For "rain" see [1] using the mechanical energy of falling rain drops. For "cold" see [2] the idea of using the potential energy of snow on mountains (or hills)

For "rain" see [1] using the mechanical energy of falling rain drops. For "cold" see [2] the idea of using the potential energy of snow on mountains (or hills). Maybe create artificial avalanches. For "darkness", no idea. :) ----- [1] http://phys.org/news120216714.html http://phys.org/news120216714.html [2] http://www.newton.dep.anl.gov/askasci/eng99/eng99635.htm http://www.newton.dep.anl.gov/askasci/eng99/eng99635.htm