We haven’t seen a floating offshore wind turbine like this before. Touchwind claims its innovative single-blade turbines will solve a number of problems by reducing costs and downtime by using a single, huge blade without any fancy active pitch control.
Most of the world’s best wind resources are offshore, too deep in the ocean to be harnessed with typical fixed-tower turbines. The deep sea can thus make a large clean energy contribution, while causing much less disturbance to residents and wildlife than onshore wind farms.
But the technology to harness offshore wind from floating devices anchored to the ocean floor has not yet been established, so there is a kind of gold rush in progress as a few different designs make it on spec sheets, in wave tanks and prototypes. Let’s dip into the test. They are all hoping to find the sweet spot between cost, power output, cost, longevity, reliability, cost, ease of construction, ease of installation and maintenance, cost, cost and cost.
Buoyant barrel floats attached to the seabed
Dutch company Touchwind has an interesting idea… waka waka. It is designed around a huge single-piece rotor, sitting on the end of a pole that is draped over a large barrel, with a large floating buoy suspended below it.
Touchwind says this giant double blade should cost about 30% as much as triple-blade arrangements on conventional turbines. This requires no expensive active blade-pitch control systems, and where most standard turbines would need to shut down at wind speeds above 25 or more m/s (90 km/h/56 mph). It is rated for speeds up to 70 m/s (252 km/h/157 mph). Less downtime equals more productive hours and more energy.
The blade is angled slightly upward from the mast. At low wind speeds, the mast leans straight, effectively keeping the blade out of the water with the aid of that hanging buoy. But as the wind speed increases and the blades start rotating faster, it develops lift, like the main rotor of a helicopter, and starts pulling the mast vertically.
At higher wind speeds, the larger blade pulls the tower vertically, leaving a smaller portion exposed to the wind
Thus, in high wind speeds, it sits almost flat to the horizon, greatly limiting the wind’s ability to rotate it rapidly. And as this happens, the buoy is lifted out of the water, becoming a ballast load acting against the lift of the main blade, helping to reduce the stress on the anchors on the seabed and moving the whole thing away. Are prevented from leaving and starting a new life. No one knows its name.
Like many other floating designs, it is agnostic to the direction of the incoming wind, and will float passively to orient itself in the optimal direction at all times.
Touchwind says this design lends itself to easy construction at more or less any port facility capable of handling the 200-metre (656-ft) blades required for a 12-MW turbine, and transportation and attachment to the site. It is equally easy. Ground anchor and power export cable for installation.
Touchwind says building and deploying devices from ports should be relatively simple
The company has completed both small-scale land-based and floating platform prototypes, and is beginning to expand testing thanks to new investment from Japanese shipping company Mitsui OSK Lines.
“We have been working together for a year on the further development of our floating wind turbine,” said Ricus van de Klippe, founder and CEO of TouchWind, in a press release. “Field testing with a 6-metre diameter rotor is in full preparation at Lake Oostvoorne in the Netherlands. With MOL and their investment as a shareholder we can accelerate our testing programme, prove our technology and “Can reduce time to market.”
We’re not sure when the company expects to scale up, and unfortunately, there are no estimates at this stage as to what the levelized cost of energy (LCOE) from these animals might look like. So it’s hard to understand how competitive it could be in commercial deployment, assuming development and funding proceed without too much drama.
Watch a video below.
Source: via Touchwind recharge news