Energy Intensity of Computer
Manufacturing: Hybrid Assessment
Combining Process and Economic
Input-Output Methods
E R I C W I L L I A M S *
United Nations University, 53-70 Jingumae 5-chome,
Shibuya-ku Tokyo, Japan
The total energy and fossil fuels used in producing a
desktop computer with 17-in. CRT monitor are estimated
at 6400 megajoules (MJ) and 260 kg, respectively. This
indicates that computer manufacturing is energy intensive:
the ratio of fossil fuel use to product weight is 11, an
order of magnitude larger than the factor of 1-2 for many
other manufactured goods. 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 2600 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
(81%) as opposed to operation (19%). 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.
1. Introduction
Information Technology (IT) continues to change how we
do business, research, and even socialize. Pundits speak of
IT as a revolution as important as the adoption of electricity
or the combustion engine. Given the extent to which
computers have affected our daily lives, it is difficult to
disagree. Technological revolutions also affect the environ-
mental challenges faced by societies and how to respond to
them. As Information Technology is concerned with moving
and processing bits instead of mass, its direct environmental
consequences should not be as severe as, say, adoption of
the combustion engine. Nonetheless, the environmental
impacts associated with the physical IT infrastructure (i.e.
computers, peripherals, and communications networks) are
significant. Many in rich countries use two or more computers
(e.g. one for home, one for work). Rapid technological change
implies t