Life-Cycle Assessment

Life-Cycle Assessment (or Life-Cycle Analysis - LCA) is an increasingly important analytical tool, as environmental policy focuses more and more on product and service systems instead of just production sites. LCA is most developed as a technique for evaluating environmental impacts, but it can be extended to cover other sustainability themes.

What is LCA?

A Life-Cycle Assessment (LCA) is a systematic study of environmental impacts that arise throughout a product’s life - from the winning and processing of raw materials, through component production and product manufacture, to use and ultimate disposal. LCA considers environmental impacts in a number of categories, such as resource use, climate change effect, water pollution, waste production, etc.

Conducting any LCA requires an examination of the “extended product system” – the network of activities that transforms raw resources into products, transports them to market and enables their use, then finally removes and treats items that are no longer wanted. Such systems exist for services just as they do for manufactured goods, so LCA can be applied to services as well as to physical products. These extended product systems can be examined in different degrees of detail, too, so different levels of Life-Cycle Assessment can be conducted, from highly approximate to reasonably accurate. Both qualitative and quantitative methods exist, and these two approaches are often complementary (see “Benefits of LCA”).

Qualitative LCA

Qualitative LCAs are often based on a “Matrix” structure like that shown below, with the cells in the matrix used either to record information (such as amounts of materials or emissions) or scored responses to a pre-determined set of questions.

	Materials	Energy	Emissions	Wastes
Raw Material Acquisition
Production
Distribution
Use
End-of-Life

Quantitative LCA

Quantitative studies start with a formal definition of the goal and the scope of the LCA – factors which determine the exact “extended product system” to be examined. A second data-collection stage allows a “Life-Cycle Inventory (LCI)” to be constructed: this is a catalogue of inputs to and outputs from the system defined in the first stage of the work. As far as possible, these inputs and outputs will be followed outwards through the system to its interface with the natural environment, rather than coming from other human activities (electricity inputs, for example, are followed back through generation to the primary fuels). In the third stage of a quantitative LCA, the environmental effects arising from this catalogue of emissions and consumed resources is modelled. This stage is known as Life-Cycle Impact Assessment.

A series of ISO standards (the ISO 14040 series) set out conventions for the conduct of quantitative LCA’s .

Benefits of LCA

LCA is an analytical tool. It provides environmental analysis to support decisions of many kinds. In business, LCA can provide environmental insight to inform purchasing decisions, product design, process selection or waste management strategies. The results of LCA can also be used to inform governmental policy-making at various levels. Costs can be incorporated into some LCAs to generate Life-Cycle Costings, which provide parallel financial information.

Different types of LCA (for an introduction to LCA types, see “What is LCA” ) are appropriate to different circumstances:

Matrix-based qualitative LCAs are invaluable for guiding "Green Procurement" activities. They can also help the environmental manager set priorities for action beyond the company's own operations.
Qualitative and simplified numerical LCA studies enable product developers and designers to compare the environmental credentials of different designs quickly. Making these comparisons early in the development process is important in exploring Design-for-Environment opportunities before too many design options are closed off.
Quantitative LCAs come into their own for evaluating a narrow range of well-characterised options. Carried out on existing products, they provide benchmark information against which new designs can be judged. Used late in the product development process, LCA provides more detailed evaluation of performance gains and can be used to support marketing claims concerning environmental performance.
Quantitative LCA is an excellent tool for evaluating the environmental impacts of new processes or process changes. In a recent study, EuGeos worked with a large process-industry business to quantify the environmental benefits of substituting reprocessed post-consumer waste for some of the virgin raw-material mix.
Quantitative LCAs are vital for evaluating the potential environmental benefits of product-stewardship, or producer responsibility, initiatives. EuGeos has used LCA to address questions about the real environmental value of material recovery and packaging re-use schemes - exploring the trade-offs between increased transportation and reprocessing, and reduced raw material demand.

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