King’s College Chapel, Cambridge – Assessment of data

As part of its policy on climate change, King’s College wished to place solar panels on both the north and south sides of the Chapel roof. In Re King’s College Chapel Cambridge [2023] ECC Ely 1, (“the principal judgment”) reviewed here, the court determined that a faculty would be granted either for their installation on both sides of the Chapel roof or only on the south side, depending upon an updated assessment of the potential carbon payback information. Additionally, the latter option was conditional on an assessment of the effect on the structure without an identical weight on the north roof.

The required calculations were presented to the court and assessed by the Chancellor, Re King’s College Chapel Cambridge (2) [2023] ECC Ely 2 (“the supplementary judgment”). Whilst the court’s decision is not problematic per se, it is difficult from the reported judgment to evince details of the information on which the decision was made.

Earlier assertions 

In Re King’s College Chapel Cambridge [2023] ECC Ely 1 the Chancellor set out the responses of the amenity societies and consultees in detail, [13] to [40], “because their overall contribution to the decisions that Chancellors have to make cannot be overstated” [13]. As noted in the earlier post, some of the information provided related to the College Chapel, whilst other considered the panels in relation to the College estate or to the heritage assets of Cambridge as a whole. Furthermore, whilst some energy data were the result of detailed calculation, other information did not seem to have been subjected to such rigorous scrutiny, and some (particularly in the visual aspects) reflected a degree of subjectivity. Furthermore, only the college Chapel is subject to the faculty jurisdiction.

Broadly, two issues were of concern – the energy generation from the PV array and the visual impact of the proposed 492 panels on the roof. Summarizing the situation, Leonard Ch. commented: “The fundamental question I will need to consider before deciding whether to issue a faculty is the visual impact of placing solar panels on the roof on the Chapel overall. A subsidiary but aligned issue is that of “reflection” [65]. However, underpinning this consideration were the requirements of ecclesiastical law relating to carbon emissions.

The Society for the Preservation of Ancient Buildings (“SPAB”) asserted [25] that: “The north roof will produce 60% of the electricity of that of the south roof which could result in the north roof having a carbon payback of over 10 years thus emitting more carbon into the climate between now and 2030, not less“. Clearly, solar panels do not emit carbon dioxide, and implicit in this quantitative statement is the inclusion of “embodied carbon” in the calculations; however, the emissions included in “embodied carbon” are generated prior to the operational phase of the solar panels.

The Church Buildings Council (CBC) was not satisfied that the calculations, with which they were provided initially, had included the embodied carbon of the installation in order “to arrive at an estimate of when it will break even in carbon terms. Such calculations will need to distinguish between north and south [roofs]”.

The principal judgment concluded with the granting of a faculty which was conditional inter alia on the provisions by the Petitioner on an updated assessment of the carbon payback for the north roof in light of, in particular, the CBC’s latest calculations [91(b)]. The issues relating to embodied carbon are discussed further in the postscript.

Further submissions to the court

In the supplementary judgment, the Petitioner submitted: the report from Max Fordham; the submission from the CBC; from Historic England; and two documents from the DAC. Having read these, Leonard Ch. was satisfied that “there is a clear and convincing justification for installing panels on the north roof as well as the south roof and the faculty can be issued accordingly”. However, it is difficult for the reader to reach this conclusion on the basis of the information presented in this section of the judgment (on pages 1 to 3); this commences:

The efficiency of panels on the north slope: whilst the petitioner and the CBC are now agreed that BEIS methodology should be adopted, they cannot agree which column should be used, whether the long-run marginal or the grid average column is appropriate”.

The absence of an explanation of “BEIS methodology” or the relevance of the “columns” to be used, is compounded by uncited references to “Chapter 3 of the ‘valuation of energy use and greenhouse gas emissions’ the method adopted by Max Fordham”. [It is notable that the earlier judgment, the Chancellor indicated with regret that, “even with the help of ‘word search’, I have been unable to locate those words in that report or any other report written by Max Fordham with which I have been provided [32]”].

Nevertheless, in relation to this post and with the help of a “web search”, it was possible to locate the document to which these references appear to apply: Valuation of energy use and greenhouse gas (GHG) emissions: Supplementary guidance to the HM Treasury Green Book on Appraisal and Evaluation in Central Government (January 2023). This “is a supplement to HM Treasury’s Green Book” (2020 minor updates published in 2022), and provides specific guidance on how analysts should quantify and value energy use and emissions of greenhouse gases (GHGs)”. These documents provide an essential “missing link” to the understanding of the submissions to the court.

By way of contrast to these detailed documents, the judgment noted that the DAC had “also been able to consider the latest government policy report, Powering up Britain, (March 2023)…which provides further support for the use of [roofs] for solar panels”. This “further support” is limited a single sentence in the 30-page report, viz. “Government is seeking widespread deployment of rooftop solar in commercial, industrial and domestic properties across the UK”.

The efficiency of panels on the north slope of the chapel roof

In its evidence to the supplementary judgment, the DAC submitted that the text of Chapter 3 of the BEIS document was clear and in support of the Max Fordham position [page 2, para.2]:

“The assessment concerns the change in electricity generation by the national network that will result from the deployment of the King’s PV array. Although this will fluctuate according to the weather, the overall effect of the PV array will be that just a little less electricity will have to be generated by the national network. This is a marginal change and so the marginal figures should be used”.

