Energizing Sustainable Cities

Assessing Urban Energy

Arnulf Grubler, David Fisk

• Publisher: Routledge
• Year: 2012
• Print ISBN: 9781849714396
• eBook ISBN: 9781136273629
• Edition: 1
• Topic: Arquitectura
• Subtopic: Planificación urbana y paisajismo

Urban systems now house about half of the world's population, but determine some three quarters of the global economy and its associated energy use and resulting environmental impacts. The twenty-first century will be increasingly urban. Sustainable development therefore needs first to be defined and analyzed, and then realized in urban settings. Energy is one of the key challenges, but also one of the key opportunities in the required urban sustainability transition.

The book is the result of a major international effort to conduct the first comprehensive assessment of energy-related urban sustainability issues conducted under the auspices of the Global Energy Assessment (GEA). The assessment is also unique in that it embeds energy issues into the broader sustainability agenda of cities: including housing for the poor, functional transport systems, as well as environmental quality, in addition to the challenges imposed by climate change.

Written by an eminent team of internationally renowned scholars it presents new data, new analysis, as well as new policy insights. It includes the first comprehensive global coverage overview of urban energy use and of the specifics of urban energy demand and supply. Major development and sustainability challenges of cities are assessed in detail and public and private sector opportunities and constraints of a sustainability transition examined in detail. Technological and policy options are put in a much needed context in terms of their respective role as drivers of urban energy demand as well as potentials for reductions in energy use and associated emissions of local pollutants as well as greenhouse gases. The analysis presents both a comprehensive literature review as well as novel, spatially explicit models of integrated urban energy policy analysis. The volume concludes with a summary assessment of policy options, priorities as well as paradoxes.

1
Introduction and overview

Arnulf Grubler and David Fisk

1.1 Setting the urban stage

The decade 2000–2010 marked an important watershed in human history: for the first time more than 50 percent of the global population are urban dwellers. Estimates as reviewed in this book indicate that already some three-quarters of global energy use takes place in an urban context.

Given the robust trends toward further urbanization, the energy and sustainability challenges of equitable access to clean-energy services, of energy security, and of environmental compatibility at local through global scales cannot be addressed without explicit consideration of the specific opportunities and challenges of urban energy systems. The future development of the demand for energy cannot be described without understanding changes at the level of urban settlements. Research shows how the properties of urban areas across the world, while appearing diverse, are in fact scalable, revealing distinct patterns. Just as it is possible ‘to fail to see the forest for the trees', it is possible ‘to fail to see the city for the buildings’. A comprehensive energy assessment with an explicit urban focus and embracing a systems view has to date been missing. This book aims towards filling that gap. A systems perspective on urban energy use remains underdeveloped to date and paradoxes and conundrums in conventional analysis abound. A single urban agglomeration, such as greater Tokyo, generates more gross domestic product (GDP) than the venerable pioneer country of the Industrial Revolution — the current United Kingdom. And yet, our statistical reporting systems almost exclusively focus on nation states, as represented by Systems of National Accounts, Energy Balances, or similar international reporting standards. In fact, as detailed throughout this book, the difficulty of finding data at the urban scale starts with the search for an operational definition of urban areas and thus urban populations and their energy use.

From the perspectives outlined in this book the traditional territorial-administrative boundaries that define distinct ‘cities' is complemented by an ‘urban system’ perspective, where the urban phenomenon is seen from a functional perspective that transcends traditional territorial or administrative system boundaries. Thus, an urban energy system comprises all components related to the use and provision of energy services associated with a functional urban system, irrespective of where the associated energy use and conversion are located in space, such as power plants linked to the urban area by a power grid and transport fuel requirements for movements of people and goods that are both local as well as global (arriving and departing at urban airports and ports). The full urban energy system entails both energy flows proper (fuels, ‘direct’ energy flows) as well as ‘embodied’ energy (e.g. energy used in the production of goods and provision of services imported into an urban system. Likewise direct energy uses in an urban system in turn become ‘embodied’ energy in the goods and services exported from an urban system). Such a functional perspective of urban energy systems highlights that urban locations and their growth (urbanization) are not only the clustering of people and economic activities in space, but also include the types of activities they pursue and the infrastructural and functional framing conditions (service functions) urban agglomerations provide. We contend that functional characteristics increasingly define urban areas and need to be better reflected in urban energy systems analysis, with a need to combine both ‘production’ and ‘consumption’ energy accountingperspectives. It is one of the (many) novel approaches of this book that the differences from alternative accounting methods are for the first time quantified, at least within the limits of the few available comprehensive urban energy accounts currently available. Likewise, this volume also extends — within the limits of available data — the traditional discussion of cities as defined by political and/or administrative boundaries towards urban agglomerations, including ‘periurban’ and larger metropolitan areas, all the way through to urban ‘clusters’ or ‘corridors’ to Doxiadis and Papaioannou's (1974) ‘ecumenopolis’.

