Vertical Axis Wind Turbines Ready To Go Mano-A-Mano Against Industry Heavyweights

Energy poverty never looks exactly the same. You don't have to sweat over a smoky wood stove in dim candle light to find yourself trapped by deprivation.

The isolated, small village of Igiugig, near Bristol Bay, Alaska, is a typical example of modern energy poverty. Residents had complained for years that they were paying too much for electricity. It was a legitimate beef because they knew that people living in the city of Fairbanks paid much less. Unfortunately, Igiugig is so far off the beaten path it isn't practical to truck in the expensive fuel used by the village generator. It's flown in by large bush plane instead, if weather permits. When your fuel flies and you drive, you're in trouble (see article in Alaska Dispatch News).

John Dabiri, a Caltech professor of aeronautics and bioengineering, came all the way to Igiugig last summer to slash the village's electricity bills by installing an array of vertical axis wind turbines and finally mothball the bush pilot and the pricey fuel. But it took years of lab simulations and field testing before he could finally put steel in the ground for this real-world demonstration.

First let's go back to the original idea that created Igiugig's new wind farm. About six years ago, Dabiri had a profound insight as he watched schooling fish push with their tails on small vortices coming from adjoining fish and propel themselves through the water: suddenly he was sure that traditional wind farms had been badly designed, from the turbine itself to the layout of the whole farm. That was a big intuitive leap, but then again, he's a MacArthur Fellow — that's his job.

Jumped by a factor of ten

Dabiri already knew that conventional wind farms are defensively designed to minimize the wake turbulence affecting the turbines in the rear. But that creates a problem. If you’re talking about a 100-meter diameter wind turbine blade, then there's a mile between wind turbines sacrificed just to dampen the wake effect. He wondered if his vortex-riding fish could show him how to exploit turbulence to amplify wind farm output instead.

Dabiri immediately asked grad students to simulate what would happen if a wind farm's turbines were spaced more closely together — coupled two-by-two — like his fish, so that air turbulence could spin the blades faster. Then he asked his students to substitute vertical axis wind turbines (VAWTs) for the traditional upwind, three-bladed industry standard. In the simulations, energy production jumped by a factor of 10, which sounded a little too good to be true. So Dabiri set out to prove that the same effect would occur under real-world conditions. He and his students located a small site on a windy California desert and proceeded to install 24 vertical turbines.


Dabiri sorted the turbines into a variety of configurations, all similar to the two-by-two simulation. Then he sucked up thousands of terabytes of performance data. It clearly corroborated the wildly promising lab results, particularly the tenfold increase in output. “It’s one thing to get a few percentage points,” Dabiri told a reporter. “We’re talking an order of magnitude.” (See Professor Dabiri's detailed wind engineering lecture.)

I don't want to leave the impression the Dabiri waltzed into Igiugig and blinded gullible locals with science. He received $1 million in grants from the Gordon and Betty Moore Foundation to develop the scalable vertical axis wind farm. And they seriously vetted his early research before cutting the big checks.

Overcoming failure

Building and testing the Igiugig wind farm might be the easy part. There's a well-documented history of VAWT failure that Dabiri must push against before his turbines are widely adopted. Developers and utilities still have lingering memories of disasters in California during the 1980s. That's when the whole concept crashed after blades started ripping free and flying off their supports barely a year into operation (a blink of an eye in infrastructure time). Not one of those turbines or a repowered descendent is spinning today, making them the Neanderthals of wind technology, an apparent dead end. Meanwhile horizontal axis models have multiplied and flourished, particularly after 2000 when GE and Siemens bought into the industry.

But Dabiri knows that regardless of wind's past success, it's now considered a mature industry. Hub heights can't get much higher. Blades can't get much longer. And the actual concept or turbine template is over 50 years old. In the mid-70s a 25 kW wind turbine was designed, built and installed at the University of Massachusetts at Amherst. Known as the WF-1, it was the first modern wind turbine.

Today’s “mature” wind turbine lives in the deep design matrix pioneered by the WF-1: three fiberglass blades, pitch regulation, variable speed operation, and computer control. In many ways, the WF-1 heavily influenced the modern wind industry: The first generation of American wind engineers were all trained by working on its design and operation, and many of the WF-1’s innovations appear in modern turbines. The caliber of WF-1's progeny won't surprise anyone.

The spread, ubiquity and near immortality of WF-1's intellectual property was guaranteed when it was spun off to US Windpower of Burlington, MA. US Windpower morphed into Kennetech Windpower, which was acquired by Zond Systems, later purchased by Enron Wind, which promptly went bankrupt and sloughed it off to General Electric. (Even Ben Affleck couldn't hide the WF-1 DNA hiding inside GE's most popular models.)

Buffing the flaw

Essentially, General Electric, Siemens, Vestas and other large wind turbine manufacturers have spent the last ten years loading their turbines with sensors, building remote monitoring facilities, and designing wind farm optimization software applications to wring the last bit of productivity from a tired technology. It will be a watershed moment if Dabiri's VAWT's can scale up. Then developers will have to choose between wind 1.0 and wind 2.0, the Dabiri reboot.

The fruits of wind.1's innovation can be found in upstate New York, where General Electric techs remotely monitor 25,000 wind turbines — 38GW worth of power — around the world, 24 hours a day. GE calls its command center a ROC, or remote operations center. There's a sister site in Salzbergen, Germany. Between the two, GE reports they keep its wind fleet at a 98 percent availability.

Looked at another way, these techs and their fiber-optic umbilical cords connected to hundreds of thousands of embedded sensors across the globe try to minimize turbulence. Because once wind energy developers started stacking turbines into row after row of bomber squadron-like formations, the modern wind farm was born, as in 'Houston, we've created a problem.'

Several years ago, GE developed diagnostic software to identify problems thousands of miles away down to very specific faults with parts attached to very specific turbines. GE originally claimed its remote services goosed turbine performance, adding $15,000 to $20,000 per turbine, per year. Back in 2012, GE even cited an example where one turbine out of 200 in Illinois was underperforming. When ROC technicians monitored its settings, they determined that the angles of the three blades were off by about 15 degrees and quickly had field techs climb the turbines to tweak the misalignment.

Plant-level management

This year GE finally offered plant-level wind management software to coax better overall performance from the entire wind farm.

GE’s new software allows a wind farm's turbines to act as a single unit, rather than fractious standalone mini plants. It will enable developers to recapture lost power output from waking effects.

By balancing performance and loads throughout an entire wind farm, 5-10 percent fewer wake losses are guaranteed along with improved mechanical loads (less stress) due to lower wake turbulence.

Notice that the turbulence is still there, it's just better managed. At best, it's still a frenemy, waiting to enjoy the productive slip stream effect of Dabiri's VAWT's.

This September, back in the Alaskan outback, Dabiri's research team met in Igiugig to assess the turbine performance data. The results looked good and progress will continue when another eight to 12 turbines are installed next spring. If the performance data keeps uptrending, even more will be added. The village residents couldn't be happier with the prospect of watching their electricity bills flatlining.

Will traditional turbine makers ever accept the VAWT?

Image: John Dabiri, Caltech via the Moore Foundation