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Power Earth Science Technology

Harnessing Slow Water Currents For Renewable Energy 113

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 Slow Water Currents For Renewable Energy

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  • by macraig ( 621737 ) <> on Saturday November 22, 2008 @11:39AM (#25857779)

    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)

      by Anonymous Coward

      my *other* leaky faucet

      Have you tried this? []

    • A much better idea would be a toilet turbine which would harness the power of water and gravity to flush. Any fan designed to generate energy from piss would cause quite a mess.
  • Secondary effects? (Score:5, Interesting)

    by Vellmont ( 569020 ) on Saturday November 22, 2008 @11:40AM (#25857793) Homepage

    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?

    • by canthusus ( 463707 ) on Saturday November 22, 2008 @11:51AM (#25857859)
      IANAFM also, but yes, I'd expect to see slower water, as we have extracted energy from it. With care, this need not be a bad thing - 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. Erect a vortex generator instead of groins and you can control flow and generate electricity. Downside is it may become too successful, and the silting could interfere with operation.
    • Re: (Score:2, Insightful)

      by Felix Da Rat ( 93827 )

      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)

        by maxume ( 22995 )

        "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)

          by sumdumass ( 711423 )

          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

          • by maxume ( 22995 )

            Draw some boxes. From the point of view of the water, these devices decrease the drop in elevation.

            (That is, if a given stretch of river has the effect of adding 1 unit of energy to 1 unit of water, with the devices installed, that same stretch of river will add less than 1 unit of energy to that same unit of water)

            • Draw some boxes. From the point of view of the water, these devices decrease the drop in elevation

              Well, no because the water is moving and you have to consider the weight of the water behind the point where your box is at. This will cause the water to rise until it reaches a point equal to behind it. So if you put the boxes under the water, instead of stopping the bottom third of the of the river from flowing and theoretically taking one third of it's energy, the water level will just rise above it causin

          • They line them with concrete spikes and riffraff...

            Is that what they do with petty criminals these days? Soylent erosion control is People!

            Oh, you meant "riprap" [].

            See my sig - you're in violation!

            • Actually, riffraff was the spellchecker's auto-correct. However, it seems to have been close enough for you to get the idea. Thanks for pointing it out.

              Maybe it wouldn't be such a bad Idea to use certain criminals in that way. Maybe standing knee deep in much silt screens during the rains would teach them the value of hard work. Maybe I'm just being a little too hard on them.

    • by sdpuppy ( 898535 ) on Saturday November 22, 2008 @12:11PM (#25858015)
      Sounds like the energy is taken from eddy and vortex currents which, for the most part, is lost energy anyway (destructive interference) and don't add to river currents anyway.

      If it works (both technologically and financially) , it's brilliant - harnessing energy that would be lost anyway.

      • Re: (Score:3, Insightful)

        except that it would induce additional vortex currents around the device.
        • Except that the mechanisms that cause the rivers to flow wouldn't disappear, gravity would still have an effect and the energy would be regained relatively shortly. The water wouldn't weight less and start moving uphill/upstream.

      • by arth1 ( 260657 )

        There is no such thing as lost energy. The vortices are only manifestations of the symptoms, and not the end results.
        If the energy isn't used to give the water momentum, it will increase the temperature of the water.

        By tapping into the energy of the water, you will either make it move slower, become colder, or both. This may, depending on where it is tapped, be perfectly safe. But then again, it may not be. The question is whether there are any politicians who would stop a multi-billion dollar project b

        • Not sure I understand how the water becomes colder. Can you explain?
          • by arth1 ( 260657 )

            Simplified, water can carry energy in two forms -- as kinetic energy or as heat.
            By "making the water colder" I mean that if you take out an amount of energy, and you don't reduce the kinetic energy of the water by doing so (like you do in a normal turbine), the end result /must/ be that the water is colder as a result. So "making it colder" is really another way of saying "prevent it from using that energy to make itself warmer".

            In effect, if you used 100% of the energy you take out of the water to heat it

        • Re: (Score:3, Informative)

          by instarx ( 615765 )

          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

      • Sounds like the energy is taken from eddy

        ... and this is sofa is it?

      • Re: (Score:2, Informative)

        by ldbapp ( 1316555 )
        The energy is taken from the vortices, but it's not free or otherwise lost energy. Without the cylinders in the water, the vortices would not exist. The cylinders induce them, thus converting the forward flow of the water into a form that can be harvested.

        So you are not harvesting energy that would be lost energy; you are harvesting the energy of the flow.
      • Now harness the energy of the water coming down my gutters.

      • Where does that energy go normally? Into heat? I mean, energy can't really be lost so it must go somewhere.

