Effective way to harvest power of ocean currents

Using strong ocean currents for power generation

Anyone that ever played on the beach with one of those plastic mills knows that water is a much better medium than air to make it go. A little bucket of seawater made that thing go. Blowing didn't do much. Also it's quite common in the world to generate power by building dams with large artificial lakes behind it and at the bottom of the dam where the water is released you generate power.

This in fact was already economically viable for years. Even when not many cared for CO2 emissions. Only downside is that you need to create these large lakes and that means sacrificing large areas of often build up land.

So to me it seems more obvious to use the currents in the ocean to generate power than to build windmills in that same ocean.

There are even some initiatives in doing this. They include....submerging windmills. To me that seems a bit strange. I guess if you ask a carpenter to build a car you get a wooden car.

One of the reason that the hydro-dams were and are successful is that they concentrate the power. As a result you don't need a large amount of turbines to generate the power. One will generate enough. Building a dam in the ocean, however, is not such a great idea.

There is a much simpler idea that only a tent-like construction, anchored to the ocean floor on one or two places.

A picture explains much more:

I know I'm not good at drawing. But this about the principle. One cable is to keep it in place. The other is to raise and or deploy it. Just like with a sail on a sailing boat. And the whole system hangs on large buoy.

By making the part that catches the water wide and going narrow in the end (close to the water turbine) you get a very strong current. All you need now is the water turbine to turn this into electricity.

This entire system can be build on land, transported to the right place and then simply deployed. If due to the strong currents that gets a bit difficult, the concentrator could have on the seems something like a big zipper. That way the deployment can be done with little pressure. And when its in place, close the seems and the pressure will build.

The OCS site talks about maintenance. My idea is really cheap in maintenance. All you need is a ship that docks the floating part, and does the hauling up. Release the turbine and load it into the ship. And replace it with a 'new' turbine. Then inside the ship or on shore, the maintenance and repairs on the turbine can take place in a dry environment. Same for all the other parts. The most difficult part to deploy is the anchor.

I believe this system is simple, easy to build and deploy, and generates much more power.

I do think though that it is necessary to place a net in front of the concetrator to prevent sea animals to end up in the turbine. The smaller ones get through but they are likely to just wash up at the other side. Maybe they end up a bit confused.

Advantages:

- lightweight construction

- nearly fully build on shore (except for the anchors)

- easy maintenance

- can be made mobile (i.e. for military purposes)

- high power yield

- cheap

Disadvantages

- has a bigger impact on the currents and water flows then the other solutions.

Of course there are more ways to do this. You can even use multiple generators that don't even surface or hang on buoys, such as in the example below:

That way, entire farms can be build below the water, not interfering with shipping etc. In the above example hauling the generators up for maintenance gets a bit more work though.