Wind power is a red hot market. Experts predict that from 40,000 to 60,000 new wind turbines will be put into operation every year through 2020. But will future windmills look the way they always have? Not necessarily. Think kites, fluttering panels and flying islands with enormous arms.

Wind Power Abroad

Aerogenerator X, developed by British Wind Power, looks like a two-headed sea monster extending its two long necks in a V-shape high above the water’s surface. At the top are airfoils that operate the vertical turbine, mounted on a floating platform far out at sea. This giant measures about 900 feet from one tip to the other, approximately the length of three soccer fields.

Supported by companies such as BP, Caterpillar, Rolls-Royce and EON, Aerogenerator X is one of several competing projects that capitalize on factors of size, economies of scale and low weight. Many of these projects are still in the early stages and won’t be ready to be introduced onto the market for several years.

Drilling for Power

Norwegian Sway makes the most of experiences gained by the oil industry in the North Sea, building wind power plants on floating towers that are filled with ballast and flexibly moored to the seabed. The advantage here is that you can build farther out at sea and in deeper water than with columns that are bored or drilled into the seabed.

Sway’s wind turbines are estimated to generate 20 to 30 percent more electricity in their site, which is located 30 miles off the Norwegian coast where the winds blow harder and more continuously than nearer the shore. Prototypes are currently being tested. But the major issue is whether the techniques are stable and reliable enough to cope with turbines of 10 to 20 MW>

Even further in the future are the airborne wind power projects such as the Dutch Power Plane. The power station is no more than an unmanned glider that is connected to a ground station via a cable. When it then dives the cable is rolled up and a new cycle commences.

Cutting Costs

A working prototype of a 500W silent wind turbine at Chatham Maritime, east of London.

Wind statistics from the Royal Netherlands Meteorological Institute show that one can count on a capacity utilization of 60 percent, compared with 30 percent for conventional turbines, due to the continuous strong winds that blow at greater heights. Manufacturing costs are also a fraction of what conventional power stations cost.

“We exchange steel, copper and fiberglass with mathematics, software and electronics and open the way for new energy resources,” says Richard Ruiterkamp, managing director for the company Ampyx Power, which is responsible for the Power Plane. A commercial solution should be ready by 2014. The first stage will be aimed at users who are not connected to the power grid and who use diesel generators today. Not until much later, when the large 1 MW system has been developed, will the power companies be interested. “The holy grail for all green energy is to produce cheaper than coal, and that is what we would like to acheive,” says Ruiterkamp.

Visionaries such as Francis Charles Moon, a professor at Cornell University, go one step further with a hybrid technology where fluttering panels generate wind power at night or in overcast weather, and solar cells take over when the sun shines. The project is called “Vibro-Wind,” and according to Moon it is three to five years from being introduced on the market. The idea is to harvest the wind that blows between the buildings in residential or office buildings in large towns.

Many of the new types of wind turbines seem to have been lifted from the pages of a science-fiction novel. According to Feargal Brennan, a professor specializing in offshore engineering at Cranfield University in England, where much of the work on Aerogenerator X has been accomplished, this is due to the fact that it is not possible to scale up the established technology out at sea and build on a really large scale.

Vertical Axis Wind Turbines

An artist’s rendition of preliminary working drawings of a Flying Electric Generator by Sky WindPower. This creation was named one of the 50 best inventions by Time magazine in 2008.

Danish BTM Consult reckons that using today’s technology it will cost twice as much to install new capacity in an adverse sea environment as it costs on land. Companies such as Siemens and GE have been investing for a long time now in vertical-axis wind turbines with fewer moveable parts in order to keep the costs down. Other manufacturers are trying to optimize the technology by individual adjustments to the blade angle, different toothed gearing solutions or laser-based wind measurements in front of the turbine, says Staffan Engström, head of Ägir Konsult, which develops wind turbines.

The race for MW is now going ahead at full speed. Azimut is a project conducted by Spanish Gamesa along with 11 wind power and engineering companies. The objective is to build a turbine of 15 MW by 202, twice as powerful as today’s largest turbine Enercon E-126. As a first stage the group of companies is now investing $36 million up to 2013 to produce the technology.

The European Union project Up Wind is aiming at 20 MW turbines with a rotatry diameter of 650 feet and a blade divided into two parts like airplane wings. “We will likely see 20 MW turbines in use within 10 years,” says Jo Beurskens of the Netherlands Energy Research Center.

Such turbines would be signficantly larger than the world market leader Vestas’ next colossus, V164, which has a rotor blade 538 feet in diameter on a 614-foot-tower. In contrast, the Statue of Libery is 305 feet.

Originally published in Metalworking World 3.2011, a business magazine published by Sandvik Coromant.

Text: Tomas Lundin
Photo: Grimshaw/Wind Power Ltd.