    • Oceans, Not Rivers (Score:5, Insightful)

      by Doc Ruby ( 173196 ) on Saturday November 22, 2008 @12:12PM (#25858027) Homepage Journal

      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.

      • Re: (Score:1, Interesting)

        by Anonymous Coward

        I can see a use for this in rivers as well, especially in the last few hundred miles.

        Currently, there are plenty of rivers that have to slow down the waterflow near the banks to maintain the deep summerbed. Replacing whatever structure there currently is with the "fishes" sounds like a nice experiment.

      • by maxume ( 22995 )

        Most big dams are installed for flood control. That they simplify irrigation is a nice side benefit.

        Also, note that the article specifically mentions installing them in rivers, especially if they are more fish-friendly than turbines.

        • Re: (Score:3, Informative)

          Most big dams are installed for flood control. That they simplify irrigation is a nice side benefit.

          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.

          • by maxume ( 22995 )

            Not exclusively, but that is generally the chief benefit that the government is looking at. Look at the events in this timeline (the Hoover and Southwest seem to exemplify your point):


            They include both the control and use of the river, but there weren't enough people living in that area at that time for water storage to be an issue, the big motivator was disaster control (and if you are going to make a huge reservoir, it simply makes sense to inst

        • by instarx ( 615765 )

          Nooo. Many are, but a lot of dams are built for energy production. The TVA system being the prefet example.

      • 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

      • Actually no. If you read the fine article they mention that it would work with river flow with a flow speed of 2 mph. If you follow along to the website there are papers that describe the system and equations with very straight forward math. Essentially, most any eddy producing system could apply here.

    • Less flow, less oxygen and less other nutrients (and therefore less life) in the water seem like obvious side-effects.

    • by Ex-MislTech ( 557759 ) on Saturday November 22, 2008 @01:36PM (#25858587)

      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: []

  • That's very interesting and promising that ocean areas can be tapped for energy, I hope that it's not environmentally destructive and that it doesn't provoke international conflict over who gets to use which ocean sectors.
  • SeaQuest DSV (Score:1, Interesting)

    by Anonymous Coward

    They implemented a global underwater power grid in the SeaQuest television show (from the 90's). There's some interesting technology in that show. It's on Netflix/Roku for immediate viewing.


  • by Doc Ruby ( 173196 ) on Saturday November 22, 2008 @12:02PM (#25857951) Homepage Journal

    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.

  • The Æolian Harp (Score:4, Interesting)

    by Doc Ruby ( 173196 ) on Saturday November 22, 2008 @12:07PM (#25857987) Homepage Journal

    This technology works the same way as Davinci's "aeolian harp", as immortalized in The Æolian Harp [] by Samuel Taylor Coleridge:

    The Æolian Harp

    My pensive SARA ! thy soft cheek reclined
    Thus on mine arm, most soothing sweet it is
    To sit beside our Cot, our Cot o'ergrown
    With white-flower'd Jasmin, and the broad-leav'd Myrtle,
    (Meet emblems they of Innocence and Love !)
    And watch the clouds, that late were rich with light,
    Slow saddenning round, and mark the star of eve
    Serenely brilliant (such should Wisdom be)
    Shine opposite ! How exquisite the scents
    Snatch'd from yon bean-field ! and the world so hush'd !
    The stilly murmur of the distant Sea
    Tells us of silence.
            And that simplest Lute,
    Plac'd length-ways in the clasping casement, hark !
    How by the desultory breeze caress'd,
    Like some coy maid half-yielding to her lover,
    It pours such sweet upbraiding, as must needs
    Tempt to repeat the wrong ! And now, its strings
    Boldlier swept, the long sequacious notes
    Over delicious surges sink and rise,
    Such a soft floating witchery of sound
    As twilight Elfins make, when they at eve
    Voyage on gentle gales from Faery-Land,
    Where Melodies round honey-dropping flowers,
    Footless and wild, like birds of Paradise,
    Nor pause, nor perch, hovering on untam'd wing !
    O ! the one Life within us and abroad,
    Which meets all motion and becomes its soul,
    A light in sound, a sound-like power in light,
    Rhythm in all thought, and joyance every where--
    Methinks, it should have been impossible
    Not to love all things in a world so fill'd ;
    Where the breeze warbles, and the mute still air
    Is Music slumbering on her instrument.
            And thus, my Love ! as on the midway slope
    Of yonder hill I stretch my limbs at noon,
    Whilst thro' my half-clos'd eye-lids I behold
    The sunbeams dance, like diamonds, on the main,
    And tranquil muse upon tranquility ;
    Full many a thought uncall'd and undetain'd,
    And many idle flitting phantasies,
    Traverse my indolent and passive brain,
    As wild and various, as the random gales
    That swell and flutter on this subject Lute !
            And what if all of animated nature
    Be but organic Harps diversly fram'd,
    That tremble into thought, as o'er them sweeps
    Plastic and vast, one intellectual breeze,
    At once the Soul of each, and God of all ?
            But thy more serious eye a mild reproof
    Darts, O belovéd Woman ! nor such thoughts
    Dim and unhallow'd dost thou not reject,
    And biddest me walk humbly with my God.
    Meek Daughter in the Family of Christ !
    Well hast thou said and holily disprais'd
    These shapings of the unregenerate mind ;
    Bubbles that glitter as they rise and break
    On vain Philosophy's aye-babbling spring.
    For never guiltless may I speak of him,
    The Incomprehensible ! save when with awe
    I praise him, and with Faith that inly feels ;
    Who with his saving mercies healéd me,
    A sinful and most miserable man,
    Wilder'd and dark, and gave me to possess
    Peace, and this Cot, and thee, heart-honour'd Maid !

