Highly Integrated Urban Energy, Water and Waste Systems

Highly integrated urban energy, water and waste systems Thomas Ravalde December 2018 Submitted for the degree of Doctor of Philosophy in Civil and Environmental Engineering of Imperial College London Copyright and license The copyright of this thesis rests with the author and is made available under a Creative Commons At- tribution Non-Commercial No Derivatives licence. Researchers are free to copy, distribute or transmit the thesis on the condition that they attribute it, that they do not use if for commercial purposes and that they do not alter, transform or build upon it. For any reuse or redistribution, researchers must make clear to others the licence terms of this work. Declaration of originality I declare that this thesis is my own work, and that the work of others is appropriately referenced and acknowledged. Revision fc5cfd1 on 2018-12-11 1 Abstract Urbanisation continues to bring socioeconomic well-being to an ever-growing global urban popula- tion. Nevertheless, there is an environmental and economic imperative for cities to use resources more sustainably. One way to achieve this is to take advantage of the fact that, in cities, resource management infrastructure from the energy, water and waste sectors is co-located, such that the wastes and by-products from one process can become the inputs to another (for example, sending organic waste to anaerobic digestion to produce biogas for energy generation). This thesis provides planners and policy makers with means to begin realising these intersectoral synergies, through contributions to the field of urban metabolism. First, a conceptual model is developed which can describe how a city’s mix of processes affect is metabolism. Second, methods are needed which quantify how well different sectors work together to make an area’s metabolism more efficient; to that end, analysis on historic urban resource flows show the usefulness of exergy analysis and ecological network analysis. Third, data is required which shows the possibilities for one process’s wastes to become another’s inputs; for this, a database is assembled which records the resource consumption and production of 202 types of urban resource management process, and made available under an open-source public license. Fourth, the Processes, Resource and Qualities (PRaQ) model is developed; PRaQ is a mixed-integer linear programme which simultaneously chooses the mix of energy, water and waste management processes an area could use to minimise an objective (emissions, for example), thereby taking into account intersectoral synergies. The formulation is made available as a benchmarking study to facilitate future development of the model. Applying PRaQ to a new urban development in China shows how an area’s urban metabolism can be made measurably more efficient according to various metrics. In summary, this work advances the urban metabolism concept for its application to improving urban resource sustainability, by showing how a city’s mix of process affects its overall metabolic flows. 2 Publications arising from this work Research presented in this thesis has been published in the following papers: • Ravalde, T. and Keirstead, J. (2015). Integrated Resource Planning for a Chinese Urban Devel- opment. In International Symposium for Next Generation Infrastructure Conference (ISNGI 2014), pages 59–62. UCL STEaPP. • Ravalde, T. and Keirstead, J. (2015a). A database to facilitate a process-oriented approach to urban metabolism. Journal of Industrial Ecology, 21(2):282–293. • Ravalde, T. and Keirstead, J. (2015b). Comparing performance metrics for multi-resource systems: The case of urban metabolism. Journal of Cleaner Production, 163:S241–S253. 3 Work done by the candidate The work (literature review, analysis, modelling and coding, summarisation of results and discussion) presented in this thesis has been carried out by the candidate unless otherwise stated. Dr Nouri Sam- satli shared the GAMS code for the model described in Samsatli et al. and Keirstead (2013), on which the Null model of Chapter 5 was based, and thus Dr Samsatli’s code provided inspiration for the encod- ing and architecture of code written for this thesis, though new code was developed by the candidate for the models. An initial mathematical formulation for attributing ’qualities’ to resources in the PRaQ model was proposed by Dr James Keirstead (Section 5.3.2). The published papers were written by the candidate, but benefited from feedback and proof-reading by the co-author, Dr Keirstead. 