Retrofit for the Future and the missed opportunity of offsite renewable energy

If this property’s share in our community-owned wind turbine were taken into account, it would have the lowest energy use and CO2 emissions of all properties in the recent Government-backed Retrofit Revealed report.

Retrofit for the Future

The Government’s Technology Strategy Board (TSB) funded the Retrofit for the Future competition to encourage innovation in the retrofit market and understand what actually works.  87 projects were awarded up to £150k each to retrofit social housing units, aiming to achieve an 80% reduction in CO2 levels compared to 1990 averages.  Our turbine’s project managers at Hockerton Housing Project (HHP) won funding for a project to retrofit 2 semi-detached houses in Newark, Notts, which have now been re-occupied for over 2 years.

The projects were included in a recent report by the Technology Strategy Board, Retrofit Revealed, providing the first analysis of data from the monitoring of 37 of the projects. Whilst the published results look good, they are not the full story due to the role played in the design by the Hockerton wind turbine.

As the project split the (not inconsiderable) budget between two properties, we were pleased to see that one of our retrofitted houses (property number TSB023) still had the 8th lowest level of CO2/m2 (3rd best of the all-electric properties) whilst the other (property number TSB022) was a credible 26th.  In terms of total energy use (per m2), the properties were 4th and 12th respectively.  This shows the impact of being an all-electric property, as electricity has a much higher carbon intensity than gas; and the impact of resident behaviour, as the houses are built and retrofitted to identical specifications.

The choice of going ‘all-electric’ was deliberate: it is not a finite resource like gas; and because the design off-set that electricity use through investment (from the project budget) in a local community-owned wind turbine.

The impact of this investment is not recognised by the TSB report but it has proven much more cost-effective and a lower maintenance approach than on-site renewables.  Analysis of the energy data for Property TSB023, for which we have 2 years of meter readings, shows that if its share of SHOCK turbine generation were taken into account, it would have the lowest energy use and CO2 emissions of all properties. A £1,500 investment offset 43% of the annual energy use, and at the same time the social landlord has a regular income rather than a maintenance overhead.

This offsite offset would not be recognised in the properties’ Energy Performance Certificates (EPC) either.  This matters because the Government said in their Energy Efficiency Strategy that it intends to make more policies conditional on energy efficiency. Onsite renewables would be recognised, but what about all those unable to install systems onsite due to property type, leasehold or planning restrictions? Or simply unable to afford an onsite system at higher upfront cost per kW?

Further key aspects of our design (passive solar gain, high thermal mass and buffer zones) are not fully recognised by SAP, the Government’s assessment tool, and so similarly the benefits would not be fully registered in the EPC.

Here’s hoping that TSB take a technology-neutral look at the results and feedback into SAP what really works for different properties, and their residents.




  1. It will be interesting to see what the maintenance of the properties is like over time in relation to the unimproved housing stock. I think that was what impressed me so much when I finally visited you some 13 years after the first Hockerton block was built. Just how robust the materials you used are and how little maintenance has been required. I look forward to hearing about these properties in 10 years time or more and comparing them to other refurbishment projects in the scheme.


    1. These are not the housing units at Hockerton – the article here refers to the 2 semis in Newark (see photo ) which were retro-fitted by HHP in 2010 / 11


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