Kyocera Corp. started Thursday operating the world's biggest floating solar power station, a 2.3-megawatt facility in western Japan that will help utilities improve the efficiency of solar-produced electricity. A joint venture led by the Kyoto-based electronics maker opened the "mega-solar" station on the surface of a reservoir in nearby Hyogo Prefecture, using 9,072 waterproof solar panels installed on a float made of high-density polyethylene.