Planning decision to allow photovoltaic panels on the roof of King's College Chapel

The planning decision to allow photovoltaic panels on the roof of King’s College Chapel, Cambridge, is likely to have unfortunate ramifications on historic buildings elsewhere.

A mock-up of a trial panel (Photo: Caroe Architecture).

‘King’s College’s application to put solar panels on the roof of the chapel sets a world-wide precedent. Done there, it can be done anywhere,’ tweeted Councillor Dave Baigent, vice-chair of Cambridge City Council’s planning committee, after councillors overturned the officer recommendation of refusal for 462 PV panels on the chapel’s north and south roof slopes.

This case involved planning and faculty jurisdiction. The planning committee report [1] and debate contrasted with the diocesan chancellor’s approach: ‘I am well aware that two emotionally charged considerations come head-to-head in an application such as this: the preservation of a building of outstanding beauty, and the reversal of climate change ultimately to save our planet’. (From 1 July 2022 the Faculty Jurisdiction [Amendment] Rules 2022 require all applications for a faculty to demonstrate that the development of the proposals has been considered with due regard to the Church Building Council’s guidance on reducing carbon emissions.) I urge interested readers to start with the chancellor’s decision [2] and the requirements he set, and then to delve into the planning documents.[3]

The chapel is much taller than most nearby buildings. Its roofs are low-pitched, partially hidden from view by elaborate pierced parapets, and seen from a limited number of viewpoints, the most significant public views being from the east and west. In principle, this is an almost ideal location for inconspicuous solar PV. Major roof repairs provided a once-in-a-lifetime opportunity for the college, a quinquennial inspection having identified all the lead as requiring replacement. A decarbonisation report identified potential to reduce the college’s carbon emissions by an average of 23 tonnes a year, around 1.4 per cent of the college’s annual emissions over the next 30 years. All the electrical needs of the chapel will be met by the PV, which will be exporting energy to run other sustainable investments within the college – including future ground-source heat pumps, which will serve the chapel’s underfloor heating system.

Pre-application meetings were held in late 2021, first with the diocesan advisory committee (with the conservation officer present as DAC adviser), then with the DAC, the Church Buildings Council, SPAB and Historic England. The college had intended to submit a single faculty application for the roof works and the PV, but was advised by the DAC to split the application into two parts. The Church Buildings Council formally expressed support. The college’s architect Oliver Caroe explains that the timing of the formal faculty submissions for the PV was dictated by consultee feedback to the DAC and receipt of formal DAC advice, which had first been applied for – with all the commensurate and wide-ranging consultations to statutory bodies – in March 2022. Caroe comments: ‘It was a source of real concern that the regulation processes (both secular and ecclesiastical) did not operate to respond in a timely manner.’

The planning application was submitted in August 2022, and widely publicised. The planning and heritage statement noted Church of England, university and city council climate change ambitions, and pre-application dialogue with Historic England and SPAB. There was consensus that installation of the panels would not harm the fabric of the listed building. ‘The key consideration in terms of impact on the building is whether or not the PV panels would draw the eye to such an extent that they would interfere with one’s ability to understand and enjoy the architectural and historic interest of the building… The chosen panels will not be reflective’ (para 7.7). Nine different viewpoints were agreed with the council. ‘In none of these views would PVs on the roof of the chapel cause any harm to the character and appearance of the conservation area (para 7.33). The statement referenced NPPF and Cambridge Local Plan policies.

Significant viewpoints were omitted. The interested public was not told about the trial panels. For the entire time the planning application was ‘live’, the public could not see the trial panels because the chapel roofs were effectively concealed from view, which was not what the college or design team had wanted. There was no method statement for replacing panels (but Oliver Caroe has confirmed that it will be possible to renew panels without needing scaffolding).

The statement did not mention the key international standard, BS EN 16883: 2017 ‘Conservation of cultural heritage – Guidelines for improving the energy efficiency of historic buildings’. This includes cultural, as well as environmental, economic and social among the sustainability aspects to be balanced, ‘understanding that they are complementary and mutually dependent, rather than isolated aspects’. The standard provides ‘a systematic procedure to facilitate the best decision in each individual case.’

Historic England (citing NPPF paras 155 and 158) and SPAB challenged the justification for the panels, and the claim that the ‘chosen panels will not be reflective’. Historic England concluded that the proposal would harm the significance of the chapel, and recommended ‘that the application for planning permission should be refused unless the council concluded that the harm the proposed installation would cause would be outweighed by the public benefit that renewable power generation would provide.’ The college’s agents Turley responded: ‘In reality the “harm” to the chapel is imperceptible to all but the most keen or concerned specialist; but the material and public benefit is incalculable… and, in our view, clearly outweighs any harm.’

