national grid energy (A:349, D:175).
The study highlights a perception among some participants that conservation officers have resistance towards the use of PV systems (A:310, D:98). Conversely, the conservation officer states that there is a misconception towards LPA conservation teams and that owners assume they will not get consent and therefore do not apply for LBC (C:136). The study highlights that most participants perceive greater involvement of environmental professionals in PV system LBC decisions would be positive. Whilst conservation officers are identified to “really understand how listed buildings work” (A:80), the introduction of environmental professionals would remove a perceived bias in decisions (A:346; B:93).
Most participants perceived a need for LBC applications to be assessed with a degree of individuality, given the uniqueness of listed buildings. However, contradicting this is a shared perception that Historic England guidance lacks specificity, with interview D labelling it “just very vague” (D:112). Consequentially, there was a perception that the guidance allowed for too greater degree of interpretation by conservation officers (B:97; D:98). Subsequently, interviewee D suggests that specific metrics for decisionmaking would narrow interpretation (D:126), potentially encouraging more applications due to greater assurance that they are eligible for consent.
The study identifies a desire from all stakeholder groups for some form of policy change regarding PV use. There is consensus among some participants for the relaxation of Historic England policy regarding visual impact (A:290; B:190; D:148). For some listed buildings, the
only roof suitable for PV systems is the principal elevation (B:190); subsequently, interviewee B perceives a need to be more lenient in these circumstances (B:194). Interviewee D supports this, asserting that despite recognising the importance of the cosmetic appearance of listed buildings, the reversibility of PV systems means the visual impact is not permanent (D:148). This gives weight to the argument that policy change is needed, especially given the immediacy of climate concerns. Some participants would like to see policy changes put more trust in listed building owners and assume that they will not damage the significance of their building (C:300, D:255).
The study finds that most participants perceive that introducing LLBCOs for PV use would be a good policy change, with the conservation officer stating that it would encourage more listed building owners to install PV systems (C:406). LLBCOs are perceived positively due to the ability to tailor their conditions to the local context. This is important given variations in local historical significance and geographical characteristics, such as topography (C:229, D:265). Conversely, the architect feels that a national legislative change will ensure that all LPAs will be consistent in approach (B:244). However, this view is not shared.
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This study identifies a preference among the listed building owner and conservation officer for PV systems rather than fabric energy efficiency improvements. This contradicts the guidance of built environment organisations, such as LETI (2021) and RIBA (2019), which recommend a fabric-first approach to retrofit. This study identifies that one of the greatest perceived benefits of PV systems is the minimal loss of building fabric. This result aligns with Yarrow (2016) and Ginks et al. (2017), who assert that fabric alterations, such as replacement windows, are negatively perceived due to concerns that the loss of original building fabric leads to a consequential loss of heritage value.
This study found that the visual impact of PV systems on listed buildings is a concern to stakeholders, similar to the visual impact concerns towards external fabric alterations identified by Yarrow (2016) and Ginks et al. (2017). However, the present study ascertains that despite many negative perceptions towards the visual impact of PV systems, it does not affect stakeholders’ attitudes towards the need for their use on listed buildings. Less weight was given to visual impact concerns due to the reversibility credentials of PV systems, as supported by Wise et al. (2021), which purports that the visual impact of reversible measures is less of a barrier.
Whilst it is evident that the fabric-first approach of LETI (2021) guidance is the result of technical research, this study identifies that the guidance is misaligned with the attitudes of listed building owners. As earlier established, heritage building retrofit policy is best implemented when it is influenced by owners’ attitudes (Fouseki &
Cassar, 2014; Gram-Hanssen, 2014). Resultantly, it can be deduced that whilst a fabric-first approach results in more comprehensive benefits than PV systems, it may be a less implementable retrofit policy.
The present study found that the perceived benefit of reversibility was also a determining factor in stakeholder preference for PV panels as opposed to integrated PV tile systems. This contradicts the findings of Okutan et al. (2019), whereby members of the public rated integrated PV tile systems as preferable. However, the present study supports and builds upon Davies et al.’s findings, which assert that conservation officers have a negative perception of PV tile systems due to a perceived lack of reversibility. The present study adds to this by validating that wider stakeholders, alongside conservation officers, hold this opinion.
Architectural professionals and the listed building owner perceive resistance from conservation officers towards PV system usage on listed buildings. Alternatively, the conservation officer interviewed felt that this was a misconception. This paper is unable to ascertain which belief is correct, and this would require further research to establish a conclusion. Nonetheless, the perceptions of architectural professionals and listed building owners suggest that the LBC application process may be a barrier to using PV systems on listed buildings. Furthermore, the identified negative perceptions towards the time and cost implications of LBC applications provide further support that the process is a barrier. The LBC process for PV systems acting as a barrier explains the low number of applications
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Discussion
identified by the planning study.
This study identified an inconsistency among LPAs in the refusal rate for LBC applications for PV systems. Thus, suggesting a variation between LPAs in the application of Historic England guidance and the NPPF. This supports the perception of some participants that the current policy lacks specificity and, consequently, allows for varying degrees of interpretation by the enforcing conservation officers. The identified variation in the refusal rate is similar to the variation in LPA refusal rates for SPDG, as determined by Ginks et al. (2017). Resultantly, this study provides a similar conclusion to Ginks et al. (2017) that a more explicit, metric-driven policy would reduce the scope for interpretation, resulting in more consistent decisions. Greater consistency of decisions may encourage more owners to apply for LBC, given that the time and cost expenditure for the LBC application is more assured.
On the contrary, the study highlighted that stakeholders feel that LBC decisions should be approached with a high level of individuality, given the unique historical and geographical context of each listed building. Therefore, more thorough guidance from Historic England may restrict the ability of LPAs to tailor decisions to that unique context.
