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URBAN PATTERNS FOR
A GREEN ECONOMY
OPTIMIZING
INFRASTRUCTURE
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URBAN PATTERNS FORA GREEN ECONOMYOPTIMIZINGINFRASTRUCTURE
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URBAN PATTERNS FOR A GREEN ECONOMY: OPTIMIZING INFRASTRUCTURE
All rights reservedUnited Nations Human Settlements Programme (UN-Habitat)P.O Box 30030 00100 Nairobi GPO KENYA
Tel: 254-020-7623120 (Central Office)www.unhabitat.org
HS/046/12EISBN (Series): 978-92-1-133398-5ISBN (Volume): 978-92-1-132461-7
DISCLAIMER
The designations employed and the presentation of material in this report do not implythe expression of any opinion whatsoever on the part of the Secretariat of the UnitedNations concerning the legal status of any country, territory, city or area or of its authorities,or concerning the delimitation of its frontiers or boundaries, or regarding its economicsystem or degree of development. The analysis conclusions and recommendations of thispublication do not necessarily reflect the views of the United Nations Human SettlementsProgramme or its Governing Council.
Cover photo: Redesigned shelter at a bus stop in Uberlndia, Brazil, whosepublic transport network connects the central areas of the citywith the outlying neighbourhoods along three main arteries UN-Habitat/Alessandro Scotti
ACKNOWLEDGEMENTS
Project Supervisor: Rafael TutsProject Manager: Andrew RuddProject Consultant: Mark SwillingCoordinating Author: Blake RobinsonPrincipal Author: Blake RobinsonAssistant Author: Mark SwillingCase Study Authors: Natalie Mayer, Ibidun Adelekan, Lauren Tavener-Smith,
Damian Conway, Oscar Ricardo Schmeiske, Stefanie SwanepoelLead Reviewer: Richard PalmerGeneral Reviewers: Daniel Irurah, Gordon PiriePublication Coordinator: Ndinda MwongoGraphic Contributor: Richa JoshiEditor: Victoria QuinlanDesign and layout: Samuel Kinyanjui
Printer: UNON, Publishing Services Section, Nairobi ISO14001:2004-certified
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Foreword
The city is one of the highest pinnacles ofhuman creation. Concentrating so manypeople in dense, interactive, shared spaceshas historically provided distinct advantages,that is, agglomeration advantages. Throughagglomeration, cities have the power to
innovate, generate wealth, enhance qualityof life and accommodate more peoplewithin a smaller footprint at lower per-capita resource use and emissions than anyother settlement pattern.
Figure I:Greenhouse gas emissions and containment index for selected metropolitanregions
Philipp Rode
Denver
25
GreenHouseGasemissionspercap
ita(MtCO2eq)
Metropolitan region containment index (1995 - 2005)(difference in population growth rates between core and belt)
20
15
10
0
5
Washington
HoustonFrankfurt
Portland
London
HelsinkiBrussels
Chicago
Minneapolis
Dallas
Baltimore
Philadelphia
Prague
San Francisco Hamburg
Berlin
Paris
Oslo Stockholm
1%0%-1%-2%-3%
Rsquare=0.503
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acute in fast-growing cities, particularlythose with the lowest institutional capacities,weakest environmental protections andlongest infrastructure backlogs.
Increasingly, city managers wish to learnby example. Rather than more theory andprinciples, they want to know what hasworked, what has not, and which lessonsare transferrable to their own contexts.There is much information available, butlittle time. UN-Habitat has developed thesequick guides for urban practitionerswho need condensed resources at theirfingertips. The aim is to suggest patternsthat can help cities and city-regions regainthese inherent advantages in a time ofincreased uncertainty and unprecedenteddemographic expansion.
More than half the global population nowlives in towns and cities. By the year 2050,UN-Habitat research projects that thatfigure will rise to two-thirds. This rapid,large-scale concentration of humanity in theworlds cities represents new challenges for
ingenuity, and numerous opportunities toimprove the way in which human habitatsare shaped. Most of this population growthwill be in the cities of developing countries,which are expected to grow by an additional1.3 billion people by 2030, compared to 100million in the cities of the developed worldover the same period.3
While urban population growth rates are
stabilizing in regions which are alreadypredominantly urban (such as Europe,North, South and Central America andOceania), regions with a higher proportionof rural population (such as Asia and Africa)are likely to see exponential rates of urbanpopulation growth in the coming years.4Most urbanization is likely to occur in citiesrelatively unprepared to accommodatethese numbers, with potential negative
repercussions for quality of life, economicdevelopment and the natural environment.
Although the percentage of the urbanpopulation living in slums worldwide hasdecreased, the absolute number of peopleliving in slums continues to grow.5No lessthan 62 per cent of all urban dwellers in
sub-Saharan Africa live in slums, comparedto Asia where it varies between 24 percent and 43 per cent, and Latin Americaand the Caribbean where slums makeup 27 per cent of the urban population.6If these growing cities are to be sociallysustainable, new approaches will berequired to integrate the poor so thatthe urbanization process improves inter-generational equity rather than entrenchingsocio-spatial fragmentation. Privatizedmodels of service delivery that discriminatebetween consumers based on their abilityto pay threaten to worsen inequalities,7andrequire carefully considered parameters toensure that the poor are not disadvantaged.
According to a recent World Bank study,urban population growth is likely to resultin the significant loss of non-urban landas built environments expand into their
surroundings. Cities in developing countriesare expected to triple their land areabetween 2005 and 2030, with each newcity dweller converting an average of 160metres2of non-urban land to urban land.8Despite slower population growth, cities inindustrialized countries are likely to see a2.5 times growth in city land areas over thesame period due to a more rapid decline inaverage densities when compared to their
developing country counterparts.9 As builtenvironments become less dense and stocksof built up land accumulate, the amountof reproductive and ecologically bufferingland available for ecosystems and foodproduction is diminished, reducing the abilityof city-regions to support themselves.10
While international trade has made itpossible for cities to meet their demands for
food, water and energy with imports fromfaraway lands, it is becoming increasingly
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apparent that the appetite of the worldsgrowing and increasingly affluent populationis coming up against limitations in theplanets ability to support human life onthis scale. It is estimated that our addictionto oil will result in a peak in oil extractionwithin the next decade, leading to dramaticincreases in the costs of fuel, mobility, foodand other imports. Greater demand forpotable water, combined with changing
rainfall patterns, the depletion of aquifersand pollution of groundwater, is likely tosee increasing competition for scarce freshwater resources, raising the possibility ofconflict in the near future.
The ability of ecosystems to continueproviding biotic resources like wood, fishand food, and to absorb manmade wastes- commonly referred to as the earths bio-
capacity - is also diminishing. Comparingglobal ecological footprints to the earthsavailable capacity shows that, at current
rates of resource use, we are exceeding bio-capacity by 30 per cent,11and approximately60 per cent of the ecosystems we depend onfor goods and services are being degradedor used in an unsustainable manner.12 Weare living off the planets natural capitalinstead of the interest from this capital, andthere are already signs of the devastatingeffect this will have on our societies andeconomies in depleting fish stocks, loss of
fertile soil, shrinking forests and increasinglyunpredictable weather patterns.13
The global population is reaching a sizewhere cities need to start thinking beyondtheir immediate interests to consider theirrole as nodes of human consumption andwaste production in a finite planet that isstruggling to keep pace with humanitysdemands. If cities are to survive, they
must acknowledge the warning signs ofecosystem degradation and build theireconomies in a manner that respects and
Figure IV:Ecological Footprint and Human Development Index for selected countriesand cities.
4
2
0
1,000900800700600500
6
8
10
U.S.A
San Francisco
Oslo New Zealand
Australia VancouverToronto
Canada
Hong KongShanghai
IndiaNairobiKenya
Human Development Index (HDI)
Sustainability target
EcologicalFootprint(gha/c
apital)
Bangkok
Norway
Germany
Berlin
Melbourne
Wellington
LondonUK
ChinaDelhi
Thailand
Philipp Rode
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rehabilitates the ecosystems on which lifedepends. If cities are to prosper, they mustembrace the challenge of providing shelterand uninterrupted access to water, food andenergy and improve quality of life for all of
their citizens.
