What is Life Cycle Assessment (LCA)?
- A method to assess potential environmental impacts over the life cycle of products and services according to ISO 14040/44
- ISO14040/44 is the only standardized method to assess potential environmental
impacts of products and services along its entire life cycle
Environmental impacts
- Climate change
- Acidification
- Eutrophication
- Ozone layer depletion
- Etc.
Why LCA?
LCA can assist in:
* Determining the potential environmental impacts of a product
* Comparing the environmental performance of products
* Identifying (hidden) environmental hotspots of a product (life cycles, processes)
* Identifying options for environmental improvement in different stages along a product’s life cycle (assist eco design)
* Informing decision makers in industry, government, NGOs, etc.
* Marketing (e.g. in the implementation of eco-labels, in making environmental claims, in environmental product declarations)
Limit of LCA
- LCA is able to:
– Determine the relative impacts of a product not the absolute ones
– Cannot determine the real impacts of a product, only the potential ones
– Cannot compare products with different functions
– Cannot give universal statements with regard to materials
– Cannot assess social aspects or risks - LCA depends on:
– Data quality
– Time - LCA does not deliver:
– Binary results: yes/no; black/white and can therefore only support decisions
– ONE combined result but many results for different impact categories
LCA use ‒ recent developments
There is an increasing use of LCA in market and policy!
* LCA is widely used in companies;
mainly internally for product- and process optimization,
but increasingly also for external communication
* Transparent supply chains become more and more important for companies
* In policy, LCA is increasingly used, e.g. as basis for environmental labels
* In the EU the Product Environmental Footprint (PEF), a current initiative
for implementing LCA, which gains a lot of attention
* Besides this, many other options for LCA deployment in policy exist
Methodological framework ISO 14040/44
- ISO 14040/44 is the only standardized
method to assess potential environmental
impacts of products and services along its
entire life cycle - An LCA based on ISO
14040/44 consists of
4 phases:
1. Goal&Scope definition
2. Inventory Analysis
3. Impact assessment
4. Interpretation
LCA phase 1: goal & scope definition
Goal definition
– Target of the LCA
– The reasons for conducting the LCA
* e.g. learn about environmental impacts; identify improvement potentials
– The target audience
* e.g. for internal use only or to communicate to consumers
– Whether the LCA contains comparative assertions disclosed to the public
LCA phase 1: goal & scope definition
Scope definition
– The description of product system and its functions
– The functional unit and reference flows
– The system boundaries and cut-off criteria
– The data requirements
– The allocation procedure
– The impact categories and characterization models
– The assumptions and limitations
– Type of critical review (if any)
– Type and structure of report
LCA phase 1: goal & scope definition
Function
Must define:
* Specify the functions (performance characteristics) of the system
– Functional unit as defined by [ISO 14044]:
* quantified performance of a product system for use as a reference unit (e.g. drying 1000 pair of hand)
* shall be clearly defined and measurable
– Reference flow as defined by [ISO 14044]:
* measure of the outputs from processes in a given product system required to fulfil the function expressed by the functional unit (e.g. 20 cotton towls, 2000 paper towls, 500 m³ of hot air)
LCA phase 1: goal & scope definition
System boundaries
- Defines which life cycle phases and which process steps are included in the analysis
- Process: smallest element considered for which input & output data are quantified (e.g. extraction of aluminium oxide/hydroxide from the ore)
LCA phase 1: goal & scope definition
Cut-off criteria
Criteria which allow to neglect flows or processes within the system boundaries
* Aims:
– Ensure applicability of LCAs by minimizing efforts
– Ensure symmetry within product systems
– Ensure symmetry between product systems to ensure comparability
– Estimate relevance of auxiliary products
* Types of cut-off criteria:
– Number of system levels, e.g. only direct production and tier 1 suppliers
– Mass- or energy based cut-off criteria, e.g. 3% of the product’s mass
– Impact based cut-off criteria, e.g. 5% of result
LCA phase 1: goal & scope definition
Data requirements
- Primary data
– Directly measured or collected company data - Secondary data
– Literature
– Other LCA studies
– LCA databases - Calculations
- Estimations
- Scope of data:
– Spatial scope, e.g. only European data
– Temporal scope, e.g. not older than 2010
– Technological scope, e.g. average of processes or best available technology
LCA phase 1: goal & scope definition
Impact categories
- Definition which impact categories are relevant and shall be analyzed;
common impact categories are:
– Primary energy demand; consumption of energy carriers
– Climate change: Contribution to global warming
– Acidification: Contribution to acidification of soil and water
– Eutrophication: Contribution to over-fertilization of soil and water bodies
– Summer smog: Contribution to chemical ozone creation
– Human toxicity: Contribution to human toxic impacts
– Eco toxicity: Contribution to eco toxic impacts
– Etc. - Besides the selection of impact categories, characterization models have
to be selected based on which impact category results can be determined,
e.g.: CML, ReCiPe, Traci, etc.
