The age during which convenient and abundant fossil energy resources were available to build new technologies and to support a sustained energy world transition is short.Renewable energy and methodologies have a clear role in future energy policy. Governments decided to develop aggressive long term actions that can accelerate the widespread applications of renewable energy and to get on a firm path toward a worldwide “renewable energy transition”; according to this policy 20% of world electricity production should come from renewable energy sources within 2020. Renewable energies are potential resources to provide society with efficient and environmental friendly energy. Renewable technologies clearly reduce air pollution and greenhouse gas emission and, in addition, improve the security of energy by diversifying and decentralizing energy supply, reducing the dependence to fossil fuel sources. Besides, renewable energy technologies form a dynamic sector which provides economic growth and jobs for our economies.