The way in which city spaces, buildingsand infrastructural systems are planned,designed and operated influences theextent to which they encroach on naturalecosystems, and locks them into certainmodes of consumption from which theystruggle to deviate. Urban activities havedirect and indirect consequences for thenatural environment in the short, mediumand long term, and their scale of influencetypically extends far beyond the boundariesof what is typically considered to constitutethe city. Managing the indirect, distantand sometimes obscured impacts ofcity decision making in an increasinglyglobalized world requires appropriategovernance mechanisms that improve citiesaccountability for the resources they rely on.
As nexuses of knowledge, infrastructureand governance, cities represent a keyopportunity to stimulate larger scalechange toward green economies. In a worldwhere cities are increasingly competingagainst each other economically, whereweather patterns are unpredictable and lowresource prices can no longer be assumed,cities need to proactively shape theireconomies and operations in preparation
for an uncertain future. To manage risk ina democratic manner, a balance will needto be struck between deliberative decisionmaking processes and centralized masterplanning. This can be done by empoweringplanning professionals to respond quicklyand effectively to evolving developmentswithout compromising longer term sharedvisions of a better city14.
This guide is one of a set of four aimed atinspiring city managers and practitioners tothink more broadly about the role of their
cities, and to collaborate with experts andinterest groups across disciplines and sectorsto promote both human and environmentalprosperity. The guides are based on theoutputs of an expert group meeting hosted
by UN-Habitat in February 2011 entitledWhat Does the Green Economy Mean forSustainable Urban Development? Eachguide focuses on one of the following cross-cutting themes:
Working with Nature
With functioning ecosystems forming thefoundation for social and economic activity,this guide looks at how built environmentscan be planned to operate in collaborationwith nature. It looks at how to plan citiesand regions for ecosystem health, focusingon allowing sufficient space for naturalsystems to continue providing crucial goodsand services like fresh water, food, fuel andwaste amelioration.
Leveraging Density
This guide looks at the relationship betweenbuilt and natural environments from theperspective of cities, and considers how theirimpact on ecosystem functioning might bereduced by making best use of their landcoverage. Planning the growth of cities toachieve appropriate densities and providingalternative forms of mobility to privatevehicles help to slow urban expansion ontoecologically sensitive land, and can reduce
citizens demand for scarce resources bysharing them more efficiently.
Optimizing Infrastructure
Considering urban infrastructure asthe link between city inhabitants andnatural resources, this guide looks at howinfrastructural systems can be conceiveddifferently in order to help all city residents
to conserve resources. It introduces newconcepts and approaches to the provision ofinfrastructural services, such as energy, water
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and waste treatment, and demonstrateshow infrastructure investments can act ascatalysts for urban sustainability.
Clustering for Competitiveness
Taking a broader perspective, this guidelooks at city regions and how they canbe more optimally planned to achieveeconomic objectives in a manner that doesnot waste local resources. It looks at howcompetitive advantage can be achieved at aregional scale by encouraging cooperationbetween cities with complementary areasof specialization. It also considers howinnovation for green economic development
can be encouraged through the clusteringof industries, and through collaborationsbetween government, the private sectorand academia.
Each guide contains a selection of case studiesfrom around the world that demonstratehow cities have approached sustainabilitychallenges in a manner befitting the realitiesof their unique context. Showcasing a widerange of options, the case studies are notaimed at prescribing solutions, but arerather intended to inspire the considereddevelopment of contextually relevantapproaches in other cities to enhance theirsustainability.
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Black water: Waste water containinghuman faecal matter and urine.
Cogeneration:The generation of electricityand heat at the same time.
Dematerialization:Achieving an objectiveusing a smaller quantity of a certain resourceinput than was previously the case.
Eco-efficiency: Improving profitability byreducing resource consumption and wasteproduction.
Efficiency: Using fewer inputs to achieve anequal or better outcome.
Energy carrier: A substance orphenomenon that can be used to producemechanical work, heat or light.
Grey water: Water that has been usedby humans for washing (e.g. in basins,
showers, baths and washing machines)but does not require processing by a watertreatment facility before it can be used againfor applications that do not require water tobe potable.
Infrastructure:An interconnected networkof physical artefacts and organizationalstructures that supply basic services tohumans living in a built environment.
Infrastructure service:A beneficial serviceprovided to humans by infrastructure, forexample hydration and cleansing (frompiped water), warmth and light (from theelectricity grid), and hygiene (from sewageand solid waste management systems).
Lock-in effect:The limiting of infrastructuraloptions due to the long lifespan of prior
infrastructural investments.
Membrane bioreactor: A scalabletechnology for treating wastewater that
combines a membrane filtration process witha suspended growth bioreactor containingorganisms that digest organic waste.
Passive design:Approaches to the designof human environments that providea comfortable living environment bymaximizing the advantage of the naturalfeatures of a site to eliminate or reduce theneed for electricity.
Pay-as-you-throw:A system of billing forwaste collection services whereby servicefees are based on the weight of landfillwaste collected.
Rebound effect: The tendency for efficiencygains to encourage greater consumption ofthe saved resource, which cancels out someor all of the environmental benefit of thesaving.
Rematerialization: Re-using resourcesonce categorized as waste products asuseful inputs to achieve an objective.
Resource flows: The movement ofresources and products derived from them,from one point to another.
Rising block tariff: A tariff structure for
infrastructure services whereby the firstblock of consumption is offered at a lowrate or for free, with subsequent blockscosting progressively more.
Seasonal tariff: A tariff system wherebydifferent rates are charged according to thetime of year.
Smart meter: An electrical meter that
records consumption of infrastructureservices (e.g. water, electricity, gas) andcommunicates it with a central system.
Glossary
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Social inclusiveness: Incorporating theviews of a broad range of interest groupsin city decision-making in particular thosewhose interests are typically sidelinedby economic agendas with the aim of
reaching mutually beneficial solutions.
Strategic planning:A systematic decision-making process that prioritizes importantissues and focuses on resolving them.
Substitution: Providing a human benefitin a fundamentally different manner to thecurrent norm so as to manage resources ina more sustainable manner, possibly eveneliminating the need for some inputs.
Urban agriculture: The growing of plantsand the raising of animals within and aroundcities.
Urban metabolism: The consumption ofresources and generation of wastes by aninhabited city, as likened to the metabolismof a living organism. Linear urbanmetabolisms refer to a direct flow from the
extraction of resources from beyond thecity, through to consumption within thecity and the dumping of wastes beyond itsboundaries. Instead of dumping wastes,circular metabolisms re-use them repeatedlywithin the citys boundaries to maximize thevalue derived from resources.
Whole-systems thinking: Developingcreative solutions to human problems byconsidering the inter-connections betweensystems so that human and environmentalproblems can be addressed at the sametime.
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Contents
Foreword iiiGlossary ix
CHAPTER 1: Introduction 1CHAPTER 2: Urban Resources and Infrastructure 52.1 Urban consumption is increasing, but natural limits are being exceeded 52.2 Cities represent opportunities for more sustainable resource use 72.3 Infrastructure influences resource flows 72.4 The uniqueness of each city requires customized solutions 9
CHAPTER 3: Principles for more Sustainable Urban Infrastructure 113.1. Eco-efficiency 113.2. Social inclusiveness 14
CHAPTER 4: Promoting Sustainability through Infrastructure Choices 174.1 Passive design 174.2 Incentives for resource conservation 194.3 Cascading resource use 204.4 Decentralization and semi-centralization 214.5 Food infrastructure 234.6 Whole-system thinking 24
CHAPTER 5: Strategic Planning for more Sustainable Infrastructure 275.1. Who should be involved? 275.2 Where are we now? 285.3 Where do we want to go? 295.4 How do we get there? 30
CHAPTER 6: Case Studies 336.1 Durbans closed-loop landfill site, South Africa 336.2 100 per cent biogas-fuelled public transport in Linkping, Sweden 356.3 A simple approach to Bus Rapid Transit in Lagos, Nigeria 386.4 Community-driven sanitation in informal settlements in Lilongwe, Malawi 416.5 Retrofitting apartments for energy efficiency in Sofia, Bulgaria 466.6 Incentivized recycling in Curitiba, Brazil 486.7 Portlands Climate Action Plan, United States 516.8 Singapore: doing more with less 54
CHAPTER 7: Conclusion 59
End Notes 61
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Solar hot water heaters on newly built apartment blocks in Hunchun, China
UN-Habitat/Alessandro Scotti
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CHAPTER 1: INTRODUCTION
1
Introduction
Infrastructure has a critical role to play inthe economic, social and environmentalperformance of cities. Its importance isevident in the significant funds that havebeen allocated to urban infrastructureinvestments in the financial rescue
packages introduced since the 2008financial crisis as a means of mitigatingeconomic damage. It is estimated thata total of USD 41 trillion will be neededworldwide to restore old infrastructuresystems in established cities and build newones in rapidly growing cities between 2005and 2030.15
The rationale behind extending
infrastructural services to provide access tobasic services is clear. However, resource-intensive approaches to achieving this are nolonger appropriate as we approach planetaryresource limits and pollution threatens theability of ecosystems to provide goods andservices.16 A focus on how infrastructuralservices are delivered is required and,although many cities are already trying toreconcile social and environmental interests
through their infrastructure investments,there is significant room for innovation inplanning the sustainable cities of the future.
