Al Gore has a dream, a dream increasingly shared, according to opinion surveys, by people all over the world. It is that the 19th century, the age of steam and iron and coal, will finally end and that, as Mr. Gore wrote in an article for the New York Times in 2008, the time will soon come for "21st-century technologies that use fuel that is free forever: the sun, the wind and the natural heat of the earth."

It might be better, and much more realistic, says Robert Bryce in "Power Hungry," to imagine...