Renewable energy (RE) is a subject of great interest today. It is one of the two main means for implementing climate change mitigation programmes, and presently the only perceived means for replacing the declining global fossil fuel reserves. It also helps fight poverty and assists in the global quest for gender equity by taking clean energy where it is needed most for development. It is perhaps not surprising therefore that there is so much coverage of RE in both the conventional media and the internet by media and tech writers, economists and bloggers, many of who only have a partial understanding of the technology itself. The end result is mostly promotional rhetoric that says little about the true value of the technology, and leads to a confused picture for the serious individual or decision-maker who wants to know what the technology is really capable of doing. This book provides a clear and factual picture of the status of RE and its capabilities today. The need for such a book was first realized by the author when he was engaged in a renewable energy capacity-building project encompassing countries from Europe, the Caribbean, Africa, and the Pacific. The book is largely non-technical in nature; it does however contain enough mention of the science and technology to enable readers to go further with their own investigations should they wish to. The book covers all areas of renewable energy (RE), starting from biomass energy and hydropower and proceeding to wind, solar and geothermal energy before ending with an overview of ocean energy. It begins with a simple introduction to the physical principles of the RE technologies, followed by an enumeration of the requirements for their successful implementation. The last two chapters consider how the technologies are actually being implemented today and their roles in climate change mitigation and poverty alleviation.