GE Energy has expanded its 1.5MW series of wind turbines to include the 1.5xle model, designed for efficient operation in weak wind areas. Recently, a prototype of the 1.5xle wind turbine was connected to the grid at the Klondike Wind Farm in Sherman County, Oregon, to begin its performance testing phase, which is scheduled for completion by the end of the year. 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. Test-bed trials for the 1.5xle ran for two months, with successful results. The new machine’s LM 40 rotor blade has been specifically adapted to meet the operational requirements, and also underwent extreme-load and fatigue testing. The 1.5xle series is available with tower heights of 58.7, 80 and 100 metres. The tallest version is also available in solid steel form with no concrete foundation.

Evolving from GE’s earlier 2.x megawatt series design, first introduced in 2003, the new 2.5 and 3MW machines introduce a number of industry innovations, including a permanent magnet generator, a modular converter with full power conversion and advanced control technologies. GE has already tested a 2.5MW prototype wind turbine, which was installed in May 2004 at Wieringermeer, the Netherlands, about 50 kilometres north of Amsterdam. Installation of the first 3MW machine is planned for the summer of 2006. Both the 2.5 and the 3MW 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 optimised bedplate, which joins all nacelle components on a common structure, providing increased durability. The new 2.5MW machine will be available with a 100-metre rotor diameter, while the 3MW wind turbine will offer both 90 and 94-metre rotor diameters. 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 new units also employ a permanent magnet synchronous generator. 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. A lubrication system, designed to increase reliability and lower operation and maintenance costs, automatically lubricates pitch, yaw, main and generator bearings.

The new range of electromagnetic T50 rotary encoders has been designed for heavy duty engineering applications. They are already in operation for pitch control of rotor blades of wind turbines. The diameter of the housing is 50mm and the shaft is 12mm to withstand axial and radial loads up to 250 N. The units are available both as single-turn and multi-turn versions and with incremental, absolute or analogue output signals. The resolution is up to 13 Bits per revolution. SSI-serial, CANopen and Profibus interfaces can be supplied. Special items in stainless steel can be made available for use under aggressive ambient conditions, for example in maritime climates.

Erected in summer 2003 off the Danish port of Frederikshavn in Kattegatt, the first offshore turbine to be built by a German manufacturer has generated roughly 8,000MWh electricity in its second year of operation. When taking the energy content of the wind for the production of the second year into consideration it corresponds to a production of 8,500MWh in a normal wind year, i.e. approximately 9 % larger production than estimated. Since connecting the 2.3MW turbine to the grid in June 2003, Nordex has been testing and continuously optimising all the components used in the turbine as well as its overall response under realistic maritime weather conditions. Thus, in the past few months, the pilot turbine’s pitch and gearbox, among other things, have been modified to steadily increase availability. The availability of the turbine has been continuously above 95 % in the second year.

StaClean, a fluorourethane blade coating, was first used on wind turbine blades in New Hampshire, USA, in 1989 as an ice release coating. The coating is low friction (below Teflon), flexible and tough, and can be applied in the field or factory with conventional paint spray equipment. Blades at Tahacipi Pass were coated with StaClean, in the field, after ice formations caused problems. Inspections of the blades in 2004 showed excellent condition after 14 years’ operation, without recoating. Subsequent applications include release of insects in a desert area of Palm Springs, California, since 1992, and ice release in the Yukon, Canada, for arctic ice build-up prevention since 1994. All applications show improved power output and preservation of blades after 11 years.

Vexcel Corporation, a global company involved in Earth observation technologies and services, has announced development of a software-based solution to support offshore wind farm development across Europe. The project, funded by the UK Natural Environment Research Council, is being conducted by Vexcel’s UK office in cooperation with ARGOSS, a Netherlands company specialising in marine environmental information for offshore industries. The work will result in a commercial information service, based on Earth observation data, tailored to the coastal offshore environment.