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Decarbonising the English residential sector: modelling policies, technologies and behaviour within a heterogeneous building stock


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Authors

Kelly, Scott 

Abstract

The residential sector in England is often identified as having the largest potential for emissions reduction at some of the lowest costs when compared against other sectors. In spite of this, decarbonisation within the residential sector has not materialised. This thesis explores the complexities of decarbonising the residential sector in England using a whole systems approach. It is only when the interaction between social, psychological, regulatory, technical, material and economic factors are considered together that the behaviour of the system emerges and the relationships between different system components can be explained giving insight into the underlying issues of decarbonisation. Building regulations, assessments and certification standards are critical for motivating and driving innovation towards decarbonising the building stock. Many existing building performance and evaluation tools are shown to be ineffective and confound different policy objectives. Not only is the existing UK SAP standard shown to be a poor predictor of dwelling level energy demand but it perversely incentivises households to increase CO2 emissions. At the dwelling level, a structural equation model is developed to quantify direct, indirect and total effects on residential energy demand. Interestingly, building efficiency is shown to have reciprocal causality with a household’s propensity to consume energy. That is, dwellings with high-energy efficiency consume less energy, but homes with a propensity to consume more energy are also more likely to have higher energy efficiency. Internal dwelling temperature is one of the most important parameters for explaining residential energy demand over a heterogeneous building stock. Yet bottom up energy demand models inadequately incorporate internal temperature as a function of human behaviour. A panel model is developed to predict daily mean internal temperatures from individual dwellings. In this model, socio-demographic, behavioural, physical and environmental variables are combined to estimate the daily fluctuations of mean internal temperature demand. The internal temperature prediction model is then incorporated in a bottom-up engineering simulation model. The residential energy demand model is then used to project decarbonisation scenarios to 2050. Under the assumption of consistent energy demand fuel share allocation, modelling results suggest that emissions from the residential sector can be reduced from 125 MtCO2 to 44 MtCO2 after all major energy efficiency measures have been applied, the power sector is decarbonised and all newly constructed dwellings are zero carbon. Meeting future climate change targets will thus not only require extensive energy efficiency upgrades to all existing dwellings but also the complete decarbonisation of end use energy demand. Such a challenge can only be met through the transformation of existing building regulations, models that properly allow for the effects of human behaviour, and flexible policies capable of maximising impact from a heterogeneous residential building stock.

Description

It is now widely accepted that the residential sector offers significant potential for carbon mitigation. This is true for both the overall magnitude of emissions reductions and the cost per tonne of CO2(eq) mitigated. However, both the scope and scale of potential carbon mitigation pathways remain controversial. The pace of decarbonisation is also openly debated. Examples of some of these contentions include: centralised versus decentralised energy supply; energy efficiency versus low carbon generation; demolition versus renovation of the existing building stock and behaviour change versus technological solutions. Incontrovertibly, any one of these seemingly apparent tensions is not mutually exclusive, and the ultimate decarbonisation pathway will likely consist of most if not all of these proposed solutions being implemented to some varying degree. Despite the significant potential for carbon mitigation in the built environment, deep cuts have not yet materialised. It is argued that this lack of progress stems from a poor understanding of the highly complex socio-economic, socio-dynamic and technical physical systems that underpin energy use in dwellings.Modelling this requires requires novel methods capable of capturing the complexities that arise from government policies, physical processes and technologies, human behaviour and economics. Moreover, as the effects of climate change are directly caused by the global stock of CO2(eq) in the atmosphere, the pace of decarbonisation is pivotal. New methods may prove important for representing the interactions that occur between technological sub-systems but also for modelling how the system may change over time, including feedbacks and delays endogenous to the system. The motivation for this thesis aims to explore decarbonisation opportunities from the residential sector by adopting an integrated systems perspective whilst maintaining the complexity and heterogeneity that naturally exists within the residential sector and between people.

Date

Advisors

Keywords

Buildings, Energy, Behaviour, Modelling, Systems, Building stock, Energy demand, Temperature

Qualification

Doctor of Philosophy (PhD)

Awarding Institution

University of Cambridge
Sponsorship
Cambridge Econometrics Bursary, University College London (CARB-HES dataset)