Exploring Carbon Neutral Potential in Urban Densification: A Precinct Perspective and Scenario Analysis

Bin Huang,Lida Liao,Stephen Pullen,Ke Xing

doi:10.3390/su12124814

Bin Huang, Lida Liao + Show 2 more

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https://doi.org/10.3390/su12124814

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Abstract

Decarbonising the urban built environment for reaching carbon neutrality is high on the agenda for many cities undergoing rapid expansion and densification. As an important urban form, precincts have been increasingly focused on as the context for urban redevelopment planning and at the forefront for trialling carbon reduction measures. However, due to interplays between the built forms and the occupancy, the carbon performance of a precinct is significantly affected by morphological variations, demographical changes, and renewable energy system deployment. Despite much research on the development of low-carbon precincts, there is limited analysis on aggregated effects of population growth, building energy efficiency, renewable energy penetration, and carbon reduction targets in relation to precinct carbon signature and carbon neutral potential for precinct redevelopment and decarbonisation planning. In this paper, an integrated carbon assessment model, including overall precinct carbon emissions and carbon offset contributed by precinct-scale renewable energy harvesting, is developed and applied to examine the lifecycle carbon signature of urban precincts. Using a case study on a residential precinct redevelopment, scenario analysis is employed to explore opportunities for decarbonising densification development and the carbon neutral potential. Results from scenario analysis indicate that redevelopment of buildings with higher-rated energy efficiency and increase of renewable energy penetration can have a long term positive impact on the carbon performance of urban precincts. Meanwhile, demographical factors in precinct evolution also have a strong influence on a precinct’s carbon neutral potential. Whilst population size exerts upward pressure on total carbon emissions, changes in family types and associated consumption behaviour, such as travelling, can make positive contributions to carbon reduction. The analysis also highlights the significance of embodied carbon to the total carbon signature and the carbon reduction potential of a precinct during densification, reinforcing the notion that “develop with less” is as important as carbon offsetting measures for decarbonising the precinct toward carbon neutrality.

Highlights

With the fast pace of spatial urbanisation and the expansion of urban population, most cities around the world, especially those in the Asia-Pacific region, have been continuously densified with expansion and redevelopment
This paper presents an integrated carbon assessment model that captures factors of urban evolution and renewable energy penetration to support the evaluation of decarbonisation options on a precinct scale
The overall precinct carbon signature can be assessed with four distinct but inter-linked components: (1) total lifecycle carbon embodied in precinct objects, renewable-energy harvesting units (RHUs), and transport systems; (2) total carbon emissions associated with energy consumption for the operation of precinct objects; (3) total carbon emissions associated with travels of precinct occupants; and (4) total carbon offsetting contributed by renewable energy harvesting

Summary

Introduction

With the fast pace of spatial urbanisation and the expansion of urban population, most cities around the world, especially those in the Asia-Pacific region, have been continuously densified with expansion and redevelopment. Much of these can be attributed to residential buildings [3,6] Significant proportions of such carbon footprint are consumption-based, including both the direct and the life-cycle carbon emissions associated with objects (e.g., buildings, equipment, infrastructure, space) and socio-economic activities (e.g., production, services, transport, lifestyle, and entertainment) within the geographical boundary of a city. These encompass those emissions occurring outside the city boundary but related to (or “embodied” in) goods and services consumed by functions and residents inside the city [7]. As reported in the study by Wiedmann et al, commercial and public sectors are responsible for only one third of consumption-based carbon emissions, whilst the rest (close to two thirds) are contributed by households, attributed to buildings, electricity and transport as well as public and commercial services [8]

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