LCA phase 1: goal & scope definition
Scope definition
- The scope should be defined in a way that it allows for reaching the defined goal of the study
- As LCA is an iterative procedure, it may be necessary to modify the scope during the course of the LCA study (data availability)
LCA phase 2: life cycle inventory (LCI)
- All material flows entering and leaving the product system are compiled in an inventory (Input / Output Table)
- In and outputs shall be traced back to resource extraction from the environment and emissions into the environment (elementary flows)
LCA phase 2: life cycle inventory (LCI)
Steps in the life cycle inventory analysis
Qualitative life cycle inventory analysis
* Determination of type of environmental interferences along the product’s life span
* Qualitative description of the In- and Outputs occurring in the different processes in a flow chart
* Definition of consistent terminology for In- and Outputs and units
* Development of data acquisition sheets
* Description of type of data acquisition
* Definition of calculation procedures relating data to functional unit
Quantification
* Data acquisition in count- and measurable units
* Data validation (Differentiation between “real” zero or lack of data, analysis of abnormalities),
* Normalization of process data to its function (e.g. operating hours, cleaned surface, etc.)
* Normalization of data to functional unit
* Documentation of data sources, measurements, etc.
* If there are by-products, in- and outputs need to be allocated between the main and the by products
LCA phase 2: life cycle inventory (LCI)
Data sources
Data can be collected according to the following hierarchy:
1) Primary data sources: collected directly at the company, e.g. own measurements
* Measurements (if possible continuous)
* Invoices
* Process control systems
* Approval documents
* Emission declarations and monitoring of facilities requiring a license
* Waste balances and records of waste disposal
* Company internal quality and environmental management
* Environmental declaration and reports
* Health and safety systems
* Etc.
2) Secondary data sources:
* LCA databases
* Literature
* Previous studies
* Etc.
3) Calculations:
* Physical calculations, e.g. energy demand to heat up a material
* Chemical calculations, e.g. determination of emissions based on stoichiometric
relations
4) Estimations
LCA phase 2: life cycle inventory (LCI)
Databases and software
Databases: Gabi-Database, Ecoinvent
Software: Gabi, SimaPro, Umberto, OpenLCA
LCA phase 2: life cycle inventory (LCI)
Allocation
Often one process produces more than 1 products
* Question: How to distribute the environmental burden between products?
How deal with allocation?
1. Avoid allocation due to:
– Detailing into subsystems, e.g.: allocation of a company’s total emissions to different products can be avoided if individual production routes are considered separately
– System expansion, e.g. allocation between the products steel and slag can be avoided, if it is assumed that slag substitutes sand in road construction. Emissions of sand production can be subtracted from total emissions of steel/slag production to determine environmental load of steel production
2. Allocation based on physical properties
– Example: Distribution of a refinery’s environmental burden to its products based on mass or energy shares
3. Allocation based on different (e.g. economic) relations
– Example: Distribution of environmental burdens caused by a copper-gold
-zinc mine based on market values. This makes more sense than a mass based allocation in which 1 kg of zinc would have the same environmental burden as 1 kg of gold
- Allocation principle: The sum of in and outputs has to be the same before and after the allocation
- If the choice of the allocation procedure influences the result of the LCA, this should be made transparent by means of a sensitivity analysis
LCA phase 2: life cycle inventory (LCI)
Recycling
Principle of first responsibility vs. Principle of last responsibility:
- Recycling in LCA requires the distribution of environmental burdens resulting
from primary production, recycling processes, and disposal
Allocation between life cycles - There is no right or wrong – decisions are based on value choices:
– Conservative: Principle of first responsibility – environmental burden of primary
production is fully allocated to the first life cycle and cannot be “lost”
– Risk-oriented: Principle of last responsibility – environmental burden of primary
production is shifted to the last life cycle. There is a danger that environmental
burden is “lost”, if the last life cycle uses a first responsibility allocation.
– Compromise: Equality approach, economic allocation, discounting, approach, etc. –
environmental burden is allocated between all life cycles - There are no right or wrong but adequate or inadequate solutions, e.g.:
– In order to apply the equality approach, the number of life cycles has to be known –
works out for PET bottles but not for cars
– Principle of first responsibility may be too conservative for reusable bottles
– Quality based allocation may be appropriate for alluminium products to consider
downcycling - If the choice of the allocation procedure influences the result of the LCA, this
should be made transparent by means of a sensitivity analysis
LCA phase 3: life cycle impact assessment (LCIA)
- In the life cycle impact assessment, in and output flows complied in the life cycle inventory are “translated” into environmental impacts
…provide information to help assess a product system’s LCI results so as to better understand their environmental significance…
- to determine potential environmental impacts for a product system
LCA phase 3: life cycle impact assessment (LCIA)
Impact categories
Class representing environmental issues of concern to which LCI analysis results may be assigned
* Climate change
* Acidification
* etc.
LCA phase 3: life cycle impact assessment (LCIA)
Classification
The in and output flows compiled in the life cycle inventory (resources, emissions, etc.) are assigned to environmental impact categories
In the classification there are three groups of LCI results:
1. Elementary flows, which contribute to no impact category
2. Elementary flows, which contribute to exactly one impact category
3. Elementary flows, which contribute to different impact categories
LCA phase 3: life cycle impact assessment (LCIA)
Characterization
- Multiplication of each emission (LCI) with a characterization factor (CF)
- CF = individual contribution of the emission to the environmental impact