    • First, I was wondering if fish ought to file a class-action lawsuit if the inventor tries to patent it. After seeing this, though, it might be more effective to bring a lawsuit by resurrecting Davinci as a zombie.

  • by mangu ( 126918 ) on Saturday November 22, 2008 @12:11PM (#25858009)

    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.

    • by owlnation ( 858981 ) on Saturday November 22, 2008 @12:28PM (#25858151)

      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.

      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.

      • Ppl can use boolean expressions to help find what
        they need so they do not need to code
        for lack of knowledge in searching.

        see ... AND, OR, NOR, etc etc

        A good portion is built right into their advanced
        search features: []

      • Re: (Score:3, Interesting)

        by xant ( 99438 )

        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

        • by argent ( 18001 )

          I think the worst example of this is probably ".NET". How do you search for that? "dotnet"? "" works pretty well for their own site, but most references to ".NET" are standalone, and you have to try mixing in other keywords like "windows".

          At least with "There" you can search for their domain "", because people seem to refer to it that way in self-defense.

          • by xant ( 99438 )

            > in self-defense

            True dat. There are lots of reasons for that self-defense, too, not just ambiguity in language.

            People are acutely aware of what constitutes a good name and what doesn't, even if they don't really think about it. "Gimp" ain't it. "there" ain't it. "string of unpronounceable consonants" ain't it. "FCKEditor" ain't it. Since we have this problem in meatspace, I see nothing inherently broken about the fact that we also have it on the Internet.

            • by argent ( 18001 )

              Yah, but if a company's named "Bland" you're still going to be able to find it in the Yellow Pages. It's when you want to find who's having problems with "Bland" in Google that you're in trouble. Doesn't matter whether Bland's a brand of muffler or mp3 encoder.

              The Internet turns all the knobs to 11.

              • by dkf ( 304284 )

                The Internet turns all the knobs to 11.

                Except for the ones it turns to 0.

          • by Repton ( 60818 )

            .NET -- a new technology brought to us by the company that introduced COM. In 2015 Microsoft will introduce its successor framework, ORG, and Google will give up in disgust.

        • by dkf ( 304284 )

          Suppose "what you want" is to name your project "The".

          Reminds me when I was googling for an eatery called "This and That" a few years ago...

        • I think an easy solution in this case is to give capitalization some weight. Is it fully capitalized? Then treat it like an acronym. Is it partially capitalized? Give business or project names more priority than if it wasn't capitalized. Nobody I know is going to capitalize a simple noun, like "music", so "MUSIC" shouldn't be treated the same way.

          Then again, I got mad when I switched my web page from a Windows server to a Linux server, and none of my links worked because I used to capitalize all my ima

        • Is there some way Google is going to find that when someone wants to learn about "The"?

          Yes: a much better page analysis engine, which could understand a little bit of language structure(*), just enough to be able do detect from the context when "the" is just this very frenquently occuring english word (and doesn't need to be taken into consideration), and when the structure of other words around it tend to say that it is a different word which is important (an acronym).

          Note that currently Google is able to somewhat do this already. Type in "who" and you get relevant answers (Wolrd Health Orga

      • by hey ( 83763 )

        Google should be case sensitive.

    • Why would you want to search for acronyms. I immediately found it when I was googling for "Vortex Induced Vibrations for Aquatic Clean Energy".

      No, seriously, there must be a better way. Something not involving 3 trillion acronym's. Thought about something along the line of using human understandable sentences. In this case for example it could be something like "Weird looking generator for slow currents"
      • Strange. Was aiming to make that sentence an irony, but after making a quick Google search with it actually showed VIVACE as first hit.
  • by Anonymous Coward

    Why not put these things in the city sewage pipes and harness the power of the flush

  • Burning oils found in the earth - Yeah I can understand how that'd be bad for the environment
    Stealing raw energy from water or air - Couldn't this be even worse for the environment?

