Windmill off the shores of Fukushima Prefecture © Kyodo News
In order to prevent global warming and environmental pollution, making use of natural energy sources has been expanding throughout the world. In Japan, there has been a study of building a new type of wind power facilities, which floats a windmill in the middle of the sea. Wind power generation - which combines the windmill and the electricity generator - uses many precision machines and electronic components, and there are many excellent Japanese companies who own such technologies. There are also companies that deal with the building of oil and gas production facilities which float on the sea, and their installation that is actually used in marine oil fields throughout the world. Various fields of Japanese technology are used in researches on how to build a large offshore wind power that involves precision machines, and how to send a steady amount of electricity to the land.
A windmill 80 meters in diameter
In November 2013, one huge windmill began power generation about 20 kilometers off the coast of Fukushima Prefecture which suffered a serious damage during the Great East Japan Earthquake. The windmill has 80 meters in diameter, and is 106 meters high from the water surface. It is moored to the seabed with six chains and their anchors at 120 meters of depth, so it would withstand even a wave of 20 meters high at the time of typhoons. It is capable of producing 2,000 kilowatt of electricity, which is equivalent to the electricity consumed by 1,700 to 2,000 households.
Moving windmill from the factory off the shores of Fukushima Prefecture © Agency for Natural Resources and Energy
Windmill arrived at Fukushima Prefecture offshore © Agency for Natural Resources and Energy
Electricity relaying marine substation. Power generating windmill can be seen in the distance.
© Agency for Natural Resources and Energy
The electricity generated by the windmill is sent to the “marine substation” that is floating on the sea and located two kilometers away. Here, the voltage is amplified so that electricity may not become weak while it travels 18 kilometers of distance to the land. In the substation, there is equipment that can observe the wind direction and wind force up to 200 meters of height in the sky using laser beams, and there is a heliport in case the station cannot be reached from the sea because of high waves.
The construction of the offshore wind power was planned by the Japanese government, and was supported by participants such as Japanese universities, machine makers, and shipbuilding companies. Two more large-sized windmills are to be built by the spring of 2015. They both have the diameter of 160 meters and the height of 200 meters from the sea level. One windmill is capable of producing 7,000 kilowatt of electricity, which is the largest in the world among existent offshore wind power generators. Special steel materials and a welding system were adopted at the base portion of the windmill in order to withstand powerful offshore wind and high waves. Since it takes time and effort to maintain and repair such equipment on the sea far from the land, study has been done on how to monitor the state of the generator from a distance.