Section 2 of this Quick Guide starts withan overview of the challenge of ever-increasing resource consumption in thecontext of planetary limits, and proposesthat cities can act as agents for change thatallows their large populations to live less
wastefully. It considers how infrastructuresystems can be viewed as an opportunityto shift cities onto a more sustainable pathby paying close attention to the resourcesthat pass through them, and the manner inwhich they support the activities of the city.Emphasis is given to the need to treat eachcity context differently, based on its stageof development, pace of growth and theresources it has available.
Section 3 introduces two basic principlesaround which sustainable infrastructurecan be designed: eco-efficiency and socialinclusiveness. The three dimensions ofeco-efficiency are explained and illustratedwith the use of case studies from aroundthe world, and the importance of socialinclusiveness is highlighted as a meansof ensuring that green interventions
uplift marginalized groups rather thanworsening inequality.
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Section 4 introduces concepts that caninspire more eco-efficient approaches tothe provision of infrastructural services
and visions of what a sustainable citymight look like. Section 5 highlightskey considerations in the formation of astrategic plan for infrastructure that ensuressocial inclusiveness and encourages whole-system thinking.
Section 6 includes eight case studies thatdemonstrate examples of how infrastructurecan be approached in a more sustainablemanner than would otherwise have beenthe case:
In Durban, South Africa, a new approachto the construction of landfills allowsfor greenhouse gases to be capturedto generate renewable energy insteadof contributing to global warming; forwater to be recycled on site instead offresh water being piped in and addingto wastewater burdens; and for the
employment of poor people in thecultivation of indigenous trees to re-vegetate the site instead of destroyingits biodiversity.
In Linkping, Sweden, public buses arefuelled with biogas instead of diesel,significantly reducing air pollution,greenhouse gas emissions, landfill wasteand vulnerability to oil price fluctuations,
while providing bio-fertilizers to localfarmers to improve their crop yields.
In Lagos, Nigeria, a low-cost alternativeto the public transport systemsimplemented in other countries wasdesigned to make best use of existingcity assets. It was set up in record timeto address the citys crippling trafficcongestion and improve mobility for the
poor.
In Lilongwe, Malawi, a community withinadequate access to water and sanitationdeveloped their own alternative to
waterborne sewage systems, allowingthem to meet their sanitation needsaffordably without needing expensiveinfrastructure to supply fresh water andcarry away sewage.
In Sofia, Bulgaria, poor householdshave been able to reduce the costs ofheating their homes and reduce demandfor electricity from polluting sources
by improving the insulation of theirapartments so that they retain more heatthan they were originally designed to.
In Curitiba, Brazil, poor people have beengiven incentives to collect waste and torecycle; items such as bus tickets andlocal food are offered in exchange forbags of waste brought to central depots.This allows for waste collection servicesto be extended to informal areas without
requiring expensive and polluting wastecollection vehicles, and promotes the useof public transport and healthy eating.
In Portland, United States, anintegrated Climate Action Plan (CAP)was formulated in collaboration withinterest groups from government, thepublic sector and the community toreduce greenhouse gas emissions. The
plan includes improvements to publictransport, provision of paths for non-motorized transport routes, creationof marketplaces for trading locally-produced food, collection of recyclableand organic waste and generation oflocal renewable energy.
In Singapore, a diverse group ofstakeholders formed a comprehensive
strategy to reduce reliance on water piped
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from Malaysia. This includes significantinvestments in the construction ofadditional reservoirs to retain rainwater,
new water treatment plants to allow forwater to be re-used, as well as enhancedefforts to repair leaks in the existingdistribution system to reduce wastage.
While there are many more examples ofthe different ways in which infrastructureservices can be delivered that allow foreco-efficiencies and social inclusiveness,
those included here provide an insightinto some of the options available fromwater and sanitation to energy and waste.
The solutions have been developed to suitthe realities of each context, and ratherthan demonstrating how cities shouldapproach infrastructure, they can inspirethe considered development of contextuallyrelevant approaches in other cities.
Section 7 concludes with a summary of thekey lessons from this guide.
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Redesigned shelter at a bus stop in Uberlndia, Brazil, whose public transport network connects the
central areas of the city with the outlying neighbourhoods along three main arteries
UN-Habitat/Alessandro Scotti
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2.1 Urban consumption isincreasing, but natural limitsare being exceeded
Cities are estimated to be responsible forthe consumption of roughly 75 per cent of
all natural resources and for the productionof approximately 70 per cent of all CO2emissions despite occupying only 3 per centof the Earths land surface.17In the secondhalf of the twentieth century, a combinationof natural growth of urban populations andurbanization (migration of rural populationsto the city) has resulted in higher incomesfor more people and an increasing demandfor resources worldwide. As cities continue
to attract investment and skilled workers,rising income levels, rather than populationgrowth, are expected to be a more significantdriver of economic growth.
Between 2010 and 2015, an additional 460million people will enter the middle classin China, India, Russia, Indonesia, Brazil,Turkey, Mexico and South Africa.18By 2025,the number of households earning over
USD 20,000 per year iin emerging economycities will be 1.1 times greater than thenumber in developed region cities in thetop 600.19 Consumption driven by choice(for example, building swimming pools)as opposed to need (for example drinking
water) is expected to increase substantially inthese emerging markets as higher incomesraise demand for material possessions andmodern lifestyles. It is estimated that Indiacould potentially increase its aggregateurban consumption sixfold between 2005and 2025, and consumption could increasemore than sevenfold in China.20
As cities have grown, global resource
consumption has increased faster than theglobal population and there has been anoticeable shift toward the consumptionof non-renewable construction materials.Between 1900 and 2005, global materialresource use increased by a factor of8 - almost twice as fast as populationgrowth.21 Construction materials saw themost significant growth, increasing by afactor of 34, while industrial minerals and
i Households with incomes of USD 20,000 and above are commonly identified by companies as those with purchasing power
beyond necessities.
Urban Resourcesand Infrastructure 2
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ores grew by a factor of 27. Fossil fuelsgrew by a factor of 12. Despite a fourfoldincrease in population over the period,biomass extraction only increased 3.6 times.Biomasss share of total material use hasdropped significantly from three quarters toone third, indicating a significant shift awayfrom renewable toward non-renewableresources over the past century (fig 2.1).
The rapid growth of cities will depend onsignificant increases in global resourceextraction and consumption in the comingyears. Under a freeze and catch upscenario, the world population will continueto grow but resource consumption per capitawill stay roughly at 2000 levels in developedcountries to allow developing countries toraise their consumption to the same levels
by 2050. For developing countries, thiswill require increasing average metabolicrates by factors of 2 - 5, raising the global
average to 16 tons per capita per year andtripling annual global resource extraction.By 2050, global resource extraction wouldbe in the region of 140 billion tons annually.Average per capita carbon emissions wouldtriple which, along with population growth,would result in a fourfold increase in totalemissions to 28.8 GtC (gigatonnes ofcarbon) per year higher than the worst
climate change scenario envisaged by theIntergovernmental Panel on Climate Change(IPCC).22
The problem with the business-as-usualscenario is that it assumes an unlimitedsupply of goods and services to meetgrowing demand. It ignores the finitenature of many of the commodities onwhich growth depends, some of which have
either reached the peak of their extractionpotential or will do so in the foreseeablefuture (for example, oil). There are also
Source: UNEP (2011) Decoupling natural resource use and environmental impacts from economic
growth, A Report of the Working Group on Decoupling to the International Resource Panel. United
Nations Environment Programme.
Figure 2.1:Global metabolic rates and income, 1900-2005.