Consequently, this study argues that the widespread use of LLBCOs for PV systems would provide a more suitable solution. The interviews highlighted that most stakeholders would prefer implementing policy change at a local level rather than a national level. As identified by the literature review, LLBCOs must contain specific conditions that must be fulfilled by those enacting the order. LPAs would be able to tailor the conditions of their LLBCO to align with local historical and geographical constraints. This is an advantageous solution when compared to
increasing the specificity of the national Historic England guidance, because it enables LPAs to respond to the unique constraints of their locality. Additionally, Historic England (2015) details that the conditions of an LLBCO must provide measurable targets. Therefore, LLBCO use would negate the lack of specificity in national guidance that this study identifies as a potential barrier to using PV systems. Furthermore, using LLBCOs across English LPAs would avert the negative perceptions of time and cost implications associated with the current LPA application process for PV systems. LLBCOs do not require owners to submit the documentation required of a LBC application, which is typically expensive to produce. Whilst LLBCOs also avoid the long time it takes to determine LBC applications.
A further benefit of implementing wider use of LLBCOs is that it would respond to the consensus of participants for greater trust to be given to listed building owners regarding energy efficiency improvements to their properties. The nature of LLBCOs puts more onus on owners whilst still allowing LPAs to intervene if necessary.
The study found that all participants agreed that greater integration of environmental professionals into heritage conservation decisions would be beneficial. This integration may be critical to encouraging the widespread use of LLBCOs for PV systems. This finding is supported by the successful implementation of this approach within RBKC Council, whereby a dual heritage conservation and sustainability team worked together to issue England’s first LLBCO for PV systems.
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Conclusion
This research paper investigates stakeholder perceptions regarding the suitability of PV systems on listed buildings and the legislative context governing their use. A very small sample limits the validity of this study, as a more reliable and defined correlation in attitudes may have been observed by a more extensive study. Additionally, a larger sample would have provided a more representative sample of each stakeholder group. To verify the findings of this paper, interviews with more people from each stakeholder group are required. Further conservation officers and listed building owners must be interviewed due to the identified biases of those interviewed in this paper.
Furthermore, the small sample size of surveyed LPA databases poses a further limitation to this study. Whilst the planning data survey proved to be a valuable tool to assess current policy implementation, it is not representative of all LPAs. This study would have obtained a more representative view with a larger sample size of surveyed LPAs. However, this was not possible due to the time-intensive nature of the research strategy.
The literature review identified that very little research had been undertaken in this study area, and as such, this paper provides several new insights. The results revealed a preference among
conservation officers and listed building owners for the use of PV systems when compared to fabric energy efficiency improvements. Additionally, all stakeholders identified reversibility and minimal damage to existing building fabric as critical perceived benefits. The study also highlights the perception that PV panels sitting on top of a roof are more acceptable than integrated PV tile systems.
This paper suggests a need to align policy regarding the use of PV systems on listed buildings with the attitudes of stakeholders. This is supported by the literature, which purports that the implementation of energy efficiency improvements to listed buildings is significantly improved if policy is representative of owners’ attitudes. The present study proposes that the policy change most aligned with the expressed attitudes would be the introduction of LLBCOs to LPAs across England. This option is preferred by most stakeholders as it accommodates a localised approach. Legislation requires any LPA operating LLBCOs to publish annual reports on its success. RBKC Council will publish its first annual report for its PV system LLBCO in late 2023. Therefore, this offers a field of further research to progress the present study.
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Illustrations
Figure 1 – Sun Fixings, Year. Case Study: Gloucester Cathedral [Online]. Sun Fixings. Available from: https://www.sunfixings.co.uk/case-study/gloucester-cathedral/ [Accessed 03 January 2023].
Figure 2 – By Author
Figure 3 – Adapted from Chartered Institute of Housing, 2022. UK Housing Review 2022 shows faster progress is needed to tackle poor energy efficiency of older homes [Online]. London: Chartered Institute of Housing. Available from: https://www.cih.org/news/uk-housing-review-2022-shows-faster-progressis-needed-to-tackle-poor-energy-efficiency-of-older-homes [Accessed 05 January 2023].
Figure 4 – Adapted from Office for National Statistics, 2022. Energy efficiency of housing in England and Wales: 2022 [Online]. London: Office for National Statistics. Available from: https://www.ons.gov. uk/peoplepopulationandcommunity/housing/articles/energyefficiencyofhousienergyefficiencyofh/2022 [Accessed 05 January 2023]
Figure 5 – Royal Borough of Kensington and Chelsea Council, 2022. Local Listed Building Consent Order. London; Royal Borough of Kensington and Chelsea Council. Available from: https://www.rbkc. gov.uk/newsroom/solar-power-more-homes-kensington-and-chelsea#:~:text=The%20Council%20 is%20the%20first,for%20individual%20listed%20building%20consent. [Accessed 20 November 2022].
Figure 6 – LETI, 2021. Climate Emergency Retrofit Guide. London, LETI.
Figure 7 – Solar Power World, 2014. Anatomy Of A Rooftop Solar Mounting System [Online]. Solar Power World. Available from: https://www.solarpowerworldonline.com/2014/03/anatomy-rooftopsolar-mounting-system/ [Accessed 30/01/23].
Figure 8 – Tesla, 2020. How do Solar Tiles Work? [Online]. Archdaily. Available from: https://www. archdaily.com/930969/how-do-solar-tiles-work [Accessed 30/01/23].
Figure 9 – By Author
Figure 10 – By Author
Figure 11 – By Author
Figure 12 – By Author
Figure 13 – By Author
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