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Project: Life Cycle Assessment of IT hardware Summary: Life Cycle Assessment (LCA) refers to the
quantitative characterization of the environmental impacts of products and
services over the chain of processes include mining, manufacture, operation
and disposal. A life cycle perspective can lead to qualitatively different
understanding of environmental management. This is particularly true for IT
products. For example, a study of the supply chain use of energy, chemicals
in the supply chain yielding a 32MB DRAM memory chip showed that at least
1,200 grams of fossil fuels and 72 grams of chemicals are needed to produce
one 2-gram memory chip. The amount of environmentally sensitive materials
used far belies its tiny size, fossil fuels for production are some 600 times
the weight of the chip. By comparison, the total fossil fuel needed to
produce an automobile is 1-2 times of its weight and 4-5 times for an
aluminum can. The production chain yielding silicon wafers from quartz uses
160 times the energy required for typical silicon, indicating that
purification to semiconductor grade materials is energy intensive. Due to its
extremely low-entropy, organized structure, the materials intensity of a
microchip is orders of magnitude higher than that of
“traditional” goods. A follow-up study of the total energy used
in producing a desktop computer with 17-inch CRT monitor estimates that 6,400
megajoules (MJ), equivalent to 260 kg of fossil fuels. This high energy
intensity of manufacturing, combined with rapid turnover in computers,
results in an annual life cycle energy burden that is surprisingly high:
about 2,600 MJ per year, 1.3 times that of a refrigerator. In contrast with
many home appliances, life cycle energy use of a computer is dominated by
production (80%) as opposed to operation (20%). Extension of usable lifespan
(e.g. by reselling or upgrading) is thus a promising approach to mitigating
energy impacts, as well as other environmental burdens associated with
manufacturing and disposal. The project work to develop life cycle
methods and results to improve the characterization and management of the
life cycle of IT hardware. Methodologically the focus is on improving
characterization of uncertainty in life cycle inventories and reducing this
uncertainty using hybrid methods. Recent papers address time trends and the
effects of increased purity demands on energy use in manufacturing. Publications: Case Studies in Energy Use to Realize
Ultra-High Purities in Semiconductor Manufacturing, N. Krishnan, E.
Williams and S. Boyd, to appear in Proceedings of the 2008 IEEE International
Symposium on Electronics and the Environment, Measures and Trends in Energy Use of Semiconductor
Manufacturing, L. Deng and E. Williams, to appear in Proceedings of the 2008 IEEE
International Symposium on Electronics and the Environment, San Francisco, CA
(2008) Carbon Emissions Embodied in
Importation, Transport and Retail of Electronics in the U.S.: A Growing
Global Issue, C. Weber, H. Scott Matthews, J. Corbett and E. Williams, in 2007 IEEE
International Symposium on Electronics and the Environment, IEEE: Piscataway,
New Jersey, 174-179 (2007) Energy intensity of computer manufacturing: hybrid analysis combining process and economic input-output methods, E. Williams, Environmental Science & Technology 38(22), 6166 - 6174 (2004) (view abstract) The environmental impacts of
semiconductor fabrication, E.
Williams, Thin Solid Films 461(1), 2-6 (2004) Forecasting Material and Economic Flows
in the Global Production Chain for Silicon, E. Williams, Technological Forecasting and Social Change 70(4),
341-357 (2003) The 1.7 Kilogram Microchip: Energy and Material Use in the Production of Semiconductor Devices. E. Williams, R. Ayres, and M. Heller. Environmental Science & Technology 36 (24). 5504-5510. Dec. 15 (2002) (view abstract) Contact: For more information and/or copies of
publications, please contact: Eric Williams |
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