Technology to generate power from slow moving river and ocean currents

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Chris Connors of MAKE has a post about "a new way of generating electricity with the slow moving currents found in most of the rivers and oceans of the world." (Video here.)

VIVACE 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 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.

VIVACE stands for Vortex Induced Vibrations for Aquatic Clean Energy. It doesn't depend on waves, tides, turbines or dams. It's a unique hydrokinetic energy system that relies on "vortex induced vibrations."

Ocean currents can power the world, say scientists

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  1. Despite the picture, the articles talk about vertical cylinders being drawn up and down by the vortices created by water flowing past. This is not completely unreasonable and potentially eliminates the “magnets and expensive breaky bits under water” problem.

    You have to be careful when talking about “vortex energy”. While there are real, measurable vortex effects to be found all around us, and these have been harnessed empirically for centuries (when turbines were first introduced, millers found that round leets could cause their turbines to spin more efficiently, which was at the time mathematically inexplicable) there’s also a lunatic fringe of vortex fanatics who believe that Marconi and Tesla are alive and living on Mars where they are fighting Hitler’s space-alien allies using zero-point vortex energy. Seriously. You can be having a perfectly reasonable conversation with somebody and then you mention vortices and whizzzzzz! the loony juice comes spurting out.

  2. I feel like there are new prototypes of these kinds of generators coming out every week. But why do we only ever hear about them when they are in prototype stage? Do any weird and new generators ever get out of the lab and start providing meaningful amounts of power?

  3. My questions come from a place of relative stupidity about these kinds of power sources (i.e. wind and water). Perhaps someone can help me out.

    One of the Laws of Thermodynamics essentially says, You Can’t Get Anything For Free, so doesn’t stuff like this effectively disrupt (or decrease) the effects and power of ocean currents? Couldn’t that screw things up down the line?

    I mean, let’s say I put a Stick in the ocean at point A, and without anything intervening, the currents will transport it to point B. Now, if I put something that “harnesses the power of the currents” in the middle of the A-B pathway, wouldn’t the Stick only make it to 75% of B? Or end up along a different trajectory, arriving at point C?

    So, if we cover the ocean floor with these generators, doesn’t that mess up all the current oceanic processes? Currents aren’t where they used to be, that screws with temperatures, and animal migrations, and ship routes? Is it not enough to make a difference? How do we know?

    So many questions!

  4. #2 SamSam

    Even nuclear (fission) reactors never really worked out. If you sneak inside the containment building all you’ll find are a bunch of people in sweaters rubbing balloons on their chests with one hand on the grid.

  5. @ #3 Cheekan.

    Technically, yes, you’re correct, the energy *is* being removed from the surrounding fluid. This is the same as with wind turbines as well. If the amount of energy removed was sufficient, it *could* engage undesirable effects down the years. The dividing line is the proportion of the amount of energy that was being removed from the system to the total estimated amount of energy present – on this there’s no clear answer, only guesses and estimations in that it’s a highly non-linear dynamic system where direct proportionality of cause and effect don’t apply cleanly.

    However, to give a sense of the scale, it is estimated that the total amount of kinetic energy in the atmosphere at any one point in time is roughly 7.5×10^20 J, and in the oceans, of which knowledge is less confident, an estimate in the order of about 10^17 J. Yearly energy use of the world could be said to be about 10^19 J. So feasibly, if we tried to rely solely upon these renewable sources, it would most likely result in climate energy cycle problems. Realistically, however, given that about 2.5×10^23 J of sunlight energy strike the earth’s surface every year, it would be possible to diversify energy extraction methods so as to avoid any dire complications in any one area.

    Great question by the way.

    [Source: the estimates are via Bent Sørensen’s tome “Renewable Energy: It’s Physics, Engineering, Environmental Impacts, Economics, and Planning” ISBN:0126561532]

  6. Three questions:

    1. Why are we talking about this now? The original news was from Nov 2008/Jan 2009. Have there been new developments or something?

