Green Engineering 101: Building a Sustainable Planet, Michael Lepech, Stanford Engineering

© 20112011 Stanford eDay 16 July 2011

Green Engineering 101

Michael LepechDepartment of Civil and Environmental Engineering

Stanford University

2011 Stanford Engineering eDay

16 July 2011


Our Environment


Our Behavior


Why do we do this?


Engineering a greener world

• Systems Modeling

• Flow Accounting

• Impact Assessment

• Valuation

• Guided Design

• Environmental Looping

• Final Assessment




• Flow Accounting


• Valuation

• Guided Design


• Final AssessmentInputs Outputs



Inputs Outputs

Impacts


• Flow Accounting


• Valuation

• Guided Design





Inputs Outputs

Value, $$$$$$


• Flow Accounting


• Valuation

• Guided Design





Inputs Outputs

Value, $$$$$$


• Flow Accounting


• Valuation

• Guided Design





Inputs Outputs

Impacts, Value, $$$$$$


• Flow Accounting


• Valuation

• Guided Design




Case Study


What does it take to make chocolate chip cookies?

• Flour

• Baking Soda

• Salt

• Butter

• Sugar (and Brown Sugar)

• Vanilla

• Eggs

• Chocolate Chips?


What does it take to make chocolate chip cookies?

• Flour

• Baking Soda

• Salt

• Butter

• Sugar (and Brown Sugar)

• Vanilla

• Eggs

• Chocolate Chips


Sugar Production

Sugar Production Video

Fields & Harvest Sugar Cane Transportation

GrindingPressingRefiningBagging

Energy and

Materials

http://www.youtube.com/watch?v=UV7QiFz8ekw


ISO 14040 Life Cycle Modeling

Material

Processing

Use

Manufacture

& Assembly

Retirement

& Recovery

ServiceDisposal

Raw Material

Acquisition

Reuse

Primary

Materials(e.g., ores, biotic

resources)

Recycled

Materials(open loop recycling)

Primary

Energy(e.g., coal)

Air pollutants(e.g., Hg)

Water

pollutants(e.g., BOD)

Solid waste(e.g., MSW)

Products(e.g., goods, services)

Co-products(e.g., recyclables, energy)

RemanufactureRecycling

Center for Sustainable Systems (2003)

T

T

T

T

T

T


Bill of Materials (Batch Recipe)

• Flour 2.25 cups

• Baking Soda 1 teaspoon

• Salt 1 teaspoon

• Butter 1 cup (2 sticks)

• Sugar (and Brown Sugar) 1.5 cups

• Vanilla 1 teaspoon

• Eggs 2

• Chocolate Chips 2 cups


US Electricity Life Cycle Inventory

Kim. S. and Dale, B. (2005)


Environmental Footprint of a Batch (24)E

coP

oin

ts

Flour

ButterChocolate

Eggs

Sugar

Baking Soda, Salt, Vanilla

Greenhouse Gases

Ozone Depletion

Acidification

Eutrophication

Heavy Metals

Carcinogens

Summer Smog

Winter Smog


Carbon Footprint of a Batch of Cookies

78g CO2-eq per cookie


Environmental Impact Flow

One Chocolate Chip Cookie




ISO 14040 Life Cycle Modeling

Material

Processing

Use

Manufacture

& Assembly

Retirement

& Recovery

ServiceDisposal

Raw Material

Acquisition

Reuse

Primary

Materials(e.g., ores, biotic

resources)

Recycled

Materials(open loop recycling)

Primary

Energy(e.g., coal)

Air pollutants(e.g., Hg)

Water

pollutants(e.g., BOD)

Solid waste(e.g., MSW)

Products(e.g., goods, services)

Co-products(e.g., recyclables, energy)

RemanufactureRecycling

Center for Sustainable Systems (2003)

T

T

T

T

T

T


Environmental Footprint of a Batch (24)E

coP

oin

ts

Flour

Butter Chocolate

EggsSugar

Baking Soda, Salt, Vanilla

Greenhouse Gases

Ozone Depletion

Acidification

Eutrophication

Heavy Metals

Carcinogens

Summer Smog

Winter Smog

MixingTrucking

Baking


Carbon Footprint of a Batch of Cookies

310g CO2-eq per cookie



One Chocolate Chip Cookie

US Energy

Production


Our First Design Conclusion…

NO BAKE COOKIES!


