In its current Technology Quarterly the Economist has a sidebar article on the impact of increased efficiency in power converters for portable electronics (aka “wall warts” or “energy vampires”). This is a drum we’ve been beating for years and a prime reason we raised our sights from portable design to green design, looking at the larger impact of design decisions.
These little boxes are ubiquitous and inconspicuous but hardly innocuous. I’ve got 14 of them in my house alone. As of 2005 they reportedly consumed four percent of the electricity used by the average U.S. home, or over one percent of total U.S. power consumption.
Wall warts to date have been simple linear supplies with transformers that suck electricity 24/7 whether anything is connected to them or not. Typically 50-80% of the power they consumed was lost as heat.
In 2002 the Natural Resources Defense Council started talking to manufacturers, utilities and the government about shifting to solid-state converters. Two years later the EPA mandated increased energy efficiency in wall warts, which is resulting in a wholesale conversion from transformer-based to IC-based devices with 80-90% efficiency. As the Economist points out,
“For consumers the switch has meant lower power bills and smaller, lighter power adaptors. For the world as a whole it has meant a sharp drop in global power consumption worth around $2 billion a year—saving 13m tons of CO2 annually worldwide, the equivalent of closing down eight coal-fired power stations.”
At under $2 each, there was never an incentive for manufacturers to move to higher-efficiency devices—in fact the increased cost was a positive disincentive. But somebody had to look at the larger picture, and the EPA did; now every power adaptor sold in the U.S.—and increasingly worldwide—is a high-efficiency, solid-state device. Nice work, people.
Now about that 52” flat-panel plasma TV you’ve been thinking about buying…