EGEE 401
Energy in a Changing World

Life Cycle Thinking

Tshirt with Life-cycle of a tshirt written on it.  Explained in caption
Figure 10.2: T-shirt with Life-cycle of a t-shirt written on it.
Click Here for Text Alternative of Figure 10.2

Life-Cycle Assessment of a T-Shirt

The figure is a T-shirt with a flow chart on it. The flow chart has nine items linked with arrows that flow from the one item to the next in a circle. Here the flow chart is described as a list:

  1. Raw Materials (fertilizer, energy, water)
  2. Processing (energy, cleaners, dyes)
  3. Manufacturing (energy waste)
  4. Packaging (paper, plastics, waste)
  5. Transport (energy)
  6. Use (bleach, detergents, water)
  7. Use can either flow to: Disposal, Reuse, or Recycle
  8. Recycle flows back to Raw Materials and the cycle continues
Credit: Worldwatch Institute, Worldwatch Paper 166: Purchasing Power: Harnessing Institutional Procurement for People and the Planet, July 2003,

Reading Assignments

Read A Brief History of Life-Cycle Assessment

Open Greening The Economy Through Life Cycle Thinking and read Executive Summary (page 6) and Section 5.5 Trade-Offs and Unexpected Consequences--Avoiding the Pitfalls (pages 40-41)

What is a "trade-off"? It is the "balancing of factors all of which are not attainable at the same time" or "giving up of one thing in return for another." (Merriam Webster dictionary) For example, my hens would like to free range all the time, but would also like to stay alive! So, our tradeoff is that they stay in a closed coop overnight and when I'm away, but, when I am home and generally nearby they roam freely. Usually works, but last week, I looked up to see Pearl in the mouth of a coyote running for the woods. Oh no!!! So sad, Pearl was my friend for nearly 6 years and layed beautiful blue-green eggs. Her last egg was waiting for me, still warm, in the coop. So, this was a tradeoff--she couldn't be outside AND perfectly safe. We gave up some safety, so that she could scratch, chase bugs, and take dirt baths.

From these readings, we know that life cycle thinking is an holistic approach, considering products (and services) through all phases. Life cycle management provides a methodology for putting this approach into action. Life cycle tools are used to measure, monitor, and communicate the impacts of products and services, including social and environmental impacts. The whole idea is to put the relevant information "into people’s hands where and when they need it so that they can make good decisions--to protect the environment, improve the lives of the people who produce the goods, and safeguard the health of the people who use them."

One specific and very important tool is life cycle assessment (LCA). LCA is" a tool that can be used to evaluate the potential environmental impacts of a product, material, process, or activity." (EPA) LCA addresses the cradle-to-grave environmental impacts of products, process or service, from raw material acquisition through manufacturing/production, use/reuse/maintenance, and finally disposal and waste management.

LCA can be used to compare the environmental impact of different options. Here's a classic: "The ongoing debate over disposable diapers versus washable diapers centers on the assertion that the disposable product is less desirable from an environmental perspective. It uses more natural resources to manufacture, and it takes up more room in landfill when discarded. On the other hand, the reusable diaper consumes energy, water and detergents every time it is cleaned for reuse. So what is the answer?" (Source: International Institute for Sustainable Development)

This is where LCA comes in. You'll remember we approached LCA earlier in our discussion of alternative fuels and the importance of taking into consideration all the environmental impacts, including those from land-use changes. The graphic above demonstrates the range of environmental impacts over the lifetime of something as simple as an everyday t-shirt!

In practice, however, LCA is anything but simple! It is a formal scientific methodology, the procedures of which are described in the ISO 14000 environmental management standards.

Reading Assignments

Another source you may find helpful (not required!): FAQs for more information on EISA 2007 and lighting choices.

Scan closely The Lifecycle of a Jean Interesting, right?!