Vertical axis wind turbines were practically written out of collective memory just a few years ago, banished on account of cost and engineering obstacles. Suddenly they are back in the picture, thanks partly to the US Department of Energy. If all goes according to plan, the offshore wind industry can take also take credit for the revival.
Whatever Happened To Vertical Axis Wind Turbines?
For those of you new to the topic, vertical axis wind turbines are just what they sound like. In contrast to the familiar three-bladed, gigantic wind turbines that spin on a horizontal axis high off the ground atop a very tall tower, vertical axis turbines take up much less air space. That’s partly because they are generally used for small-scale wind projects, but mostly it is on account of their blades, which hug the hub in a vertical configuration. The turbines can be located much closer to the ground, and the blades can be engineered in a startling variety of configurations.
The big question is whether or not vertical axis wind turbines can generate enough electricity to justify the cost. Until recently, the answer was: meh.
The Return Of Vertical Axis Wind Turbines
In other words, there is a reason why leading global wind developers have not invested significant dollars in the vertical axis area (if you can find one, drop us a note in the comment thread).
Back in 2017 our friends over at Wind Power Engineering took a look at the state of affairs and outlined the obstacles:
“It is well known that a VAWT is quiet, safe, and does not need a tall tower. However, hardly any commercialized large VAWT have been launched despite of the efforts of countless engineers. The reasons are obvious: the problems of aerodynamic efficiency, self-starting, structural stability, and safe braking remain unsolved. The problems have to be solved for any type of wind turbine,” they wrote.
Nevertheless, the technology continues to entice engineers in search of a challenge. Assuming these challenges are solvable, the solutions could be expensive, and the next hurdle would finding a market for them.
A good place to start would be in the area of military procurement. Sure enough, vertical axis wind turbines made the cut last month, when the US Air Force Research Laboratory released a list of eight companies selected for its new “Expeditionary Energy Campaign” program.
The campaign zeroes in on cutting edge technologies including wireless transmission and robotic assembly along with solar and wind energy. The conventional tall, three-bladed turbine is not a good fit for expeditionary forces that are trying to keep a low profile, which could explain why the Air Force tapped the Icelandic vertical axis firm IceWind for the program.
Texas Is Hearting Vertical Axis Wind Turbines
Things always seem to get interesting in the renewable energy field when Texas is in the mix. The iconic oil and gas producing state emerged as an early adopter and national leader in the wind energy field during the Obama administration. Solar energy, energy storage, and green hydrogen are also in the mix, so it’s no surprise to find that IceWind chose to launch its US business in Texas.
It’s also no surprise to see Texas dabbling in the emerging area of floating offshore wind turbines, and that’s where things get even more interesting.
Texas sits on the Gulf of Mexico, which could mean it is primed for activity in the offshore wind area, except that it isn’t. Last year the Energy Department’s National Renewable Energy Laboratory ran the numbers on offshore wind resources in the Gulf, and they tapped Louisiana as a more economically viable option for the region.
Not to be discouraged, Texas has lent the University of Texas at Dallas to fulfill a new offshore wind turbine project funded by ARPA-E, which is the Energy Department office tasked with providing financial muscle for high risk, high payoff R&D programs that private sector investors shy away from.
This is not going to be your parent’s offshore wind turbine. ARPA-E wants to see a new generation of low cost, floating offshore wind turbines.
As ARPA-E sees it, the problem with today’s floating wind technology is that the wind turbines are modeled on the same conventional three-blade, vertical axis configuration as land based turbines, and they require a large, expensive platform in order to float.
ARPA-E put out the call for new designs for floating offshore wind turbines, and the University of Texas answered with a vertical axis design. Here, let’s have ARPA-E explain it:
“VAWTs [vertical axis wind turbines] offer advantages over traditional offshore wind designs because they have a lower vertical center of gravity and center of pressure; require a smaller, less expensive floating platform; do not need yaw control systems; and have the potential to reduce operations and maintenance costs due to platform-level access to the drivetrain.”
UT-Dallas won the funding in April of 2020 and is expected to deliver the goods next April, so it won’t be long before we see a new vertical axis wind turbine that sports aero-elastic tailoring, coordinates “active plasma on-blade flow control with rotor speed control to reduce torque variability,” and sits on a lightweight, stable, and presumably inexpensive platform.
Offshore Wind & Vertical Axis Turbines
UT-Dallas is not the only player in the floating vertical axis wind turbine game, which seems to have suddenly burst into life.
ARPA-E can take part of the credit. Back in 2019 it launched an offshore wind funding initiative called ATLANTIS, aimed at bringing down the cost of floating wind turbines by soliciting radical new designs, such as that proposed by UT-Dallas.
Sandia National Laboratory also chipped in, with a 2017 study that identified cost-optimal designs for floating offshore vertical axis wind turbines.
More recently, the UK’s Oxford Brookes University put in its two cents, noting that “the vertical turbine design is far more efficient than traditional turbines in large scale wind farms, and when set in pairs the vertical turbines increase each other’s performance by up to 15%.”
Just last month the University of Strathclyde, Glasgow also released a study suggesting that floating vertical axis wind turbines could be an economically feasible alternative to conventional floating turbines. The turbines could be packed together more densely, and costs related to maintenance and repair would be minimized.
Texas & Vertical Axis Wind Turbines
That could explain why Texas is so interested in the technology. The aforementioned offshore wind study was based on conventional turbines. Floating vertical axis turbines could be a whole new kettle of fish, enabling the Lone Star State to sail its wind power leadership into the Gulf of Mexico.
Don’t hold your breath for the vertical axis wind farm of the future. The technology is still in early stages, and costs for conventional floating wind turbines keep falling.
However, it does appear that vertical axis wind turbines are heading out to sea. If and when floating vertical axis wind turbines do happen, keep an eye out for new wind farm designs that incorporate solar panels, wave energy, or all three — plus hydrogen-producing systems, too.
Follow me on Twitter @TinaMCasey.
Featured image courtesy of University of Texas – Dallas.
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