How WindFlip Will Deliver Gigantic Floating Turbines to Site

To tow the new gigantic off-shore wind turbines now being developed in Europe far out to sea, a Norwegian company has devised a clever and simple mechanism. Their WindFlip tows the turbine out almost horizontal – and then when it gets to the site, tilts it up into position – using only the weight of seawater to do it.

The structure contains 29 air filled compartments. Once at the site each of the compartments inside the Windflip is sequentially filled with water, causing the stern to slowly submerge, so that both the Windflip barge and the turbine it is holding flip up 90°. Then it releases the turbine for connection with a pre-installed mooring spread, and then tips the barge back to horizontal by clearing the ballast tanks of seawater with compressed air.



Why DOE-Funded Floating Turbines May Change Future of Offshore Wind

This week, Statoil has an application for a pilot demonstration of their Hywind floating wind turbine 12 miles off the coast of Maine before the new Bureau of Ocean Energy Management for approval. The demo would be the fruition of a project begun in 2009, and funded by the Department of Energy.

Then Maine Governor John Baldacci had visited Norway to inspect Statoil’s Hywind floating turbine project with state and university officials and business leaders and encouraged Statoil to consider his state for deep-water testing of the commercial floating wind turbine technology in the Gulf of Maine. A return visit introduced Norway’s Statoil to turbine construction expertise in Maine, visiting the Vinalhaven wind turbines on the Fox Islands constructed by Cianbro.



Wind Turbine Big Enough To Land A Helicopter On Scotland Has It Covered

Scotland has an ambitious and admirable goal: 100% renewable energy. Taking steps toward reaching this goal, the Scottish government approved an offshore test site for a new 6MW wind turbine.

2-B Energy, based in the Netherlands, has permission to install an innovative two-bladed wind turbine approximately 70 feet off the coast of Methil in Fife, according to Scottish energy minister Fergus Ewing. 2-B is one of several companies which has a lease in the 2010 offshore wind demonstration leasing round, which is supposed to help develop wind farms offshore and in deep water.



By Tyler Hamilton

Wind power is one of the fastest-growing forms of power generation in the United States, with more capacity added onshore than coal and nuclear generation combined over the past four years. But to sustain that high growth rate into the next decade, the industry will have to start tapping offshore wind resources, creating a need for wind turbines that are larger, lower-maintenance, and deliver more power with less weight.

To support research in this area, the U.S. Department of Energy has awarded $7.5 million to six projects, each aiming to develop advanced drivetrains for wind turbines up to 10 megawatts in size. Five of the projects use direct-drive, or gearless, drivetrain technology to increase reliability, and at least two use superconductivity technologies for increased efficiencies and lower weight.

Current designs can’t be scaled up economically. Most of the more than 25,000 wind turbines deployed across the United States have a power rating of three megawatts or less and contain complex gearbox systems. The gearboxes match the slow speed of the turbine rotor (between 15 to 20 rotations per minute) to the 2,000 rotations per minute required by their generators. Higher speeds allow for more compact and less expensive generators, but conventional gearboxes—a complex interaction of wheels and bearings—need regular maintenance and are prone to failure, especially at higher speeds.

On land, where turbines are more accessible, gearbox maintenance issues can be tolerated. In rugged offshore environments, the cost of renting a barge and sending crews out to fix or maintain a wind-ravaged machine can be prohibitive. “A gearbox that isn’t there is the most reliable gearbox,” says Fort Felker, direct of the National Renewable Energy Laboratory’s wind technology center.

To increase reliability and reduce maintenance costs, a number of companies—among them Enercon and Siemens of Germany, France’s Alstom and China’s Goldwind Global—have developed direct-drive or “gearless” drivetrains. In such a setup, the rotor shaft is attached directly to the generator, and they both turn at the same speed. But this introduces a new challenge: increased weight.

To achieve the power output of a comparable gearbox-based system, a direct-drive system must have a larger internal diameter that increases the radius—and therefore the speed—at which its magnets rotate around coils to generate current. This also means greater reliance on increasingly costly rare-earth metals used to make permanent magnets.

Kiruba Haran, manager of the electric machines lab at GE Global Research, one recipient of the DOE funding, says direct-drive systems get disproportionately heavier as their power rating increases. A four-megawatt generator might weight 85 tons, but at eight megawatts, it would approach 200 tons.

