Full set of modelling produced in relation to S6W-01241: FOI release

Information requested

I refer to the answer to S6W-01241. Under FOISA, please provide the full set of modelling produced by the Scottish Government, which is referred to in the answer to the question, where it is stated "Scottish Government modelling suggests that it could cost a total of £3.4 billion to bring 62% of Scottish social housing up to EPC band B using existing technology."

I.e. for the sake of clarity please do not simply provide the excerpt of the model that shows £3.4 billion to bring 62% of Scottish social housing up to EPC band B using existing technology, rather provide the full package of modelling that was performed that produced this work.

Response

The full set of modelling which underpins the estimated “total cost of £3.4 billion to bring 62% of Scottish social housing up to EPC band B using existing technology” is contained in the attached Excel workbook.

When interpreting the data, it is important to bear in mind the following context:

• These are indicative costs provided by seven volunteer social landlords who participated in the case study, and these costs were provided by them solely for the purpose of estimating likely costs if the new standard were to be introduced.
• The costing exercise was undertaken in 2018, and thus reflects costs and the state of technology as they existed at that date.
• The costs will also not reflect any changes to the overall regulatory environment since that date.

The methodology followed to produce these costs is set out from Page 14 onwards in the Consultation on the Energy Efficiency Standard for Social Housing post-2020 (EESSH2) Consultation on the Energy Efficiency Standard for Social Housing post-2020 (EESSH2). Key extracts are copied below (Social Landlord Case Studies) for ease of reference. I have also set out below (Guide to the Modelling Workbook) notes on what the Excel workbook contains to aid understanding of the modelling.

Social Landlord Case Studies
"53. In estimating the impact of the proposed new standard, a similar process was undertaken to that which was introduced when developing EESSH1. A number of social landlords, both local authorities and RSLs, volunteered to model how much of their stock could be upgraded to the new standard, and at what cost. The volunteers were selected to represent a broad range of landlords (e.g. landlord/dwelling type, urban/ rural). Their stock comprises around 19% of local authority stock, 5% of RSL stock, and 12% of total social sector stock. The representativeness of the case study stock was assessed using Scottish House Condition Survey (SHCS) data. This indicated that the stock of the case study landlords was broadly representative of the wider Scottish social housing stock.

54. In the first stage of the modelling, landlords upgraded their stock to meet EESSH1 in 2020, and reported how much of their stock would already comply with EESSH2 in 2020. The second stage involved applying a set of reasonable measures to the dwellings which failed to meet EESSH2. These measures are classified as “reasonable” on the grounds that they offer reasonable payoff in terms of fuel bill savings relative to the cost of installing them. The third stage involved applying a set of additional measures to the upgraded stock, and recording dwellings that will meet EESSH2 after reasonable and additional measures had been applied. “Additional measures” refer to measures which tend to offer a lower payoff than reasonable measures. The fourth and final stage involved recording dwellings that will meet EESSH2, after reasonable, additional and further energy efficiency measures have been applied. The set of “further measures” was not pre-specified, but instead landlords were free to model the impact of any other upgrades that they thought might be relevant for their stock…

59. As the case studies cover a significant share of the total social housing stock (c.12%), and the case study stock is broadly representative of the wider social stock, the case study results were grossed up to estimate indicative figures at the Scottish level….”

Guide to the Modelling Workbook
SAP – sets out which version of Standard Assessment Procedure (SAP) was used by each landlord

Stock type – gives a breakdown of the stock of each landlord, by dwelling form (flat, four-in-block, nondetached and detached houses) and fuel type (gas, electric, biomass, other), and then summarises the case study stock by fuel type and build form – this data was compared to Scottish House Condition Survey data to show that case study stock was broadly similar to the overall social sector stock.

EESSH1 – sets out the proportion of each landlord’s stock which is modelled as being able to meet EESSH1, including after the application of measures where necessary.

EESSH2 – sets out the EESSH2 attainment rates for each landlord (1) based on stock already in compliance with EESSH2 in 2020, (2) after the application of reasonable measures, (3) after the application of reasonable and additional measures, and (4) after the additional of reasonable, additional and further measures.

Unit costs – sets out the indicative unit costs for each measure which were provided to case study landlords, alongside actual unit costs used by landlords in their modelling

Number of measures – sets out the number of measures of each type modelled by each landlord

Total cost of measures – sets out the total cost of type of measure modelled by each landlord

Summary – summarises the results with respect to (1) average unit cost by broad category of measure (i.e. whether reasonable, additional or further measure), the EESSH2 compliance rate after each stage of the modelling, and the percentage point improvement in the EESSH2 compliance rate after each stage. The results are presented for (1) all case study landlords, (2) case study landlords which are local authorities, and (3) case study landlords which are Registered Social Landlords.

Sector summary – this grosses up the results presented in the summary tab to represent the social sector as a whole, assuming the case study landlords are broadly representative. This grossing up is done separately for the local authority sector (using the results in the summary tab for those case study landlords who are local authorities, and multiplying by the total local authority stock in Scotland where necessary) and for the Registered Social Landlord sector (using the results in the summary tab for those
case study landlords who are Registered Social Landlords, and multiplying by the total Registered Social Landlord stock in Scotland where necessary).

The sector summary tab also shows, by way of comparison, results from a similar exercise undertaken in parallel using the National Housing Model (NHM). In producing these results, social housing stock profile data was drawn from the Scottish House Condition Survey. The NHM then applies Standard Assessment Procedure (SAP) methodology to identify a suitable package of measures to achieve the target EPC score at the lowest cost, reporting on the costs incurred to achieve this standard and the resulting benefits in terms of fuel bill, energy and carbon savings. Further detail on the NHM modelling is set out from page 16 onwards in the Consultation on the Energy Efficiency Standard for Social Housing post-2020 (EESSH2) Consultation on the Energy Efficiency Standard for Social Housing post-2020 (EESSH2).

Comments – set outs some notes relevant to the interpretation of individual landlord data.

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FOI202100229071 - Information released

File type

Excel document

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113.8 kB