Tokyo's Zephyr Corporation, which makes small-scale wind turbines, unveiled a new turbine at the end of February. The 1 kW Air Dolphin Mark Zero Z-1000 is made from aluminium, weighs 17.5 kg and has a rotor diameter of 1.8 metres. The Air Dolphin will generate 1200-1440 kWh a year in an average wind speed of 6 m/s. Due to the turbine's low mass, Zephyr says it tracks wind better than larger turbines in areas with turbulent wind flow. The firm says the turbine features a number of innovations, including its rudder and rotor designs. It has "silent disrupter blades" which Zephyr says cut airflow noise by 80% -- their design is based on the wings of owls, known for their ability to swoop silently on their prey, it says. In addition, the turbine's body has a "no screw" assembly, making it robust in a wide range of weather conditions. The turbine has been tested all around the world, from the Shetland Islands in the UK to Ulan Bator, the capital of Mongolia, and is on sale in Japan for ´472,500 ($4046).