Society desperately needs to find ways to generate power other than burning fossil fuels, but some alternatives cause environmental damage of their own. Case in point: large wind turbines. The spinning blades of modern-day wind turbines, whose tips can travel at speeds of 150 miles per hour or more, pose a significant risk to birds.
People who want clean energy but who care about birds can find themselves torn between two unpleasant alternatives when it comes to wind power development, and so it's no surprise that anyone offering a third way out might attract attention. And in the last few weeks, the Spanish startup Vortex Bladeless has been getting that attention.
Vortex Bladeless is attracting that notice because of its new bladeless wind turbine design, which the company claims is quieter, cheaper, and more efficient than conventional wind turbines -- and safer for birds. But do the company's claims stand up to scrutiny?
Conventional wind turbines convert wind energy into electrical power by using a pinwheel-type set of blades. A strong wind sets the blades spinning, and the blades' hub in turn spins a generator. At its simplest, a generator is a set of magnets surrounded with coils of electrical wire: when the magnets spin, their rotating magnetic fields induce current in that wire, which is then tapped as electrical power.
Vortex Bladeless claims its first generation of bladeless wind turbines would generate electrical power in essentially the same way, changing mechanical energy into electrical power by means of a generator. But instead of using spinning blades to turn a generator, Vortex Bladeless' design takes advantage of oscillating wind turbulence to do the same thing.
Here's a video in which Vortex Bladeless execs explain the very basic concept underlying their product:
I say "very basic" because the video is almost completely devoid of the kind of technical information that would allow anyone knowing a little bit about wind energy, electrical and mechanical engineering, or even basic science to evaluate whether the company's turbines will actually work.
In theory, there's no reason why a design like Vortex Bladeless's couldn't turn wind energy into electrical power. The company isn't the first to think about using wind oscillations to generate power instead of spinning a fan. That idea's been around for decades, long enough that the Solar Energy Research lnstitute (SERI) studied the technology for the Department of Energy in 1983. (SERI is now known as the now known as the National Renewable Energy Laboratory.)
SERI studied a few different kinds of oscillating wind power technology back in the early 1980s. One of the class of designs they studied, the so-called "oscillating vane" design, was substantially similar to Vortex Bladeless's design. SERI's verdict, 32 years ago?
It appears, then, that most of the advantages of the oscillating vane are the same as those of the comparable [standard wind turbine, which] has advantages that the oscillating vane does not have.
The biggest problems SERI identified with oscillating vane technology stemmed from precisely the kind of movement the turbines would be intended to exploit: the seemingly random, back-and-forth movements caused by wind turbulence oscillation. In order to generate a significant amount of power, the vane has to sway at a reasonably high speed. But those speeds of oscillation increase stresses on both the vane and on the foundation keeping the vane upright.
In other words, it's not so much that oscillating vane technology can't generate power: it's just uncertain that it could generate power for very long without breaking down. And frequent breakdowns mean increased cost of energy. Meanwhile we do know how to account for spinning in our mechanical engineering, which gives the pinwheel class of turbines a bit of an advantage. Not that they don't break down: they do. But they don't break down often enough to provide a significant financial disincentive to building them.
That said, 1983 was a long time ago, and engineering has advanced a bit since then. Can it be that materials and techniques available today might allow Vortex Bladeless to build oscillating vane turbines that work well enough to be economically feasible?
In this video, Vortex Bladeless's David Suriól suggests the company might be on the right track in limiting a few kinds of mechanical failure, including taking the gears that would have transmitted mechanical energy to the generator and replacing them with magnets, thus removing a wear-and-tear failure point:
But again, Suriól's video is frustratingly short on detail. For instance, those magnets: how would they work? How much power did the prototypes Suriól shows actually produce, and for how long? What was each unit's Mean Time Between Failures?
We may have answers before too long: Vortex Bladeless intends to test a production model, the four-kilowatt Vortex Mini, later this year. (The company plans to crowdfund those tests starting in a couple weeks, which may account for the rah-rah tone of some of the reporting on the product.) If Vortex Bladeless makes those test results public, we might be able to assess whether the product lives up to its hype.
And make no mistake: if that hype proves accurate, that could be a very good thing. Not only would the world's flying wildlife breathe a little bit easier, but the promised lower noise and smaller footprint could mean these oscillating vane wind power generators could be sited more easily in the built environment, making a potentially attractive addition to urban landscapes. And since the oscillating vane design takes advantage of the kind of turbulence caused when wind blows past other objects, it might prove feasible to cram a whole lot of the things close together, reducing the wind sprawl seen so often these days in the American West. It all depends on the pesky details of design and testing in real-world conditions.
For all their problems, conventional wind turbines are prevalent in industry for a reason: they work. We'll be watching the results of Vortex Bladeless' testing -- or as much of those results as the company makes available. But the history of renewable energy is littered with ideas that sounded too good to be true, some of which would need to violate the laws of physics to work as advertised.
Vortex Bladeless probably wouldn't need to violate any laws of physics to make its product successful. But the company is up against some very tricky engineering issues that may well make its turbines fail to compete in the real world.
Just a reminder that we need to look especially carefully at technology when we really, really want it to work.