Ocean Current Energy

[Gardamorg]

While ocean currents move slowly relative to typical wind speeds, they carry a great deal of energy because of the density of water. Water is more than 800 times denser than air, so for the same surface area, water moving 12 miles per hour exerts about the same amount of force as a constant 110 mph wind. Ocean currents thus contain an enormous amount of energy that can be captured and converted to a usable form. It has been estimated that taking just 1/1000th the available energy from the Gulf Stream would supply Florida with 35% of its electrical needs.

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[Moontanman]

Ok, how do you suggest we tap this energy?

[CraigD]

Originally Posted by Gardamorg

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Pretty good website .

A google custom search for “ocean current” shows we’ve discussed this quite a lot at hypography. Despite some odd claims there, my favorite discussion was in “Underwater Suspension Tunnels Prevent Global Warming”.

Originally Posted by Moontanman

Ok, how do you suggest we tap this energy?

As shown at the linked website and many linked from hypography threads, there are a lot of ways to generate power from ocean or tidal current. None of them are especially unconventional, resembling wind turbines and similar in principle to the hydroelectric generators common in large dams.

A major challenge, regardless of the generator design, is transmitting power it to where it’s needed, and practical issues such as maintaining the generator and transmission machinery. The strongest, and therefore best, ocean currents are many kilometers offshore, far from consumers. Underwater power transmission cables, while not uncommon, are more expensive and less reliable than above ground or land buried ones. And, obviously but often overlooked, many major power consumers are far inland. Unlike fossil fuel, nuclear, or other land-based powerplants, you can’t put ocean or tidal current generators near these places. So ocean current generation poses nearly as great transmission challenge as generation.

As with most alternative power sources, the real challenge for systems like this are to be cost competitive with conventional systems. This post has some rough cost estimates for supplying 100% of US electric power from ocean current hydroelectric generators, bottom line: $10 trillion.

[Moontanman]

I wonder how much of an ocean current can be disrupted by energy collection and not affect the weather? It was stated that 1/1000 of the gulf stream energy could be used to provide 35% of the energy use of Florida. What I wonder is how much of the energy of the gulf Stream could be used before the weather patterns of the North Atlantic begin to be affected? Even .001 of the flow could be enought to affect weather patterns.