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Harnessing Slow Water Currents For Renewable Energy
Posted by
Soulskill
on Sat Nov 22, 2008 11:16 AM
from the hydroelectric-for-those-who-won't-give-a-dam dept.
from the hydroelectric-for-those-who-won't-give-a-dam dept.
Julie188 writes "Slow-moving ocean and river currents could be a new, reliable and affordable alternative energy source. A University of Michigan engineer, Michael Bernitsas, has made a machine that works like a fish to turn potentially destructive vibrations in fluid flows into clean, renewable power. This is is the first known device that could harness energy from most of the water currents around the globe because it works in flows moving slower than 2 knots (about 2.3 miles per hour). Most of the Earth's currents are slower than 3 knots. Turbines and water mills need an average of 5 or 6 knots to operate efficiently. Further details and a few brief movies of the technology are available, as well as a video explanation by Professor Bernitsas himself."
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Harnessing my leaky faucet? (Score:3, Funny)
I wanna harness the slow water current of my leaky faucet to trickle-charge my laptop; can I do that? If that works, I'll move on to trying to harness my *other* leaky faucet.
Re: (Score:2, Funny)
Have you tried this? [4flomax.com]
Secondary effects? (Score:5, Interesting)
I'm not a fluid mechanic, but I wonder what the effects would be of slowing down already slow moving river water. Increased silt deposits? More flooding upstream? Anyone with more knowledge about river flows care to comment?
Re:Secondary effects? (Score:4, Insightful)
Parent
Headlines. (Score:5, Funny)
- for example, groins have been constructed on parts of the Thames to slow the water near the banks, encouraging scour of the main shipping channel
Has there been any ship collisions with those. If so was there a headline like this?
Ship hits Thames in groin.
Parent
Re:Secondary effects? (Score:4, Funny)
Erect a vortex generator instead of groins and you can control flow and generate electricity.
Yes, but you completely ignore the benefits of erecting groins.
Parent
Re: (Score:2, Insightful)
From the look of the system, there wouldn't appear to be too much slow down. Probably about on par with tossing a reasonably sized rock into a stream.
Of course, it's a matter of scale. One rock? not much impact, but throw to many in, and you have a dam. So I think the impact this system would have depends most on how much power it generates and how many can be fit on a given body of water before having a damming effect.
Re: (Score:3, Insightful)
"A damming effect" would never be a problem, the slower the water is moving the less energy available for extraction, so you would stop installing them long before the water stopped moving. I would guess that capital return rates would convince investors to stop installing them long before environmental impact became a significant problem.
Re: (Score:3, Insightful)
Are we all forgetting what caused the water to move in the first place? I mean the last couple of comments sort of act like this is a car on flat land coasting and we are talking about hitting the brakes every once in a while or introducing obstacles to slow it down. Imagine the same but with the car constantly coasting down hill.
Gravity is forcing the waters motion. It is going from one place that is higher to another that is lower in elevation. You have other factors like force and so on to consider but s
Re:Secondary effects? (Score:5, Interesting)
If it works (both technologically and financially) , it's brilliant - harnessing energy that would be lost anyway.
Parent
Re: (Score:3, Insightful)
Re: (Score:3, Informative)
The Colorado River at Phantom Ranch averages 80,000 ft3 of water per second, or 2.4 x 10^9 cc. The energy that would have to be extracted to cool that water by 0.001 degrees C would be 2.4 x 10^6 calories.
2.4 x 10^6 calories = 10^9 joules.
watts = joules/second, so that would be 10^9 watts, or 1 million kilowatts/second would be extracted. Now that's a lot of power for a 1/1000 degree temperature drop.
Another way to look at it is that it would take a million kilowatts to heat 80,000 ft3 of water 0.001 degre
Oceans, Not Rivers (Score:5, Insightful)
This device targets ocean currents, not rivers. Ocean currents already have too much energy (by historical comparison), accumulated in twistier undersea currents from the decades and centuries of escalating Greenhouse effects.
River current power is what is captured by hydroelectric dams. Which have their own problems, but we're already stuck with them. More ocean hydroelectric could allow us to release some dams that have too high a cost (environmentally or operationally) to justify their power output. Though application of these generators in rivers might just be a low-impact replacement for dams. However, the dams also deliver irrigation and drinking water, so we're probably stuck with them for the long haul.
Parent
Re: (Score:3, Insightful)
while you're probably right in that this technology will be most useful by extracting the vast amounts of energy contained in the ocean (absorbed solar energy) it will likely be deployed in a lot of rivers as well. in fact, the video mentions that the pilot project is being built on the Detroit River. so it's not just coastal cities who are going to benefit from this technology.
i think it's interesting that this technology is expected to be much more cost-effective than conventional solar power. and the abi
Re: (Score:3, Informative)
That may be the case where you live but here in the the western U.S., the majority of dams have been built for water storage purposes, followed in number by dams built for generation of hydropower. Relatively few have been built exclusively for flood control; I can think of a couple in the Los Angeles area and that's about it.
