Developers trying to harness Earth’s energy Mr. Gene Kelley at W2 Energy, the United States, believes that wings offer a better answer for capturing wind energy than propellers. They say that their “WindWing” based on some fundamental concepts, can replace current propeller-driven wind turbines and produce much more energy at a fraction of the cost. The use of a wing, as opposed to a propeller, creates a simpler and more efficient way to capture the energy of the wind, according to Mr. Kelley. The prototype consists of four wings on one end and weights on the other. The weighted end of the bar is short – 1 ft long compared with the 10 ft on the other end where the wings sit. As the lever is built at a 10:1 ratio, the force of the wind is magnified so that 90.7 kg of lift on the wings translates into 1 tonne of useful force. In practical application, the ratio will be determined by factors such as wind conditions and wing length. A breeze of 6.7 mph starts to push the wing end upwards. When the wings reach the top, a position sensor is tripped and the wings tilt downwards, changing their “angle of attack”. The wings get pushed downwards until they reach the bottom before the wing angle changes again. The system moves gently, with springs on the central pole that compress as the bar reaches the top and bottom of its movement and springs back to shove the bar in the opposite direction. The up-and-down flapping is less likely to kill birds than a propeller. With the WindWing, the wings put more surface area in contact with the wind. This gives more lift, which translates into more power. The prototype is 40-60 per cent efficient at deriving power from the wind. More than one WindWing turbines could be stacked on a single tower to get the most out of the different wind speeds. The angle of the wings can be adjusted so that there is a high angle for a light wind and a low one for a strong wind. The design is also scaleable, so that the wings could range from the size of a conference room table to that of a Boeing 747. Source: www.venturacountystar.com New generation wind tower technology In the United States, NRG Systems Inc. has announced its XHD NOW system featuring the new 50 or 60 m XHD TallTower. The XHD TallTower, which is the foundation of NRG’s new system, is its next-generation tower. It is ice-rated under structural engineering standard TIA/EIA 222-F. The 50 m and 60 m towers, use 10 inch and 8 inch diameter steel tubes, respectively, and come with a strong base plate. Interchangeable parts simplify installation and maintenance throughout the life of the towers and streamline production. The XHD TallTowers also offer multi-anchor layout options. A small footprint can be used for installations along ridge lines or in places where forest or crop clearing has to be minimal. Contact: NRG Systems Inc., 110 Riggs Road, Hinesburg, Vermont 05461, United States of America. Tel: +1 (802) 482 2255; Fax: +1 (802) 482 2272. Source: www.windtech-international.com China’s 1.5 MW wind power generator The first 1.5 MW wind power generator of China, fully designed and built in the country, has rolled out of the assembly line of Guangdong Mingyang Wind Power Technology Company. The generator, expected to cost at least 20 per cent lower than comparable imported or joint venture products, is designed specifically to weather China’s climate and is resistant to typhoons, sand storms and extremely low temperatures. The company’s production capacity of wind power generators is expected to rise from the current 450 units per year to 1,000 units by 2010. Source: www.chinadaily.com.cn Wind turbine with compact nacelle Japan’s Mitsubishi Heavy Industries Ltd. has developed and patented a wind turbine generator that sports a nacelle with comparatively less size and weight. The nacelle has its main shaft connected to a rotor head equipped with blades and it integrally rotates with the rotor head. The turbine includes a gearbox that speeds up the rotation of the main shaft. The resulting rotational speed drives a generator. A drive train extending from the main shaft to the generator via the gearbox is installed in the rotor head. The generator is preferably a synchronous one and the gearbox is preferably a traction drive. Source: www.freepatentsonline.com Voltage control for wind generators General Electric Co. of the United States has patented a wind turbine generator control system that has relatively fast regulation of voltage near the individual generators but, at the same time, relatively slower overall reactive power regulation at a sub-station or wind farm level. The relatively slow reactive power regulator is used to adjust the set point of the relatively fast voltage regulator. The faster voltage regulation can be at the generator terminals or at a synthesized remote point. Source: www.freepatentsonline.com Multi-megawatt wind turbines Nordex AG, Germany, is extending its range of multi-megawatt turbines with the introduction of the N100, a 2.5 MW wind turbine specially designed for moderate wind conditions. Nordex’s new turbine follows in the footsteps of its N80/2500 and N90/2500. The prominent feature of the N100 is its 49 m long rotor blades, resulting in a large rotor diameter of about 100 m. At 7,823 m2, this produces an increase of 23 per cent in rotor sweep compared with the N90/2500 turbine, making the N100 particularly suitable for weak wind conditions with average wind speeds of 6.5-7.5 m/s. The turbine will be certified in accordance with DIBt2 and IEC 3a. It is supplied in a 50 Hz version, with a 60 Hz version also available for the United States market. Pilot production is to begin in 2008, and serial production in 2009. Source: www.windtech-international.com Wind turbine designs for low wind speeds Windflow Technology, New Zealand, is developing three versions of its Windflow 500 wind turbine, in a bid to target international markets. The company is readying for the possibility of supplying turbines to wind power markets in countries such as India and China. But first it needed to design turbines that could operate at lower wind speeds, said Mr. Geoff Henderson, CEO of Windflow Technology. Windflow 500 turbines have been designed to commence generating power at 11 knots, but the wind speeds in China and India are around 8 knots. Mr. Henderson said wind power is seen as a low-cost renewable option for India and China, where more electricity generation is desperately needed. However, it would be one or two years before Windflow is in a position to enter those markets. Windflow also has plans to design a turbine that could run efficiently alongside diesel generators. Many remote islands relied on diesel to supply electricity and Windflow proposes to design controls where the diesel generator stops completely when the wind power kicks in, thus maximising fuel savings. The company is also designing a turbine that would run on 60 Hz or 1,800 rpm, allowing it to be compatible for the North American market. The existing Windflow turbines run on 50 Hz or 1500 rpm. Source: www.stuff.co.nz Diffuser-augmented wind turbine Composite Support and Solutions Inc., the United States, has secured patent on a diffuser-augmented wind turbine assembly. In the new invention, the diffuser has a cylindrical central section, which supports a rotor drum that, in turn, supports turbine blades without requiring a central support shaft. Wind energy drives the turbine blades and rotor drum, which drives a generator to produce electrical power. The device can also be operated in reverse as a wind-generating fan by supplying electricity to the generator to act as a motor, according to the patent information. Source: www.freepatentsonline.com