Noise barriers along highways can be used as a source for clean energy. Used to dampen the loud sounds of traffic, these noise barriers just sit there, usually not even very pretty. So engineers at the Eindhoven University of Technology in the Netherlands created barriers with colored panels that receive light and direct it to the edges of the panels where solar cells harness the energy. Thanks to the colored panels, the sound barriers suddenly look stunning, too. The technology is currently being tested on Dutch highways.