What is Life-cycle Assessment (LCA)?

Phases of a product's lifecycle

Every product that you use has impacts on the environment. Those impacts happen not just while you own the product, but also before and after you own it. Nearly every product passes through several phases in its lifetime:

Raw materials: The materials that are used to manufacture the product are either extracted from the Earth by mining, drilling and similar processes, or they are recycled from previous products.

Manufacturing: In order to fabricate the product, a factory consumes energy and materials. Some of the materials, especially process chemicals, do not end up in the product, but rather are discarded and therefore have environmental impacts that are not easily known by the consumer.

Packaging, storage and transportation: The packaging used to transport and sell the product consumes energy and materials in its manufacture. Transportation of the product from the factory to store shelves, and then to the purchaser's home, also costs energy. Even storage of the product in a warehouse has impacts associated with construction and use of the warehouse.

Use: Some products have large environmental impacts while they are under use by the consumer. For instance, automobiles output large quantities of air pollutants and greenhouse gases as they are used, and homes consume large quantities of energy when they are heated and cooled.

Disposal: Most discarded products become "municipal solid waste," meaning they are either buried in a landfill or incinerated. Some products are partially or fully recycled, a process that itself requires certain amounts of heat, transportation and chemicals.

Environmental Impacts

Traditionally, environmental impacts of a given product or phase of a product are catalogued across a spectrum of environmental realms, for instance, air quality, water quality and land use. ILEA has chosen instead to measure the environmental impacts of each phase of a product's lifecycle by measuring the total energy consumed during that phase. Read more about why we make this choice in the Why Energy section.

By adding together the energy consumed in each product phase, one can calculate an energy content for the product: the total amount of energy consumed during the product's entire lifetime. The energy content is also known as the "embodied energy" of the product, and is a rough but effective measure of that product's total environmental impact.

Things you do each day can also be thought of as products. For instance, taking a shower is equivalent to purchasing a certain quantity of hot water, and vacuuming the living room is equivalent to purchasing a certain quantity of electricity. This way you can know the environmental impacts not just of what you buy in the store, but also of many other activities in life.

Last Modified on October. 1, 2004.

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