International Herald Tribune: Algae, those simple, aquatic plants, are composed of carbohydrates, proteins and plant oil. The algal oil can be processed into biodiesel or nonpetroleum gasoline, the carbohydrates into ethanol, and the protein into animal feed or human nutritional supplements. The whole biomass can generate methane, which can be combusted to produce electricity. Processors can extract chemicals to replace petrochemicals. As algae grows, it absorbs carbon dioxide. And it can be used to clean sewage …