GE ENERGY HAS EXPANDED ITS 1.5-MW SERIES OF WIND TURBINES to include the 1.5xle model, designed for efficient operation in weak wind areas. A prototype of GE's (Husum, Germany) 1.5xle wind turbine recently was connected to the grid at the Klondike Wind Farm in Sherman County, Oregon, U.S., to begin its performance-testing phase, which is scheduled for completion by the end of the year.

“With the introduction of the 1.5xle, GE's 1.5-MW series now is available with the ideal rotor diameter for every wind classification,” says Ulrich Uphues, platform manager, 1.5-MW series for GE Energy's wind segment. GE's 1.5se wind turbines feature a rotor diameter of 70.5 m (231 ft) for strong or class I wind areas; the 1.5sle has a 77-m (253-ft) rotor diameter, ideal for class II; and the new 1.5xle offers a rotor diameter of 82.5 m (271 ft) for class III or weaker wind applications.

For the prototype 1.5xle unit, a few mechanical adjustments were required to accommodate the larger rotor diameter. “The pitch bearing, pitch system, rotor hub and blades, gears and towers were enhanced to meet the higher demands,” explains Uphues. Test bed trials for the 1.5xle ran for two months with successful results.

In addition to expanding its 1.5-MW series, GE Energy has launched its newest wind power technology. Evolving from GE's earlier 2.x MW series design, first introduced in 2003, the new 2.5-MW and 3-MW machines introduce several innovations, including a permanent magnet generator, a modular converter with full power conversion and advanced control technologies.

GE already has successfully tested a 2.5-MW prototype wind turbine, which was installed in May 2004 at Wieringermeer, the Netherlands, about 50 km (31 miles) north of Amsterdam. Installation of the first 3-MW machine is planned for the summer of 2006. Both the 2.5-MW and 3-MW wind turbines are expected to be commercially available in Europe by the end of 2006.

At the heart of the new wind turbines is a force-flow optimized bedplate, which joins all nacelle components on a common structure, providing increased durability. The 2.5-MW machine will be available with a 100-m (328-ft) rotor diameter, while the 3-MW wind turbine will offer both 90-m (295-ft) and 94-m (308-ft) rotor diameters; these increased rotor sizes offer higher energy capture. Advanced control features, including a sophisticated pitch regulation system with power/torque control capability, and improved use of the drive train damper mitigate the increased loads of the larger rotor.

Both units also employ a highly efficient permanent magnet synchronous generator, enabling higher efficiency at lower wind speeds. A new bearing design substantially increases the life and reliability of the gearbox by preventing bending and thrust loading produced in the rotor from impacting the gearbox.