Three Gorges Energy has connected the world's first 16-megawatt monster offshore wind turbine to the power grid. With a mind-boggling 260-meter (853-ft) rotor diameter, this towering colossus will supply clean energy for about 36,000 Chinese homes.
It doesn't look all that out of place, standing in a field of other, lesser goliaths, but this MingYang Smart Energy MySE 16-260 is the largest ever connected to the grid. The "engine room" and generator housed in the hub on top of its 152-m (500-ft) tower weigh in at a gargantuan 385 tons, and each of its three 123-m (404-ft) blades adds another 54 tons, hanging off one side of the generator shaft.
Every time it completes a full revolution, it sweeps about 50,000 sq m (540,000 sq ft) of air (that's seven-odd soccer fields in the internationally accepted layman's units), and sends up to 34.2 kWh of energy into the Chinese power system. Annually, it's expected to contribute about 66 gigawatt-hours.
This demonstration unit sits in the Fujian offshore wind farm in the Taiwan Strait, where it'll take advantage of a natural wind tunnel effect. According to the Three Gorges Group, this location experiences level 7 "near gale" conditions with winds exceeding 32 mph (51 km/h) more than 200 days each year.
Indeed, the area is prone to typhoons, so this enormous turbine has an opportunity to prove its mettle against the elements. It's designed to withstand winds up to 179 mph (287 km/h) – that leaves a margin over the most violent conditions ever measured in the Western North Pacific: Typhoon Tip, which featured sustained winds of 160 mph (260 km/h) in 1979. Mind you, the way weather systems are flying off kilter as climate change continues to advance, it's hard to know what to expect going forward.
Offshore wind turbines will continue to grow in size; the China State Shipbuilding Corporation was already building an 18-megawatt turbine back in January and it seems reasonable to expect a 20-MW announcement any day now.
The area of a circle being pi times the square of the radius, every meter added to the length of a turbine's blades has an outsized effect on the swept area from which energy can be harvested, so bigger is definitely better.
The engineering and logistics involved in manufacturing and deploying these things are thus getting wilder by the day, and both Mingyang and the Three Gorges Group have earned themselves a beer by getting this monster completed and into service.
Source: Three Gorges Corporation via Xinhua
I wonder if adding a second set of blades (on smaller) wind turbines to hang on the opposite side of the tower would be beneficial? If designed around that, it might help lower loading on the bearing and driven shaft assembly. It would still carry a lot of weight, but would reduce torsional loading, allowing for more air supplied energy for a given shaft size. I would imagine someone has thought of this already, I'm just surprised it isn't done and wondering why.
Wot about 5 bladed set-ups ? ? ? ? ?
(As/wot woz arrived at by all previous windmill makers for a general optimum design for post & vertical blade set-ups)
Interesting idea. I am not an engineer but it got me thinking. Your concept would perhaps act as a counterbalance to the load but would the total weight of two sets of blades require a redesign of the tower itself to carry 'double' the weight ?. Also and presumably, the blades would have to have an 'opposite' contour to catch the wind, if they revolved in the same direction. However, I seem to recall that contra rotating propellors for aircraft were developed for several WW11 aircraft including the Spitfire, Seafire and Mustang.
The concept is not new either but of course they were mechanically powered.
https://en.wikipedia.org/wiki/Contra-rotating_propellers
Just a few thoughts.
A simple and probably pointless exercise but if you got hold of two child's toy windmills (on a stick) and held them up as near as back to back as you can and see if they both rotate in the wind.
That would be too expensive, complicated, noisy and ugly.
They can counterbalance the rotor weight much simpler with the generator on the other side.
It sure is a big one. What is the payback period?
Probably direct drive, because that is the fad. But it is a dead end, because it requires an inverter. Wind power can never reach its full potential if the industry continues to rely on inverters. They are inefficient, unreliable and expensive, and they produce dirty power. The electrical grid can't stand much more of it.
The only way to eliminate the inverter is with a geared turbine. See the DeWind D8.2 and D9.2 machines. Vestas is now the only company that manufactures only geared turbines, but their turbines still require inverters. They have not yet understood the huge importance of DeWind's technology.