LIFE CYCLE ANALYsis (LCA) is a means of quantifying how much energy and raw materials are used and how much (solid, liquid, and gaseous) waste is generated at each stage of a product, process, service, or system's lifetime. An LCA is the environmental impact over the entire lifespan of the entity in question, and can be used to help reduce anthropogenic impacts on the climate. Life cycle analysis is also known as a life cycle assessment, life cycle inventory, eco-balance, net energy analysis, materials flow analysis, cradle-to-grave analysis, cradle-to-cradle analysis, well-to-wheel analysis, resource analysis, and environmental impact analysis. The environmental impact can be converted to a carbon footprint or land area in ecological footprint (or eco-footprint) analysis.
There is no agreed-upon methodology for LCAs. The most institutionalized LCAs methodology is the codification into the ISO (International Organization of Standards) 14000 environmental management standards, which assists organizations to minimize negative environmental impacts, comply with applicable laws and regulations, and to continually improve on these metrics. ISO 14040 to 14044 covers LCAs and pre-production planning and environment goal-setting. LCA can, however, be very complex, and reliable data are difficult to compile. Thus, studies on similar systems, products, and processes often vary considerably in their final results. In the literature covering the LCA of controversial technologies (such as nuclear energy), the results may be biased. Provided all reports state the methodology used and the assumptions made, LCAs do, however, provide a useful indication of where to concentrate work on essential improvement, and which technologies should be adopted to reduce the environmental impact of a product or process, in terms of energy and raw materials used and wastes produced.
life cycle analysis and the energy sector
In the context of climate change and its largest contributor, the energy sector, LCAs generally focus on an energy LCA that includes both tangible and intangible costs of energy production from the initial project conception, to the final step of returning the land to its original or its next-use state. Tangible costs have always been included in the industry analysis and include such items as facility construction, fuel source development, post-extraction land remediation, and waste disposal. Because different forms of energy use have adverse impacts, not only on nonusers, but also the entire biosphere, intangible costs are important. These include the impact of the release of carbon dioxide into the atmosphere.
In the past, conventional energy proponents often overlooked costs (both economic and energy-related) due to plant decommissioning because of weak regulations and oversight. This allowed some energy producers to hide the true lifetime costs of energy production, thus projecting a false image of both economic and environmental benefit. Examples include ignoring nuclear waste storage, or the cost of reclaiming strip-mined land, or mountaintop removal mining in the Appalachian Mountains. Complete LCA's are difficult to perform, especially on emerging technologies, such as solar photovoltaic cells, whose fabrication is constantly undergoing improvements, and which has not been in mass production long enough for recycling or disposal to become established. Often in the energy sector, energy LCA is used because it is less complicated than a full LCA; energy consumption data are more reliable (often metered for individual processes). Ideally, an energy life cycle analysis would include: raw material production energy, manufacturing energy of all components, energy-use requirements, energy generation (if any), end of use (disposal) energy, and the distribution/transportation energies in between each stage.
To utilize LCA in policy decisions on climate change, it is imperative to understand the boundaries of the operations that produce the process, because if any part of the system contained within the boundaries is changed, the other inputs and outputs will also change. Deciding what constitutes the cradle and what is the grave (or next cradle) for such studies has been one of the major points of contention in the evolving discipline of LCA. For example, in calculating the embodied energy for transportation as just one component of the LCA in the recycling of plastic, the simplest case would be limited to the fuel used for the recycling trucks. In more detailed LCAs, the embodied energy of the trucks would be included; particularly if the trucks were only used for plastic recycling (otherwise, the fractional use would be taken into account). Such a study would normally ignore second, third, and greater generation impacts, such as the energy required to fire the bricks used to build the kilns used to manufacture the truck components.
In addition, recycling itself lends considerable complexity to LCAs. For some materials such as aluminum, which can technically be recycled an indefinite number of times (with some melt losses), there is no longer a grave. In the case of paper, however, taking into account recycling is even more complex. Paper can theoretically be reprocessed four or five times before fibers are too short to have viable strength for paper, but even then it may still be useful in a down-cycled product like cellulose insulation.
For these reasons, an LCA can never produce one simple result. The results are tables of ranges of figures showing quantities of resources used and wastes produced. Any comparison between similar processes or products will depend on subjective judgments on the relative importance of energy consumption, raw material use, and waste generation.
sEE ALso: Carbon Footprint; Ecological Footprint; Energy.
BIBLioGRAPHY. D.F. Ciambrone, Environmental Life Cycle Analysis (CRC Press, 1997); M.A. Curran, Environmental Life-Cycle Assessment (McGraw-Hill, 1996); C.T. Hendrickson, L.B. Lave, and H.S. Matthews, Environmental Life Cycle Assessment of Goods and Services: An Input-Output Approach (RFF Press, 2006); B.W. Vigon, Life-Cycle Assessment: Inventory Guidelines and Principles (CRC Press, 1994).
Joshua M. Pearce Clarion University of Pennsylvania
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