"Historically, the transition from one energy system to another, as from wood to coal or coal to oil, has proven an enormously complicated process, requiring decades to complete. In similar fashion, it will undoubtedly be many years before renewable forms of energy -- wind, solar, tidal, geothermal, and others still in development -- replace fossil fuels as the world?s leading energy providers. Nonetheless, 2015 can be viewed as the year in which the epochal transition from one set of fuels to another took off, with renewables making such significant strides that, for the first time in centuries, the beginning of the end of the Fossil Fuel Era has come into sight..."