1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000
7,000
Income
Ores and Industrial mineralsFossil energy carriersConstruction mineralsBiomassIncome Internal dollars cap/yr
Metabolic ratet/cap/yr
6,000
5,000
4,000
3,000
2,000
1,000
0
14
12
10
8
6
4
2
0
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needs are met, making it possible for life tocontinue in the city.
Infrastructure networks link city dwellers tothe goods and services from nature that theyrely on. These systems transform naturalresources into a series of flows that allowfor human needs to be met in the form ofinfrastructural services. For example, oilis transformed into mobility services, coalis used for lighting and heating services,and water provides hydration and assistswith sanitation. In addition to providinghumans with access to beneficial inputs,infrastructural networks also channel awayunwanted by-products in the form ofwastes. From this perspective, the city canbe compared to a living organism sustainedby a metabolism of flows through itsphysical space.35 Studying the patterns ofmatter and energy moving through cities iscritical in finding solutions to improve themin a manner that allows for resources to bemore sustainably managed.36
Technical infrastructure networks shape -and in turn are shaped by - socio-economicsystems.37 The manner in which they
meet service needs has direct and indirectconsequences for economic competitiveness,social inclusiveness, quality of life and
the environmental impact of cities.38
Policymakers who focus only on the directand immediate benefits of infrastructureinvestments on the economy run the risk ofmaking environmental trade-offs, but it isimportant to remember that cities can onlysupport human life and economic activity ifthe ecosystems on which they depend forwater, food and energy are functioning.
Infrastructural services can be deliveredin a number of different ways, withdifferent implications for resource useand environmental impact. Where newinfrastructure investments are being made,it is important that the full range of optionsis considered and that space for innovationis allowed. Infrastructure typically has along lifespan and, as a result, it commitscities to certain patterns of productionand consumption for many years.39 Once
commitments have been made to anunsustainable form of infrastructure, like acoal-fired electricity network, the lock-ineffect can prevent cities from implementing
Source: Hodson, M. and Marvin, S. (2010). World Cities and Climate Change. Berkshire: Open
University Press/McGraw-Hill
New build/new construction
Existing city /retrofit
IntegratedNetwork
Specific
Constructing new urban networked
technologies
Linkpings biogas-powered buses
Durbans closed-loop landfill site
Lilongwes waterless Skyloos
Retrofitting existing urban networked
infrastructures
Lagoss BRT
Curitibas recycling collection system
Bulgarias energy-efficient housing
retrofits
New urban developments as integrated
eco-urbanism
Masdar, Abu Dhabi
Songdo, South Korea
Treasure Island, San Francisco
Reconfiguring cities as systemic
urban transitions
Portlands Climate Action Plan
San Joses Green Vision
Sustainable Singapore Blueprint
Figure 2.2:Four types of rebundled network ecologies.
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more sustainable alternatives for decades.Rapidly growing cities that are yet to supplycertain infrastructural services to their
citizens have an opportunity to make choicesthat prevent them from getting lockedinto unsustainable methods, and allowthem to gain competitive advantage overindustrialized cities by ensuring that theirinvestments promote sustainable resourceuse and do not harm the environment.
2.4 The uniqueness of each cityrequires customized solutions
While all humans share the samebasic needs, each city faces differentinfrastructural challenges according toits context, pace of growth and level ofdevelopment. Each city has a unique setof opportunities and obstacles to servicedelivery, which shape the options available.Developed cities may have more capital attheir disposal for infrastructure investments,but the extent to which they are locked in
to existing infrastructure networks maylimit their options relative to a city thatis growing rapidly and is yet to invest ininfrastructure. Where rapidly growing citiesmay be focusing on investments in newinfrastructure, established cities might betterachieve resource savings by maintaining andimproving existing networks, for example byfixing leaks in water pipes. City transitionstoward more sustainable infrastructures
can be broadly categorized into whetherinfrastructural systems are built from scratchor retrofitted, whether they focus on just oneinfrastructure type or an integrated networkof infrastructural services, as demonstratedin fig 2.2.
In addition to leveraging the advantages ofexisting infrastructure (for example, usingexisting roads for bus rapid transport (BRT)
systems instead of building new transportcorridors, or re-opening abandonedmountain springs to supplement potable
water instead of building new dams), citiesneed to take into account the naturaland human resources they have at their
disposal when deciding how to provideinfrastructural services. Cities in areas wherewater is scarce (or is likely to become scarcein the foreseeable future) are not suitedto providing sanitation services that relyon potable water; they need to be moreinnovative with the resources available sothat they can provide the same infrastructuralservice level with less or no fresh water. Thishas been achieved in the development ofwaterless toilets in informal settlementson the outskirts of Lilongwe in Malawi.Similarly, cities with sizeable numbers ofunemployed people and inaccessible roadsystems may wish to involve the poor in thecollection of household waste as a means ofcreating jobs, as has been done in Curitibain Brazil.
Depending on levels of informality,inequality and the resources and willpower
to address these issues, aspirations as tothe manner in which infrastructural servicesshould be met require careful consideration.The growth of slum cities is transformingwhat is understood by the word city40to describe a unique set of urban dynamicsand modalities in high density, low incomeareas that access some or all of their servicesvia informal means. The western city isno longer the only legitimate template for
defining the city and there is a growingneed for non-western reference points forrethinking our deepest assumptions aboutthe purpose, meaning and impact of thecity.41 The assumption that slums are onlya passing phase while cities move froma primitive pre-modern urban formtowards the modern networked city isno longer valid, and there is a strong needfor innovative approaches to infrastructure
that can connect the occupants of informaldwellings with services in a contextuallyrelevant manner.
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Main access road to the newly built second link bridge from Johor Bahru, Malaysia to Singapore
UN-Habitat/Alessandro Scotti
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If infrastructure is to be used as a means ofbreaking the negative relationship betweencity growth and sustainability, a newunderstanding of the role of infrastructureis required. Sustainable infrastructurehas to meet the needs of the people it
services without incurring environmentaldamage. Possibly, it even needs to movebeyond this to achieve net environmentalbenefits by rehabilitating damaged naturalenvironments.42 However, in cities wherethere is limited access to basic services,the needs and voices of those who haveno access to them cannot be ignored.Sustainable infrastructure therefore shouldreconcile environmental interests with
human interests, particularly those ofunderprivileged groups. This can be capturedin two central concepts: eco-efficiency andsocial inclusiveness.43
3.1. Eco-efficiency
The term eco-efficiency can be definedas the delivery of competitively pricedgoods and services to satisfy human
needs and improve quality of life whilstreducing resource intensity and negativeenvironmental impacts wherever possible.
In short, deriving more value with lessimpact. It was coined by the World BusinessCouncil for Sustainable Development in theearly 1990s as the business communityssolution to sustainability. Eco-efficiencyfocuses on identifying and capitalizing on
opportunities that improve profitability (i.e.economic benefit) by reducing resourceconsumption and waste production (i.e.ecological benefit).44 It fosters innovationand competition by encouraging businessesto identify opportunities for environmentalimprovements that yield an economicbenefit, and in the process improve valuefor consumers.
Applying the principles of eco-efficiency tothe operation of cities allows citizens to derivegreater benefit from their tax contributionsand rates whilst reducing the amount ofresources required and pollutants emitted.45It allows for quality of life, competitivenessand environmental sustainability to bemaximized at the same time, and is ofgreat relevance to governments makinginfrastructure investment decisions on a
limited budget due to its economic logic andability to attract private investment.
Principles for moreSustainable UrbanInfrastructure 3
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Eco-efficiency encompasses the followingthree objectives:48
l Reducing consumption of resources
l Reducing environmental impact
l Increasing service value
3.1.1 Reducing consumptionof resources
This includes a range of approaches toreduce the amount of inputs required toachieve a given output. It is primarily aboutimprovements in resource productivity, whichcan be described as the amount of usefuloutput acquired per unit of natural resourceinput. This can be achieved on multiplescales, from household appliances up tocities and city regions, depending on thescope considered. Improvements in resource
productivity are often recommended as afirst step towards sustainable resourceuse due to the financial benefits of deriving
greater benefit from inputs. In the case ofinfrastructure, examples of this principleinclude repairing leaks in water distribution
pipes to reduce non-revenue losses,replacing streetlights with energy efficientLED bulbs to save electricity, and using fuel-efficient buses for public transport to saveon fossil fuels.
