Life Cycle Assessment, LCA
More about LCA
Examples
Environmental Risk Assessment, ERA
Life Cycle Cost, LCC
 
Eco-efficiency

More about LCA

The aim for this section is to give an overview of the LCA technique and not to give a comprehensive description of LCA since there are several good textbooks available on this topic. 

LCA is a technique to assess the potential environmental impacts associated with a product or service throughout its life cycle, by: 

  • Goal and scope definition: Defining suitable goal and scope for the LCA study.
  • Inventory analysis compiling an inventory of relevant inputs and outputs of a product system. 
  • Impact assessment: Evaluating the potential environmental impacts associated with the selected inputs and outputs. 
  • Interpretation: Interpreting the results.  

LCA considers the potential environmental impacts throughout a productís life cycle (i.e. cradle-to-grave) from raw material acquisition through production, use and disposal. Examples of categories of environmental impacts included in commercial LCA software tools are resource use, human health and ecological consequences. The limitations of the LCA technique can be overcome by complementing with other tools and methods e.g. Environmental Risk Assessment.

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The LCA study can assist in: 

  • Identification of improvement opportunities for the studied product or service throughout its whole life. 
  • Decision-making in industry, governmental and non-governmental organizations.
  • Selection of relevant environmental performance indicators and adequate measurement techniques.
  • Marketing opportunities for products, e.g. to use LCA data for eco-labeling, environmental product declaration (EPD), etc.

The International Standards ISO 14040-14043 provides principles, framework, and methodological requirements for conducting LCA studies. The framework of LCA includes definition of goal and scope, inventory analysis, impact assessment and interpretation of the results, as illustrated in the figure below.

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© ISO 1997, ISO 14040:1997(E)

Goal and scope definition 
The first part of an LCA study consists of defining the goal of the study and its scope. The goal of the study should include a statement of the reason for carrying out the study as well as the intended application of the results and the intended audience. In the scope of an LCA the following items shall be considered and described: 

  • The function of the product system.
  • The functional unit. 
  • The system boundaries. 
  • Allocation procedures. 
  • Type of impact assessment methodology and interpretation to be performed. 
  • Data requirements. 
  • Assumptions and limitations.
  • Data quality requirements. 
  • Type of critical review, if any. 
  • Type and format of the report required for the study. 

The scope should describe the depth of the study and show that the purpose can be fulfilled with the actual extent of the limitations. 

Functional unit 
The functional unit is a key element of LCA which has to be clearly defined. The functional unit is a measure of the function of the studied system and it provides a reference to which the inputs and outputs can be related. This enables comparison of two essential different systems. For example, the functional unit for a paint system may be defined as the unit surface protected for 10 years. A comparison of the environmental impact of two different paint systems with the same functional unit is therefore possible.

System boundaries 
The system boundaries determine which unit processes to be included in the LCA study. Defining system boundaries is partly based on a subjective choice, made during the scope phase when the boundaries are initially set. The following boundaries can be considered: 

  • Boundaries between the technological system and nature. A life cycle usually begins at the extraction point of raw materials and energy carriers from nature. Final stages normally include waste generation and/or heat production. 
  • Geographical area. Geography plays a crucial role in most LCA studies, e.g. infrastructures, such as electricity production, waste management and transport systems, vary from one region to another. Moreover, ecosystems sensitivity to environmental impacts differs regionally too. 
  • Time horizon. Boundaries must be set not only in space, but also in time. Basically LCAs are carried out to evaluate present impacts and predict future scenarios. Limitations to time boundaries are given by technologies involved, pollutants lifespan, etc. 
  • Boundaries between the current life cycle and related life cycles of other technical systems. Most activities are interrelated, and therefore must be isolated from each other for further study. For example production of capital goods, economic feasibility of new and more environmentally friendly processes can be evaluated in comparison with currently used technology.

Data quality requirements 
Reliability of the results from LCA studies strongly depends on the extent to which data quality requirements are met. The following parameters should be taken into account: 

  • Time-related coverage.
  • Geographical coverage.
  • Technology coverage.
  • Precision, completeness and representativeness of the data.
  • Consistency and reproducibility of the methods used throughout the data collection.
  • Uncertainty of the information and data gaps.

