A group of researchers at FermentAlg, led by Pierre Calleja, have invented a street lamp that is powered by algae. Yes, algae; those tiny microorganisms responsible for that green sludge you might find on your pond. This streetlamp exploits the process of photosynthesis that these algae carry out. Photosynthesis is the system used by certain organisms to convert light energy (from the sun) into chemical energy (sugars) that can be used as fuel, using carbon dioxide amongst other things. These lamps can store the energy produced by these algae during the hours in which the sun shines, generating a super green and environmentally friendly lamp.
Check out the video from the TEDx talk here: