The magic of ocean currents is that they surround every continent on Earth and they run all day, every day. That's what sets this energy source apart from wind, solar, tidal, or wave—all of which are cyclical, meaning that during certain periods they don't produce power.
The ocean-current generator we're planning to build would float 100 to 200 feet below the sea surface. The device is a 65-foot-diameter cylinder shaped to speed up water flow, with propeller blades attached to its frame. As water flows through, it strikes the blades and spins a rotor, which generates electricity. A 17-foot center opening would allow animals to pass through unharmed. We estimate that in the Gulf Stream, a few miles offshore from West Palm Beach, Florida, the five-knot current would turn the blades about eight times per minute, generating about a megawatt of power.
We are designing the turbine to steer itself into the best current so that it generates maximum power, which is principally why our small submersibles manufacturing group, Triton Submarines, is involved. To make the turbine float, we'd create it partly out of syntactic foam, a buoyant material that we can shape easily but won't collapse under high ocean pressures. The device would be tethered to the seafloor with a cable and adjustable straps that lengthen or shorten to move it in response to onboard water current, depth, and power output sensors.
The cable would then transmit power to a seafloor junction box, which would boost the voltage, convert it from AC to DC, and send it to a collection and distribution center onshore. In the future, we imagine an array of anywhere from 15 to 50 generators working together.
Our goal is to produce a $5-million device, which could pay for itself in five or 10 years. With funding, we could have our first working model within a year.
—Patrick Lahey, president of Triton Submarines in Vero Beach, Florida. (Eaton Corporation is handling the electrical transmission, and Eclipse Group leads deployment and maintenance.) As told to Flora Lichtman
Im kinda confused as to how this isnt supposed to kill a bunch of fish...
A 17 foot opening between where the blades meet sounds good but I still wonder how many fish are going to get maimed in the almost 50 foot blades (I assume because no one really states how long the blades are... The cocktail napkin they scanned in does no justice to this idea).
One dolphin gets killed and the eco nuts will have it shut down.
I'm kind of confused on how it won't at least maim marine life as well. Also, how long do they last? What are the long term effects on the ocean currents they are to be placed in?
I wonder it holds up seaweed and barnacle growth and how maintenance able it will be too?
I don't get the confusion. The article plainly states that they expect it to rotate approximately 8 times per minute. If we round up to 10 rotations per minute, that is still 6 seconds per rotation. The diameter is stated to be 65ft for a circumference of 204ft, so the blades will move around 23 mph at its fastest speed on the outer edge, to around 6 mph near the 17 ft center opening.
But that isn't the whole story. This isn't a fan blade being turned by a motor, which churns and chops through the water. The rotation is being generated by the flow of the water itself, of which the fish would be a part of and so would at most be pushed into the flat of the blade and not impacted by the edge as it and the water column pushes by. Even in a worst case scenario, if one did get edgewise at the outside of the turbine, it may be bruised from a 23 mph rotational impact, but certainly not "chopped up". That is assuming of course, that the dolphin a previous poster mentioned(not a fish btw)which can swim faster than 23mph doesn't simply swim out of the way.
Oh yes, that 23 mph number is after I rounded up to 10 rotations per minute. Given the 8 rotations in the article, it would be closer to 18mph. Usain Bolt has been clocked at just over 27 mph for a comparison.
A turbine cost of $5M/MW is almost 3-times the current cost for commercial wind turbines. Can't see how this concept would make economic sense.
The issues against the turbines are pretty much irrelevant, yes with a $5 million price set for the first ones the initial price is high for the amount of energy produced. The cost of production will come down after produce is in full stride and open them up to be commercialized. The environmental impact will not be as substantial to the native life as previous comments had suggested. Huckleseed is right about all of the facts about the underwater turbines. The only problem I have is that they plan on converting for AC to DC power at the underwater junction box and the transferring it to an onshore source. The lose of energy could be quite substantial since the turbines will be fairly deep and far away from the onshore facility. The gulf steam core that I have read about being utilized is about 250m below the surface and I am assuming that it will be off the shore to ensure that safety measures and depth can be met.
Not much growth at depths without sunlight (ie; barnacles). This system would work in tidal regions as well. While global tide streams may be constant, they are as some have said, very far from the end user so losses are a factor. IMO spend more time figuring out tidal generators instead.
This reminds me of a Pop Sci cover illustration from the 80s. I like the cheap mooring and kite-like tether, instead of the usual submerged-windmill design, but shrouded turbines are only popular for high-speed or space-limited designs. A pure tension tube might work underwater, but usually the material is better added to the blades. Hubless designs are always more expensive and problematic. Bob Stuart
A simple funnel made from mesh or netting could be constructed to route the sealife through the 17 ft opening. Any sealife that swims against the current, into the blades probably was too stupid to live much longer anyway.
Yeah, I think I remember seeing this in the late 70's or early 80's. If it hasn't happened for the last 30+ years, why is it going to happen now?
These work better and restore our climate back to 300ppm which will restore our Northern summertime Arctic Ice extent/mass...
I was wondering if you have the generation and transmission of power mislabeled. Normally A/C issued is used for transmission of power over long distances not D/C. Can you please clarify.