Wind Lift for Assembling Large Wind Turbines Using the Lift-up Method

Development of the Wind Lift™ equipment for assembling large wind turbines using the lift-up method

Obayashi Corporation has, jointly with TOMOE RESEARCH & DEVELOPMENT., LTD. (https://www.tomoegiken.co.jp/english/), developed the Wind Lift equipment which uses the lift-up method to assemble large wind turbines in construction work without using ultra-large cranes.

Wind Power Generation Businesses are one kind of power generation business utilizing renewable energy, which have been getting attention in recent years. Regarding wind power generation, large generators are increasingly being adopted in order to increase the power generation efficiency, and as a consequence of this wind turbines themselves are getting larger, as the diameter of the rotor, which is comprised of the hub (the central part of the wind turbine), blades (the sails of the wind turbines), etc., is getting larger, the towers are getting higher, etc.
Larger turbines have the advantage that they can capture the strong winds higher in the air, but there are also restrictions, on the transportation of materials, construction conditions, etc. so as of May 2017, wind turbines with a power generation capacity of the 3 MW class (tower height of about 90 m) were the largest on land.
There are multiple construction methods used in the construction of wind turbines, but two methods are generally used: the full rotor assembly construction method under which the hub and blades are assembled horizontally on the ground and lifted to the top edge of the towers while the structure is raised, and the single blade installation method under which the hub and blades are each directly installed on the top of the columns.
For all of these construction methods, a 1,200 t-grade ultra-large crane is necessary in the construction of the 3 MW-class wind turbines for the assembly and installation of the members, but procurement of these ultra-large cranes is difficult because there are only about a dozen of them in Japan, and in addition it is not easy to transport them to the worksite. Furthermore, there was the issue that a large construction yard was necessary with the full rotor assembly method.
The Wind Lift we have developed on this occasion is equipment which assembles wind turbines by lifting up the members using the equipment, without using an ultra-large crane, even when the 3 MW class wind turbines are constructed. Similar equipment has been developed before, but we have realized greater functionality, including the ability to construct the 3 MW-class large wind turbines and the addition of a structure-raising function for the rotor, etc. In addition, by using this equipment, a place for installing an ultra-large crane, etc. becomes unnecessary, so the work can be carried out in a minimum-sized construction yard.
By using this equipment, it is possible to cut costs by 10% to 20% compared to conventional construction methods; for example, the preparatory work for securing a construction yard can be reduced. Furthermore, the risks at the time of construction due to strong winds, etc. can be lowered. Moreover, this equipment can be delivered with a vehicle equivalent to a 10-ton truck, so construction-related restrictions are eased.
We used this equipment in the construction of the wind turbines for the Mitanehamada Wind Power Station (Mitane, Akita Prefecture), the first Wind Power Generation Business of the Obayashi Group, which was constructed in 2017, and as a result we realized a cut in costs of approximately 10%.

The main features of Wind Lift are as follows.

1. The work can be realized in a minimum-sized construction yard, reducing construction costs

   Wind Lift lifts up the members with jack-up type equipment, so it is not necessary to install an ultra-large crane for assembly even when the 3 MW-class wind turbines are constructed. Furthermore, this equipment has the functions of assembling the hub and blades horizontally in advance high in the air where it is possible to avoid obstacles such as standing trees, and then lifting them up to the top edges of the towers while raising the structure, so assembly space on the ground is unnecessary.

   The construction space can be reduced by up to 30%, so preparatory work such as the trimming of standing trees or preparation of the land can be reduced; furthermore, the costs for an ultra-large crane are also unnecessary, so it is possible to reduce costs by 10% to 20%.

   

2. Compatible with a wide range of construction conditions

   This equipment can be delivered using a transporter vehicle such as a 10-ton truck, so it can be delivered to a variety of places such as mountainous areas, remote islands and cramped sites. Furthermore, delivery and removal are easy, so it is possible to quickly carry out maintenance work such as sudden replacement or repair of equipment after the wind turbines have commenced operation, etc.