Life Cycle Assessment (LCA) is a technique for assessing the potential environmental impacts associated with a product.
- LCA allows to look from the cradle to grave of a product or system and checks on the environmental impact of each stage so that you can ways of improvement.
It also allows you to compare the environmental performance of two products.
- LCA background
The origins of the LCA methodology can be traced to the late 1960's (Miettinen &Hamalainen, 1997).
Initial studies were simple and generally restricted to calculating energy requirements and solid waste.
During the oil crisis of the early 1970's, extensive energy studies based on Life Cycle Inventories (LCI) were performed for a range of industrial systems (Fava et al., 1994).
By the end of the 1980's, numerous studies using LCA had been performed, mainly by private companies in Sweden, Switzerland and the USA (Huppes, 1994; Udo de Haes, 1994).
However, these studies were performed using different methods and without a common theoretical framework.
Since 1990, attempts have been made to develop and standardise the LCA methodology under the coordination of the Society of Environmental Toxicology and Chemistry (SETAC) (Udo de Haes, 1994).
In 1993 SETAC published a "Code of Practice", which presents general principles and a framework for the conduct, review, presentation and use of LCA findings.
An international standard for LCA put together by the International Standards Organization has recently emerged.
Azapagic (1999) has reviewed aspects of the ISO standards, and compared them with the SETAC methodology, finding that both are similar.
The main difference is the interpretation stage, where ISO includes further analysis and sensitivity studies.
The immediate precursors of life cycle analysis and assessment (LCAs) were the global modelling studies and energy audits of the late 1960'sand early 11970's
These attempted to assess the resource cost and environmental implications of different patterns of human behaviour.
- LCAs were an obvious extension, and became vital to support the development of eco-labelling schemes which are operating or planned in a number of countries around the world.
In order for eco-labels to be granted to chosen products, the awarding authority needs to be able to evaluate the manufacturing processes involved, the energy consumption in manufacture and use, and the amount and type of waste generated.
A key feature of LCA is thus that the system boundary is drawn "from cradle to grave", so that the inputs are primary resources and the physical outputs the set of all flows to the environment.
This integrative approach avoids substituting one set of environmental problems for an another set.
Three common types of problem shifting can thus be evaluated:
(i) shifting from one stage of the life cycle to the other, e.g. substituting a hazardous raw material by a less hazardous one, which may however require more intensive (and waste producing) preprocessing;
(ii) shifting from one problem to another, such as replacing a gaseous emission
problem with by the introduction of gas scrubbers producing solid waste or liquid effluent;
(iii) shifting from one location to another, e.g. when a plant switches from coal-firing to electric power the emissions are shifted from the plant to the power station site.
- Why perform LCAs?
LCAs might be conducted by an industry sector to enable it to identify areas where improvements can be made, in environmental terms.
Alternatively the LCA may be intended to provide environmental data for the public or for government.
In recent years, a number of major companies have cited LCAs in their marketing and advertising, to support claims that their products are 'environmentally friendly' or even 'environmentally superior' to those of their rivals
Many of these claims have been successfully challenged by environmental groups.
- All products have some impact on the environment.
Since some products use more resources, cause more pollution or generate more waste than others, the aim is to identify those which are most harmful.
Even for those products whose environmental burdens are relatively low, the LCA should help to identify those stages in production processes and in use which cause or have the potential to cause pollution, and those which have a heavy material or energy demand.
Breaking down the manufacturing process into such fine detail can also be an aid to identifying the use of scarce resources, showing where a more sustainable product could be substituted.