    2. Has anyone actually produced a functioning prototype / functional production ready…thing? Where can I see this thing actually produce electricity?

    3. If said prototype/product exists, is it reverse scaleable? I.E. Could we create small working versions of this and put it in streams / creeks in backyards across the planet? (Could a small device be plopped into a backyard creek, and then used to charge batteries used to power a small outbuilding like a garage?)

  7. I wonder if these things could also be installed in city sewers? I also think it would be good to investigate capturing energy by water that flows down skyscrapers

    i.e. water for toilets, sinks, etc is pumped to the top of an 80 story building, could all the grey water drain into one central shaft that has a chain driven turbine at the top and bottom of the shaft that has buckets that sit at each floor. When there is enough weight in the buckets (especially on the top floors) the chain ‘unlocks’ the weight of the buckets pull the chain, turn the turbines and tip the grey water into the sewage system below as they pass the bottom turbine and head back up? I’m not sure if this would produce much power at all, but perhaps it could.

    1. As an example, the Chrysler building is 77 stories, with about 1.2 million square feet of office space. An average office cubicle is 100 square feet, I’ll guess that accounts for 1/3 the area (the rest is hallways, common space, etc.) So I’d estimate about 4,000 occupants.

      Assuming 12,000 flushes a day (three per person per day) and 2 gallons per flush (low-flow toilets are around this level) and averaging the height of the toilets at 450 feet (about mid-way to the top floor).

      Doing the math, at a pint per pound the world around (pre-metric) that’s 12,000 flushes * 2 gallons * 8 pounds * 450 feet or about 86 million foot-pounds. At about 0.0004 watt-hours per foot-pound, I come up with about 33 kWh per day. I’m paying about 10 cents per kW-h, so it’s about $3.30 per day, or just over $1,000 per year worth of energy. About 25 cents worth per person. I’m sure a skyscraper would be paying less than the residential power rate.

      I did a similar a while ago to see if I could harvest any significant energy as water fell from my roof to my rain barrels, sadly, it was negligible energy.

  8. This isn’t a half-bad idea actually. Anyone who’s been sailing can tell you if you get anything (seaweed, loose line) stuck on your rudder, you’ll know it immediately due to the vibration in the tiller/wheel. Most sailboats move between 3 and 5 knots, although with enough surface area you should be able to coax a flat surface to vibrate enough to generate electricity.

  9. I’m afraid I can’t post a link because this is from CoEvolution Quarterly/Whole Earth Review a long time back (maybe BB pal Kevin Kelly remembers it):

    A set of airfoil-shaped “wings” on a chain, driving a pulley/generator combo – worked in any kind of slow flow, supposedly.

  10. @ #5 Treq

    Wow, that was a fantastic answer! Thanks for being so thorough, it helped put the whole thing in context.

    It seems safe to say, then, that solar power, being “external” (at least in the sense of outside of the planet) is the place where we have the most to gain in terms of energy utilization. Certainly, there’s room in the others, as you mentioned, but man, if we could just harness that sun up there….

    Thanks again for answering a question I’ve had for a long time!

  11. Am I the only one that thought “this is such a simple design, how come nobody thought of it before?”

    Then I got to erosion, surely creating a current full of conflicting forces like this is gonna have some effect on the riverbanks right? (as cheekeen, I’m way outside my area of expertise so sorry if I sound a bit dumb)

  12. The sad fact is slow moving means low energy. There’s a reason we dam up rivers to harness energy, the higher the water the more speed it picks up when falling into turbines and the more energy we get. It’s the old e=mc2, speed is an essential component. Many energy project fantasies are ignoring this fact.

  13. I had a career as an Aeronautical Engineer for 60 years and my last project was developing the Giromill wind energy turbine that was tested by the Department of Energy at Rocky Flats, CO. I also developed and tested a river current turbine, called the Aquagiro, in the Missouri River. The biggest problem we had to contend with was floating debris like whole trees during flood stage. My problems and test data has been published.

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