This principle also covers the recycling andre-use of resources so that they may bereincorporated into the system as inputs,thus reducing net requirements for newresources. The metabolism of typical moderncities can be described as linear in thatthey extract resources from beyond theirboundaries, make use of them within thecity and deposit the resulting solid wastesback into the external environment - often indangerous concentrations.49,50,51By re-usingwastes as inputs or closing waste loops,cities can move towards a more circularurban metabolism. Wastes that might serveas valuable substitutes for new resources
include packaging and other materials sentto landfill, solid and liquid wastes generated
The rebound effect
Efficiency improvements may not always
achieve net reductions in resource usage dueto what is known as the rebound effect.This describes the tendency for efficiencygains to encourage greater consumption ofthe saved resource, which cancels out thenet environmental benefit.46The reboundeffect can be particularly high in developingcountries, where there is unmet demand.However, the negatives of an overall increase
in resource use in such contexts might becounter-balanced by social developmentpositives that contribute to enhancingoverall sustainability in a less resource-intensive manner than might otherwise havebeen the case.47(For example, savings fromenergy efficient appliances might be usedto power additional lighting for studying
at night).
Case study: Durbans closed-loop landfillsite
The Mariannhill landfill site in Durban, SouthAfrica, is an example of how the principles ofwaste re-use have been applied to a landfillsite in order to save on resources and minimize
the environmental impact of its operations.Liquid run-off is contained and polished
onsite using natural reed beds for irrigationwater and to settle dust, thus eliminating freshwater requirements. Methane gas released
by the waste is captured and used as a fuelto generate renewable electricity, which thesite sells on to the grid. Indigenous vegetationremoved from the site is being cultivatedat an onsite nursery that supplies plants to
other municipal projects, and will ensure thatecosystems can be re-established when thelandfill is closed. (Full case study in Section 6.)
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by humans and animals, methane generatedby decomposing organic matter, andwaste heat from electricity generation and
industrial processes.
Moving toward circular metabolismsis necessary if cities are to build theirresilience to climate change and otherexternal shocks.52,53,54,55 By viewing waste,pollution and resource depletion as systemicinefficiencies to be avoided, cities can be re-arranged in pursuit of zero waste societiesthat make efficient use of all the resources attheir disposal (including those once viewedas wastes). Where cities have traditionallyexpanded the boundaries of the hinterlandson which they depend for survival as ameans of supporting growth, there is agrowing trend towards re-localization andattempts to create self-supporting circularmetabolisms in some of the worlds leadingcities.56 Efforts to re-incorporate wastesinto the economy instead of dumpingthem on the natural environment allow for
them to circulate within the city for longer,delivering more value and reducing the totalthroughput of resources required.57
For an example of collaboration betweenindustries to promote a circular metabolism,see the Kitakyushu case study in theClustering for Competitiveness guide.
3.1.2 Reducing environmental impact
This refers to efforts to avoid or reducepollution and emissions into the air, waterand soil, as well as fostering the sustainableuse of renewable resources so that theyare not depleted. This can be applied toinfrastructural services in the manner inwhich energy is generated (for example,using wind turbines instead of coal-firedpower plants), a citys approach to solid
waste management (for example, wasteminimization instead of incineration), or themanner in which green infrastructure (for
example, watersheds, forests and arablelands) is managed as a provider of valuableecosystem services that alleviate some of the
pressures placed on manmade infrastructurenetworks.
3.1.3 Increasing service value
In some cases, there may be opportunitiesto provide more benefits to the end-
user by adopting different approaches toinfrastructure systems than those commonlyimagined. Instead of limiting infrastructuralsolutions to a predefined set of outcomes,a holistic understanding of citizens needscan open up opportunities for multiplebenefits to be derived through a singleinvestment. An example of this is usingnatural watercourses to manage stormwater instead of constructing unsightly
concrete channels, thus providing beautifulrecreational spaces whilst purifying thewater free of charge. Another example
Case study: 100 per cent biogas-fuelledpublic transport in Linkping, Sweden
In the 1970s, the city of Linkping wassuffering from air pollution as a result of
emissions from its diesel-fuelled public buses.
Methane-rich biogas was identified as aclean-burning substitute fuel that wouldsave the city money by reducing the publictransport systems dependence on expensiveoil imports. The citys wastewater is combined
with residues from local agricultural activities,
meat processing industries and restaurants,and the methane this releases is capturedand used to fuel its fleet of public buses.In addition to reducing air pollution, theprocess has cut the volume of waste sent forincineration in Linkping by around 3,400
tons annually, and the solid residues can bere-used as bio-fertilizer to allow nutrients toreturn to the soil in a useful form insteadof being buried in toxic concentrations at alandfill. (Full case study in Section 6.)
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is providing shared public transport as analternative to promoting cars through roadinfrastructure, thereby reducing commuter
stress and encouraging social cohesionwhilst saving time, fuel and money.
3.2. Social inclusiveness
Social inclusiveness requires that all cityresidents are treated equally in their accessto employment and services like freshwater and mobility. The term inclusive isgenerally used to refer to the involvementof a broad range of people from across thecity in decision making processes, with theaim of incorporating their contributionsand reaching mutual agreement.58 It isoften assumed that poor people are notinterested in environmental issues, yet theiroccupation of marginal lands in areas proneto flooding, pollution and illegal dumpingmeans that their lives are directly affected bythe citys poor environmental management.Sometimes, they have more at stake than
wealthier members of society who arephysically further away from these realities.59
Local governments struggling to caterfor expanding demand for infrastructuralservices in growing cities often resort tooutsourcing them through private-basedmodels, which reinforces disparities inservice quality and costs determined bythe area they are serving.60 The provision
of niche services to those who can affordthem results in barriers being erected toexclude those who cannot, with negative
Case study: A simple approach to Bus
Rapid Transit in Lagos, Nigeria
Lagos is an example of a rapidly growingAfrican megacity that has, until recently, beenstruggling to provide mobility services to itsgrowing population. Rising incomes haveresulted in the increasing ownership of privatevehicles and the use of unregulated, privately-owned transport companies. Their addition tothe inadequate and poorly maintained roadnetwork contributes to severe traffic congestion
that raises commuting times, stress levelsand air pollution. In 2006, the governmentformulated a Strategic Transport Master Planaimed to address poor mobility in the city,
especially for the poor. Instead of addingmore roads, the existing road network wasincorporated into the design of a Bus RapidTransit (BRT)-Lite system. The first phase ofthis system was operational in just 15 monthsand cost significantly less than the overseassystems it was inspired by. In addition toproviding a safer alternative to cars and poorly
maintained private buses, average journeytimes have decreased substantially. Time spentwaiting at bus stations has been reduced fromaround 45 to 10 minutes, reducing exposureto air pollution and lowering passengers riskof contracting respiratory diseases. Instead ofrelying on a private transport model, the useof existing road infrastructure to provide anorganized public transport system has providedvalue to residents in many forms, and has
helped to make the city more liveable. (Fullcase study in Section 6.)
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Case study: Community-driven sanitation in
informal settlements in Lilongwe, Malawi
A deficency in piped water and sanitationinfrastructure within the Mtandire informalsettlement outside Lilongwe, Malawi, poseda sanitation challenge to landlords wishing
for an alternative to the space-intensive andgroundwater-polluting pit latrines. Withoutinfrastructure, waterborne sewage was notan option, so civil society groups workedwith landlords and builders to develop aresponse which was contextually determinedand responsive to householders needs andaspirations. After some trial and error, theSkyloo was developed. Some of its manybenefits are that water is not required,groundwater is no longer being pollutedand waste can be easily and safely collectedfor re-use in agriculture. The developmentof this solution took time, but involving thecommunity has ensured their buy-in, and theuse of Skyloos is spreading without outsideintervention because they are well suited to
the needs of the context. (Full case study inSection 6.)
consequences for social inclusiveness,equality and sustainability.61Engaging withdisadvantaged communities in forminginfrastructure strategies allows for areas ofcommon interest between city managersand the poor to be identified, and thiscan inspire social entrepreneurship and
innovative solutions that are less costlyto the city than those that may otherwise
have been implemented by governments ordevelopment agencies.62
For an example of how innovativepublic transport can be used to includemarginalized groups, see the Medelln cablecar case study in the Leveraging Densityguide.