    Just because it's 'clean' and doesn't create any byproduct doesn't mean the earth is gonna be O.K. with it? Even solar energy, as long as the panels to collect are on earth, are disrupting the natural state of things (better then asphalt though)

    Solar panels in space, is the only 'clean' energy that would have no effect besides ma

    • by MR.Mic ( 937158 )

      Solar panels in space, is the only 'clean' energy that would have no effect besides maybe blocking the view of Sol from far away systems.

      Except that you're piping energy, which eventually turns to heat, directly to earth.

      There is no energy transfer that can happen which does not affect change in any auxiliary connected systems, no matter how minuscule the change.

    • Solar panels warm the planet. Here is something to annoy and confuse the Greenies: The only way to cool the planet is to build desalination plants (or build nuclear plants with distilled water as a byproduct) and irrigate the deserts. We can turn the vast deserts of North America green which will cool the world. However, in order to do so, we must have higher levels of CO2 :)
      • We "must" have higher levels of CO2? Really? And desert irrigation is the only way to cool the planet? I am skeptical.

        Solar panels warm the planet how? By increasing the amount of sunlight striking the Earth's surface? I think you may be mistaken there.

        • What better way to cool the planet than to green the deserts? We don't currently produce enough food for the whole planet, so creating lush landscapes in barren deserts seems like quite the solution for our many problems. Think jobs, economy, agriculture, feeding people, cooling the planet, solving the fresh water crisis... and yes, plants need CO2 for food. If we green the deserts we will need higher levels to support them. Now, imagine you cover the deserts in solar panels instead. Darker colors retain
          • What better way to cool the planet than to green the deserts?

            Yes, that's what you should have said. It's a good question, and outside my ability to answer. However, to say that it is the only way to cool the planet is highly misleading.

            We don't currently produce enough food for the whole planet.

            That appears to be incorrect. []

            Your arguments run counter to themselves. "If we green the deserts..." "Darker colors retain heat." So by that logic, we should leave them as deserts so to better reflect the sun's heat.

            Solar cells are designed to convert sunlight to electricity, not heat. An efficient solar cell will not add heat to the

            • Your response is well written, but you are wrong. For one you are comparing an inorganic solar panel to a living tree. Trees cool the atmosphere by releasing water vapor. I do not agree with you that solar panels will cool the planet. Only living, carbon absorbing lifeforms will do that (short of dumping dangerous chemicals into the atmosphere).

              You linked old data... current food prices are declining and growers are cutting back production in protest (sorry can't link it at the moment). Additionally, tra
              • Water vapor is a greenhouse gas [], it does not cool the planet. Inorganic materials have been shown to absorb carbon dioxide. If employed on a large scale it would reduce the levels of atmospheric carbon, thus cooling the planet. It would probably not be cost-effective and is almost certainly not the right way to go about things, but that certainly dispels the notion that plants are the only thing that can cool the planet.

                Dark things absorb solar radiation and re-radiate it as heat. Solar panels absorb solar

  • Haven't we done enough damage without slowing down the earth's oceans?

  • I'd wondered before if something like the windbelt ( would work in a small stream or river. You would have the same constant flow over the belt, and I'd guess it would create the same oscillations (though probably not as much). I'm not an engineer, just curious.

  • I'm on the edge of a good wind zone, so investing in a classic wind generator for my yard would not have a good roi, but something like this would be wonderful, especially since the shapes sound like they might be aesthetically pleasing and perhaps the entire device would be quieter...

    I want one in my yard!

  • A few alternatives (Score:3, Interesting)

    by ishmaelflood ( 643277 ) on Saturday November 22, 2008 @05:25PM (#25860023)

    Self rectifying water turbine, always turns the same way even if the water flow reverses []

    and if you really want fishy like motion then []

    The thing is enormous - 50 feet high, generating 300 hp. Full size proto is under construction.

    • I wonder how well these things would deal with seaweed. The Cetus design says it's "weed shedding" - can't imagine it working real well in an area with alot of seaweed though.
  • Why doesn't anyone use water wheels anymore? They work on gravity alone, not water speed, right? (At least the "water goes into a bucket on the wheel from the top of the wheel" type.)

    Are/were they just too inefficient?

  • All of us known that these is a convert of one form into other. Not thing really get generated!

    When you wast energy by let the appliance do nothing, you slow down the current, the wind, and harm the environment!

    Please stop those stupid thinking! Please do not practice wastful life and yall to protect the environment.

    The Green Movement have been the big harm to the world, especially when people start to act to change the environment in the name of protection!

    We should not feel guilty by wanting a better life

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