The future development of urban energy systems is characterized by specific challenges and opportunities. The high density of population, economic activities, and resulting energy use severely limit an obvious sustainable energy choice: renewable energy. In many modern larger cities locally collected renewables can provide for only some 1 percent of urban energy use which implies large-scale imports of renewable energies generated elsewhere, much like in the currently dominating fossil energy systems. The diversity of activities and energy uses characteristic of urban systems opens numerous opportunities for intelligent energy management (e.g., electricity–heat cogeneration and ‘heat cascading’, in which different energy end uses can ‘feed’ on waste energy flows from energy conversion and industrial applications). Both diversity and density (at least above a critical threshold value of some 50–150 inhabitants/hectare of gross¹ settlement area) can be considered as key strategic assets of urban areas that help to use energy more efficiently by energy-systems integration, compact energy-efficient housing, and co-location of activities that can help to minimize transport distances and automobile dependence. The provision of transport services via high-quality urban public transport systems is a unique option for cities, generally not practical or economically viable in low-density sub-urban or rural contexts.

The vital urban infrastructures all depend on energy to function: water supply, treatment and waste water disposal, transport and communication systems, complex webs of food and material supplies and the resulting disposal of wastes, and, of course, energy supply itself for power and heating. Many urban infrastructures have shown great adaptability, but disasters such as hurricane Katrina's impact on New Orleans, or the 9/11 attacks on New York, show that urban systems and their populations are vulnerable because of infrastructural interdependence. Each urban infrastructure system is almost always managed in isolation, but this ignores their interdependence, and common vulnerabilities. Treating them in isolation also misses their potential synergies and efficiency gains. This highlights the importance of a systems perspective as well as of improved planning. But this will require new institutional frameworks and the inclusion of all relevant stakeholders to address the complex coordination issues across sectors and across spatial scales.

Urban agglomerations are dominant in terms of location of human activities, in the production and consumption of many goods and services, and in associated energy use. They are also unique centers of human capital, ingenuity and innovation, financial resources, and local decision-making processes, which are all ‘human’ resources/capital that can be mobilized, and at a vast scale. The urban scale is also the appropriate one to identify and realize many options in promoting energy efficiency that may not always be apparent at more centralized levels of policymaking.

1.2 Objectives and approach

Given the above, the broad objective of this book is to assess urban energy issues in an increasingly urbanizing world from a systemic perspective that focuses on the specific energy challenges and opportunities represented by urban settlements.

The specific objectives of this book are to perform first a global assessment to establish the order of magnitude of urban energy systems and their drivers, then develop some generalized explanations of urban energy use, and finally stress-test these explanations through case studies at the local and regional levels, drawing on specific examples of individual cities.

This book addresses the systemic and structural interlinkages of urban systems and how these interact within and outside traditional territorial urban system boundaries. It adds to the information and knowledge of traditional sectorial energy studies (buildings, industry, transport) by addressing the integrated issues specific and unique to urban systems. Sectorial perspectives are therefore addressed here only to the extent that they contain an explicit urban specificity, e.g. (public) urban transport systems, or urban energy cogeneration systems.

Urbanization is a multidimensional phenomenon that can be described from demographic, geographical, or economic perspectives. Empirical data are well developed for demographics (e.g. through regular population censuses) and for land-use perspectives (e.g. through remote sensing data). Conversely, there is a paucity of widely available and comparable economic data at the urban scale. Systems of National Accounts that underlie much of the available economic data were developed and continue to be used predominantly by national governments at the national scale, with comparatively few applications at the urban scale. The literature on urban land use and urban land-cover changes, while most valuable for describing a physical dimension of urbanization, is of limited use in an energy assessment despite the richness of quantitative data available. After all, it is not the square kilometers of urban extent that can explain urban energy use, but only the linkage of urban land use with demographic and economic data and characteristics as reflected through urban form and population density, infrastructure endowments, level and structure of economic activities, lifestyles of city dwellers, among others. Therefore, demographics (population sizes and their characteristics) is adopted quite naturally as a fundamental driver and core metric to discuss urbanization and urban energy use in this volume, drawing on the urban land-use change and economics literature only to the degree necessary to understand urban energy use and its variation through derived metrics centered on population, like population density, or per capita incomes and expenditures, in addition to more narrow disciplinary land use and economic perspectives metrics, such as urban extents/form or economic structure.