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An Energy park (solar panels, pumped-storage hydroelectricity) in Geeshacht, Schleswig-Holstein,
Germany Wikipedia/Quartl
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The adoption of standard infrastructuremodels in rapidly modernizing citiesaround the world runs the risk of limitingcreativity and sidelining more innovativeopportunities for making cities moresustainable. With this in mind, this section
will introduce the following key ideas thatcan assist in the formation of new visions forcities and infrastructure systems that supportthe sustainability principles described inSection 3:
l Passive design.
l Incentives for research conservation.
l Cascading resource use.
l Decentralization and semi-centralization.
l Food infrastructure.
l Whole-system thinking.
4.1 Passive design
Although buildings might not be considereda part of the infrastructure system, theyrepresent the spaces in which most
infrastructural services are accessed, sotheir design and operation has an impacton the resource efficiency of these services.Buildings provide shelters for people andtheir most important role is to keep out theelements and maintain indoor temperatures
within a comfortable range. Nearly 60 percent of the worlds electricity is consumedin commercial and residential buildings,varying according to consumption patterns,climate and geographical location.63Whilemany modern buildings use electric heatingand cooling systems to moderate indoortemperatures, the incorporation of passivedesign principles into built environmentscan significantly reduce or even eliminate
these energy demands.
Passive design aims to provide a comfortableliving environment by maximizing theadvantage of the natural features of asite (for example, sunlight and airflow) toeliminate or reduce the need for activespace heating, cooling, ventilation orartificial lighting powered by electricity.64Passive design principles include facing
windows towards the equator to harnessthe warmth of the sun, using insulation andmaterials with high thermal mass to retain
PromotingSustainability throughInfrastructure Choices4
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heat or coolness when required, usingcourtyards and opening windows for cross-ventilation, and shading windows to block
out the hot summer sun but to allow in thelower-angle winter rays.
In many cases, the planning and design ofmodern human settlements unwittinglyignore the advantages presented by thelocation, and in so doing commit residentsto unnecessarily high energy bills. Passivedesign principles relevant to the localcontext can often be found in traditionalapproaches to the design and constructionof buildings that were used beforeelectricity became widely available. Whilethe international green building movementembraces passive design principles andcontinues to augment them with new, hightech materials and automated products thatmake buildings even more energy efficient,the use of locally developed approaches tocreate passive buildings are by far the mostcost effective solutions particularly for the
developing world.65
The application of passive design principlesto new building projects can have a majorimpact on their future energy requirements,but it is also possible to retrofit existingbuildings so that they require less electricity.The installation of ceiling, wall and floorinsulation, double-glazing, roof lights,window coatings, opening windows and
vents can be used to improve the thermalefficiency of existing buildings, and it is nosurprise that the retrofitting of buildings forenergy efficiency is becoming big business.A recent study estimates that the retrofittingof 40 per cent of the building stock in theUnited States by 2020 represents a USD 5billion market that can generate 6.25 millionjobs over 10 years. 66
While passive design is most commonlyapplied at the building level, neighbouringstructures in the city can rob a site of its
natural benefits. For example, tall buildings
can block out sun and wind, industrialactivity can pollute the air, and streetsrunning in certain directions make it difficultfor buildings to orientate themselves towardthe sun whilst maximizing available space.This has repercussions for city planning,zoning and height restrictions in the city,and should be considered when formulatingor revising regulations.
Suggested reading:Van Lengen, J. (2008).The Barefoot Architect A handbook forGreen Building. California: Shelter Publications;
Case study: Retrofitting apartments forenergy efficiency in Sofia, Bulgaria
Bulgarias Demonstration Project for theRenovation of Multi-family Buildings wasstarted in 2007 to address the poor energyefficiency of apartment buildings constructedduring the socialist era. Energy performancewas on average 2.5 times worse than therecommended minimum standard, makingit extremely costly for residents to heat theirhomes when state energy subsidies werewithdrawn. Buildings in the project wereselected on a needs basis for a package ofenergy efficiency upgrades, including theinstallation of insulation, replacement of doorsand windows, sealing of air gaps and renovation
of facades and public areas. Residents werebrought together in homeowners associationsto contribute their time and labour, and acombination of loans and subsidies wereoffered to enable homeowners to repay thecost of the upgrades from the savings ontheir energy bills. By February 2011, 1,063
households in 27 multifamily buildings hadbeen upgraded resulting in an estimated 8.5megawatt hours of energy savings and reduced
CO2 emissions of 2.2 tons per annum. Theproject has created 219 jobs per annum, andhas resulted in improved comfort levels, lowerenergy bills and greater community cohesion.(Full case study in Section 6.)
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Behling, S. & Behling, S. (2000) Solar Power- The evolution of sustainable architecture.
New York: Prestel.
4.2 Incentives for resourceconservation
Eco-efficiency should not be viewed as asupply-side intervention alone. Changingthe behaviour of end-users in supportof a more resource efficient city can beencouraged by economic measures thatgive them incentives them to consume morewisely. The environmental costs incurred inthe provision of infrastructural services areoften not adequately reflected by their costs,allowing the market to send the wrongsignals to end-users.67If resources are to beconserved so that cities can operate withinenvironmental limits, these signals need tobe adjusted to reflect reality whilst allowingfor basic human needs to be served.
With potable water and waterborne sewage
services in water-scarce areas, water pricesthat are low or unrelated to the volumesconsumed provide little incentive to save,and can result in an ever-escalating demandfor more expensive sources of water aspopulation and affluence levels rise. Thefollowing are ways to promote moreprudent use of water.68
l Metering allows for water charges to
reflect the volumes consumed, andencourages end-users to use less potablewater. Regular, accurate and clear billingis a useful means of drawing attentionto water consumption behaviour, andcomparisons with the consumption ofneighbours can harness the influenceof social norms to reduce consumptionii.Pre-paid or post-paid metering can beadopted, and both can be executed in a
manner that allows for a free basic waterallowance for low-income households.Smart meters allow for data to be
analysed remotely, whereas manuallyread dumb meters can be used as anopportunity to create jobs and spreadinformation about water saving.
l Differential tariffs can be used toencourage users to keep potable waterusage low (rising block tariffs) orinfluence consumption behaviour atdifferent times of the year to suit weatherconditions (seasonal tariffs). Free basicwater allowances, cross-subsidized byhigher tariffs for larger consumers, canhelp the poor to meet their needs whilstensuring that metering does not conflictwith their human rights. Chargingdifferent rates for different grades ofwater can encourage the recycling ofnon-potable water as a replacement forpotable water in irrigation, toilet flushingand industrial uses.
l Regulations that specify waterefficiency standards (e.g. for taps,appliances or industries) or waterconsumption behaviour (e.g. irrigation orcar washing) can be used to ensure thatend-users consume potable water withina recommended range. In water scarceareas, this may require specificationson rainwater harvesting and grey water
recycling in new buildings to minimizetheir impact on demand for water.
While water is a useful example of how toincentivise eco-efficiencies, the principleof incentivising appropriate behaviour canalso be applied to the consumption ofelectricity, and to a certain extent to otherinfrastructural services. Smart electricitymetering can allow for differential tariffs at
ii For example, U.S. energy company, Opower, achieved an average 2.75 per cent reduction in household energy use over 16
months by automatically sending personalized information on each households energy consumption relative to their neighbours.
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different times of day to shift some energyuse to off-peak periods, reducing the needfor additional supply capacity during peak.Combined with household generation ofrenewable energy, it can reduce energybills or even earn households revenue fromcontributions to the grid. Similarly, the
principle of measurement can be appliedto solid waste management services,where pay-as-you-throw billing systems
charge for waste collection according tothe weight of waste to be sent to landfill,which encourages household separation ofrecyclables and organic waste.
4.3 Cascading resource use
Cascading resource use refers to matchingdifferent resource grades to specific enduses, thus reducing the need for resourcesto be in their highest quality form (forexample, electricity or potable water).69Obtaining electricity and water that is pureenough to drink often comes with a sizeableenvironmental and resource impact, andyet many of the functions these resourcesperform could be met using lower gradesof energy or water. Cascading resourcesfrom one use to another as the qualitydeteriorates allows for more utility to be
Source: World Bank (2010) Suzuki et Al.
Eco2Cities: Ecological Cities as Economic Cities.
Washington D.C.: World Bank.
Illustration by Don Foley
Figure 4.1:Cascading water use.
Figure 4.2: Energy wastage incurred in the use of coal-fired electricity to meetinfrastructural service needs
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derived from the same amount of resources,and saves on the costs of delivering highest-grade resources for all applications.
