Ocean Currents Can Power The World, Say Scientists

[DeSwiss]

Ocean currents can power the world, say scientists
A revolutionary device that can harness energy from slow-moving rivers and ocean currents could provide enough power for the entire world, scientists claim.

The Telegraph
By Jasper Copping
Last Updated: 2:39PM GMT 29 Nov 2008


Existing technologies require an average current of five or six knots to operate
efficiently, while most of the earth's currents are slower than three knots (Photo: AP)

The technology can generate electricity in water flowing at a rate of less than one knot - about one mile an hour - meaning it could operate on most waterways and sea beds around the globe. Existing technologies which use water power, relying on the action of waves, tides or faster currents created by dams, are far more limited in where they can be used, and also cause greater obstructions when they are built in rivers or the sea. Turbines and water mills need an average current of five or six knots to operate efficiently, while most of the earth's currents are slower than three knots.

The new device, which has been inspired by the way fish swim, consists of a system of cylinders positioned horizontal to the water flow and attached to springs. As water flows past, the cylinder creates vortices, which push and pull the cylinder up and down. The mechanical energy in the vibrations is then converted into electricity.

Cylinders arranged over a cubic metre of the sea or river bed in a flow of three knots can produce 51 watts. This is more efficient than similar-sized turbines or wave generators, and the amount of power produced can increase sharply if the flow is faster or if more cylinders are added. A "field" of cylinders built on the sea bed over a 1km by 1.5km area, and the height of a two-storey house, with a flow of just three knots, could generate enough power for around 100,000 homes. Just a few of the cylinders, stacked in a short ladder, could power an anchored ship or a lighthouse.

Systems could be sited on river beds or suspended in the ocean. The scientists behind the technology, which has been developed in research funded by the US government, say that generating power in this way would potentially cost only around 3.5p per kilowatt hour, compared to about 4.5p for wind energy and between 10p and 31p for solar power. They say the technology would require up to 50 times less ocean acreage than wave power generation. The system, conceived by scientists at the University of Michigan, is called Vivace, or "vortex-induced vibrations for aquatic clean energy".


http://www.telegraph.co.uk/earth/energy/renewableenergy/3535012/Ocean-currents-can-power-the-world-say-scientists.html">MORE

- You know, it occurred to me while reading this piece, that all of our best solutions for energy and therefore for our future, are tied to things we carved into stones in our long past: Earth (geothermal), Wind (windmills), Fire (solar) & Water (oceans & rivers).

Odd, that.
==============================================================================
DeSwiss


http://www.atheisttoolbox.com/">The Atheist Toolbox


"Just a little reminder, about why it's so important
that we develop alternative energy sources...."


"Prayer is just a way of telling god that his divine plan for
you is flawed -- and shockingly stingy" ~ Betty Bowers

[silverweb]

1. Excellent news!

[DeSwiss]

19. Yes it is!

- Looking at your hippie emoty, I thought you might like this:

[silverweb]

20. I'm just an old hippie...

... but I know just what to do.

LOL

:spank:

[HeresyLives]

2. Excellent news and interesting observation.

I hadn't noticed that before, but it's true now I think on it. Thank you.

[DeSwiss]

14. Yep.

- And it only took us around 8 or 9 thousand years to figure it out. We're geniuses!!!

[hlthe2b]

3. Would this be safe for aquatic life?

They mention it might be safer than dams and turbines, but seems they need to look at this a bit more closely.

[DeSwiss]

8. From their website....

Sunday, November 30, 2008
VIVACE (Vortex Induced Vibrations Aquatic Clean Energy)

A novel approach to extract energy from flowing water currents. It is unlike any other ocean energy or low-head hydropower concept. VIVACE is based on the extensively studied phenomenon of Vortex Induced Vibrations (VIV), which was first observed 500 years ago by Leonardo DaVinci in the form of “Aeolian Tones.” For decades, engineers have been trying to prevent VIV from damaging offshore equipment and structures. By maximizing and exploiting VIV rather than spoiling and preventing it, VIVACE takes this ‘problem’ and transforms it into a valuable resource for mankind.

Vortex Induced Vibrations (VIV) result from vortices forming and shedding on the downstream side of a bluff body in a current. Vortex shedding alternates from one side to the other, thereby creating a vibration or oscillation. The VIV phenomenon is non-linear, which means it can produce useful energy at high efficiency over a wide range of current speeds.


Vortex Induced Vibrations Oscillates Objects in Fluid Currents

VIVACE devices have many potential advantages, which improve installation survivability in the hostile underwater environment and enable low-cost power production by decreasing capital cost and minimizing maintenance.

* High energy density - permits low cost energy to be produced from relatively small installations - requiring up to 50 times less ocean acreage than wave power concepts.
* Simple and rugged moving parts - allows for robust designs that can operate for long periods in the underwater environment with minimal maintenance.
* Low dependence on ocean/river conditions - application of non-linear resonance permits useful energy to be extracted over a wide range of current speeds.

VIVACE and other renewable energy technologies also face regulatory hurdles. Again, VIVACE is advantaged by salient benefits over other technologies.

* Non-obtrusiveness - installations can be positioned beneath the surface, thereby avoiding interference with other uses, such as fishing, shipping and tourism.
* Compatibility with marine life - VIVACE utilizes vortex formation and shedding, which is the same mechanism fish use to propel themselves through the water.

