Visit windpowermonthlyevents.com for the latest on our upcoming conferences and webcasts

Germany

Germany

Enercon adds high tower E-101 to range

GERMANY: Direct-drive pioneer Enercon of Germany installed a prototype 3MW E-101 turbine in June, a second-volume model to go with the 2/2.3/3MW E-82 series.

It comes with 101-metre rotor diameter and either a 99- or 135-metre hub height. The rated power is calculated at a favourable 12m/s, making it a medium wind-speed turbine, but Enercon Belgium representative Bernhard Fink claims the rotor-blade design is efficient and, together with a high tower, it is also suitable for low wind-speed conditions.

The rotor blade has Enercon's characteristic winglet tip and unusual airfoil shape that widens from a slender outer section towards the centre spinner. Enercon claims that the aerofoil has achieved an aerodynamic power coefficient close to or even beyond the maximum 59.3%, known as the Betz limit. "Total system efficiency and all measured losses in the generator, power converter, controls, bearings and cables together reflect this value," adds Fink.

Enercon's direct-drive wind turbines use the company's in-house manufactured and electrically excited ring generators. Unlike nearly all its competitors, which use the more compact and lighter neodymium-based permanent-magnet generators, Enercon has not been affected by the recent price explosion of neodymium, a rare earth element.

Air-cooling has been standard Enercon technology until a 3MW water-cooled E-82 model was introduced in 2008. And from the first 1.5MW E-66 all successor airand water-cooled models up to 3MW have been fitted with a generator of around 5.3-metre outer diameter. Innovative E-101 generator-design features include load-optimised cast components for the stator instead of a fabricated welded steel structure. Also, both the stator and rotating part are water cooled.

The E-101 design has also considered logistical challenges. "The market increasingly demands larger more powerful turbines, but our objective was to retain the recognised E-70 and E-82 transport and logistics standards in the E-101. This explains the unchanged generator outer dimension," says Fink. "We further designed the concrete-steel 135-metre tower as a concrete bottom section comprising multiple coning rings with a standard 57-metre tubular-steel section in three individual parts on top."

The solution enables the use of small, inexpensive cranes for assembling the concrete tower and a bigger crane for the steel parts, nacelle and rotor. "Most importantly, our capability to install complete wind turbines within one-week has been retained," he adds.

Set against competing 3MW turbines, the E-101 - with a 250-tonne top-head mass - is not a lightweight concept, but this difference can be attributed to design philosophy. "In case of any doubt about a certain load for instance, we always choose to build in an extra safety margin even if it gives a small weight penalty," says Fink.

Before commenting please read our rules for commenting on articles.

If you see a comment you find offensive, you can flag it as inappropriate. In the top right-hand corner of an individual comment, you will see 'flag as inappropriate'. Clicking this prompts us to review the comment. For further information see our rules for commenting on articles.

comments powered by Disqus

Windpower Monthly Events

Search more than 4,500 companies in the Windpower Directory

Latest Jobs