answer:There is no single “the answer” to our energy problems. Algae is a good partial answer, because it can potentially be a large source of cheap, renewable fuel. We already grow renewable “biofuels”—corn, soybeans, sugarcane, and to a lesser extent switchgrass, which are processed into ethanol that is eventually used in gasoline. The problem with these biofuels is that you generally need to grow them on land that could be used for food crops (or they are food crops, like corn and sugarcane). Thus, growing plants for fuel ends up crowding out the food supply, which makes food more expensive. Algae, on the other hand, can be grown in water tanks on non-arable land. So they don’t crowd out the food supply. The problem is the science of extracting algae oil and converting it into fuel is still in its infancy. Growing and processing algae would also use energy, which would have to come from another source.