DD2184 London Building Stock Model

Type of decision: 
Director's decision
Date signed: 
20 December 2017
Decision by: 
Fiona Fletcher-Smith, Executive Director of Development, Enterprise and Environment

Executive summary

The Mayor is committed to tackling fuel poverty and improving the energy efficiency of London’s homes.

In his draft Fuel Poverty Action Plan, he therefore committed to make available a new open-source, pan-London Energy Performance Certificate (EPC) data model in 2018 (the “London Building Stock Model”). This paper seeks approval for expenditure of up to £120,000 on this new address-level modelling tool that will help the GLA and boroughs identify and target London’s households (including those in fuel poverty) and businesses with energy efficiency improvements. The modelling tool will also inform the GLA’s guidance and support to boroughs on how they can legally and responsibly use data to identify households in fuel poverty, which in turn will help their enforcement of the Minimum Energy Efficiency Standard (MEES) which come into force from April 2018. Finally, it will enable boroughs and other agencies to identify the worst performing non-domestic buildings, enabling better targeting of business energy efficiency programmes, in particular those designed to support SMEs by helping them to reduce energy bills.

The modelling tool will provide a central database for all energy and carbon data collected through the Mayor’s Energy for Londoners programme and associated policies.


That the Executive Director, Development, Enterprise & Environment, approves expenditure of up to £120,000 on services required to create a new pan-London Energy Performance Certificate (EPC) data model.

Part 1: Non-confidential facts and advice

Introduction and background

The Mayor has an ambition to re-establish London’s position as a leader in tackling climate change and has set a target for London to become a zero-carbon city by 2050. Making London zero carbon will require economy-wide decarbonisation. This will involve changes to the way in which Londoners travel, work and live, including how energy is sourced and generated. Energy efficiency will have to increase dramatically, including by ensuring homes and workplaces are highly insulated. The fossil fuels used for heating and powering buildings, transport, and industry will have to be replaced by renewable energy sources. London’s grids will need to become smarter at balancing energy demand with available supply, and low carbon travel will be the default option.

Making London zero carbon will ensure long-term economic growth and new business opportunities, alongside wider environmental benefits, such as improved air quality and a healthier society. The Mayor’s Energy for Londoners programme aims to transform London’s energy system by reducing energy demand and improving the security of supply by ensuring more local energy is produced. This will help keep energy bills fairer, thus protecting the most vulnerable, and reducing carbon emissions.

Over the last few years, GLA officers have lobbied government on making Energy Performance Certificate (EPC) data (which estimate the energy use and associated annual carbon emissions of a building) available and free of charge. In 2016 the raw data was made available and the GLA now holds all available EPC records for buildings in London. The data set is incomplete, however: EPCs are only available for around a third of all domestic buildings. Display Energy Certificates, which show the actual energy performance of building, should also be available for large public-sector buildings. There are also a number of national and GLA programmes that install energy efficiency measures in buildings, however there is currently no single repository for collating information on what has been installed. We therefore need to combine several existing data sets into a single, easy to use database.

It remains a challenge to combine and over-lay energy performance data with socio-economic information to accurately identify fuel poor households. As highlighted in the Mayor’s draft Fuel Poverty Action Plan (FPAP), we want to remove this barrier, developing for the first time a London built-environment model (the “London Building Stock Model”) which displays information at an individual building level. This high-level of granularity will transform the approach to the targeting of energy efficiency and fuel poverty programmes under Energy for Londoners (EfL), giving a street by street view of London’s buildings.

Objectives and expected outcomes

The primary objectives of the London Building Stock Model are:

a. to help achieve objective 6.1 in the Mayor’s draft London Environment Strategy to reduce the emissions of London’s homes and workplaces while protecting the most vulnerable by tackling fuel poverty by enabling the easy identification of fuel poor households and low efficiency non-domestic buildings. This tool will enable both the GLA and external bodies e.g. boroughs and charities to better target policies and measures to help for example, fuel poor homes and businesses in London
b. allow for an identification of the number and location of buildings that do not comply with the Minimum Energy Efficiency Standards coming into force in 2018 and how many would be affected by the possible future tightening of national standards. This will be useful to inform national policy decisions and provide valuable information to potential investors and other interested third parties.

