[Boerseun]

There's a lot of ideas for alternative energy, like solar panels and windfarms.
The issue I have with these is the obvious - the sun sets every day, and the wind isn't constant either.
So how about building a huge turbine, giving it vanes so it'll always be presenting itself head-on to the stream (like a windmill), attach it with cable to a heavy weight to anchor itself and chuck it in the sea where there's a decent current? This turbine can be constructed from light, strong, non-eroding materials like a carbon sandwich, and due to the enormous torque presented by the ocean current, you can connect it to a generator with a high-ratio step-up gearbox. The whole unit can be sealed, and the powercable delivering power to the grid can be laid along the seafloor so as not to experience strain from the current.
Harvesting energy from the ocean currents is in fact using solar energy, but there's a lot more torque and power to be tapped than using windfarms - and it's non-polluting, and out of sight.
I can't see this approach being expensive at all, and an array of these spread along the coastline should be able to deliver a fair amount of power to the grid.
Any comments?

[C1ay]

Reminds me of this article a bit.

Your idea would require more than an anchor though. If you have water current driving a turbine that rotaional energy will create somewhat of a counter-rotational torque on the housing that contains it so that housing would need a torque arm to prevent rotation. If the output of the turbine is connected to a load that resists rotation, like a generator driving an electrical load, the translated torque will be even greater requiring more of a torque arm. By the time it were finished I think you would end up with a regular hydro-electric dam in the ocean. That may work to provide some energy but you must also consider that fluid with take the path of least resistance. If the water can go around the dam with less resistance then it will.

[Boerseun]

Originally Posted by C1ay

Reminds me of this article a bit.

Your idea would require more than an anchor though. If you have water current driving a turbine that rotaional energy will create somewhat of a counter-rotational torque on the housing that contains it so that housing would need a torque arm to prevent rotation. If the output of the turbine is connected to a load that resists rotation, like a generator driving an electrical load, the translated torque will be even greater requiring more of a torque arm. By the time it were finished I think you would end up with a regular hydro-electric dam in the ocean. That may work to provide some energy but you must also consider that fluid with take the path of least resistance. If the water can go around the dam with less resistance then it will.

If you have a flat, broad base to the turbine housing as it is suspended at an optimal depth where the current is strongest, and you link both end of the base to the anchor, rotational torque shouldn't present too much of a problem - and you'll have large vanes ensuring the turbine housing will have the right attitude towards the current.
As for the issue with taking the path of least resistance, sure - but the same is applicable to air, and windmills seem to work fine.
Yes - I suppose you could liken it to a hydroelectric dam, except that no damwall is needed; we just drop a couple of turbines in the stream and tap the solar energy trapped in the ocean currents.

[Boerseun]

...coming to think of it, you could have two counter-rotating turbines on one housing. That should cancel out any rotational torque on the anchor-mounts.

[C1ay]

Originally Posted by Boerseun

...coming to think of it, you could have two counter-rotating turbines on one housing. That should cancel out any rotational torque on the anchor-mounts.

That would work. Coupled with wave energy the yield could probably be pretty significant.

[Tormod]

I think we are already trying out wave turbines on the Norwegian coast, but I am not sure about the details.

Here is an interesting product, though:
http://www.wavedragon.net/technology/specifications.htm

[UncleAl]

Your thinking is contaminated by Enviro-whiner propagandistic swill. The simple solution to "renewable" power generation is to line the shores of every body of water and river with

http://math.ucr.edu/home/baez/physic...ippy_bird.html
http://sci.vu.edu.au/~drw/dippybird/Dippybird.html
http://nicholnl.wcp.muohio.edu/Dingo...kingBird1.html
http://www.backstreet.demon.co.uk/od...nkingbirds.htm
http://www.thedrinkingbird.com/
http://www.physlink.com/estore/cart/...inkingBird.cfm
http://bednorzmuller87.phys.cmu.edu/...s/demo531.html

As the beam pivots it drives a generator. The technology is perfected and out of patent. Was that so hard? (top hat optional)

[Tormod]

Lol!

[Boerseun]

Once again, I am humbled: Uncle Al indeed rules the known Universe. Here we sit and speculate about potential power sources, and Uncle Al comes to the rescue. I mean - a hydroelectric scheme of any sort would look kinda stupid with a top hat on, but with these dippy birds we can make it not only aesthetically pleasing, but fun as well!

Coming to think of it, I saw a dippy bird ages ago in a shop display in Newcastle, and I could never for the life of me figure out how it worked. These are a couple of handy links, Meister Al!

[C1ay]

A specially modified dippy bird does not even need water to operate, just the sun.