From 2008 to 2014, the Enercon E126 wind turbine was the biggest wind turbine in the world.
Currently, at 7.5MW it is only 2MW off the biggest machine, the MHI Vestas V164
It was originally built in the 2000s as a 6MW windmill with the first version coming online in 2007. It was developed from an earlier machine, the Enercon E112 4.5MW
In 2008, it was uprated to 7.5MW. It features a 136-metre hub height and a 127-metre rotor.
Enercon E126 in Detail
It is estimated around 40 E126 generators are operational. These are all located in northern Europe.
The E126 has evolved slowly. However, a number of elements are the same now as they were originally. For example, the generator’s diameter is 12-metres while the drive system comprises a main pin and front-mounted generator.
The tower base holds four medium-voltage transformers and switchgear cabinets. While the Enercon E126 is designed to remain operational albeit at reduced output level after failure.
All Enercon turbines operate at 400V AC-voltage, which is converted into a DC-current inside the nacelle and fed down the tower. Once there the DC-power is converted into AC-power.
Inside the wind turbine
Once you have gone up the E126 tower, the ground floor of the nacelle is reached via a spiral staircase around the inner tower wall that goes to an elevator.
Once out of this lift, rather than using ladders, additional spiral staircases are fitted for the final 20-metres up into the nacelle.
According to those who have visited the machine, it is possible to crawl to the front of the turbine in the nacelle and feel the bearing temperatures.
The top of the nacelle can be reached via a final ladder.
Wind farms to using the windmill
One major project to use the E126 is the Zuidwester wind farm in the Netherlands.
The wind farm was developed by RWE and is 90MW. It uses 12 E126s.
Speaking about the project RWE construction manager Rick van Mensvoort said at the time of construction in 2015: “We were able to install the first wind turbine.
In a first step towards installation, the 156-tonne nacelle was placed on top of the concrete tower at a height of 135 metres with a lattice-boom crane.
He added: “This was followed by the 220-tonne generator and the hub with the central rotor section, which weighs 350 tonnes – the equivalent of roughly 250 medium-sized cars.”