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Underwater Ocean Kites To Harvest Tidal Energy
eldavojohn writes "A Swedish startup has acquired funding for beginning scale model trials of underwater kites, which would be secured to a turbine to harness tidal energy for power. The company reports that the kite device allows the attached turbine to harvest energy at 10 times the speed of the actual tidal current. With a 12-meter wingspan on the kite, the company says they could harvest 500 kilowatts while it's operational. This novel new design is one of many in which a startup or university hope to turn the ocean into a renewable energy source."
Because of the tides, the Earth's rotational energy is being stolen by the moon, which is using that energy to slowly escape from orbit. (This is a diminishing effect over time, that will eventually reach equilibrium.) But when we leach this energy for our own purposes, we are changing the delicate balance of that equation. ...Siphon off too much energy from the tides, and we could either increase the rate at which the Earth is slowing, bring the moon crashing down upon us, or both!
Won't somebody think of the children? We owe future generations a planet fit to live on and capable of sustaining the future.
HSJ$$*&#^!#+++ATH0
NO CARRIER
now whales can enjoy the "renewable revolution" like migratory birds and bats do with windmills.
THL phish sticks
Seems this would be relatively high maintenance. Anyone who owns a boat knows that stuff can and will grow on it, which will have to be cleaned off eventually, no? Setting aside the initial cost, which isn't mentioned, wouldn't the maintenance be costly?
Careful what you ask for. You might get it.
Faster! Faster! Faster would be better!
If they're anything like my kites, they'll just end up nose-first in the silt.
Great minds think alike; fools seldom differ.
short answers: No, there is. The sun. No.
Like windmills, PV solar (and arguably, thermal solar), this will use a ton of capital (in multiple dimensions -- energetic, costs, and materials) to harvest very diffuse energy. The cries to subsidize installation -- and possibly operational -- costs will start almost immediately.
Dog is my co-pilot.
Tidal forces are from the moon, and over time the moon is getting farther away. Clearly, if we harvest tidal energy we will force the moon away faster as it makes up for the difference. If NASA times it just right, we could put people on the moon, launch the moon at Mars and have people walking on Mars just months later. Melt the polar icecaps on Mars, use tidal kites there, and repeat as needed to keep using the moon as our Earth/Mars space shuttle. Add Phobos and Deimos into the mix and space tourism can take off.
Next, we use the tide from the sun to travel to Alpha Centauri.
My webcomic
The solution is obvious. I am selling gravity credits to absolve you of your moon-doom guilt. Each credit you purchase represents energy gathered from sources not directly linked to the moon's potential energy plus some of the profits will be used to fund missions that will increase the moon's potential energy. This gravity offset program will save the earth for our posterity. As the administrator of this program, I will, of course, take a percentage of the sales as compensation. My motives are, however, purely in the interest of the future.
One last thing: Sometimes I wonder; "Is that someone's signature? Or do they type that at the end of each post?"
Well ok. Anything wrong with that?
I was having difficulty visualizing this technology, from the text description. Here is a YouTube video that sheds more light. Spoiler: essentially the tethered kite does figure-8 patterns to continually move the turbine through the water.
http://www.youtube.com/watch?v=1qCDRj8TE9Y
Pretend I said something meaningful or insightful here.
Thats not how it works.
The kite is really a steerable sail that moves back and forth across the current, thereby increasing the velocity through the attached turbine.
An animation is available at http://www.ebase.se/minesto/animation.htm
fava
And as with all numbers, the devil is in the detail.
Tide power is generated by water flowing through a turbine. As a result, what matters is the surface of the turbine times the apparent water speed. That gives you a volume over time, which in turn controls how fast the turbine spins. Considering that apparent water speed depends not only on the size of the tide, but the local ocean floor geometry, and the output of the turbines can vary wildly depending on where they're located.
Finally, you made a key mistake in your calculation: a tide turbine doesn't capture the up and down movement of the tide - it captures the horizontal flow of water as it flows from point A to point B. This means that your entire calculation is completely useless. It isn't captured twice a day, it is captured constantly with an oscillating efficiency. The energy captured is only marginally related to a mass of water falling the height of the tide - the falling is translated into horizontal speed, where g is completely overwhelmed by local geometry. And lets not even get into real and apparent water flow, turbine construction, efficiencies, etc...
Really, you could have saved yourself a lot of time and just said "I don't know how this works".
Those who can, do. Those who can't, sue.