Life cycle analysis or life cycle assessment (LCA) quantifies how much energy and raw material are used and how much (solid, liquid, and gaseous) waste is generated at each stage of a product's life. Ideally an LCA would include quantification of material and energy needed for:[1]
- raw material extraction,
- manufacturing of all components,
- use requirements,
- generation (if any -- e.g. Photovoltaics),
- end of use (disposal or recycling),
- and the distribution/transportation in between each stage.
There are also theories for expanded versions of analysis where you include minor or indirect inputs like the factories and warehouses electricity/energy use, what type of method all the employees use for trips to and from work and so on. But this is normally regarded as too much work to investigate in. The choice of how many inputs to include is arbitrary and depends on the question(s) that motivated the LCA in the first place.
- If the focus is narrowly on a production process, the methods and amount of employee travel may be considered irrelevant.
- If the focus is on reducing the emissions or environmental impact of an entire organization, then more distant impacts of the organization's activities should be included, including travel by employees that would not otherwise have occurred in the organization's absence.
When using LCA to compare alternatives (for example, several different technologies for generating electricity, producing food, etc.), it is important to use a consistent basis, so the comparison is fair. An LCA that includes more sources of greenhouse gas emissions, such as employee travel, may make a particular technology look worse in comparison to an alternative technology for which the LCA omits such sources.