Powerful Wind Turbine: Rotor Blades in One Cast

2007-Nov-07 |  Siemens has developed a method with which rotor blades for wind turbines can be manufactured in one cast and without seams. The research magazine "Pictures of the Future" reports that these blades can withstand winds with air masses of up to 100 tonnes for approximately 20 years. The blades are used to generate power without emissions — for example, in a 3.6-megawatt turbine, the world’s most powerful series machine for sea based wind farms. In 2007 alone, the company will have installed wind power stations with a collective capacity of 1,500 megawatts.

In the Danish town of Brande, Siemens Wind Power uses its integral blade process to manufacture rotor blades that are up to 52 meters in length and weigh approximately 12 tonnes. These blades are produced without adhesives or chemicals. Their principle constituent is a glass-fiber reinforced synthetic which, in contrast to the PVC otherwise typically used, is recyclable. Moreover, the seamless blade exhibits an unprecedented robustness that makes it ideal for use on the open sea, in "offshore" stations. Over the course of its service life, the blade can even withstand winds of hurricane force. In the future, the rotor blades will be as long as 60 meters and drive even more powerful turbines.

The wind turbine that currently ranks as the most powerful in the world has an output of 3.6 megawatts (MW), which is 1.3 MW more than the model that previously held that title, and a hundred times greater than the output of the first wind turbines 25 years ago. Recently, Siemens installed the first offshore wind farm with 3.6 MW turbines, the Burbo Wind Farm. Located in the approach to Liverpool Bay, the farm has a total capacity of 90 MW and was completed in only one and a half months. Beginning in late 2007, the Burbo Wind Farm will supply over 80,000 households. In 2007, Siemens will have set up enough wind power stations to produce four billion kilowatt-hours per year, which is about 12 percent of the electricity consumption of Denmark.

Siemens is the leader worldwide in the offshore business, and the demand for wind energy is rising. In response to the interest in the U.S. alone, Wind Power recently opened a rotor blade factory in Fort Madison, Iowa. The plant covers 30,000 square meters and has an annual production capacity of up to 600 blades.