Chances are you've heard of hybrids and biofuels, but what about oil-producing yeast and turbinelike buoys that transform ocean waves into electricity? Those are just a couple of the alternative-energy sources that may power the future according to Fred Krupp, president of the Environmental Defense Fund and coauthor, with Miriam Horn, of the new book Earth: The Sequel (Norton). "Everyone knows the current story of melting glaciers, rising sea levels, worsening hurricanes, dying coral reefs," said Krupp. "'The Sequel' is the story of what happens next." Newsweek's Katie Paul talked with Krupp about ... the next industrial revolution. Newsweek: You seem to be a big fan of solar energy. Why do you think there's so much promise to it? Fred Krupp: We have two chapters on solar energy at the beginning of the book because we think there's tremendous potential there. Every hour, the sun provides the earth with as much energy as all of human civilization uses in an entire year. So, if you could capture just 10 percent of it on a ... 100-mile square piece of land, you could power the entire United States. With solar thermal energy, capturing heat instead of immediately going to electricity, one advantage is that you can store hot water much more cheaply than you can store electricity. There is tremendous potential there, even before advanced batteries are developed, and reason to think solar energy can compete. [Newsweek:] And besides solar? How are they addressing some of the negatives associated with biofuels? [Krupp:] I think we've come to understand that the current generation of biofuels has problems and that we need a whole new generation.