1. A Scientific Way to Look at Going Green!
Life Cycle Assessment
A Scientific Way to Look at
Going Green!

2. What does it mean to be Green?? What is Sustainability??
Topics to discuss in class regards to sustainability: “Environmentally friendly
Sustainable products, Green product, Environmentally preferable, Biodegradable, Recyclable, Ozone friendly, Eco-design, Greenwashing”
United Nations World Commission on Environment and Development (1987) Sustainable Development definition :
“… development that meets the needs of the present without compromising the ability of future generations to meet their own needs.”

3. Sustainability Environmentally Friendly Sustainable Products
Green product
Environmentally
Preferable
United Nations World Commission on Environment and Development (1987) Sustainable Development definition:
“… development that meets the needs of the present without compromising the ability of future generations to meet their own needs.”
Biodegradable
Recyclable
Ozone friendly
Eco-design
Greenwashing
wwblog.miragestudio7.com

4. What Can the Earth Handle?
World Population Statistics
UN Population Division
The estimate of Earth’s Maximum supportable population is 13.4 billion.
Looking at the population statistics, where are we headed?
Renewable Energy Source Will Limit Our Growth!
Population (2007)
Annual Growth
Rate
(00 – 07)
World
6.7 Billion
1.24%
LDC
5.4 Billion
1.44%
MDC
1.2 Billion
0.36% US
301 Million
1.03%
Average per capita energy consumption is 3 kW/person
US 12 kW/person
Industrialized 7.5 kW/person
Denmark 5.1 kW/person
Developing 1kW/person

5. Being Green is Trendy . . . . . . . . . . . What Does Science Say?
Industry is looking for ways to green their products and manufacturing processes.
Individuals and Families are looking to green their homes and lifestyles.
How can you tell if something really is green??
What is currently happening to achieve this goal?
Scientists perform a Life Cycle Assessment (LCA)

6. Life Cycle Assessment WHAT CAN BE DONE WITH LCA?
Definition:
“Compilation and evaluation of the inputs, outputs and the potential environmental impacts of a product system throughout its life cycle”
This establishes an environmental profile of the system!
ISO = International Organization for Standardization
Ensures that an LCA is completed
in a certain way.
WHAT CAN BE DONE
WITH LCA?
Product or project development and improvement
Strategic planning
Public policy making
Marketing and eco-declarations

7. Product Life Cycle
M, E
M, E
M, E
M, E
M, E
M, E R a w M a t e r i a l M a t e r i a l M a n u f a c t u r e U s e
& R e t i r e m e n t T r e a t m e n t A c q u i s i t i o n P r o c e s s i n g
& A s s e m b l y S e r v i c e
& R e c o v e r y D i s p o s a l W W W W W W r e u s e r e m a n u f a c t u r e c l o s e d - l o o p r e c y c l e o p e n - l o o p r e c y c l e
M, E = Material and Energy inputs to process and distribution
W = Waste (gas, liquid, or solid) output from product, process, or distribution
Material flow of product component

8. What Makes Up LCA Goal & Scope Definition
What is the purpose of the LCA and who is the audience?
Inventory Analysis (LCI)
What is the function & functional unit?
Where are the boundaries?
What data do you need?
What assumptions are you making?
Are there any limitations?
Impact Assessment (LCIA)
What are the environmental, social, and economic affects?
Interpretation
Ways to reduce environmental impacts.
What conclusions can you draw from the study?
What recommendations can be made?

9. Goal and Scope Wooden Pencil vs. Mechanical Pencil
Goal = Compare 2 writing utensils for classroom use.
Scope: Wooden Pencil (T = Transportation)
Process Flow Diagram
Retailer
Use
End of Life
Lumber Forest
Lumber Mill
Manufacture T T T T T T
Rubber
(Landfill)
Sharpening T
Graphite T
(Electricity)
Packaging T
Brass

10. Scope: Mechanical Pencil
PE = Polyethylene
PP = Polypropylene
Both materials are plastic polymers (large molecules) used to make many products.
Retailer
Use
End of Life
Oil
PE / PP
Manufacture T T T T T T
Rubber
(Landfill) T
T = Transportation
Graphite T
Packaging T
Spring

11. Function & Functional Unit
Example
Service provided by a system
What it does!
Functional Unit
Gives the function a number value
Allows comparison between products
Reference point
Wooden Pencil vs. Mechanical Pencil
Function = “Writing”
Functional Unit = “1 meter of writing”

12. Items To Consider?? Inputs What is needed to make the substance!
Energy
Materials
Labor
Outputs
What comes out of the system!
Products (electricity, materials, goods, services)
Waste
Emissions
Co-products

13. Data Collection Life Cycle Inventory Analysis
Time-sensitive = past 5 years
Geographical = does it match the location from the goal
Technology = best available technology for process
Representativeness = reflects population of interest
Consistency = matches the procedure
Reproducibility = another person could find it
Never Forget Precision: The consistent reproducibility of a measurement Completeness: Covers all the areas outlined in the scope

14. LCA in Action: Think About It. Paper Plate vs
LCA in Action: Think About It! Paper Plate vs. China (Plate You Wash & Reuse)
What is the function?
What is the functional unit?
What materials & resources are used?
What does it take to produce both?
What are the impacts to the environment?
Is there waste?
Does washing the China produce waste?
What types of data do you need?
How do you know
which is better?

15. Data Analysis Environmental Impact Categories
Global Warming Potential
Gases in the atmosphere that absorb and emit radiation
Trap heat from the sun
Water vapor, CO2 , CH4 , ozone, NO2
Abiotic Depletion
Consumption of non-living resources
Human Toxicity Potential
Value that shows harms to humans from chemicals
Land Use
How much land is needed

16. Environmental Impact Categories Continued . . . . .
Eutrophication
Increase in chemical nutrients containing nitrogen or phosphorus
land or water
overgrowth of plants
killing organisms at bottom of water
Water Use
Mercury
Acidification
caused by pollution from fuels & acid rain
low pH
Smog (Winter or Summer)
Energy Use
Solid Waste
Oil
AND MANY MORE!!

17. Evaluate 2 products using the LCA method and make change!
Where Do We Go From Here?
What is the purpose of all this data??
Scientists can make recommendations of choices that are less impactful
Scientists can analyze a particular impact and focus on a solution
Industry & Individuals can take a closer look at how they can make a difference
Class Project
Evaluate 2 products using the LCA method and make change!

18. Where Does Our “Stuff” Come From?
Let’s check it out with
“The Story of Stuff”

19. Department of Civil and Environmental Engineering
Special Thanks
Dr. Michael Lepech
Department of Civil and Environmental Engineering
Stanford University