Environment

Siemens unveils world's largest wind turbine blades

Siemens unveils world's larges...
A Siemens B75 blade in its mold
A Siemens B75 blade in its mold
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A Siemens B75 blade in its mold
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A Siemens B75 blade in its mold
Remarkably, the 75-meter-long (246-ft) blades consist of a single component made from epoxy resin and balsa reinforced with glass fiber
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Remarkably, the 75-meter-long (246-ft) blades consist of a single component made from epoxy resin and balsa reinforced with glass fiber
The sweep of the completed turbine will cover 18,600 sq m
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The sweep of the completed turbine will cover 18,600 sq m
A custom vehicle for transporting extra-long wind turbine blades
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A custom vehicle for transporting extra-long wind turbine blades
The blade length of 75 m is not a kick-in-the-pants off the wingspan of an Airbus A380
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The blade length of 75 m is not a kick-in-the-pants off the wingspan of an Airbus A380

Siemens has released pictures of its truly gargantuan B75 wind turbine rotor blades. As you might imagine, the prototype turbines that will use these blades boast some staggering statistics of their own (Airbuses at the ready, please).

Remarkably, the 75-meter-long (246-ft) blades consist of a single component made from epoxy resin and balsa reinforced with glass fiber, cast in a gigantic mold using a process Siemens has cunningly named IntegralBlade.

Initially, three B75 blades will be put to use in a prototype 6-MW offshore turbine at Denmark's national test center at Østerild. The sweep of the completed turbine will cover 18,600 sq m (200,200 sq ft) and the tips of the blades will move at 290 km/h (180 mph) at full lick. At a wind speed of 10 m/s (19.4 knots), the turbine will be hit by 200 tons (181 metric tonnes) of air every second.

The blade length of 75 m is not a kick-in-the-pants off the wingspan of an Airbus A380
The blade length of 75 m is not a kick-in-the-pants off the wingspan of an Airbus A380

The blade length of 75 m is not a kick-in-the-pants off the wingspan of an Airbus A380 (at 79.75 m or 261.6 ft), meaning that in a Y-position, the airliner could easily pass within the 154-meter (505-ft) sweep's radius above the blades (spatially at least. In practice this isn't recommended).

Siemens has already seen 6-MW turbines installed at the UK's Gunfleet Sands wind farm, albeit with 60-m (197-ft) blades. Thanks to a process Siemens has branded "QuantumBlade," it claims the B75s weigh four fifths of conventional blades. "The weight reduction is achieved by using specially designed blade profiles that are also shaped in a way that delivers maximum rotor performance at a range of different wind speeds," the company says.

Source: Siemens, via Wired UK

22 comments
Bill Bennett
Good Gawd, that is impressive, incredible actually
Nantha Nithiahnanthan
It is so impressive that one can't help wondering how it is transported to the installation site.
Slowburn
At this point I am not convinced that longer is better in wind mill blade design. I think that a shorter blade with a greater chord length (distance from leading to trailing edge of the blade) would work better. The shorter blades would have a higher RPM at the same blade tip speed which reduces the step up the transmission has to make to get an efficient speed for the generator. It could make the windmill blades look more like shovels than sword blades though. I'd keep the greater tower height for the smoother air and greater wind speed.
Alec Sevins
Why is this something to brag about? One of the main problems with wind turbines is their sheer size and presence on the visual landscape, not to mention the noise from such large blades cutting the air. You can call these monsters "green" but they blatantly industrialize any landscape they're installed on, and we're running out of areas that won't be affected by their blight. They should be working to make wind turbines smaller, if anything. When they reached 400 feet enough was enough!
Slowburn
re; Nantha Kumar Nithiahnanthan They use a really long trailer with steering and a driver at both ends and presumably blocker vehicles to open space for lane changes and cornering. The special permitting process probably adds several thousand $ to the cost of the windmills. Hopefully the factory is near the relevant docks given that the windmills are designed for open water.
Greg Zeng
From what is not mentioned: noise is the same frequency & loudness? Later studies show that these turbines cannot be spaced as close as smaller turbines. As to blight on the visual landscape: are they better for off-shore sites - fewer transporting for installation, noise & ugliness for landviewers, etc.
Slowburn
re; Alec Sevins I think the wind to electricity concept is flawed because of the inefficiency of electrical storage, and the constant variation in wind speed changes the output of the windmill on a second by second basis ignoring power usage. I would like to see windmills compress air or lift water and generate the electricity from the stored energy on an demand basis. Personally I would prefer a few gigawatt nuclear power stations built on ships operated over deep water but the actual footprint of wind is tiny and the effect on the surrounding environment is even less. Bigger windmills make for less footprint per megawatt. If you stop throwing a tissy fit every time you see a windmill you will find that they bother you less and less. Actually that is true about just about everything and I need to follow my advice more myself. Just imagine the windmills hidden behind a cloud of smoke.
Grunchy
Why do these windmills always have 3 blades and not some other number? There is a lot of empty space between the 3 that could be producing more power, why not use it especially given the cost of the central support tower? Jet engines for example have hundreds of blades. I would love to see the cost-benefit breakdown that proves 3 is the ideal number.
Slowburn
re; Grunchy Three blades are easy to balance and for generating electricity the higher the RPM the better and fewer blades supports a higher RPM while removing the same amount of the energy from the wind as more blades moving at a lower RPM. I think that with the RPM being limited by blade tip speed that going to four blades might be an improvement but my brother an electrical engineer at a windmill manufacturing company disagrees and I certainly do not have the proof. And with people like Island Architect beating Bill Allison's dead horse just about every chance he gets makes it less likely that a four blade design would even get computer analyzation time.
bandito
Grunchy, its simple geometry. 3 blades will always be balanced giving a much smoother power-production. Also, more blades would mean each blade would be passing into the turbulent air created by the previous one. So more blades, would need smaller blades, which would be less efficient. You would hope the designers ended up with 3 from optimizing blade design vs number of blades. A major problem with bigger blades is the tip speed exceeding mach1.0 As for installation, they'll be produced at a factory on a quayside, loaded straight onto barges and towed out to sea.