Cathode-ray-tube TVs,with their familiar protruding backsides, may look bulky and primitive next to today's sleek flat-screen models, but they've still got two big advantages: they're cheap, and they're relatively energy efficient. Plasma flat screens, for example, still cost $2,000 or more apiece, and they use up to five times as much electricity as CRTs. They're such energy hogs, in fact, that global adoption of plasma TVs could increase electrical demand noticeably, increasing both the chances of blackouts and the volume of greenhouse gases emitted by power plants.

At the very least, plasma screens are sure to put additional stress on the electrical grid, which has lately approached its breaking point in states such as California. A typical plasma display consumes about 1,000 kilowatt-hours of power annually, compared to approximately 233 kilowatt-hours for an average CRT, according to a study by the United Kingdom's Department of Environment, Food, and Rural Affairs. And in ten years, it is widely believed, half of all TVs will be flat-panel displays, although it's unclear whether plasma, liquid-crystal displays, or newer technologies will predominate.