While many definitions of clean technology exist, the one that I gravitate towards is technologies that harness renewable materials and energy sources or reduce the use of natural resources by using them more efficiently and productively.
Clean tech covers a wide range of technologies; from solar photovoltaic, wind power, biofuels, and biomaterials, to portable power, smart grids, water desalination, fuel cells, and plug-in hybrid vehicles. It also includes some more exotic technologies such as tidal power, microbial fuel cells distributed hydrogen generation, and nanotechnology-based materials. Yes, even energy efficient technology is considered a "clean" technology (they call it the "nega-watt"; the watt of power you never have to use is the cleanest of all). Read full article