Life Cycle Assessment

Scott Matthews

Civil and Environmental Engineering

Carnegie Mellon University

LCA patterns of use

• More for larger firms than smaller.• More a tool for a pull strategy than for a push

strategy.• Acceptance substantially vary among

countries (more accepted by developed countries than developing countries).

• LCA started to become a part of the regulatory system in Europe but not in the US.

Some results from the Survey by Frankel and Rubik (1999)

Source: Frankl&Rubik, 1999

Important applications of LCA perceived by industries

Growing and harvestingcotton

Seed removalPacking in bales

FertiliserPesticides

25 MJ

Pr oduct ion of

polyest er

48 MJ

Pr e-t r eat ment , bleaching, (dyeing), post -t r eat ment

Bleaching agent s, sodium hydrox ide, opt ical

br ight ener, ant i shr inking agent s

30-80 lit er wat er

25- 90 MJ

Reuse0 ,1 * 1 kg

S ewing of unif or m

1 kg

Wash (100x)

2500 lit er wat er1,5 kg washing agent

600 MJ

S pinningSpinning oil

6 MJ

Ext r uding,

cut t ing and packing

7 MJ

Use (100x)I nciner at ion

0 ,8 * 1 kg

Deposit0 ,1 * 1 kg

Dr ying, ir oning,

pr essing (100x)

200 MJ

WeavingSize

20 MJ

S pinningSpinning oil

6 MJ

Ext r act ion of

oil and nat ur al gas

0 ,5 kg 0,5 kg

Credit ingheat & power

19 MJ

Credit ingunif orm

0,1 * 1 kg

Credit ingindoor heat ing

in t ot al 200 MJ

Disposal

Use

Resources and materials

Manufacture

Example of process-flow diagram(aggregated): Source: Hauschild, 2003

Product system of a uniform (cloth)

Example of “required data” table (Inputs and outputs table - part) (source: International Aluminum Institute, 2003)

Identifying required data (cumulative input mass - part) (source: Suh, 2000)

Example of inventory result (part) (source: International Aluminum Institute, 2003)

Paper vs. Plastic Grocery Sacks: Comparison of Three Studies

Allen & Bakshani

Graedel & Allenby

Ciambrone

PE

60,790 sacks

Energy

[M BTU]

40 40 34

Air pollution [lb] 73 76 59

Paper

30,395 sacks

Energy

[M BTU]

50 49 39

Air pollution [lb] 195 198 49

In-Class Assignment• Suppose you need to choose a new copier for

an office. In a small group:– Define appropriate goals and scope for a life cycle

cost and environmental life cycle assessment.– Define appropriate environmental indicators (e.g.

electricity or energy use).– Define major benefit or cost categories to consider– Develop a set of processes to be considered (i.e.

inputs and outputs identified and estimated).• We will have reports from groups by end of

period.

Example: Copier LCA• In GaBi demo, explore under Processes,

Production, Materials, Metal• Look at steel (3 options)• Can also see plastic, etc options• Double click to see inputs/outputs

– Generally shows normalized impacts for 1kg of output item (eg 1 kg of ABS plastic)

– The data records refer to a process that requires many inputs, and produces 1 kg of ABS plastic (as well as many other outputs)

Complexity

• We’ve been looking at fairly small, streamlined LCI problems

• How does the method scale?

Structure of a Process-based LCA Model

process

processprocess

process

process

process

process

process process

process

processprocess

process

process

sub-system1

process

process process process

processprocess process

sub-system2

The Boundary Issue• Where to set the boundary of the LCA?• “Conventional” LCA: include all processes, but at least

the most important processes if there are time and financial constraints

• In EIO-LCA, the boundary is by definition the entire economy, recognizing interrelationships among industrial sectors

• In EIO LCA, the products described by a sector are representing an average product not a specific one

Circularity Effects• Circularity effects in the economy must be accounted for: cars are made

from steel, steel is made with iron ore, coal, steel machinery, etc. Iron ore and coal are mined using steel machinery, energy, etc...

emissions

product

system boundary

RESOURCES

waste

Economic Input-Output

Life-Cycle Assessment

(EIO-LCA)

Economic Input-Output Analysis• Developed by Wassily Leontief (Nobel

Prize in 1973)• “General interdependency” model:

quantifies the interrelationships among sectors of an economic system

• Identifies direct & indirect economic inputs• Can be extended to environmental and

energy analysis

EIO-LCA Implementation

• Use the 498 x 498 input-output matrix of the U.S. economy from 1992 – 491 for 1997

• Augment with sector-level environmental impact coefficient matrices (R) [effect/$ output from sector]

• Environmental impact calculation:

E = R[I - D]-1F

Data Sources in EIO-LCA (1997)

Data Latest

Year

Available

Source

Economic input-output matrix 1997 U.S. Dept. of Commerce

Electricity consumption 1997 U.S. Dept. of Commerce

Fuel use 1997 U.S. Dept. of Commerce

Toxic chemical emissions (TRI) 2000 U.S. EPA ’s TRI database

Conventional air pollutant emissions 1999 U.S. EPA ’s A IRS database

Life Cycle Stages

• At each stage, there are some inputs used and some outputs created that need to be identified

• Example: automobile production– Direct: smoke from factory– Indirect: smoke from suppliers’ factories

I-O and Supply Chains

$20,000 Car:

Engine

$2500 $2000 $1200 $800 $10. . .

Conferences

Other Parts

Steel

Plastics

$2500Engine:

$300 $200 $150 $10. . .

Electricity

Steel Aluminum

Effects Specified

• Direct– Inputs needed for final production of

product (energy, water, etc.)• Indirect

– ALL inputs needed in supply chain – e.g. Metal, belts, wiring for engine– e.g. Copper, plastic to produce wires– Calculation yields every $ input needed

EIO-LCA Software

• Internet version http://www.eiolca.net/• About 1 million users to date• About 1,500 registered users

– update notices– other benefits

• First LCA tool completely free on Internet in full version (not a ‘demo’)