Reusability of data is also highly dependent on sufficient data documentation. One example of a format for sufficient environmental data documentation is the LCI data documentation software SPINE@CPM Data Tool and the LCI database SPINE@CPM Database. These where developed within the CPM collaboration, in order to enable an effective and efficient handling of environmental information. For more information about SPINE see http://www.globalspine.com/

The ISO/TS 14048 data documentation format, described in reports found under reports on this site, is another format for transparent, reusable documentation focusing on data quality.

Related report:

An interpretation of the CPM data quality requirements in terms of ISO/TS 14048 data documentation format.

More reports about data quality can be found on: http://www.cpm.chalmers.se/html/publication.html and www.imi.chalmers.se.

Inventory analysis (LCI) 
LCI comprises all stages dealing with data retrieval and management (see figure below). The data collection forms must be properly designed for optimal collection. Subsequently data are validated and related to the functional unit in order to allow the aggregation of results. A very sensitive step in this calculation process is the allocation of flows e.g. releases to air, water and land. Most of the existing technical systems yield more than one product. Therefore, materials and energy flows regarding the process as a whole, as well as environmental releases must often be allocated to the different products. This is recommended to be made according to a given procedure: 

  • Wherever possible, allocation should be avoided. 
  • Where allocation is not avoidable, inputs and outputs should be partitioned between its different functions or products in a way that reflects the underlying physical relationships between them. 
  • If the latter is not possible, allocation should be carried out based on other existing relationships (e.g. in proportion to the economic value of products).

The data collection is the most resource consuming part of the LCA. Reuse of data from other studies can simplify the work but this must be made with great care so that the data is representative. The quality aspect is therefore also crucial.

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© ISO 1998, ISO 14041:1998(E)

Related reports:

First examples of practical application of ISO/TS 14048 Data Documentation

Introduction and guide to LCA data documentation using the CPM documentation criteria and the ISO/TS 14048 data documentation format.

Establishment of CPM's LCA database

Facilitating Data Exchange between LCA Software involving the Data Documentation System SPINE

More reports about ISO/TS 14048 and SPINE can be found on: http://www.cpm.chalmers.se/html/publication.html and www.imi.chalmers.se.

Impact Assessment (LCIA) 
LCIA aims to evaluate the significance of potential environmental impacts using the results coming out from the LCI phase. The ISO14040 suggests that this phase of an LCA is divided into the following steps: 

Mandatory elements:

  • Selection of impact categories, category indicators and characterization models.
  • Classification, i.e. assignment of individual inventory parameters to impact categories, e.g. CO2 is assigned to Global Warming. Common impact categories are Global Warming, Ozone Depletion, Photooxidant Formation, Acidification and Eutrophication.
  • Characterization, i.e. conversion of LCI results to common units within each impact category, so that results can be aggregated into category indicator results.

Optional elements: 

  • Normalization. The magnitude of the category indicator results is calculated relatively to reference information, e.g. and old products constitutes baseline when assigning a new product. 
  • Weighting. Indicator results coming from the different impact categories are converted to a common unit by using factors based on value-choices.
  • Grouping. The impact categories are assigned into one or more groups sorted after geographic relevance, company priorities etc.

The methods that are usually used for LCIA are e.g. EPS (Environmental Priority Strategies), ECO (Ecological scarcity) and ET (Environmental Theme).

Related reports:

A Systematic Approach to Environmental Priority Strategies in Product Development (EPS) Version 2000 - General System Characteristics

A Systematic Approach to Environmental Priority Strategies in Product Development (EPS) Version 2000 - Models and Data of the Default Method

Interpretation 
The aim of the interpretation phase is to reach conclusions and recommendations in accordance with the defined goal and scope of the study. Results from the LCI and LCIA are combined together and reported in order to give a complete and unbiased account of the study. The interpretation is to be made iteratively with the other phases.

The life cycle interpretation of an LCA or an LCI comprises three main elements:

  • Identification of the significant issues based on the results of the LCI and LCIA phases of a LCA.
  • Evaluation of results, which considers completeness, sensitivity and consistency checks.
  • Conclusions and recommendations.

In ISO 14040 standard it is recommended that a critical review should be performed. In addition it is stated that a critical review must have been conducted in order to disclose the results in public.

For more information see International Organization for Standardization (ISO).