The life cycle analysis or LCA is an approach to estimate the environmental impact of a product or service throughout its lifecycle. There are currently two standards that specify LCA:
– ISO 14040: It defines the principles and framework of LCA.
– ISO 14044: This standard further clarifies the requirements for LCA and guidelines for conducting a LCA.
- An approach based on the life cycle:
The LCA is based on several principles. Firstly, it is an approach based on the life cycle. It is necessary to integrate all stages of product life. We generally distinguishes the following phases:
– The extraction of raw materials;
– The manufacture of the product;
– The distribution;
– Use of the product;
– The end of life: recycling, incineration, landfill, etc…
There are also all transport stages that occur during the life cycle of the product.
This life-cycle oriented approach allows a systematic approach and avoids any transfer of impact of a life cycle phase to another.
- An environmental approach:
The second principle is that LCA is an environmental approach. This approach focuses on the environmental impacts of a product, therefore the social or economic impacts are not considered in this approach.
- A relative approach:
It is also important to know that LCA is a relative approach. Indeed, first of all it is necessary to establish the functional unit to be used for LCA. This functional unit quantifies the service provided by a product. Example of functional unit of a mobile phone:
“Using a mobile phone for 11 minutes per day over a period of two years.”
The notion of functional unit makes the results of a LCA relative, there are no absolute results and comparison of results of two LCAs can only be done on the basis of an identical functional unit.
- A transparent approach:
Transparency is also one of the essential principles when conducting a LCA, to ensure proper use of data and a correct interpretation of results.
- A scientific approach:
Conducting a LCA is primarily based on a scientific approach. Finally, the analysis of life cycle based on the principle of completeness, that is to say that this is a transversal approach taking into account the largest possible number of environmental aspects (impact on air, water, soil, etc.)
The several steps of LCA
A life cycle analysis has four stages:
1) The definition of the goal and scope of the study:
This is during this phase that are defined the purpose and scope of the study, the functional unit, if it is a comparative study or the recipients of the study (industrial, general public, other).
2) The inventory phase of life cycle:
This is the most important phase of the implementation of a LCA. This is to collect all the information on inflows and outflows on the life cycle of the product. Inflows are eg raw materials, energy use, etc.. Outflows related emissions to air, water, soil, or the production of recycled materials.
3) Impact assessment:
Once the inventory is completed, the next step is to assess the impacts for all environmental impacts selected for the study associated with each flows listed during the inventory. The assessment of these impacts can be done through particular characterization models.
4) Results interpretation:
Once the impact assessment carried out, the last phase of LCA is the interpretation of results. This interpretation is to present the results of the LCA in accordance with the objectives of the study. The interpretation may result in recommendations for the use of the product or ways for re-design to reduce potential environmental impacts of the product studied. During interpretation, it is sometimes possible to distinguish the phase of the life cycle that has the greatest impact or determine the origin of the most significant environmental impacts.
Figure 1: Differents stages of a LCA according to ISO 14040
The characteristics of LCA results
There are two essential features of a life cycle analysis. First, a LCA assesses potential impacts of a product or service on the environment. Results do not means real impacts generated by a product or service.
Then the LCA is a multi-criteria approach that focuses on several different environmental aspects. Therefore, it is not possible to aggregate the results of the impact assessment phase through a single score. (Example: no addition possible between impacts on water and impacts on air of a product!).
Among the notable requirements for conducting a life cycle analysis, we may notice the requirement of data quality. This must be consistent with the objectives of the study (comparison of products, re-design of product, communication, etc.).
The other requirement for LCA is the requirement of a critical review. The critical review is a process whereby LCA results are analyzed by a external party to the study but also by interested parties. Critical review ensures the consistency of results against objectives of the study but also to provide them additional credibility.
Although life cycle analysis is a global method for assessing impacts of a product on the environment, there are some limitations to consider. First, as described above, it is only to assess the potential impacts and not real or measured of a product or service.
Moreover, the results are particularly dependent on assumptions made at the beginning of the study (scope of the study, functional unit, etc.) but also data quality (availability, confidentiality, complexity, etc.). Therefore, achieving this kind of study requires a important level of knowledge and skills.
With regard to product design, one factor limiting the LCA is the amount of data needed to conduct the study. When developing a new product, the life cycle analysis needs to have sufficiently advanced knowledge of product and therefore have arrested a significant number of technical choices that will determine the subsequent impact of the product.
Finally, the life cycle analysis is focused on assessing environmental impacts of a product, it is not uncommon that the recommendations that may emerge from the interpretation of results are in conflict with other interests in product such as economic or social considerations.
There is currently a very large number of life cycle analysis tools. Some of these softwares include databases for performing the life cycle inventory. These programs also offer assessment methods to classify and characterize the impacts on a number of indicators.
These programs include the following:
– Simapro – Edited by Pre Consultants http://www.pre.nl/
– GaBi – Edited by Pe-International www.gabi-software.com
– Umberto – Edited by IUF Hamburg http://www.umberto.de/en/
– EIME – Edited by Bureau Veritas CODDE http://www.codde.fr/
– TEAM – Edited by ECOBILAN http://ecobilan.pwc.fr/en/boite-a-outils/team.jhtml
Some software is dedicated to specific sectors such as construction (Eco-Bat, Equer, …).
Examples of LCA results
LCA of a mobile phone
The LCA results may lead to recommendations on the use of the product, as in the case of a LCA performed by CODDE for ADEME.
- Analyzed product:
An average second generation mobile phone.
- Functional unit:
“Using a mobile phone for eleven minutes a day over a period of two years.”
- Recipient of the results of the study:
The public may acquire or renew a mobile phone.
- The results of the study:
Following this study the results showed the importance of the manufacturing phase of this type of product over its life cycle. The recommendations from this study are:
– Avoid models with large LCD screens, which have a GPS or clamshell mobile phone.
– Do not leave the charger connected when it is unused; if possible use a dynamo charger.
– Extend the life of the phone before the renewal.
– Make recycle old phone instead of store it when it is no longer used.
This study has been the subject of a web page allowing the public to test the influence of habits of using a mobile phone on the environmental impact of it.
Comparative LCA of shopping bags
The second case is a comparative study sponsored by a brand of mass distribution on different types of bags. The objective here is to offer its customers the solution with lowest impact.
- Products studied:
Several products have been studied here, the disposable plastic bags, reusable plastic bags, paper bags and biodegradable bags.
- Recipient of the study:
The mass distribution brand at the origin of the LCA.
- Functional unit:
“Pack 9000 liters of goods bought in shops.”
- Results of the study:
The results of this study have shown interest in the use of reusable plastic bags since they are actually reused a number of times sufficiently large relative to disposable plastic bags.
LCA of an eco-designed water meter
The last example deals with a study of redesign of an existing product. The life cycle analysis of the existing water-meter was used to guide design decisions and replace the brass body of the product by a composite material to reduce the weight of the object and reduce environmental impacts (mainly on resources depletion, and manufacturing step).
– ISO Standard 14040: http://www.iso.org/iso/en/catalogue_detail?csnumber=38498
– ISO Standard 14044: http://www.iso.org/iso/en/catalogue_detail?csnumber=37456
– Life cycle analysis of a mobile phone. (Study by CODDE for ADEME – 2008)
http://www.ademe.fr/internet/telephone-portable/site-web/portable.pdf – french
– Comparative life cycle analysis of shopping bags (study by Ecobilan for ADEME – 2004)
http://www.ademe.fr/htdocs/actualite/rapport_carrefour_post_revue_critique_v4.pdf – french