Having read these further submissions Leonard Ch. was satisfied that there was a clear and convincing justification for installing panels on the north roof as well as the south roof and the faculty could be issued accordingly. In addition, it follows that “any concerns which I raised about the effect on the roof of an uneven load, and which seem to have been confirmed by a structural engineer, fall away”.

He also noted that addition of an overlay such as Solarskin [an adhesive overlay which might make a difference to the visual impact pf the panels] would reduce their effectiveness by approximately 10%, and was unlikely to be of any sufficient visual benefit to make the loss of effectiveness justifiable. Nevertheless, this was not one of the conditions on granting a faculty.


In its initial response in October 2022, Historic England (“HE”) commented:

“[40(b)] Whilst the Church of England’s RouteMap to net-zero provides a clear indication the importance of renewable energy generation, it does not provide guidance on how to set this against the “strong presumption against proposals which will adversely affect the special character of a listed building”.

That position has now been clarified by the present case. In the principal judgment, having first considered Re St John the Baptist, Penshurst [2015] (Court of Arches) and following the guidance in Re St. Alkmund, Duffield [2013] Fam 158, the Chancellor determined that the harm would be less somewhere above minimal; “the harm is much reduced because there are only some places from which the roof can be seen and, in the context of the building as a whole, both inside and out, the roof is not the feature which has led to its international renown” [85].

In terms of “how clear and convincing is the justification for carrying out the proposals”, he was satisfied that the scheme would allow the Chapel to reach net-zero in respect of its electricity demands, and “[a]lthough not bound to do, so, they have fulfilled the Diocesan and Church of England aim to be net-zero as a church within the diocese” [85]. Leonard Ch. concluded [emphasis added]:

“[90]. I have no doubt that this project is in accordance with the fifth mark of mission. Showing the church to be at the forefront of taking measures to combat climate change is in strong support of its mission generally.

I agree with the view expressed by SPAB that this is likely to be regarded as a precedent, which if not done well, could have adverse consequences for other highly designated buildings contemplating similar schemes. I judge that, through the careful planning that has been done on this scheme, it has been “done well” and it ought to act as encouragement to other churches, and possibly other public buildings, to take a careful look at whether they can also contribute to reducing carbon emissions.

In coming to this decision, I have not lost sight of the fact that this is a Grade I listed building of an exceptional nature but, as I have already found, I do not judge that this will cause serious harm to the Chapel.”



An important issue was the treatment of embodied carbon (by whatever name called), and how this relates to the achievement of the Church’s “net zero” targets. Embodied or embedded carbon is associated with the emissions released through extraction, manufacturing, transportation, assembly, maintenance, replacement, deconstruction, disposal, and end-of-life aspects of the PV panels. As such, these emissions are distinct from the operational phase of the panels, although they are taken into consideration such as the carbon “pay-back” period for their installation.

The BEIS guidance to which the Petitioners and Max Fordham allude, supra, states: “…there is no requirement to include embedded emissions in the UK inventory “… [para 3.40 and footnote 19]”, “although…the decision-making and appraisal process should take into account the impact of UK policy on emissions from abroad if it is appropriate…proportionate and practical.”

The Church of England’s document A Brief Guide to Solar Panels and Faculty states [emphasis added]: “The environmental impact (‘embodied carbon’) of the installation itself should be considered and weighed against the clean electricity produced (‘operational carbon’) to estimate – at least roughly – when the panels will pay back from an environmental perspective“. Consequently,

  • regardless of the length of the pay-back period used, the PV panels will, mutatis mutandis, generate the approximately same amount of electricity both throughout this period and then when this period is ended.
  • if embodied carbon is incorporated into the emission calculations, a longer pay-back period will be associated with lower calculated emissions for each year during this period.

Use in judgments

In the supplementary judgment, the Chancellor noted [emphasis added]:

“Using the agreed BEIS methodology, the long-term marginal figures created a carbon payback time of 7.4 years for the north slope [6.4 years in the principal judgment (at [48(b)]) and 4.5 years for the south slope, the north slope having, therefore, a 69% efficiency of the south slope. The column preferred by the CBC would not produce a carbon payback over the lifetime of the panels.

No data are given which quantify this last assertion, although the panels’ life time is alluded to at [42] of the principal judgment; this also noted that “[o]f the eleven different makes of panel were compared and the REC-Alpha Pure 410 was selected [48(a)]. The premium warranty package on the manufacturer’s data sheet indicates that 92% output is guaranteed after 25 years, with up to 25 years product and labour coverage.


The issue of “embodied carbon” arose again in Re St. Michael Wandsworth Common [2023] ECC Swk 2, dated 12 May 2023, about six weeks after the second judgment on King’s College Chapel. This concerned the replacement of the existing gas boiler and radiators with a ChurchEcoMiser system, involving the installation of 23 new electric radiators. The DAC commented [emphasis added]:

“[19]. …as regards earlier DAC advice/comments about factoring in ‘embodied carbon’ (i.e. the carbon emissions involved), there is not yet an agreed methodology to assess embodied carbon objectively and accurately within these types of proposals and to weigh it up against reductions in operational carbon emissions“.

Embodied carbon is not in scope of the Church of England’s net zero carbon target until after 2030, although CBC Guidance states “churches can take action now, and it is important to consider when carrying out maintenance and renovations to further aid emissions reduction”.

Last updated 21 May 2023 at 07:24.

David Pocklington

Cite this article as: David Pocklington, "King’s College Chapel, Cambridge – Assessment of data" in Law & Religion UK, 17 May 2023,


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