I ride my bike to work. It seems so pure. We're constantly urged to "go green" -- use less energy, shrink our carbon footprint, save the Earth. How? We should drive less, use ethanol, recycle plastic and buy things with the government's Energy Star label. But what if much of going green is just bunk? Al Gore's group, Repower America, claims we can replace all our dirty energy with clean, carbon-free renewables. Gore says we can do it within 10 years. "It's simply not possible," says Robert Bryce, author of "Power Hungry: The Myths of 'Green' Energy." "Nine out of...