This book reviews alternative and renewable energy resources in order to pave the way for a more sustainable production in the future. A multi-disciplinary team of authors provides a comprehensive overview of current technologies and future trends, including solar technologies, wind energy, hydropower, microbial electrochemical systems and various biomass sources for biofuel production. In addition, the book focuses on solutions for developing countries. Conventional energy sources are finite, and estimates suggest that they will be exhausted within a few decades. Finding a solution to this problem is a global challenge, and developing countries in particular are still highly dependent on fossil fuels due to their rapidly growing populations accompanied by a huge growth in primary energy consumption. Moreover, the most common conventional energy sources (coal and petroleum) are non-sustainable since their combustion exponentially increases greenhouse gas emissions. As such, there is a pressing need for clean energy based on alternative or renewable resources, not only to ensure energy supplies at an affordable price but also to protect the environment.