INFRASTRUCTURE ECOLOGY: AN

EVOLVING PARADIGM FOR

SUSTAINABLE URBAN DEVELOPMENT

Pandit, A.; Bras, B.; Minne, E. A.; Dunham-Jones, E.;

Augenbroe, G.; Jeong, H.; James, J.-A. C.; Newell, J. P.;

Weissburg, M.; Brown, M. A.; Chang, M. E.; Xu, M.;

Begovic, M. M.; Yang, P.; Fujimoto, R. A.; French, S. P.;

Thomas, V. M.; Yu, X.; Chen, Y.; Lu, Z.; Crittenden, J. C.

E-Mail: john.crittenden@ce.gatech.edu; Arka.Pandit@gatech.edu

City

People

Economy

Transportation

Energy

Water

Waste

Buildings

Parks

Government

And many

more…

Industry

2

Q: With the next

generation of

infrastructure, what

are the implications

if we design, build,

and operate these

systems separately,

as we have done in

the past?

INFRASTRUCTURE

ECOLOGY

Sustainable Urban Systems

• Sustainable Urban Systems: Key questions

• How are energy, materials, information, and water utilized by the

different configurations and populations of systems?

• How can we reduce energy, emissions, materials and water inputs

and increase the creation of wealth and comfort?

• How do “communities of infrastructure” emerge from the cultural,

physical, and economic conditions of the region?

• Infrastructure Ecology:

• A Hyper Nexus of material use, water, energy,

transportation, land use/planning, commercial and

residential buildings, community design, and

socioeconomics as they occur in urban

environments.

Interconnection between Urban Infrastructure

System , Natural Environmental Systems and

Socio-Economic Systems

Incre

asin

g S

pati

ote

mp

ora

l S

cale

Interconnections within Urban

Infrastructure Systems Water for Energy:

• Average consumptive use in US: 2.0 Gal/kWh

• 0.5 Gal/kWh for thermoelectric; 18.0 Gal/kWh for hydroelectric

Energy for Water:

• 4% of total electricity consumption in US for water and wastewater sector;

19% in California

• 80% of the requirement is for conveyance and distribution

Energy for Transportation:

• 28% of the total energy consumption in the US (in 2008)

Transportation and Land Use:

• Empirical estimates suggest that one new highway built through a central

city reduces its central-city population by about 18%.

• Land Use, Water and Energy:

• Use of rainwater harvesting and other LID techniques in the urban area of

southern California would result in a savings of 573–1225 GWh per year.

Interconnections within Urban

Infrastructure Systems

• The water footprint for biofuels may

be 10 to 1000 times higher than

conventional gasoline on a life-cycle

per vehicle mile travelled basis

depending on whether the feedstock

crops are irrigated or not

• If all personal transportation in the

metropolitan Atlanta, GA region was

electric, the increased water demand

(evaporative loss) needed to produce

the electricity (under present generation

mix) to charge the fleet of electric

vehicles would be almost identical to the

current domestic demand (estimated at

100 million gallons per day)

Water for Transportation:

Impact of Biofuels Impact of Automobile Electrification

False Creek Neighborhood Energy Utility

Vancouver, BC: City of Vancouver

Sewage heat recovery supplies

70% of annual energy demand

and reduces ghg 50%

IMPLICATIONS FOR

DECISION MAKING

Sustainable Water Resources Management

Agriculture

Energy People (Municipal &

Industrial)

Ecology / Environment

Key Challenges in Infrastructure Ecology (After Allenby 1999)

13

Goal

Focus

Nature of Engineered system

Engineering psychology

Scientific Model

Technology adaptation

Scale

Impact awareness

“Home run”-fix problem

for good

Artifact design,

construction &

performance

Control & complete

systems definitions

Primarily

technical and economic

Low

Short term/Local

Reductionist

(e.g., based on toxicology)

Minor adaptation

Maintain dynamic

systems in desired states

Systems dynamics: links,

feedback, loops,

nonlinearities & discontinuities

Management of complex

"non-controllable" systems

Coupled human-natural

systems

High

Long term/Regional or global

Integrative(e.g., based on

sustainability)

Major evolution of social

and technology systems

Engineering (e.g., Water

Treatment Plant)

Sustainable Engineering

(e.g., Sustainable Water

Resource Management) Characteristics

ADVANCING THE SCIENCE OF

INFRASTRUCTURE ECOLOGY:

ENGINEERING COMPLEX SYSTEMS

Engineering Complex Systems - Our

Goals Understand and predict the emergent properties of urban

infrastructure systems and their resilience to internal and external

stressors

Identify how flows of resources (information, energy, and materials)

are utilized within complex urban systems and reduce material and

energy investments by learning how these resources are utilized on

a system-wide scale

Develop the cyber infrastructure to gather information monitor,

model and visualize the complex emergent properties

Integrate the human perspective into urban infrastructure to

produce socially sustainable outcomes and policies

Develop the pedagogy of engineering complex systems in the

context of sustainable and resilient urban infrastructure

Interactions between Infrastructure and

Socio-Economic Environment

Macro

Micro

Infrastructure

Systems

Water

Energy

Heating/

Cooling

Transportation

Socio-

Economic

Environment

Business

Neighborhood

Housing

Jobs

Emergent Properties: land use, water, energy and material

consumption, transportation quality, quality of life, and other

sustainability metrics.