Prototype, funded by the U.S. Department of Energy and the Office Naval Research, is currently operating in the Marine Hydrodynamics Laboratory at the University of Michigan. This device has met and often exceeded expectations; thereby, providing strong evidence to proceed to the next scale, a multi-kilowatt field demonstration.

http://www.vortexhydroenergy.com/

[gblady]

4. my sweet little uncle....

age 80 something, several years ago
had the concept to harness the tidal power...
complete with diagrams...
hand wrote to all his legislators and governer...
....nary a response.

[DeSwiss]

10. Four word$:

Oil, Hydro, Coal, Nuclear

- I meant five: Lobby

[sakabatou]

5. As long as the currents hold, this is good news

[DeSwiss]

12. Well, if the currents stop...

... I'd say we've have bigger problems.

[sakabatou]

23. MUCH bigger problems.

[ContinentalOp]

6. I worry about the environmental impact. Hydroelectric dams have the worst environmental impact,

depending on how you look at it.

[DeSwiss]

11. See above:

http://www.democraticunderground.com/discuss/duboard.php?az=view_all&address=389x4559668#4559716

[tinrobot]

7. Might work well in conjunction with other technologies

A rough calculation puts Los Angeles as needing a field of about 12x18km (7.5x11 miles) to run it's 1.2 million homes, and at least 4-5 times that much for the entire metro area. We're talking 300-400 square miles of ocean floor. Think of this as approximately the entire width and length of the 26 mile channel between Long Beach and Catalina.

That's a lot of ocean floor to cover, and the environmental impact of something that large would be noticeable.

But if this was used on a smaller scale in conjunction with solar, wind, and geothermal, along with increased efficiencies in building design... could be workable.

[DeSwiss]

15. I agree completely.

- Besides, it doesn't make sense to put all of our eggs into one basket. We need all "hands on deck."

[BlooInBloo]

9. Convince me it doesn't cost more to implement than the energy you're getting out of it...

and then convince me that it's a scalable solution, and you've got me sold.

[DeSwiss]

16. As for cost:...

...from the article:

Systems could be sited on river beds or suspended in the ocean. The scientists behind the technology, which has been developed in research funded by the US government, say that generating power in this way would potentially cost only around 3.5p per kilowatt hour, compared to about 4.5p for wind energy and between 10p and 31p for solar power. They say the technology would require up to 50 times less ocean acreage than wave power generation. The system, conceived by scientists at the University of Michigan, is called Vivace, or "vortex-induced vibrations for aquatic clean energy".

As to its scalability, it would seem to me that all coastline cities could benefit and those readily accessible to rivers. I wouldn't expect that anyone sees this as some kind of "silver bullet" where this is an end-all as opposed to other alternative approaches. And from http://www.vortexhydroenergy.com/">what I've read, it doesn't require energy inputs to create more energy other than those in creating and maintaining the devices. They are designed to simply react to the energy produced from natural wave motion and currents, as low as 1 mph, where hydro take 5 to 6 mph, and this technology's size comparable to existing wave turbine technology, is 50x smaller.

So rather than the energy simply dissipating naturally as it normally would, it is harnessed using this mechanical design, with lowly springs and cylinders -- and then transfers that energy into a grid of similar devices. The devices are tethered underwater allowing more normal use of the waterways. The article's title refers to the "potential energy" available using this technology. But obviously we would never want to rely upon a single source for our energy.

- Well, we all know where that can lead....

[BlooInBloo]

17. "would potentially"... "would seem to me"...

That's not convincing.


EDIT: Besides - being a little bit cheaper than something that's prohibitively expensive isn't really the best tack to take.

[DeSwiss]

21. Every idea starts out as only "potential" Bloo.

- Even the realities we use everyday, were once just somebody's possibility.

[BlooInBloo]

22. True that. And the vast majority of them go nowhere....

Hence there's little reason for excitement, until certain practical engineering hurdles have been *shown* to have been overcome. Not just "might be" overcome.

[Cleita]

13. Ocean currents affect the climate and migration of sea life.

I hope this isn't going to be like daming rivers. Dams are pretty destructive.

[DeSwiss]

18. It appears to me to be...

...the antithesis of a dam. Dams are huge obstructions (and often destructive as you mention) because they're designed to be. It's a necessary design for them to be able to create the levels of water pressure which will translate into 5 to 6 mph water flows, which is what is needed using current turbine technology. This is a totally different approach. These devices don't obstruct the natural environment, but rather sits within it and uses its natural wave and current motion, and then transfers the energy from that motion into an electrical grid.

The design discussed in the article and http://www.vortexhydroenergy.com/">here, state the devices are tethered, meaning they are suspended underwater and deep enough to avoid interfering with the waterway's normal uses. Dams suck all kinds of wildlife (and the occasional human) into the massive maws leading to the turbines to create the water pressures for constant electrical flows. We have them everywhere I look here in TVA land. These devices apparently don't generate any kind of motion or wave action themselves, so I don't see how that could interfere with the growth of vegetation, etc., and thus upset the natural food-chain cycles. But everything we do has some impact.

- But then, we're a part of the environment too. It'll be interesting to see where they go with this....

[bluesmail]

24. Time is running out. Hurry up world. n/t

[kentuck]

25. Hydroelectricity...

Been around since the TVA but this could expand the idea to our coasts and that would be the end of gasoline and Big Oil companies because we could then build electric cars and sell the excess energy back to a grid for a discount. Nightmare of all nightmares...we may see .99 per gallon for gasoline before this is over? :-)

[qwlauren35]

26. I Love the People Who Post These Threads.

They always inspire me, and it's so hard for people to start arguments over them.

They deserve every K&R.