4 Resources arising from this work Where possible, I have made this work publicly available as open-source, in the spirit of helping others use, and build-upon the findings here. The work of this thesis has provided two tools to the urban metabolism research community: • The first is a database of processes which manage energy, water and waste in urban areas, recording the relative quantities of energy, water and waste resources these processes consume and produce. This is introduced in Chapter 4 and Ravalde and Keirstead (2017a). The database is available at https://github.com/tomravalde/urban-metabolism-process-database. • The second tool is a ‘benchmark problem’, which was used to test various possible formulations of the model this thesis develops. This is introduced in Chapter 5 and is available at https:// github.com/tomravalde/model-development-code. This enables others to test their own developments of the model on the same test problem which was used to develop the model in this thesis. For the sake of transparency, I have also made available: • The code for the case study to which the model was applied in Chapter 6. This can be found at https://github.com/tomravalde/shann-gu-case-study. • The source of the thesis itself. This thesis has been written using R-markdown1, which means that embedded within the text of the thesis is all the R-code used to manipulate and/or visualise any data which forms part of this thesis. The thesis source is available at https://github. com/tomravalde/thesis. 1An The knitr R-package (Xie, 2018) converts the R-markdown source (i.e. an *.Rmd file) into a markdown file (i.e. *.md, Gruber (2018)). A programme called pandoc – see MacFarlane (2017) then converts this to a TEXfile (*.tex), which is con- verted into this PDF via the LATEXdocument preparation system. Keiran Healy has made a well-argued justification for this type of workflow, as well as a helpful explanation of how to set it up (Healy, 2017). 5 Acknowledgements The completion of this thesis was only possible with the support of many people. In particular, I would like to thank my first supervisor, James Keirstead, whose insight and encourage- ment stimulated so much of the work here. I am indebted too to Ivan Stoianov who very kindly took over supervision part-way through the research. I am grateful too for Prof. Geoffrey Levermore and Dr Christian Onof for their helpful feedback during the viva voce. Imperial College have supported me by providing both funding (via the EPSRC Doctoral Training Part- nership) and a superb set of friends and colleagues (both academic and administrative). I would like to thank those in the Environmental and Water Resources Engineering Section, particularly my fellow members of the Urban Energy Systems group, and especially Stefan Pfenninger. Others in the Depart- ment have provided both their technical expertise and their friendship, in particular, Craig Buchanan, Mark Bruggemann, Li Ma and Karl Smith. I owe much to the wider academic community, including Prof. Chris Kennedy (University of Victoria) who provided the urban metabolism dataset used in Chapter 3, and Dr Yingru Zhao and her team (Xiamen University) who provided the case study for Chapter 6 and who generously hosted me for a week in China. The data for this case study was provided by the Shaan Gu Power Company Limited. I would also like to acknowledge Dr Nouri Samsatli for developing the urban energy systems formulation on which the model developed in Chapter 5 was based, and to thank him for sharing that model’s code. The online community more generally have also shaped this thesis, and I have enjoyed joining those who advocate for reproducible research and open source data and tools. Finally, thank you to my friends from Imperial College and Christ Church Kensington, and to all others who have supported me along the way, and most of all, my parents. 6 Contents Abstract 2 Publications arising from this work 3 Resources arising from this work 5 Acknowledgements 6 Contents 7 List of Figures 12 List of Tables 18 Abbreviations, acronyms, symbols, units of measurement, and other notation 20 1 Introduction 30 1.1 Urbanisation: the challenges ................................ 32 1.1.1 Environmental challenges ............................. 34 1.1.2 Economic challenges ................................ 37 1.2 Urbanisation: the opportunity ............................... 39 1.2.1 Intersectoral synergies ............................... 40 1.2.2 Intersectoral synergies in practice – industrial symbiosis ............ 42 1.2.3 Systems optimisation ................................ 43 1.3 Urban metabolism – the theoretical framework ...................... 45 1.4 Aims and scope of the study ................................. 46 7 Contents 1.4.1 Definition of thesis title and research boundaries ................ 47 1.4.2 Research question .................................. 49 1.4.3 Contributions .................................... 49 1.4.4 Thesis structure ..................................

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