Decisions, behaviors of Individual Agents and the relationship

of individual agents: location choice, traffic activity, and

willingness to pay

65%

35%

0%

20%

40%

60%

80%

100%

0 5 10 15 20 25 30Year

Percentage of households as compared to total households after30 years

Percentage of households in single-family houses as comparedto total households after 30 years

Percentage of households in apartments as compared to totalhouseholds after 30 years

41%

59%

0%

20%

40%

60%

80%

100%

0 5 10 15 20 25 30Year

Business As Usual

(BAU)

More Sustainable Development

(MSD)

Agent-based Modeling: Simulating the Adoption Rate

for More Sustainable Urban Development

Impact fee for Low Impact Development

non-compliance penalty:

• $13,000 per unit for single-family

house

• $1,500 per unit for apartment home

Principal Agents: Prospective

Homebuyer, Homeowners, Developers,

Government

Implemented Policy Tool

After 30 years:

• 40% reduction in potable water

demand from centralized plant in MSD

as compared to BAU

• 36% increase in net property tax

revenue generation in MSD as

compared to BAU

Policy Implementation Effect

INFRASTRUCTURAL SYMBIOSIS:

REORGANIZING THE FLOWS FOR

SYSTEM LEVEL OPTIMIZATION

The Synergistic Effects of

“Infrastructural Symbiosis” • Designing UIS using an infrastructure ecology approach alters and

reorganizes energy and resource flows, allowing one to consider the

potential synergistic effects arising from infrastructural symbiosis.

• The accumulated synergistic

effects of this particular model of

infrastructure ecology is significant:

• reduced water and energy

consumption,

• lower dependence on centralized

systems,

• larger share of renewables in the

electricity mix,

• reduced vehicle-miles travelled, &

• an increase in tax revenue.

INFRASTRUCTURE SYMBIOSIS

Decentralized Water Resource

Development: Low Impact

Development & Greywater Reclamation

Water Flows within the Urban System with

LID Implementation: Case Study of Atlanta, GA

• Individual water use (91 Gpcd) in 2-story apartment (RG-1)

• Implemented LID technologies: rainwater harvesting, grass pavement,

rain gardens, and xeriscaping

• Reduces dependence on the centralized potable water system by ~50%

(entire non-potable demand)

• Uncontrolled Stormwater runoff (kGal/cap-yr) : 16 → 0

Unit: Gallon per capita per day (Gpcd)

Water Flows within the Urban System

with Reclamation Option: Case Study of

Atlanta, GA • Individual water use (91 Gpcd) in 2-story apartment (RG-1)

Implementation of Greywater Reclamation : Case

Study of Atlanta, GA

• Benefits:

• 60% satisfaction of residential water demand regardless of

population density

• Reduces dependence on the centralized potable water system by

~60% (entire non-potable demand)

• Reduces stress on the centralized wastewater treatment plant by

~60%

• Citywide implementation of Hybrid (Reclamation + Centralized)

System would save the city ~$1.0 million per year in energy

costs.

• Challenges:

• Has no effect on stormwater runoff

• Does not increase ecological services

INFRASTRUCTURAL SYMBIOSIS

Decentralized Energy Production:

Combined Heat and Power (CHP)

Recapturing Lost Heat in Combined Heat &

Power System

Air-cooled

Microturbine

Absorption

Chiller

Electricity

Heating

Cooling

Building Energy Requirements Met by

CHP Using Air Cooled Microturbines

30kW

MT

Electricity:

477MWh

(54%)

Thermal:

452.5 MWh

(123%)

60kW

MT

Electricity: 778

MWh (66%) Thermal: 900

MWh (140%)

Grid

Energy

Electricity:

218MWh (46%)

Electricity:

260MWh (34%) 2 6-story

apartment

buildings

12 Single

Family homes

Thermal load includes heating and cooling demand

437600 Gal

(54%)

985300 Gal

(66%)

Water for

energy

savings

INFRASTRUCTURAL SYMBIOSIS

Decentralized Energy Production:

Integration of Renewables and Vehicle-

to-Grid (V2G)

NO-PV

40% PV

Simulation Results in Hourly

Resolution

The large variation in PV output

demands a higher capacity of

spinning reserves

Plug-in Hybrid Electric Vehicles (PHEVs) and Vehicle-to-Grid (V2G) power

Credit: Kempton and Tomić, 2005

PHEVs can send power back to the grid when parked, and function as distributed

storage for intermittent energy from renewable sources

US demand-supply balances during

maximum demand with various V2G

ratios in 2045

30% V2G penetration could reduce ~100 GW or about ⅓ of the total peak

demand of ~300 GW in US by 2045

Source: Modelling Load Shifting Using Electric Vehicles in a Smart Grid Environment – © OECD/IEA 2010