Design Challenge


Design Challenge

• Designing a “green” no bake dessert…

– Design constraint

CO2-eq < 78g

– Must use one graham cracker and one spoon of frosting!


Design Challenge


– Parts list….

Item Impact (g CO2-eq)

Graham Cracker 25

Chocolate Frosting (1 spoon) 15

Vanilla Frosting (1 spoon) 13

Marshmallow 6

Chocolate Chips 1

Sprinkles (1 spoon) 5

Hershey Kiss 8


How do we use this at Stanford?


Advanced Materials for Green Infrastructure

ECC (Engineered Cementitious Composite)


Ductile Cement-based Materials

Concrete

Normal Fiber

Reinforced Concrete

HPFRCC (ECC)

w or


1

0

cos2/

0

)()()(),()(

fL

z

e

f

fdzdzppgLP

A

V

Stress vs. Crack Opening Relation

0

1

2

3

4

5

6

7

0 0.1 0.2 0.3 0.4 0.5

Crack Opening, d (mm)

Str

ess,

s (

%)

M45

8%

14%

21%

Stress vs. Crack Opening Relation

0

1

2

3

4

5

6

7

0 0.01 0.02 0.03 0.04

Crack Opening, d (mm)

Str

ess, s (

MP

a)

M45

21%

13%

8%

`

Nanotailoring of Green ECC

• Increasing carbon content decreases interfacial friction

• 40% reduction in complimentary energy

Str

es

s,

(MP

a)

Crack Opening, (mm)

Increasing Carbon Content

Virgin PVA Fiber Nanocoated PVA

Str

ess,

(MP

a)


ECC Link Slab Concept

Links two adjacent bridge

spans through continuous

deck

ECC material accommodates

adjacent span deformations

Combined flexural, axial, and

environmental loads

Concrete DeckContinuous Reinforcement Shear Stud ECC Link Slab Deck Interface

Steel Beam Debonding Paper Concrete SidewalkConcrete Railing


Steel Beam Debonding Paper


Steel Beam Debonding Paper Concrete SidewalkConcrete Railing

Concrete DeckContinuous Reinforcement

Shear Stud Deck Interface

Steel Beam Debonding Paper

ECC Link Slab


Life Cycle Model

MOBILE6.2

Emissions

Model

NONROAD

Emissions

Model

KyUCP

Traffic Flow

Model

Life Cycle Assessment Model

Life Cycle Cost Model

Model ParametersUser Input and System

Definition

Environmental

Sustainability Indicators

- Resource Depletion

- Energy Use

- Global Warming Potential

Social Cost Factors

- Agency Activity Emissions

- Vehicle Emissoins

- Vehicle Operating Costs

- User Delay

Agency Cost Factors

- Construction Material

- Distribution

- Construction (Labor & Equip)

- End of Life Costs

Agency Costs Social Costs

Keoleian et al, Journal of Infrastructure Systems March 2005 51-60


Detailed Impact Flow (CO2-eq)

• Full life cycle model is comprehensive and detailed

– 203 nodes visible of 36 908


Infrastructure Sustainability Indicators

• Total primary energy consumption is dominated by traffic-related energy

Total Primary Energy Consumption

by Life Cycle Stage

0

10000

20000

30000

40000

50000

60000

70000

80000

90000

ECC Conventional

Gig

ajo

ule

s (

GJ

)

EOL

Distribution

Materials

Construction

ΔTraffic

Keoleian et al, Journal of

Infrastructure Systems

March 2005 51-60


Plastics from Waste Methane


OFU Gimsøystraumen Bridge

Total span: 839 meters Maximum clearance to the sea: 30 meters

Spans: 9 Opened in 1981

Main span: 148 meters


Management Results

Environmental Impact

Budgets

CO2 Impact Budget

CO2 Accrual


Targeting “Sustainability”

• Target reductions to achieve a stabilized atmospheric carbon-equivalent concentration of 490ppm -535ppm (Scenario II) by Year 2050 (Year 2000 baseline).

IPCC AR4


Design Challenge


– Design constraint

CO2-eq < 78g

– Must use one graham cracker and

one spoon of frosting!


Final Thoughts…

• We need to take better care of our planet.

• Engineers are a big part of that!

–Green design is a big part of Stanford Engineering

– Lots of ways to design “green” that respect the choices and values of many people


Thanks!

Questions?

Michael D. Lepech

[email protected]

stanford.edu/~mlepech


Technology

Green Engineering 101: Building a Sustainable Planet, Michael Lepech, Stanford Engineering