This book sheds new light on how microbes can be used as effective and sustainable resources to produce green energy in the form of biogas, algal diesel, ethanol, hydrogen and direct electricity. It discusses topics such as microbial energy conversion technologies, including ethanol production by microbial catalytic reaction, biomethanization, biodiesel from microalgae, microbial fuel cells, and the microbiological production of hydrogen. The book will inspire scientists to find new approaches to meet local energy demands with the help of sustainable microbial resources available in and around a given location.