An eco-audit guides decision making during design or redesign of a product and it points to the aspects of design that a fuller LCA should examine. Early in the design process, the detailed information required for a rigorous LCA is not available, and even if it were, the formal LCA methods are sufficiently burdensome to inhibit their repeated use for rapid "What if?" exploration of alternatives. As we have seen, an eco-audit, though approximate in every way, frequently reveals differences that are sufficiently large to be significant. LCA tools such as SimaPro, GaBi, MEEUP and the Boustead Model (see the appendix to Chapter 3) can be used in this way, but they were not designed for it. Others are much simpler to use. One—the CES eco-audit tool7—is described in the appendix to this chapter. It implements the procedure shown in Figure 7.1, enabling the inputs and delivering the outputs shown there.
7.9 Summary and conclusion
Eco-aware product design has many aspects, one of which is the choice of materials. Materials are energy intensive, with high embodied energies and associated carbon footprints. Seeking to use low-energy materials might appear to be one way forward, but this can be misleading. Material choice impacts manufacturing; it influences the weight of the product and its thermal and electrical characteristics and thus the energy it consumes during use, and it influences the potential for recycling or energy recovery at the end of life. It is full-life energy that we seek to minimize.
Doing so requires a two-part strategy, developed in Chapter 3. The first part is an eco-audit: a quick, approximate assessment of the distribution of energy demand and carbon emission over a product’s life. This provides inputs to guide the second part: that of material selection to minimize the energy and carbon over the full life, balancing the influences of the choice over each phase of life—the subject of Chapters 8 and 9. The eco-audit method described here is fast and easy to perform, and although approximate, it delivers information with sufficient precision to enable strategic decision making. This chapter has introduced the procedure and tools—the appendix describes one in more depth—illustrating their use with case studies. The exercises that follow provide opportunities for exploring them further.
7.10 Further reading
Burnham, A., Wang, M. and Wu, Y. (2006), "Development and applications of GREET 2.7", Argonne National Laboratory, ANL/ESD/06-5. www. osti. gov/bridge. (A report describing the model developed by ANL for the U. S. Department of Energy to analyze life emissions from vehicles).
Ashby, M. F., Ball, N. and Bream, C. (2008), The CES EduPack eco-audit tool: a white paper, Granta Design, www. GrantaDesign. com. (A user guide for the CES eco-audit tool.)
