A Department of Energy-funded research group spanning several American universities is proposing a wind energy scheme involving almost unimaginable scales. The technology, which is still several years off from even being tested, would be capable of generating 25 times the power of a contemporary conventional wind turbine, but it would also come at a cost: really big-ass turbine blades.
How big? Each blade would span 656 feet, dwarfing the current largest blades in use (262 feet). This would require towers to be at least a third of a mile tall, or about 100 feet taller than the Empire State Building. The group's work was reported this week in the Los Angeles Times.
The new turbine blades are more properly known as Segmented Ultralight Morphing Rotors. The utility of such big honking blades is partially that they're not always so big. As wind speeds increase, the blades are capable of retracting. As the wind mellows, they again extend, capturing a larger volume of air in motion. This retractability would also be helpful for moving the blades from their manufacturing location to the turbine sites—transporting even normal turbine blades is an ongoing challenge.
The blades would be most likely installed offshore. Towers would be outfitted with only two blades apiece (vs the current three), and, to minimize strain, would face downwind rather than into the wind.
"Conventional upwind blades are expensive to manufacture, deploy and maintain beyond 10-15 MW," Todd Griffith, the project's lead blade designer, said in a Sandia National Laboratories news release. "They must be stiff, to avoid fatigue and eliminate the risk of tower strikes in strong gusts. Those stiff blades are heavy, and their mass, which is directly related to cost, becomes even more problematic at the extreme scale due to gravity loads and other changes."
Worth noting is that all of this exists only on paper, so far.
"The concepts have all looked very promising, but they're all pure simulations," Eric Loth, an engineering professor at the University of Virginia, told the Times. "Now we're actually going to build something. That's where the rubber meets the road."
The first prototype will be only a tenth the scale of the final product and it should be ready for testing by 2019. So, yes, this is all a ways off. The first proper supersized wind farm shouldn't be expected earlier than 10 or 15 years.