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COMPUTING SCIENCE

The Computer and the Dynamo

Brian Hayes

Net Savings

The mirror image of the Greening Earth Society is the Center for Energy and Climate Solutions, a division of the Global Environment and Technology Foundation, which describes itself as "a nonprofit dedicated to building the infrastructure for sustainable development." The center's director, Joseph Romm, presents a view diametrically opposite to that of Huber and Mills. The Internet has not inflated energy use, he says, but instead produces a net savings of energy, mainly through "dematerialization." For example, software delivered online saves energy that would have been expended on manufacturing and shipping. Other efficiencies of electronic commerce allow companies to reduce inventory levels, saving the energy needed to build and operate warehouses. Telecommuting saves gasoline.

The trouble is, measuring these diffuse effects of computer and communications technology is probably even harder than documenting the direct electricity demand of the Internet. Furthermore, the two trends are not mutually exclusive; in principle, Romm and Mills could both be right. The Internet economy could be saving energy overall but still consuming more electric power—in effect siphoning energy out of automobile gas tanks and dumping it onto the coal heaps of electric generating stations.

On the specific issue of electricity consumption, Romm points out that growth in demand actually slackened at just about the time the Internet boom began. Before 1996, according to Romm's figures, electricity output was growing at 2.9 percent per year, but since then the growth rate has been only 2.2 percent. Therefore, if computers and the Net have suddenly introduced enormous new loads, other uses of electricity must have held steady or declined.

The governmental body charged with gathering statistics about the production and consumption of electricity is the Energy Information Administration, or EIA, within the Department of Energy. Their figures on consumption come from surveys of three sectors—residential, commercial and industrial—which each consume about a third of the nation's kilowatt-hours.

The EIA data on computer power demand were summarized in February 2000 by Jay E. Hakes, who was then the Administrator, in Congressional testimony. In the residential sector, Hakes said, PCs account for about 2 percent of electric power consumption, and in the commercial sector about 3 percent. Because computers are not a significant factor in the industrial energy budget, the computer's share of total electricity use works out to 1.6 percent.

One might suppose that the government statistics would carry enough weight to put an end to the argument, but there are enough complications and inconsistencies to leave room for doubt. In the residential survey, a PC was defined as a CPU and a monitor, but printers and other accessories were relegated to a different category, "electronics," which also included some audio and video equipment. The electronics category accounted for 10 percent of residential electricity use—five times the PC segment. How much of that 10 percent should be allocated to computer peripherals? In the commercial survey, laser printers were included in the computer category, but "Internet-related infrastructure equipment" was counted under another heading. Although it seems implausible that any rearrangement of the data could make up the difference between 1.6 percent and 8 or 13 percent, the differences in classification make comparisons awkward.




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