November 14, 2023
By Tina Casey

New Floating Offshore Wind Turbine Features Vertical Axis Technology

A new vertical axis design for floating offshore wind turbines tilts in the water like the mast of a sailboat (courtesy of World Wide Wind).

New Floating Offshore Wind Turbine Features Vertical Axis Technology

ARPA-E, circular economy, floating offshore wind, floating offshore wind turbines, norway, Recycling, University of Texas, US Department of Energy (DOE), usa, vertical axis wind turbines, Waste Reduction

The Norwegian startup World Wide Wind is on a mission to prove that vertical axis wind turbines can conquer the floating offshore wind market. That’s going to be a tough row to hoe, but the researchers have been building the case for a new generation of turbines to cut costs and suck more power from offshore locations, too.

Vertical Axis Offshore Wind Turbines Are Respectable Now

CleanTechnica has seen some pretty strange-looking vertical axis wind turbines over the years. In a vertical axis system, the blades rotate around a central pole like a merry-go-round, or in some cases, an egg beater. That provides plenty of leeway for variety in design.

Vertical axis technology also allows for more variation in the height of the turbine compared to the familiar three-bladed, horizontal axis turbines that sit on top of a tall tower like a pinwheel.

Additionally, vertical axis design provides for a more compact silhouette than conventional wind turbines, which rely on longer blades and taller towers for maximum efficiency.

The vertical configuration got a bad rap in the early 2000s, when its main application was in the market for small-scale wind turbines in urban areas and other settings where large-footprint systems are impractical. At the time, performance and certification standards were yet to be developed, leading to issues with unkept promises and underperformance (see more vertical axis coverage here).

Now that the regulatory environment has stabilized, researchers on the prowl for next-generation renewable energy technology are taking another look at vertical axis engineering, including offshore as well as onshore applications at the megawatt scale.

ARPA-E Is Prowling For New Vertical Axis Floating Offshore Wind Turbines

Energy stakeholders are particularly interested in the potential for vertical axis technology to cut the cost of offshore wind. That includes the US Department of Energy, which has tasked its high risk, high reward ARPA-E office with administering the ATLANTIS floating offshore wind program, aimed at new and “potentially disruptive” designs in floating offshore wind technology for deep-water applications.

Keep an eye on the University of Texas at Dallas, where researchers at the school won a $3.3 million grant in 2020 to develop a new vertical axis design for floating offshore wind turbines.

“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,” ARPA-E explains.

The UT-Dallas system features aero-elastic tailoring of the rotor and a system that coordinates active plasma on-blade flow control with rotor speed control.

A New Twist On Floating Vertical Axis Offshore Wind Turbines

With the funding period set to close in 2024, keep an eye out for an update from UT-Dallas. In the meantime, World Wide Wind caught some attention from the clean tech media when it introduced its new floating offshore wind turbine concept last year, and it hasn’t been letting the grass grow under its feet.

The device, which looks something like a rotor sail with hoop skirts, is designed to remediate the instability and power loss issues that bedevil conventional vertical axis technology. Instead of a single set of rotating blades, it deploys pairs of blades that rotate in opposite directions.

According to WWW, it’s the first use of counter-rotating blade sets in a vertical axis wind turbine.

Adding to the odd-looking silhouette is another vertical axis design choice aimed specifically at floating offshore wind applications. Conventional wind turbines are designed with the generator housed in a structure called a nacelle, located at the top of the tower where the blades are attached. Instead, WWW places the generator at the base of the shaft. The weighted bottom enables the shaft to tilt at an angle with the wind like the mast of a sailboat, rather than sitting bolt upright in the water.

Putting The Circular Economy To Work

On November 1, WWW announced that it has signed an agreement with the construction and engineering firm AF Gruppen to test a 19-meter prototype of its vertical axis floating offshore wind design at an AFG facility at Vats, located on the southwest coast of Norway.

If all goes according to plan, the 30-kilowatt prototype will be followed by a 1.2 megawatt pilot project, with an eye on commercial production at 24 megawatts before 2030. The potential for a 40-megawatt version is also somewhere out there on the horizon.

World Wide Wind notes that the engineering of a vertical axis turbine is relatively simple, leading to supply chain savings and opening up more opportunities for local manufacturing.

The supply chain angle also involves reducing the lifecycle carbon footprint of manufacturing wind turbines. With that in mind, last January WWW entered into an agreement with the leading Norwegian firm Hydro to develop recycled aluminum as a sustainable material for its floating offshore wind turbine.

In terms of supporting the recycling principles of the circular economy, the Hydro agreement complements the prototype testing partnership. AFG is both a construction and a deconstruction firm, with extensive experience in decommissioning and recycling offshore oil and gas structures in the North Sea.

But Will It Work?

As for whether or not WWW can shepherd its technology past the prototype stage, that remains to be seen. Plenty of vertical axis turbines have come and gone over the years, so CleanTechnica generally exercises caution when covering news in this area. We look for indications that the technology has raised interest among notable public funding agencies, investors, academic institutions and other experts with a professional reputation at stake.

For example, last week we took note of a new onshore wind turbine concept supported by the Bill Gates energy innovation fund, Breakthrough Energy Ventures. The wings-and-rails configuration is like nothing ever seen before, but apparently Breakthrough and other investors see some potential.

Another indication of newsworthiness is interest from industry partners. WWW falls into that category through its partnerships with Hydro and AFG.  Hydro was tasked with assembling industry partners as part of its agreement with WWW, and the roster now includes the firms Jotun, Moelven, and FRAM Marine.

Supporting agencies featured on WWW’s website include the independent research organization SINTEF, the maritime classification society DNV, the wind energy consulting firm Kjeller Vindteknikk, and the Norwegian wind energy development agency FME NorthWind, among others.

Sweden’s Uppsala University is also on board, which is interesting on account of the school’s history of activities in the vertical axis wind turbine area.

Yet another indication is whether or not general R&D support is emerging in a new direction, and it is. One example of next-generation innovation in the vertical axis field is the Sandia National Laboratories branch of the US Department of Energy, which has been floating — so to speak — the idea of a vertical axis floating offshore wind turbine that doesn’t have a central axis at all. Instead, it deploys guy wires to hold the blades in position.

“These wires can be shortened or lengthened to adjust for changing wind conditions to maximize energy capture while controlling strain,” Sandia explained in a recap of the project last year. “Additionally, replacing the shaft with wires reduces the weight of the turbine even more, allowing the floating platform to be even smaller and less expensive.”

CleanTechnica is reaching out to the lab for an update, so stay tuned for more on that.

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Image: A new vertical axis design for floating offshore wind turbines tilts in the water like the mast of a sailboat (courtesy of World Wide Wind).