GE believes it can develop an eight-megawatt generator that weights only 50 tons by adapting the superconducting electromagnets used in magnetic resonance imaging. Unlike a permanent magnet, an electromagnet creates a magnetic field when an electric current is applied to it. When made from coils of superconducting wire, it has no electrical resistance, making it more efficient, with the caveat that it must be cooled to minus 250 °C. The approach would eliminate the need for rare-earth materials, assuming GE can lower the cost enough to make it commercially viable.

Florida-based Advanced Magnet Lab, which also received DOE funding, believes it can build a 10-megawatt generator that weighs just 70 tons. As with GE’s technology, the core of the company’s innovation is a superconducting direct-drive generator. The company has developed a compact coil design based on double-helix windings that can carry high currents and handle the immense magnetic forces produced in the system.

Advanced Magnet Lab president Mark Senti says the high cost of superconducting materials and of cryogenically cooling makes no sense for today’s three-megawatt wind turbines. But beyond six megawatts, he argues, the systems become competitive with conventional generator designs. At 10 megawatts, “it gives you the highest power-per-weight ratio.”

There’s also significant room for advancement. Senti says most superconducting wiring costs $400 per meter today, but new materials made out of inexpensive magnesium and boron powders promise to lower costs substantially. With improvements in manufacturing and less expensive cooling techniques, Senti figures superconducting technology could eventually become economical for wind turbines as small as two megawatts, making it ideal for both onshore and offshore markets.

Superconductivity isn’t in everyone’s plans. One of the other funding recipients, Boulder Wind Power, is focused on designing a better stator—stationary coil—for direct drive systems. Instead of copper wiring wound around a heavy iron core, the company’s stator is made of printed circuit boards. These lightweight components can be manufactured in high volume and assembled in modules, making them easier to repair in remote offshore locations. “With this design, you just send a couple of guys out there to remove a stator segment and literally plug in a new one,” says Derek Pletch, vice president of turbine development at Boulder Wind.

NREL, meanwhile, is taking a hybrid approach by designing a medium-speed drivetrain that uses a simpler single-stage gearbox and a medium-sized generator. Felker says the approach can be easily adapted to existing designs and be picked up in the marketplace faster. Clipper Windpower and Dehlsen Associates also received funding. After six months, the DOE is expected to shortlist the designs and contribute an additional $2 million to each project for performance testing.

Source: technologyreview

Wind power manufacturer Vestas has announced it will complete the largest offshore wind turbine in the world. The V164-7.0 MW will be a colossal offshore turbine being designed for the roughest North Sea conditions — notorious for its violent winds.

In its press announcement about the offshore endeavor, Vestas stated: “Lowering the cost of energy In relation to offshore wind is essential for the industry. Some of the major stepping stones in achieving this are size and subsequent increased energy capture, which means a need for much bigger turbines that are specifically designed for the challenging offshore environment.”

When completed, the wind turbine rotor will measure 164 meters (538 feet), surpassing Spain’s current 420 foot rotor. The size is almost equal to two American football fields. Vestas CEO, Ditlev Engel, said he is pleased to show a commitment to the offshore wind industry by introducing the V164-7.0 MW: “Seeing the positive indications from governments worldwide, and especially from the UK, to increase the utilization of wind energy is indeed very promising.”

Engel can be seen on this video discussing the development of this machine.

As reported by EcoFriend, this project will certainly “be a big step forward, especially in view of the goal set by EU – to get 13 percent of total power from renewable sources by 2020.”

Anders Søe-Jensen, president of Vestas Offshore, believes the offshore wind market will expand over the coming years, especially in regions like the Northern part of Europe, where the conditions at sea are particularly rough.

The most outstanding feature of this new turbine is its size and resulting increased energy capture. The turbine will function with a medium-speed drive-train solution.

“We actually kept all options open from the start, running two separate parallel R&D development tracks: one focusing on direct drive and one on a geared solution,” says Finn Strøm Madsen, President of Vestas Technology R&D. “It soon became clear that if we wanted to meet the customers’ expectations about lowest possible cost of energy and high business case certainty we needed a perfect combination of innovation and proven technology and so the choice could only be to go for a medium-speed drive-train solution.”

Vestas is a pioneer of the wind industry, has installed 580 offshore turbines, 43 percent of the world’s offshore turbines. Production of the 7 MW turbine is expected to begin in 2015.

Source: cleantechnica