LCA Exam Answers New Update
(Verified A+ Pass)
3 Benefits of LCA - Answers -✔✔1. Compare different products based on multiple
environmental criteria
2. Identify potential for shifting problems from 1 media to another (ex; air --> water) or
from one location to another (auto tailpipe --> power plant)
3. Identify hotspots in the LC process that could be targeted for improvement
4 Phases of LCA - Answers -✔✔1. Goal Definition and Scoping
2. Inventory Analysis
3. Impact Assessment
4. Interpretation
Goal definition and scoping - Answers -✔✔define and describe the product, process or
activity. Establish the context in which the assessment is to be made and identify the
boundaries and environmental effects to be reviewed
Inventory Analysis - Answers -✔✔Identify and quantify energy, water, and material
usage and environmental releases (ex; air emissions, solid waste, water contamination)
Impact Assessment - Answers -✔✔Assess potential human and ecological effects of
energy, water, material usage and environmental releases identified in inventory
analysis
Interpretation - Answers -✔✔Evaluate the inventory analysis and impact assessment to
select the preferred product, process, or service with a clear understanding of the
uncertainty and the assumptions used to generate the results
Steps of Inventory Analysis - Answers -✔✔1. Create process flow diagram
2. Develop data collection plan
3. Collect data
4. Evaluate and report results
EROI - Answers -✔✔energy derived or delivered/
energy invested or spent
"Energy Return on Invested"
, (net energy analysis)
Relevant for energy systems whose primary function is to deliver useful energy
Ways of Handling multi-output production systems - Answers -✔✔(joint production of
multiple useful products)
1. Disaggregation
2. Allocation
3. System expansion or avoided burden approaches
Disaggregation - Answers -✔✔sub-divides the unit process that delivers multiple
predicts into a sufficient number of smaller sub-processes unit each has only ONE
product
- can be challenging to collect data at such an in depth level
Allocation - Answers -✔✔Apportion total burdens across different joint products in
proportion of...
- physics characteristics such as mass, volume, energy content
- economic value of each product
Example of the importance of handling multi-product systems - Answers -✔✔LC GHG
of ethanol = ~70gCO2/MJ
(Gasoline = 95gCO2/MJ)
1 bushel corn = 2.8gall ethanol + 18lbs distiller's grain
receives coproduction credit for DG (substitute for raw corn)
would otherwise be ~105gCO2/MJ
System Expansion - Answers -✔✔If 2 systems can't be compared directly because of
differences in scope, we may need to expand the system boundary of one or both
systems to make them equal in scope
If process AB yield both A&B while process C only yields C, then AB and C can't be
compared directly
Addition vs Subtraction Based System Expansion - Answers -✔✔If process D yields D,
a substitute for B, then AB is compared to C+D
AB = C + D
Subtraction: AB-D = C
(Verified A+ Pass)
3 Benefits of LCA - Answers -✔✔1. Compare different products based on multiple
environmental criteria
2. Identify potential for shifting problems from 1 media to another (ex; air --> water) or
from one location to another (auto tailpipe --> power plant)
3. Identify hotspots in the LC process that could be targeted for improvement
4 Phases of LCA - Answers -✔✔1. Goal Definition and Scoping
2. Inventory Analysis
3. Impact Assessment
4. Interpretation
Goal definition and scoping - Answers -✔✔define and describe the product, process or
activity. Establish the context in which the assessment is to be made and identify the
boundaries and environmental effects to be reviewed
Inventory Analysis - Answers -✔✔Identify and quantify energy, water, and material
usage and environmental releases (ex; air emissions, solid waste, water contamination)
Impact Assessment - Answers -✔✔Assess potential human and ecological effects of
energy, water, material usage and environmental releases identified in inventory
analysis
Interpretation - Answers -✔✔Evaluate the inventory analysis and impact assessment to
select the preferred product, process, or service with a clear understanding of the
uncertainty and the assumptions used to generate the results
Steps of Inventory Analysis - Answers -✔✔1. Create process flow diagram
2. Develop data collection plan
3. Collect data
4. Evaluate and report results
EROI - Answers -✔✔energy derived or delivered/
energy invested or spent
"Energy Return on Invested"
, (net energy analysis)
Relevant for energy systems whose primary function is to deliver useful energy
Ways of Handling multi-output production systems - Answers -✔✔(joint production of
multiple useful products)
1. Disaggregation
2. Allocation
3. System expansion or avoided burden approaches
Disaggregation - Answers -✔✔sub-divides the unit process that delivers multiple
predicts into a sufficient number of smaller sub-processes unit each has only ONE
product
- can be challenging to collect data at such an in depth level
Allocation - Answers -✔✔Apportion total burdens across different joint products in
proportion of...
- physics characteristics such as mass, volume, energy content
- economic value of each product
Example of the importance of handling multi-product systems - Answers -✔✔LC GHG
of ethanol = ~70gCO2/MJ
(Gasoline = 95gCO2/MJ)
1 bushel corn = 2.8gall ethanol + 18lbs distiller's grain
receives coproduction credit for DG (substitute for raw corn)
would otherwise be ~105gCO2/MJ
System Expansion - Answers -✔✔If 2 systems can't be compared directly because of
differences in scope, we may need to expand the system boundary of one or both
systems to make them equal in scope
If process AB yield both A&B while process C only yields C, then AB and C can't be
compared directly
Addition vs Subtraction Based System Expansion - Answers -✔✔If process D yields D,
a substitute for B, then AB is compared to C+D
AB = C + D
Subtraction: AB-D = C