In SPAB’s view, ‘the level of harm would be less than substantial, and may therefore be acceptable if a clear and convincing justification can be provided’, but ‘we can see no evidence in the application or elsewhere that the college has an adopted and funded sustainability strategy.’ SPAB saw this as a key point as ‘in order to provide the clear and convincing justification of carbon reduction required, a proposal of this type must form part of a building/estate approach.’

The officer report referenced one letter supporting the proposal, and the sustainability officer’s comment: ‘Support… only if… deemed that the renewable energy/sustainability benefits of the scheme outweighed the possible negative impacts on the heritage asset and historic environment.’ Officers concluded ‘that the proposals give rise to less than substantial harm of moderate significance’, that ‘the proposal is therefore contrary to policies 29, 61 and 63 of the Cambridge Local Plan 2018 and the NPPF, paragraphs 199–200 and 202’, and that ‘the magnitude of the public benefit derived from the solar panels in this case does not outweigh the less than substantial harm identified to the heritage interests of the Grade I listed chapel.’ They recommended refusal.

The committee amendment sheet included another letter in support; objections from IHBC member Robin Uff and me; and updated performance projections, reflecting technological improvements to the proposed panels.

At the planning committee meeting, the committee’s only architect member (and executive councillor for planning policy) left the meeting before the King’s College item. Objectors, including Historic England, were heard before supporters of the application: the Provost of King’s, and four ward councillors (not members of the committee). The debate turned on balances between public benefit (both as an exemplar seen by millions of people, and from any carbon saving) and ‘less than substantial harm’ to the listed building. The officer recommendation was overturned, and planning permission granted, by six votes to nil.

The committee’s decision [4] delegated approval of conditions to the chair, vice-chair and opposition spokesperson. Historic England had no formal locus in this, as no listed building application was involved for this Grade I building (unlike the similarly controversial one regarding Trinity College New Court – see my article in the 2022 IHBC Yearbook). The decision notice [5] includes a condition requiring the panels to be removed within 30 years, and an informative covering maintenance and fire safety.

How many Context readers have seen this decision quoted as a precedent for all historic roofs, anywhere? Does it set any form of precedent? In the absence of a clear anchor, such as BS EN 16883:2017, the Cambridge councillors’ politically simple message, and view of public benefit, were almost bound to trump professional complexities. The public consultation was inadequate because the trial panels were invisible throughout the consideration of both applications.

The annual carbon savings to which the councillors attached great weight are comparable to the carbon cost of just 28 people flying from London to New York [6], a point not put to the committee. ‘Less than substantial harm’ to the internationally outstanding significance of the chapel, with minimal impact on historic fabric, provides no general justification for solar PV on other historic buildings, whose roofs form a substantial part of their significance, and whose fabric may in some cases require alteration to carry the weight of PV. What may (just) work in terms of visual impact on the uniform, part-concealed roof slopes of King’s College Chapel, certainly will not on the irregular profiles and rich textures of old tiles or thatch. So, no precedent: each case has to be considered on its merits.

No general conclusions should be drawn from this highly individual and flawed case. Historic England’s recommendation left it to the council to determine the balance between the public benefit of the renewables and the harm to the listed building. The Cambridge councillors have done just that, determined to be radical in the fight against climate change. Their message is out. The heritage sector must face up to the implications.

References:

1 Cambridge City Council Planning Committee Report http://bc-url.com/ctx176jp1 http://bc-url.com/ctx176jp2
2 http://bc-url.com/ctx176jp3
3 http://bc-url.com/ctx176jp4 to see the planning application documents and supporting information
4 http://bc-url.com/ctx176jp5
5 http://bc-url.com/ctx176jp6
6 Savings according to updated figures on amendment sheet 27. See http://bc-url.com/ctx176jp7 and http://bc-url.com/ctx176jp8

This article originally appeared as ‘A world-wide precedent for solar panels?’ in the Institute of Historic Building Conservation’s (IHBC’s) Context 176, published in June 2023. It was written by John Preston who had many dealings with King’s College during his 22 years with Cambridge City Council. He engaged with this proposal as Sustainable Traditional Buildings Alliance heritage chair (and raised it at IHBC policy committee), and as a local professional, resident and artist. He is very grateful for the input of Oliver Caroe, the college’s architect, Christian Brady of Cambridge City Council, and Historic England.