URBAN DEVELOPMENT

SIMULATION AND LARGE SCALE

WATER SAVINGS CARBON

EMISSION REDUCTIONS FROM

LID AND CHP

RESIN Meeting Sept. 24, 2009

SPATIAL DATABASES FOR URBAN MODELING - 1

The SMARTRAQ project

Supports research on land

use impact on transportation

and air quality

1.3 million parcels in the 13

metropolitan Atlanta non-

attainment counties

RESIN Meeting Sept. 24, 2009

SMARTRAQ DATA AND ATTRIBUTES

Address

Road Type

City

Zip Code

Owner Occupied

Commercial/Residential

Zoning

Sale Price

Sale Date

Tax Value

Assessed Value

Improvement Value

Land Value

Year Built

No. of Stories

Bedrooms

Parking

Acreage

Land Use Type

Number of Units

X,Y Coordinate

Estimated Sq Feet

Total Sq Feet

Projected Growth Scenarios for Atlanta Business As Usual

Year 2030

More Sustainable Development

Year 2030

34

110

66

24

0

20

40

60

80

100

120

140

160

Energy fromGrid with CHP

Energy fromGrid

GW

h (

in t

ho

usa

nd

s)

Energy (Thermal)

Energy(Electricity)

Atlanta Energy and Water Demand Projections (with low flow fixtures + rooftop rainwater harvesting + decentralized CHP system)

4964

1521

728.5

706.85

0

1000

2000

3000

4000

5000

6000

Energy fromGrid

Energy fromGrid with CHP

MG

D (

Mil

lio

n G

all

on

s p

er

da

y)

496.40

152.10

107.75

107.58

0

100

200

300

400

500

600

700

Energy fromGrid

Energy fromGrid with CHP

Residential+ Commercial Energy

Demand (with Air Cooled Microturbines in a

Decentralized CHP system)

Water Demand

(Withdrawal)

Water Consumption

(Evaporation)

25% reduction

61% reduction

63% reduction

More Sustainable Development Scenario

Withdrawal Evaporation

Note: water for energy calculation does not include water needed for the extraction and transportation of the raw fuel.

5,051

6,211

0

1000

2000

3000

4000

5000

6000

7000

Energy from Grid withCHP

Energy from Grid

Co

st

of

En

erg

y f

rom

th

e G

rid

( $

/year)

M

illio

ns

24

78

22

6

0

10

20

30

40

50

60

70

80

90

Energy from Grid with CHP Energy from Grid

CO

2 E

mis

sio

ns (

10

6 t

on

s C

O2)

Emissions(Electricity) Emissions (Thermal)

Potential GHG and Cost Reductions in 2030 • By 2030, implementation of CHP in all the residential and commercial buildings (new and

existing) will reduce the CO2 emissions by~ 0.04 Gt CO2. and the energy costs by $1.1 billion

per year for the Metro Atlanta region.

-45%

The 2030 grid+CHP scenarios assumed residential and commercial units in the base year were also retrofitted with

CHP systems

CO2 Emissions Energy Costs

-23%

The costs reduction calculation is only based on the cost of natural gas and the cost of electricity from firms in the

region.

SUMMARY

Summary

• Urban Systems Are All Connected and More Efficiency

Can be Achieved by Looking at Their Interactions

• Decentralized Energy and Combined Heat and Power

Can Save Energy and Water

• Decentralized Water / Low Impact Development Can

Save Water, Energy and Money

• Land Use/ Planning Is Vital in Reducing the Impact Of

Urban Systems and Examining Their Interactions

• Agent Based Models May Be Useful to Examine the

Adoption Rate of Policy Instruments

limited

scalable

centralized

decentralized

integrated disconnected

Pedagogical Implications

• Emphasis on Systems Analysis

• Instead of designing urban infrastructure one component at a time,

the focus should be on systems analysis of urban infrastructure

• Inter- and Intra-disciplinary Approach

• Engineering alone cannot achieve the goal of sustainable urban

infrastructure systems. It should include policy analysis and urban

planning as integral part of the educational focus.

• Complexity Science

• Complexity science, in particular how it relates to urban systems,

should be explored in more details to learn about the emerging

properties that are not apparent otherwise.

Resources and Upcoming Event

• Center for Sustainable Engineering: Learning

Modules and Assesment of Sustainable Engineering

Education in the US

• Call for Papers: First ASCE International Sustainable

Infrastructure Conference Nov 6-8, 2014 Long Beach

California -

http://content.asce.org/conferences/icsi2014/index.html

THANK YOU!!

john.crittenden@ce.gatech.edu

www.sustaianble.gatech.edu