Presenting, the world's longest wind turbine blade

Siemens has signed a long-term agreement with wind developer DONG Energy to produce 300 of its latest offshore wind turbines, which use B75 Quantum Blades that are about 246 feet long. The total rotor diameter is about 505 feet across.

I'm trying to come up with a mental image for this beast and I'm having a really hard time. It certainly would tower over my neighborhood. The companies say that the "swept" area is equivalent to the size of two and a half soccer fields.

Eventually, the turbines are intended for wind farms being built off the coast of the United Kingdom between 2014 and 2017 that will produce up to 1,800 megawatts of wind capacity. The unit in the photo above will be used for a second 6-megawatt prototype at a test station off the coast of Denmark.

The B75 Quantum Blade was designed to work better across a range of different wind speeds. The reason that it can be so big is because the technology is extremely light; if the turbine was built using traditional methods it would be 10 percent to 20 percent heavier, according to Siemens.

"The agreement will enable DONG Energy to install a significantly larger and more efficient wind turbine from 2014 compared to what we know today," said Carsten Krogsgaard Thomsen, acting CEO for the wind company. 

Siemens and DONG Energy were actually the collaborators for the first offshore wind power plant in the world, built in 1991 in Denmark. The two have partnered on 13 projects since that date, covering 930 turbines.