In wind farms construction at least 2 cranes are needed: a main crane to lift component such as tower segments, blades and rotor and a smaller, auxiliary crane that help the main crane during the lift operations and can be used also with steel rebars, embedded rings or anchor cages and so on.
Basically there are 2 main types of main cranes: standard track and narrow track cranes.
Standard track cranes needs around 10 meters, depending on the model, to move on access roads. For this reason, due to the increasing number of wind farms in areas with environmental problems or in mountainous regions narrow track cranes are a winning option – they need only 6 meters, and can help save money in civil works and in dismantling, transportation and subsequent re-erection of the crane.
Terex-Demag CC 2800 is one of the available models, while an alternative is the Liebherr LR1600/2. They can move with a mounted boom, on a gradient around 10º.
When they are in an open position on the crane pad, ready for lifting, they can occupy even more space of a normal crane – they need around 14 meters.
Both cranes are designed especially to hoist 75-100 tonne gondolas up to hub heights of between 90 and 130 meters above ground level.