Perhaps the best example of this is the useof potable water for a range of functionsfrom drinking, to cleaning, to irrigatingand removing waste. By matching waterquality to needs, a water system can bereconfigured to allow for more demandsto be met with the same volume of water.Image 4.1 shows how a conventional systemrelying only on potable water on the leftcan be reconfigured to use partially soiledgrey water from a hand basin or showerto flush a toilet, and the nutrient-rich blackwater from the toilet can, in turn, be usedin sub-soil irrigation systems to grow crops.By eliminating the need for fresh water fortoilet flushing and irrigation, this approachsignificantly reduces the demand for freshwater, whilst reducing the volumes of watersent to treatment works. If combined withrainwater harvesting from the hard surfaces
of the city, there is also the potential toalleviate some of the burden on storm watersystems.
The principle of cascading resource use canalso be applied to energy. While electricitycan provide a convenient, high-quality,versatile, controllable, clean-to-use andgenerally reliable source of energy, it isseldom the most energy efficient means of
providing infrastructural services such as lightand heat. The work potential or exergyof electricity is higher than most otherenergy carriers, and is typically generatedby concentrating lower grade energies.70When electricity is generated by combustingfossil fuels, it is one of the highest emittersof greenhouse gases in the world and asignificant contributor to environmentalpollution. The process of generating,
transmitting and converting electricity intouseful services is also wasteful, and over 90per cent of the original energy can be lost in
the form of heat and light, as demonstratedin Figure 4.2.
The built environments of cities require threebasic forms of energy: (1) electrical energyfor lighting and appliances, (2) mechanicalenergy for motors and moving equipment,and (3) thermal energy for controllingtemperatures. In many cases, electricity isused to serve all three functions, yet theconversion of lower energy sources toelectricity and back to light, motion or heatincurs a high energy debt due to energylosses in conversion and distribution.71 Forlow grade applications like light and heat,it is more energy efficient to make useof energy carriers other than alternatingcurrent (AC) electricity.
An energy mix that makes use of lowerforms of energy and aligns them to theenergy services required by end-users canhelp to reduce energy wastage with positivebenefits for urban temperatures, climate
change, pollution and resource depletion.Waste heat from electricity generationand other thermal processes can be usedin domestic and industrial heating, drying,cooking and water heating applications,and even for cooling in warmer climates.Cogeneration refers to the production ofelectricity and heat at the same time, andcombined heat and power (CHP) plants arebecoming more popular in the colder parts
of Europe, where the heat generated in theproduction of electricity can be piped toheat nearby buildings.72
4.4 Decentralization andsemi-centralization
For most of the twentieth century, newinfrastructure facilities for the generationof electricity, processing of wastewater and
management of solid waste were largein scale and located on the outskirts ofhuman settlements where they were less of
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a nuisance to ratepayers. This centralized,supply-driven approach persists today,reliant on extensive service delivery networks
of wires, pipes, vehicles and roads toconnect these facilities to their end users. Asindicated in Figure 4.2, inefficiencies in thesenetworks can result in significant resourcewastage, while ongoing maintenanceexpenses add significantly to the costs ofoperation. In addition, large centralizedfacilities that exceed the needs of theircustomers can incur disproportionately highmaintenance costs if run below capacity, forexample corrosion resulting from low flowvelocities in water treatment works. For newinfrastructural facilities to be eco-efficient,they need to be sized and located to matchthe service needs of consumers.
Justifying large centralized facilities oneconomies of scale alone runs the risk ofoverlooking larger dis-economies of scale,which raise the costs and financial risksof these investments (for example, the
requirement for larger areas of land restrictssite options to those further out of town,requiring a more extensive grid network).In the United States, recognition of these
dis-economies has noticeably reversed thetrend toward the construction of ever-larger central thermal power plants since
the 1970s.73
The economic advantages ofbetter matching power generation capacityto customer needs have become apparent,and micro power generators, like solarcells, wind turbines and fuel cells, are beingseen as less risky investments due to theirrelatively quick installation time and abilityto respond swiftly to changing energydemand and disasters.
Recent technological advances, such as thegeneration of electricity from the sun andwind, and package water treatment plantsusing membrane bioreactors and othertechnologies, now allow cities to consideralternatives to centralized infrastructurefacilities that do not cause offense or harmto neighbours, they deliver services tailoredto local needs, require less substantialinvestments in distribution networks andfacilitate cascading resource use. While fully
decentralized household-level infrastructureservices may be an option for wealthierhomeowners, semi-centralized facilities ata district or neighbourhood level present a
Source: Schramm, S. (2011). Semicentralised water supply and treatment: options for the dynamicurban area of Hanoi, Vietnam. Journal of Environmental Assessment Policy and Management,
13 (2), 289. Illustration by Susanne Bieker.
Figure 4.3: Comparison between conventional centralized infrastructure facilitiesfor wastewater and solid waste (left), and a Semicentralized Supply and TreatmentCentre (right) that combines infrastructural functions and generates multiple usefulservices
Wastewater
waste
Wastewatertreatment
plantSemicentralized
Supply andTreatment Centre
energy
Treated Watere.g Irrigation
fertilizers
stabilised waste
servicewater
grey-water
waste &sludge
black-water
Wastetreatment
plant
Treatedw-water
treatedwaste
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middle ground approach that can be set upon smaller pockets of land within less time,making them suitable to rapidly growing
urban areas that are not adequately servicedby infrastructure.74
Semi-centralized Supply and TreatmentCentres (STCs) located within aneighbourhood are an example of semi-centralized infrastructure. As illustratedin figure 4.3, the centres manage andtreat different types of waterborne wasteflows separately and can supply reclaimed,or service water, for applications likeirrigation, toilet flushing and street cleaning;can salvage nutrients for use as fertilizer;and can generate biogas from sewagesludge for generating electricity andheat.75 The anaerobic digestion processused in the extraction of biogas stabilisesthe biodegradable fraction of the sludge,reducing the volume sent to landfill by asmuch as 60 per cent. By integrating variousinfrastructural services, semi-centralized
STCs can be tailored to suit the uniqueneeds of the local context, and allow fornumerous economies from matching servicedemand to supply capacity.
Suggested reading:Gutterer, B., Sasse, L.,Panzerbieter, T. and Reckerzgel, T. (2009).Decentralised Wastewater TreatmentSystems (DEWATS) and Sanitation inDeveloping Countries: A Practical Guide.
Water, Engineering and DevelopmentCentre, Loughborough University, UnitedKingdom, in association with BremenOverseas Research and DevelopmentAssociation (BORDA), Germany.
4.5 Food infrastructure
Although food is not typically consideredto be an infrastructural service, viewing the
city as a life-supporting system that needsto provide food and deal with wastes opensup opportunities for synergies between
infrastructural systems to support foodproduction as a key function of the city.One of the oldest approaches to closing
organic waste loops was to use solid andliquid organic wastes in the production offood in urban and peri-urban farms. Wherethese wastes once provided nutrients foragriculture, they are now typically eitherdumped in open land or water, or transportedto landfills while food is imported fromelsewhere. In many cities, the perpetuationof this approach has resulted in the twinproblems of rising food prices and mountingwastes, which can either result in pollutionor rising landfill costs when suitable sites fillup and garbage has to be transported toevermore distant locations.
To address these issues and move towards amore circular economy, cities can encouragethe development of localized food systemsthat re-incorporate organic waste streamsas inputs for urban agriculture (fertilizer,animal feed, irrigation). Urban agriculture
can be loosely defined as the growing ofplants (for food, materials and fuel) and theraising of animals within and around cities.It is different from rural agriculture becauseit is integrated into the urban economic andecological system, employing the labourof city residents, using organic wastes forirrigation and fertilization, and becomingpart of the urban food system.76
Incorporating food production into thefunctions of the city creates numerousopportunities for organic solid wastes andliquid wastes to be re-used, and this can befacilitated by decentralizing the treatmentof solid waste and waste water. Solid wastesassociated with food preparation, gardenmaintenance and certain manufacturingprocesses can be processed and compostedto deliver nutrients to the soiland improveits water retention properties. In arid areas, acascading approach to water managementallows for lower grades of waste water
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to replace potable water for irrigation.Care needs to be taken to ensure that thiswater does not contain toxic chemicals
and other contaminants, and that it doesnot pass on pathogens and vectors tohumans. For example, plants grown for useas construction materials, fuel, fibre and soon, are better suited to irrigation with wastewater than food crops are, but if food is tobe grown then fruit from trees has a lowerrisk of pathogen contamination than leafcrops. Low cost approaches, such as the useof sunlight, time and intermediate plantsor animals (for example, the use of wastewater to grow algae to feed livestock) canalso be taken to reduce risks.77
In addition to promoting circular resourceflows within the city, urban agriculture canhelp to make fresh food more affordable by
reducing the need for chemical fertilizersand insecticides, and reducing the need forlong-distance transport and cold storage offood. This can result in significant savings infossil fuel consumption and reductions ingreenhouse gas emissions. It also has thepotential to make better use of parts of thecity and its periphery that are under-utilized orconsidered unsuitable for building (rooftopsand floodplains).78 Urban agriculture canhave positive effects on health, improveliving environments and provide part-timeemployment opportunities for teenagers,the elderly and child-carers in low-incomeareas. As a low capital, high labour sector,the considered inclusion of farming andinformal food trading into city planning(for example, by creating allotment gardensand market places) creates opportunitiesfor entrepreneurship and stimulation of thelocal economy, while reducing dependence
on imported food and improving resilience.
