This book focuses on the current situation of two technologies for electricity production from renewable energy sources, wind and solar photovoltaic energy, analysing and describing both technologies in detail. Four regions of the world, with distinct energy markets and conditions, are explored. Together, the USA, Europe, China and Japan represent one third of the world's population and occupy 25% of the planet, therefore offering a representation of a global picture. In each of these regions, the development of the solar and wind energy is examined, and the economic implications are described.