(from:World Wide WindTech AS）
Traditional HAWT wind turbines require many heavy components – including the drive train, gearbox, generator, and huge blades – that need to be fastened to the top of a long pole.
Because of this, the challenges of installing conventional wind turbines on floating offshore platforms are much more daunting. With this in mind, some engineers and operators are looking at so-called vertical (VAWT) wind turbine options.
As shown, the VAWT is able to extend each set of blades upwards and place the rest of the heavy head at the bottom, so the device tends to be in a natural upright state.
When receiving wind energy from all directions, it does not need to turn to face the wind, thus reducing the heavy gear components on the HAWT scheme.
Under the same breeze, the efficiency of VAWT scheme is generally much lower than that of three-blade HAWT wind turbine.
But on the other hand, we can also place it closer without compromising performance – meaning the VAWT can put out more power on the same ocean.
The novel floating VAWT scheme proposed by World Wide Wind is designed for large-scale scalability on the sea.
Interestingly, the top turbine, which is mounted on the central blade, can rotate in one direction. And another turbine near the bottom of the tower can move in a different direction.
In a sense, World Wide Wind is two VAWT wind turbines “into one” – one fixed to the “rotor” and the other to the “stator”.
Contra-rotating vertical turbines (CRVTs) relatively double the rotational speed and generate significantly more power than static stators.
At the same time, this design places heavier, and often-maintained, components at the bottom of the main structure (under the pontoon), close to where the tethers and cables connect.
But for the average person, it may not be very comfortable with its “not fully upright” design, because the huge wind power tower will tilt with the wind.
In this regard, World Wide Wind explained that the blades are designed to sweep over a tapered area, helping to reduce the turbulent wake in the lower part of each floating tower, thus allowing operators to deploy more of these devices to designated locations.
And thanks to the ability to tilt, the company’s VAWT wind turbines are also better able to withstand sudden and violent wind gusts, as well as damaging vibrations.
In terms of power generation efficiency, Mingyang Smart Energy’s industry-leading HAWT competitor with a height of 262 meters (794 feet) can reach 16 MW.
However, World Wide Wind claims its VAWT solution can be scaled more easily – to an even more staggering 400 m (1312 ft) in height, and is rated at up to 40 megawatts per unit.
In an interview with Recharge, a representative of World Wide Wind said its estimated levelized cost of energy (LCoE) was less than $50 per megawatt — less than half of what the U.S. Department of Energy set for 2027 for offshore wind projects.
The company is currently working to accelerate the development of the CRVT counter-rotating vertical wind turbine through rapid prototyping, with a view to having a 3-megawatt model up and running in 2026. If all goes well, it is expected to build a larger 40-megawatt model in 2029.