f you added up all the cell phones, laptops, DVD players, plasma TVs, cable boxes, and other assorted electronic gadgets typically found in American homes, the number would run (easily) into the billions. And make no mistake -- those machines are hungry for power. Combined with household appliances like air conditioners and desk lamps, they suck up a whopping 21 percent of the nation's total energy supply, more than a trillion kilowatt-hours of electricity a year. The power plants that supply all that juice typically burn oil, coal, or natural gas, which makes the average home responsible for producing twice as much carbon dioxide (CO2) as the average car. But while politicians and environmentalists continue to joust over how to satisfy our nation's energy cravings -- should we drill for oil in Alaska's Arctic National Wildlife Refuge or improve the fuel economy of America's cars? -- a handful of innovators have quietly devised some ingenious ways to reduce the impact of our insatiable electronic desires. Sometimes it's as simple as building a better lightbulb (see Innovation #3). Sounds like a small thing, but save a kilowatt here and a kilowatt there and pretty soon you've eliminated the need for hundreds of CO2-belching power plants.