The model will also improve our understanding of London’s buildings and combine existing data sets into a single, user friendly model by:

a. developing a geographic information system (GIS) platform to host a spatial database for all domestic and non-domestic buildings in London. This platform will need to be flexible so that newly available data on new and existing buildings can be incorporated for example when new EPC or DEC (Display Energy Certificates) data becomes available or following the annual reporting of the impact of energy efficiency programmes
b. mapping the key characteristics of each building in London. These characteristics should include but are not limited to:

o building type
o building fabric
o building tenure and occupancy
o energy supply
o energy demand and fuel consumption
o conservation indicators
o socio-economic indicators
o building energy rating and emissions estimate

c. record energy efficiency measures already implemented by national energy efficiency programmes (e.g. through the Carbon Emissions Reduction Target and Energy Company Obligation) alongside GLA energy programmes
d. where EPC information is missing, estimate energy and carbon performance using known building characteristics
e. develop a user-friendly interface allowing data analysis and reporting to be undertaken quickly and easily.

While the core purpose of the London Building Stock Model is to provide a flexible analytical tool on London’s buildings to help the targeting of the Mayor’s programmes, it is anticipated, however, that the model may in the future need to incorporate the impact of London’s zero carbon pathways on the building stock out to 2050. The modelling architecture should therefore be flexible enough to allow for a temporal dimension to be added at a later date (although this does not form part of its initial scope).

The expected outcomes of the stock model are as follows:

a. complete mapping of London’s building stock showing buildings overall estimated or actual building energy and carbon performance, and possible energy efficiency measures yet to be installed
b. identification of the worst performing buildings and the homes most likely to be in fuel poverty.

We plan to procure and appoint a contractor to design and develop the London Building Stock Model, through a competitive tender. We will welcome consortium bids due to detailed nature of this work – to our knowledge there is no single organisation that holds all of the data required for constructing this modelling tool.

The Invitation to Tender will be issued in December 2017 and bids will be expected in early January 2017. We expect to award the contract around mid-January.

Once complete, the model will be GLA’s authoritative tool for understanding the energy performance of London’s buildings and how EfL programmes can target action. The GLA will make available to London boroughs a ‘LITE’ version of the model which will support, for example, how they can legally and responsibly use data to identify households in fuel poverty, which in turn will help their enforcement of the Minimum Energy Efficiency Standard (MEES) which come into force from April 2018.

Equality comments

The GLA will take appropriate steps to ensure that there are no potential negative impacts expected on those with protected characteristics. Those with protected characteristics will gain from the positive benefits of this scheme in equal measure should their homes be selected for trial, and there will be equality of access to participate in the delivery and benefit from the project, without discrimination.

It is expected that the modelling tool will have a positive impact on lower income and fuel poor households, that is, it will help the GLA, borough and others more accurately target support and improve awareness of the energy performance of homes and help target activity to reduce energy consumption.

Other considerations
    1. The key risks and issues for delivery of these projects are set out in the table below:



Likelihood (out of 5)


(out of 5)



Poor project scoping reduces value of work to the GLA, specifically the ability to use the model to target mayoral programmes.




GLA to produce detailed brief and scope to align with draft Environment Strategy objectives and commitments. All EfL teams to be consulted on project scope. 


Project lacks longevity.

Lack of long term support and refresh of data causes project to become outdated quickly.





GLA to allocate in-house analysis support to ensure external analysis is embedded in existing and future GLA model development. Project scope includes ability to update model at a later date and the provision of model user guides.

Lack of access to raw data requires high levels of interpolation, reducing accuracy of model 




Timing of stock model has been delayed intentionally until the release of Energy Performance Certificate data. All GLA datasets will be made available for project use.

Confidentiality of data restricts publication of model as a public interactive tool.




Project scope includes requirement for multiple access levels. Public version of model will protect any confidential data.

Financial comments

Executive Director’s approval is being sought to spend up to £120,000 on services required to create a new pan-London Energy Performance Certificate (EPC) data model. The contract for this work is to span two financial years (expected contract end date is December 2018), therefore the expected spend in 2017-18 is £40,000 and the remaining £80,000 in 2018-19. It should be noted that the budget for 2018-19 is subject to budget setting process.

The budget to fund the cost of this contract is the Environment Energy Efficiency Budget (Evidence and Analysis).

Activity table



Agree works scope and timetable

w/c 11 December 2017

Draft Invitation to Tender

w/c 11 December 2017

Issue Invitation to Tender

w/c 18 December 2017

Award contract to contractor

January 2018

Model methodology, design and development

Jan – May 2018

GLA approve structure

May 2018

Populate model

May – July 2018

GLA approve model

August 2018

Model complete

September 2018

Model published (and project close)

October 2018

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