Concrete is not often the greenest material choice, particularly since concrete production is one of the largest single sources of carbon emissions globally. But, for wind turbine towers, the use of concrete bases can provide a number of significant benefits, including reducing the amount of concrete needed for the footings for a tower by more than two-thirds. Concrete bases can also be more economical to install and can provide faster construction times for wind towers and also can raise tower height to increase power production.
The wider footprint of the precast concrete base also adds stability to the foundation of the tower. With the precast concrete base, load is spread over a wider area, and a simpler ring footing can be utilized, which results in a 60% - 70% reduction in the concrete needed for the footing of the tower. This can result in a net reduction of the total amount of concrete used. The ring footing is easier to construct as well, since the problems associated with a mass pour can be avoided.
In addition to the construction benefits, the concrete bases increase the overall tower height to raise the turbine into more powerful winds or to allow the use of larger diameter blades. Metal towers are reaching limits for transportability and constructibility, but adding precast concrete tower base can add 30 meters (almost 100 feet) of height to the tower. This can allow larger diameter turbines to be used with existing metal towers.
Concrete tower bases can also be locally produced, rather than needing specialized manufacture as with steel towers. Precast concrete sections for these bases are actually more transportable, since they are produced in sections that are assembled together once on site. Concrete is also a sturdier product, which is less susceptible to damage and rusting and does not require regular painting like steel.Atlas CTB White Paper (PDF)
via: North American Windpower
written by Hank, August 29, 2010
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