The deployment of conventional three-bladed horizontal-axis wind turbines (HAWT) on land and sea continues to expand worldwide thanks to technological advances and support from governments. However, the development of vertical-axis wind turbines (VAWT) is quietly gaining momentum as well. Recently, ODIN Energy, a firm based in South Korea, has introduced a design for VAWT that may finally allow for the development of wind farms in densely populated urban areas.
As the name indicates, VAWTs have their main rotor shafts oriented perpendicular to the ground. If the blades are colored, a VAWT can appear like a giant barber’s pole from a distance. This design offers several advantages. Their blades do not need to be totally aligned with the direction of the wind. Only their rotor shafts have to be set transverse to the wind in order to generate power. This saves the cost of integrating components for sensing the wind direction and turning the rotor. Compared with HAWTs, VAWTs have lower requirements for geographical and wind conditions. VAWTs are also easer to maintain because their generators are on the ground. However, HAWTs currently still generate significantly more power than VAWTs.
Although HAWTs are the prevailing choice for commercial wind farms, there is a market for VAWTs. The following images and videos provided by ODIN depict a tower that consists of VAWTs stacked together. The tower can have up to 12 floors, each containing a central VAWT surrounded by panels that funnel and accelerate the airstream. ODIN’s flexible and modular design can reduce installation time and save space. At the same time, the cross section of the tower shows that the performance of a VAWT can be enhanced by leveraging certain principles of fluid dynamics.
ODIN has released the results from the trial operation of its prototype tower to several media outlets. According to its data, the new design offers a much higher power output per unit area compared with conventional wind turbines. The company also says that the VAWTs located on the upper floors of the tower can benefit from faster wind speeds and therefore achieve as much as four times the output as conventional wind turbines. The data reveal that the power efficiency of the prototype tower is 62% higher than that of a standalone wind turbine when the average rate of increase in wind speed is 16.5%. This suggests that the configuration of stacking modularized VAWTs may have a significant edge over the traditional configuration of deploying standalone wind turbines across a wide area.
In an interview with media outlets, Soo Yung Song, founder and VP of ODIN, said that there are plans to build wind energy towers in South Korea. The cost of constructing a single 10-story wind energy tower is estimated around US$1.4 million. The LCOE of this installation is estimated around US$90/MWh.
ODIN’s novel design concept appears to be applicable for wind projects in cities where the population density is high and the available space is limited. ODIN also boasts that its VAWT is quieter than most conventional wind turbines. Nevertheless, its wind energy tower is still more costly than the current generation of onshore wind farms and photovoltaic power plants. According to a report released by financial advisory firm Lazard in October, the LCOE for onshore wind power is currently between US$26/MWh and US$54/MWh. Hence, there are still some challenges to overcome before ODIN’s technology can formally enter the commercialization phase.
Brian Gaylord, principal analyst with Wood Mackenzie for Latin America and Southern Europe, wrote to media outlets that market growth is rather limited for VAWTs as three-bladed HAWTs are still much more cost-competitive and mainstream. He added that many types of VAWTs have been developed in South Korea, but none of them has gained significant market attention.
(Credit for the image at the top of the article goes to ODIN Energy.)