Less of everything really (Score:2)
Less flow, less oxygen and less other nutrients (and therefore less life) in the water seem like obvious side-effects.
Re:Secondary effects? (Score:4, Informative)
Water runs down hill due to gravity, once it is passed the device
it will return to its prior speed.
The water does not get and keep its speed from its headwaters.
It varies based on the grade as it moves downstream.
In an ocean, it is not due to grades is more about thermal
differential due to the ocean heating the water.
It might have an impact there, but some of the current
contain flows that are many times the flow of all the rivers
in the world.
Like the Antarctic Circumpolar current:
http://en.wikipedia.org/wiki/Antarctic_Circumpolar_Current [wikipedia.org]
Parent
Doubling the Global Warming Reduction (Score:5, Interesting)
Replacing petrofuels (and even their waste heat) with this alternative generator would help slow climate change from the eliminated petrofuel waste.
But there's a vast amount of energy already retained in the Earth's oceano-atmospheric system. Vast rivers of undersea currents now store truly huge amounts of energy newly accumulated since industry's byproducts started the Earth retaining more energy. Undersea currents have grown much twistier in their paths around the globe. When that energy cycles through the interconnected systems on its own rhythms, the energy is sometimes transmitted into other media than seawater, that is much more disturbed by it. This is what the El Nino / La Nina cycle is an instance of: energy from heavy sea currents periodically enters the much lighter air, pushing it around much more. That kind of cycle, in a myriad of other such interactions, contributes to larger and more frequent storms.
If we harvested some of that energy from these currents with these new devices, we would be reducing the energy in those currents. The currents would return to their previous less twisty tracks. They would have less energy to transmit to the atmosphere and other climate engines. It would take a very large scale deployment, over a substantial period of time. But the double benefit would be well worth it.
Re: (Score:3, Informative)
hmm except that I'm reading it now and it says Interesting... so I'd say the moderation system works just fine - only not on a short timeline. It's like looking at an election vote too early... maybe only the no votes happened to be counted first... doesn't mean the voted on item won't pass later.
The Æolian Harp (Score:4, Interesting)
This technology works the same way as Davinci's "aeolian harp", as immortalized in The Æolian Harp [virginia.edu] by Samuel Taylor Coleridge:
That acronym is so 1980's... (Score:5, Interesting)
FTFA: "VIVACE stands for Vortex Induced Vibrations for Aquatic Clean Energy"
There was a time when creating an acronym that made a real word was considered cute. Those were the days of the "ESPRIT" (Estimation of Signal Parameters via Rotational Invariance Techniques) and "MUSIC" (MUltiple SIgnal Classification) algorithms.
All that is in the past. These days, acronyms should Google well. Google for VIVACE, MUSIC, or ESPRIT and you'll get page after page of irrelevant sites. Scientists should try to name their projects with unique names, names that will let interested people search the web and *find* their projects.
Re:That acronym is so 1980's... (Score:5, Insightful)
No. No. No. Scientists, and anyone, should name things what they want, and Google should make a considerably higher effort to make search work MUCH better than it currently does. This just shows you how bad search is, and far it has to go. Google needs more competition.
Parent
Re: (Score:3, Interesting)
And how is Google going to do a better job of searching? Magically discern your intent from the keywords you typed in? Keywords is all we have. Make your keywords better.
Suppose "what you want" is to name your project "The". Is there some way Google is going to find that when someone wants to learn about "The"? A search for the project's name would be completely useless, and no UI change or smarter algorithm is going to fix that as long as you search by typing into a text field. What a searcher would
Re: (Score:3, Insightful)
Hey I agree with you. I've been trying to get someone to do a weighted search for a long time... no takers... I'll have to do it myself. Works like so:
Put in two words... tell the search engine that the second word is WAY more important, ie: Bass (+0) + Fish (+10)
What you should get back is a whole lot of pages about Fish where Bass is the actual keyword within that subset. Almost works like a category. Really it's multiple searches... first a search for the highest rated keyword, then a second search withi
A few alternatives (Score:3, Interesting)
Self rectifying water turbine, always turns the same way even if the water flow reverses
http://www.cetusenergy.com.au/action.php [cetusenergy.com.au]
and if you really want fishy like motion then
http://www.biopowersystems.com/biostream.php [biopowersystems.com]
The thing is enormous - 50 feet high, generating 300 hp. Full size proto is under construction.