As comprehensive energy information and accounts at the urban scale are extremely limited, developing a robust assessment storyline from the bottom-up alone is challenging. Therefore in the analyses a mixed approach of both top-down and bottom-up perspectives is adopted, combining estimates derived from ‘downscaling’ or remote-sensing approaches with bottom-up statistical information where available.

1.3 Context and origins

The origins of this book arose from a collaborative effort by the authors of the various chapters in this book under the auspices of the Global Energy Assessment (GEA), often labeled ‘the IPCC of energy’ and released in 2012. In the context of this book, GEA assumes a special role, as it represents the first international assessment in which the issue of urbanization has been raised explicitly. The inherently interdisciplinary nature of any study of urbanization as well as the dispersed nature of knowledge and disciplines involved in urban studies perhaps explains why previous major international assessments refrained from addressing urbanization explicitly. (All authors of this book are encouraged in their scientific mission by the fact that the ongoing next assessment cycle of the IPCC includes a special chapter on ‘human settlements’ to which both the GEA assessment as well as this book and its authors are contributing.) Already early on in the GEA, the writing team of its urbanization chapter realized that there is much more material to cover in this first assessment of its kind that could be accommodated within the space limitations of the overall GEA. This book therefore presents a both deepened and enlarged assessment of energy in an urbanizing world than was possible within GEA. The editors and authors of this volume would like to express their deep appreciation of the initiative GEA has taken in addressing urbanization as a core energy topic and acknowledge with gratitude all the inputs and freely shared knowledge from all contributing authors to the GEA urbanization chapter² as well as from the wider scientific GEA community that led to this book volume.

1.4 A roadmap of this book

This book is divided into three parts. Part I The urbanization context (Chapters 2–5) provides the context of the urbanization phenomenon both from empirical and conceptual perspectives. Part II The urban challenges (Chapters 6–8) reviews major challenges ahead in moving urban systems towards more sustainable development paths. Finally Part III Urban policy opportunities and responses (Chapter 9–12) addresses associated opportunities and policy responses in three key urban agenda items: transport, energy systems, and urban air-quality management. These core chapters are framed by an introduction (Chapter 1) that also includes a glossary of key terms, as well as by a summary and conclusion (Chapter 13).

Chapter 2 by Arnulf Grubler and Thomas Buettner provides a quantitative overview of the urbanization phenomenon. After reviewing the current state of urbanization, integrating multiple disciplinary perspectives including geography and land-use, demographics, economics, energy use, as well as other socio-economic and technological infrastructure indicators, the chapter focuses on the demographic dimension of urbanization, both from a historical as well as a futures (scenarios) perspectives. The chapter breaks new ground on several fronts, including a truly long-term historical perspective on urbanization that spans some 1,000 years, as well as an attempt to bracket the uncertainties surrounding future urbanization scenarios for the next 100 years that complement the long-standing central projections of the United Nations World Urbanization Prospects.

Chapter 3 by David Fisk provides a compact, ‘tour de force’ survey of the large-scale drivers and patterns of urbanization dynamics that adds the contextual and theoretical background to the quantitative assessment framed in Chapter 2. A key concept introduced in the chapter is that of complexity that is a hallmark of urban systems, both within (inter-urban) as well as in a global (intra-urban) context. An innovative feature of the chapter is to evoke Thorsten Hägerstrand's concept of ‘timing space, and spacing time’, with special reference to urban systems that are distinct in their time–geography ‘choreography’. Maximizing ‘contact potentials’, urbanites tend to move fast, as evidenced in their significantly higher observed walking speed in urban spaces compared to rural settings. The chapter concludes with a synoptic discussion of the specificities of urban energy systems, emphasizing in particular the potentials for innovation-inducement effects of urban energy and environmental constraints that give reason for cautious optimism: urban systems are highly innovative and could pave the way to a much needed sustainability transition.

Chapter 4, by Julia Steinberger and Helga Weisz addresses the intricate issue of urban systems boundaries and their implications for urban energy and greenhouse gases (GHG) accounting. Addressing the issue of where to appropriately draw systems boundaries is of critical importance in inherently open urban systems; the chapter also provides a most useful connection to concepts developed within the framework of industrial ecology and urban metabolism studies. The chapter is not only an essential primer on alternative methodologies and concepts of urban energy accounting that has not been available in any comparable form to date, but it also provides a first quantification and apples-to-apples compariso...

Table of contents

• Cover
• Half Title
• Full Title
• Copyright
• Contents
• List of plates
• List of figures
• List of boxes
• List of tables
• Notes on contributors
• 1 Introduction and overview
• PART I The urbanization context
• PART II The urban challenges
• PART III Urban policy opportunities and responses
• References
• Index