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Six Brilliant Megawatt Ideas
Page 5

Innovation No. 4

The Problem: Take another look at all those electronic gadgets around your house. Don't forget the minivac on your kitchen counter, the answering machine, and the cell phone charger. Notice that they're all attached to little black boxes that plug into the wall. These external power supplies (along with the internal ones you don't see inside your computer and other appliances) convert the alternating current (AC) coming out of the wall into the direct current (DC) that powers your gizmos. There are now 3.1 billion of those black boxes in U.S. homes and businesses; an additional 400 to 500 million are sold each year.

Unfortunately, because of poor design these boxes waste up to three-fourths of the electricity that passes through them -- about 100 billion kilowatt-hours per year. The basic problem, according to a report by Chris Calwell and Travis Reeder at the environmental research firm Ecos Consulting, is that "power supplies not only convert energy, they consume it." Most external power adapters have a small transformer that converts the voltage using two coils of wire linked by a magnetic field. With this configuration, only 25 to 60 percent of the electricity gets through to the gadget from the transformer; the rest is just wasted.

The Solution: More efficient power supplies don't need to be invented: They already exist. Internal power supplies -- the ones built into the body of your desktop computer, for instance -- supply DC voltage by rapidly switching the power on and off with integrated circuits instead of a coil. Lighter in weight and more efficient, the latest generation of these switching units pass along up to 90 percent of the electricity they convert. Two years ago, Ecos and Noah Horowitz, a senior scientist at the Natural Resources Defense Council (NRDC), convened a meeting of electronics giants -- including Apple, Canon, and Sony -- and power-supply manufacturers and suggested using the higher-efficiency technologies in all new power supplies. Intel, the chip-maker for more than 80 percent of the desktop computer industry, agreed; within the next few years, all Intel-based desktops will feature the new, more efficient power-supply technology.

Energy Star, the federal government's voluntary labeling program, plans to issue a guideline for computers based on the Intel standard this year, with NRDC's help. And Horowitz, along with U.S. government officials, has persuaded the energy agency in China -- where 85 percent of the world's power supplies are manufactured -- to create its own version of Energy Star labels for the tens of millions of external power supplies sold there each year.

Potential energy savings from desktop computers could equal 16 billion kilowatt-hours a year, "roughly enough power to supply all the homes in the city of Chicago for one year," says Horowitz.

Meet Captain Climate
Paradise Lost?
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The Innovations
Innovation No.1
Innovation No.2
Innovation No.3
Innovation No.4
Innovation No.5
Innovation No.6

For more information about Power Supplies, check out:

NRDC Energy guide

LBNL Standby Power home page

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OnEarth. Spring 2004
Copyright 2004 by the Natural Resources Defense Council