RE Power’s “5M” offshore wind turbine is definitely the King of wind turbines – a single unit that generates 5.0 megawatts of electricity at full output. With a rotor diameter of 126 meters (412 feet) and a hub height between 90 and 120 meters, RE Power’s 5M unit is the biggest wind turbine available in the world, with a total height up to 183 meters (max. hub height plus rotor radius – 600 feet). It represents the next generation in large scale wind. With this turbine, a 200 tower wind farm would generate 1.0 gigawatts at full output. Wind turbines this big are game changers, because the fewer towers involved, the more efficient wind power becomes, especially offshore.
RE Power’s 5M is designed for offshore use, and testing is now completed on twelve 5M turbines, operating both onshore and offshore.. The first one, intalled onshore in Brunsbuettel, on the west coast of Schleiswig-Holstein in Germany in 2004, has logged over four years of 95% availability. In the Beatrice oil field, 25 kilometers off the Scottish East coast, in open ocean 40 meters deep, RE Power has installed two 5M turbines. RE Power is planning to install six 5M turbines offshore near the island of Borkum in the first phase of a new German offshore wind farm, and to begin series production of the 5M in Bremerhaven.
|RE Power 5.0 MW offshore wind turbines.
Beatrice oil field, North Sea.
(Photo: RE Power)
It doesn’t end there, nor should it. RE Power intends to produce the next size up, a six megawatt wind turbine at the same plant in Bremerhaven.
It is very interesting to wonder at what point the output per unit reaches its practical limit. Are ten megawatt units possible? What about the colossal land-based vertical axis concepts, where a single unit might generate 100+ megawatts? Can wind power get cheaper as unit capacity increases, and who else manufactures multi-megawatt wind turbines?
GE Wind Energy offers the new 3.6 MW Series that, according to their website, “is a larger version of our proven 1.5 MW design, the 3.6 MW machine was specifically designed for high-speed wind sites. With a rotor diameter of 104 meters and a swept area of 8,495 square meters [2.1 acres, the area covered by the three 52 meter fans, turned to the wind], this new wind turbine is ideal for offshore markets worldwide.” The 3.6 Series is the next evolution of GE Energy’s wind turbine fleet and builds on the success of GE’s 1.5-megawatt machines, which are among the world’s most widely used megawatt class wind turbines with more than 8,600 units in service and more than 125 million operating hours.
Not to be outdone, Siemens also offers a 3.6 megawatt wind turbine unit, the “wind power station” SWT-3.6-107. With an 80 meter (or site specific) hub height and a blade length of 53 meters, with one of the three blades pointing skwards this unit stands 133 meters high (436 feet).
Vestas Wind Power Solutions has over 500 3.0 megawatt units installed around the world with their V90-3.0, which actually weighs less than its 2.0 megawatt predecessor. Fuhrlaender has the FL 2500, a 2.5 MW turbine that has a modular design, allowing this output to be achieved using variable rotor speeds, and an assortment of rotor diameters, 80, 90 and 100 meters – as well as lattice towers up to 160 meters. At a hub height of 160 meters and a rotor radius of 100 meters, each unit has an amazing total height of 210 meters (689 feet).
Nordex offers three 2.5 megawatt wind turbine products, the N100 with a 100 meter rotor diameter designed for low speed inland locations, the N90 with both low and high speed variants, and the N80 designed for high winds. Enercon manufactures the E-70 wind turbine with 2.3 MW rated power and numerous steel and precast concrete tower versions – is especially suitable for sites with high wind speeds.” The E-70 has a rotor diameter of 71 meters (233 feet) and a hub height ranging from 58 to 113 meters. At a hub height of 113 meters and a rotor radius of 35.5 meters, this unit has a total height of 148.5 meters (487 feet).
Another company with a wind turbine that exceeds 2.0 megawatts is India based Suzlon Energy, who has a 2.1 MW unit noted on their product page. Gamesa offers three models of “aerogeneradores” that all attain 2.0 megawatts, optimized in various ways with the G80, the G87, and the G90. Finally, AAER Wind Energy offers the A-2000, rated at 2.0 MW, with “an optimized torque control system combining variable-ratio superposition gear (SPG) with individual pitch control of the blades. This means that it can be operated at optimum aerodynamic efficiency throughout the whole operational range.”
When considering wind power, cost and impact are major considerations – wind power is relatively competitive based on cost. But how many wind power stations can you build? Finding sites and establishing transmission corridors is most of the battle with wind power, so the bigger the unit, the better. Still the scale of these machines is daunting – many of these wind power stations have total heights exceeding 500 or even 600 feet. By contrast, the Statue of Liberty only measures 305 feet from the water to the tip of her torch. How many of these units would replace a 1.0 gigawatt nuclear power plant?
At 5.0 megawatts each, and a 25% yield, you would need 800 of these machines. At 2.5 megawatts each, you would need 1,600 of them – that is a very, very large wind farm, on-shore or offshore. If they are placed on a grid a safe distance apart, say 500 meters (remember, they are up to 200 meters tall), then 1,600 of these units would consume an area of 200 square kilometers. At 5.0 megawatts per unit, but 1,000 meters between units, a 800 unit windfarm (25% yield) with generating capacity equivalent to a 1.0 gigawatt nuclear power plant would require 800 square kilometers, over 300 square miles. Each of these units would be nearly twice the height of the Statue of Liberty.
|The world’s first 5.0 megawatt wind turbine, operating since
2004 on the southwest coast of Schleswig-Holstein in Germany.
(Photo: RE Power)