MIT Designs "Invisible" Floating Wind Turbines
by Justin Thomas, Virginia on 09.26.06
An MIT researcher has a vision: Four hundred huge offshore wind turbines are providing onshore customers with enough electricity to power several hundred thousand homes, and nobody standing onshore can see them. The trick? The wind turbines are floating on platforms a hundred miles out to sea, where the winds are strong and steady. Since the wind turbines are not permanently attached to the ocean floor, they are a movable asset. If a company with 400 wind turbines serving the Boston area needs more power for New York City, it can unhook some of the floating turbines and tow them south.
Today's offshore wind turbines usually stand on towers driven deep into the ocean floor. But that arrangement works only in water depths of about 15 meters or less. Proposed installations are therefore typically close enough to shore to arouse strong public opposition.
Paul D. Sclavounos, a professor of mechanical engineering and naval architecture, has spent decades designing and analyzing large floating structures for deep-sea oil and gas exploration. Observing the wind-farm controversies, he thought, "Wait a minute. Why can't we simply take those windmills and put them on floaters and move them farther offshore, where there's plenty of space and lots of wind?"
In 2004, he and his MIT colleagues teamed up with wind-turbine experts from the National Renewable Energy Laboratory (NREL) to integrate a wind turbine with a floater. Their design calls for a tension leg platform (TLP), a system in which long steel cables, or "tethers," connect the corners of the platform to a concrete-block or other mooring system on the ocean floor. The platform and turbine are thus supported not by an expensive tower but by buoyancy. "And you don't pay anything to be buoyant," said Sclavounos.
See also this previous article discussing Sclavounos' proposals: An Answer for Offshore Wind?
:: Read more at Renewable Energy Access. Related: ::Norway's Hydro Develops Floating Wind Turbines
"Thar she blows!"
Do it! What are you waiting for? Only concern is grid lines snaking along the ocean floor. I imagine making and breaking high-voltage connections underwater is no easy chore.
But don't let that stop you. Remember, Henry Ford's wife drove an electric car. Anything IS possible!
I've heard concerns about that type of wind turbine killing birds. I read awhile back about a different kind. using a vertical axis instead of this horizontal one (so it looks more like an upside down egg-beater). Also, this design is more efficient and allows for much larger wind turbines.
Rex, vertical turbines are less efficient because part of the machine is moving into the wind. I can't comment on bird kills, but the two types are probably about equal. The only plus I see in the vertical axis wind turbines (so-called VAWTs) is that they don't need to be aimed. Besides that, the benefits are illusory.
Regarding the bird deaths, more cars on roads hit birds than windmills do, but if it's more efficient then i'm all for it.
I'm more concerned with them being to close and banging into each other.
"Regarding the bird deaths, more cars on roads hit birds than windmills"
Actually, cars, buildings and cats kill an order of magnitude more birds than wind turbines probably ever could, and strangely there's not a big public outcry about that.
Vertical axis windmills have failed to live up to their promise because of fairly specific aerodynamic and mechanical problems. Newer designs may address some of these:
http://www.quietrevolution.co.uk/
http://www.turby.nl/
And, as noted by others, the birdkill problem with windmills is WAY overblown, especially compared to the millions of birds that die from running into buildings each year. (Environmental Building News did a piece of buildling birdkills recently. Unfortunately, I can't link to it, because it's a subscription publication.)
I like the idea myself too (floating windfarms not birdkills...) Why couldn't structures similar to oil rigs be parked out at sea?
If we could do this with wind, why not combine with solar farms and kinetic wave energy ( see http://www.kinergypower.com/html/waveenergy.html ) as well ?
Solar electrolysis of hydrogen is a fact of life but not very common. It may be going overboard (no pun intended...) but it would seem that operations like this could be outfitted on barges or refitted (reformed?) oil tankers already in the fleet.
Just a thought.
Just because we can't see or hear the turbines anymore doesn't mean they won't be killing birds, or driving sea creatures mental with the same continuous low frequency noise that prevents widespread use of them in the UK.
Why not come up with a perhaps slightly more expensive, not so effecient design, instead of moving the problem out of sight? Isn't that the general problem with mankind? Make it nearer to perfect, then they won't need to be out at sea anyway.
p.s. can I claim them as salvage if they are abandoned at sea?
Put a wave generator on the bottom of this tower instead of a concrete weight.
Then the tower will produce more electricity.
Good comments, all. On the bird issue, it should be noted that at a few specific sites, there have been problems with raptors (birds of prey such as eagles) colliding with wind turbines in numbers that are great enough to cause concern. I believe this is something that should be predictable and avoidable, and in any event, it is not a general problem.
On vertical-axis turbines, part of the problem is that they typically require more material than propeller units, and the economics of wind are all about keeping the amount of material per unit of energy produced as small as possible.
It was initially thought, also, that an advantage of the vertical-axis design was that it did not require a tower. That's true, but it turns out that the better wind speeds are well off the ground anyway, so to capture them you need . . . a tower.
Thomas O. Gray
American Wind Energy Association
www.awea.org
www.ifnotwind.org
Emphasis on "designed".
William Hieronymus of UMass Amherst proposed something like this about thirty years ago. In his proposal, excess could be converted to hydrogen and piped ashore.
What about the transmission lines? resistance? And 100 miles out to sea is international water, so we'll need the military protecting it and those 100 miles of transmission lines. And of course, boating/flying maintenance crews out there...
Not many birds 100 miles out to sea, though.
This is a great idea, but there is one HUGE problem: the loss of electicity during the transport from the location of generation to the end consumer due too resistance of the cables will be far to high to make this solution cost effective. Electricity needs to be generated as close to the end consumer as possible to reduce the amount of electricity loss during transport. If electricity is generated many miles away from the coast then by the time the electricity actually reaches the consumers only a tiny percentage of the electricity generated will be available for use. The first and second costs for offshore windfarms is very high, due to more complicated installation and higher maintenance costs. The further offshore, the higher the second (maintenance) costs will be and the lower the amount of usefull electricity will be. Windfarms closer to shore are the more cost effective solution.
Electricity on land travels 100 miles and more all the time. And they can just use a DC current over long distances. http://en.wikipedia.org/wiki/Electric_power_transmission#Losses
And keep the voltage up.
I wonder if they would hold up in a severe storm or rogue wave? Those forces of nature beat concrete and cables. Then they would probably sink and litter the ocean floor, being too deep to salvage.
Modern Turbines turn slower than the infamous bird killers.
The real show stopper here is the same one as what stops solar towers, stirling generator fields and ocean power, and that's financing.
Our government won't finance it and no venture capitalist will risk the money for what they consider a small reward on that investment.