Nabrawind Self Erecting Tower (Nabralift) is a new tower technology developed to break the barriers that conventional towers are facing for hub heights greater than 120 meters:
- Tower manufacturing and transportation costs increase significantly, making additional hub height increase unprofitable.
- Resonances between the tower and the turning rotor are usual on conventional steel towers, increasing the tower loads and cost.
- Massive and expensive cranes are needed, with long assembly and disassembly times that delay the wind-farm installation rate.
Nabralift reduces the cost of extra large towers by 30 percent and integrates a self-erection system to erect the full wind turbine (including nacelle and rotor), avoiding large and expensive cranes. Nabralift is maintenance-free, and it is conceived to be easily integrated with any wind turbine (existing or new). Wind turbine aerodynamics and mechanical/electrical design are not affected, and the stiffness of the tower avoids any resonance with rotor turning.
Additionally, Nabralift breaks all the tower logistic barriers for any hub height. It is a game-changer technology for onshore wind farms located within islands or on mountainous onshore sites. Difficult access sites may become feasible with the self-erected tower.
The first Nabralift prototype (160-meter hub height) is already in construction and will be installed during 2018 in Eslava (Spain). It will be the third highest wind-turbine tower in the world.
The tower will be tested after erection to demonstrate operative life. For this purpose, several millions of load cycles will be applied in an innovative fatigue tower test method developed together with CENER.
Nabralift serial production and installation will start in 2018.
For more information, go to www.nabrawind.com