Suggested reading: Resource Centres onUrban Agriculture and Food Security (RUAF)website link: www.ruaf.org
4.6 Whole-system thinking
A whole-systems thinking approach todesign entails ...a process through which
the inter-connections between systemsare actively considered, and solutions aresought that address multiple problems at thesame time.79 In the case of infrastructure,this involves consideration of the pointsof intersection between water, energy,waste and food systems as opportunitiesfor achieving multiple benefits for peopleand the environment. A whole-systemsapproach is based on the understanding
that humans and their built environments
Case study: Portlands climate action plan,United States
As part of a comprehensive strategy to prepare
for climate change, Portland has identifiedfood and agriculture as one of eight key areas
through which it can achieve its ambitious
target of cutting carbon emissions by 80 percent from 1990 levels by 2050. To reduceemissions generated by the transport and cold
storage of food, the city actively promoteslocal food production and a culture of localconsumption. It does this by supportingfarmers in and around the city, providingland for farming activities, educating urbanfarmers and schoolchildren, and encouraging
entrepreneurship via farmers markets and
community supported agriculture (CSA)schemes. Instead of dumping organic wastein centralized landfills, municipal facilitiescollect food scraps and compost them toprovide a rich source of soil nutrients forurban gardens and farms. By replacingchemical fertilizers with compost, the costsof farming and emissions generated inthe production of artificial fertilizers canbe reduced whilst alleviating pressure on
landfill sites. (Full case study in Section 6.)
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rely on functioning natural ecosystems forwater, food and energy, and that damagingnatural systems can have severe negative
implications for the viability of cities.
The present configuration of cities,infrastructure systems and the policiesand regulations that shape them run therisk of getting stuck in a particular way ofthinking that is tied to industrial models ofdevelopment. This can be characterized byunhindered exploitation of renewable andnon-renewable resources - in particular aheavy reliance on fossil fuels for energy that disregards the Earths limits and isinherently unsustainable.80 While presentlyavailable technologies may help to reducethe energy and resources consumed bycities, without expanding thinking beyondcurrent sectoral paradigms to achieve wholesystem efficiencies, such interventions canonly serve to prolong the status quo ratherthan challenging it.
Instead of approaching urban sustainabilitythrough engineering interventions with alimited focus that considers only immediate
environmental impacts, a wider scope andtimescale is required at the conceptualstage to ensure that projects are alignedto the healthy functioning of the wholesystem in the interests of current and futuregenerations. Such vision is best achieved viacollaborations within and between sectorsto allow for the contribution of diverseperspectives81 when creating visions towhich engineering solutions can be aligned.
Suggested reading: Stasinopoulos, P.,Smith, M.H., Hargroves, K. & Desha, C.(2008). Whole System Design: An IntegratedApproach to Sustainable Engineering.Oxford: Earthscan.
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Road access to the causeway linking Johor Bahru, Malaysia and Singapore
UN-Habitat/Alessandro Scotti
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5Strategic Planningfor more SustainableInfrastructure
Cities contain a great deal of knowledgeabout how to construct and operateinfrastructure systems, but the replicationof resource-intensive and environmentallydamaging approaches may causeunnecessary environmental damage and
render a city unprepared for future crises. Astrategic approach to infrastructure planningbased on a strong vision of a sustainablefuture is required to ensure that all citizensbenefit from infrastructure investments, andthat the long-term interests of people andthe natural environment are advanced oncethe city is locked into the resulting modes ofoperation.
The term strategic planning refers to asystematic decision-making process thatprioritizes important issues and focuseson resolving them. It provides a generalframework for action by identifyingpriorities, making wise choices and allocatingresources (for example, time, money, skills) toachieve specified objectives.82All planning spatial, economic, sectoral, environmental,or organizational is more effective if it is
strategic. Strategic planning has becomean important tool for local governments to
ensure efficiency and effectiveness in policydesign and implementation, and it is usefulfor making sound infrastructure decisions inline with sustainability.
A strategic approach helps move away
from ad-hoc and short-term decision-making towards better long-term decisions.Given that linear approaches to planningcomplex technical networks are becomingincreasingly inappropriate,83 the iterativeprocess of strategic planning is well suitedto infrastructure planning because it allowsplanners a degree of flexibility to respondto changing circumstances and needs overtime.
5.1. Who should be involved?
Strategic planning ensures that theaspirations of different stakeholder groupsare combined in a common vision that getstranslated into objectives, which in turnprovide criteria to select win-win solutions.Moreover, it ensures the right timing andmaximizing of public-private cooperation
and public participation. To start the process,a dedicated task team should be formed to
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ensure input from a diverse range of interestgroups, including representatives of thefollowing:84
l Public authorities involved ininfrastructure development andoperation (for example, suppliers,regulators, coordinators);
l Academics specializing in urbansustainability and infrastructure who canprovide access to the latest local andinternational research;
l Consultants with expertise ininfrastructure implementation andfinancing in the local context;
l Representatives from local andinternational non-governmentalorganizations whose work addresseslocal needs and challenges amongstmarginalized groups; and
l Community organizations and unionswho might play a role in mobilizingsupport for the shared vision amongstthe public and workers.
Once the core group has been identified andthe individuals concerned have expressedtheir commitment to the strategic planningprocess, specific roles and responsibilitiesshould be assigned to ensure that everyone
plays their part.
5.2 Where are we now?
Implementing sustainable infrastructuralsolutions requires a strong footing in thelocal context. International best practicesare not guaranteed to work in all settings,and promising ideas can fail if they are notadapted to local realities.85 Infrastructural
decisions should be firmly grounded in anunderstanding of the challenges facingthe city as a whole, and the opportunities
presented by its location and the resourcesat its disposal.86
As a starting point, the city can be profiledto identify the needs of its inhabitants andthe resources it has available to satisfy thoseneeds. This process should look at:
5.2.1 Basic needs
In order to ensure that infrastructurepromotes human dignity and socialinclusiveness, it is important to understandthe magnitude and location of the greatestneed for access to basic services. The focusof this exercise should be on basic humanneeds, for example warmth, light, sanitationand mobility, and should not prescribesolutions like grid electricity, waterbornesewage systems or freeways at this stage.When calculating the magnitude of theseneeds, care should be taken to accountfor the possibility of average resourceconsumption levels diminishing as a result
of improvements to the eco-efficiency ofservice delivery.
5.2.2 Local resources
To make the best use of the citys location,renewable natural resources, such assunlight, wind, sources of fresh water andforests, should be identified and evaluated tobuild an understanding of the opportunities
they present. In addition to new resources,this study should include solids, liquids andgases currently considered to be wastes sothat opportunities for closing waste loopscan be identified in the interests of a morecircular urban metabolism.
5.2.3 Patterns of resource use
Measuring the resources used and wastes
produced by a city is an important part ofanalysing eco-efficiency and, over time,these figures can be used to track its
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progress. Once this data has been collected,eco-efficiency can be calculated by relatingresource usage back to human utility to
calculate, for example, the number ofpassenger miles a public bus derives from alitre of fuel, or the number of hours of lighta street lamp provides per watt of electricity.Similarly, eco-intensity can be used to relatethe environmental burden of pollutantsto the utility derived as a measure of thedamage caused in the delivery of a productor service.
Within these measures, categorizationof consumption and waste productionaccording to sector or location allows fora more detailed picture of urban resourceflows to be developed. This helps to ident