Most renewable energy resources originate from the sun (except for geothermal and some forms of ocean energy). Solar heat is the “motor” behind wind, biomass, and the water cycle tapped to produce hydropower; the earth core’s nuclear processes and the gravity of the moon deliver the rest. In principle, the renewable energy resources are overly abundant. The sun provides the earth with radiation that in every hour provides roughly as much energy as the whole world consumes during a whole year. Yet many new technologies are being developed in order to convert the primary energy to secondary energy carriers that can be used such as electricity, heat (water, steam, air, etc), and fuels (see Table B.1).