How much power output is needed to be feasible?

[fletcher]

One of the simplest ideas I've had along similar lines is to anchor a pontoon [sliding up & down on poles so it doesn't drift] - then on the ocean bed place a concrete anchor block with a pulley - attach a cable from the bottom of the pontoon & pass it down thru the pulley & on to a shore based geared generator [this would need a return spring or some such to wind in the cable at low tide] - a series of these buoyancy machines might be quite effective at generating electricity as long as it was stored for later use i.e. not on demand supply - just thoughts - alternatively turbines protruding from the hull of the boat/pontoon that turn in the current & are able to change direction [can't remeber the name but tug boats use this sort of drive] - have seen this same idea on the free energy page linked to this site.

Damming off an estuary or bay would be far more problematic but you would have much greater volumes of water to use - trouble is that on average around the world there would not be much head height to allow the kinetic energy of the falling water to build up & turn a turbine, in the traditional way, so you'd need lots of sluce pipes etc & lock gates etc.

[utilitarian]

Hey, thanks for the support "all!"

I didn't say it was the typical "free" energy setup like most of the other ideas in this category. I have a few simple technical design ideas that make it unique but the basic principle is using the ocean tides. 1 cubic meter of water equal 1000Kg of weight. If you drop that 2 meters  and lift it back up 2 meters once a day (really it would be twice most days) then the math would work like this "I think".

1000Kg x 2m(down) = 2000Kgm

2000Kgm x 10 N = 20,000N

20,000N = 20,000J

20,000 x 2m (up) = 40,000J

40,000J =  11.11 Watthours

It might cost billions of dollars but I believe most damns pay themselves off in the first few years. Also, where I live it averages 6+ feet up and down a day and in Alaska some places have 50ft tides twice a day.

Tim

Fritznien, so it would really have to be 100 million cubic meters of tidal water movement needed to equal a Nuclear power plant?

Ah, reminds me of that old joke.  How much does one cubic meter of Chinese soup weigh?  One ton.

Anyway, I think tidal power is great.  You can get energy both coming and going, mind you, so don't forget that in your design. You can read about the largest such tidal generation system currently in use here.  It may give you some ideas.

http://en.wikipedia.org/wiki/Rance_tidal_power_plant

[fritznien]

Hey, thanks for the support "all!"

I didn't say it was the typical "free" energy setup like most of the other ideas in this category. I have a few simple technical design ideas that make it unique but the basic principle is using the ocean tides. 1 cubic meter of water equal 1000Kg of weight. If you drop that 2 meters  and lift it back up 2 meters once a day (really it would be twice most days) then the math would work like this "I think".

1000Kg x 2m(down) = 2000Kgm

2000Kgm x 10 N = 20,000N

20,000N = 20,000J

20,000 x 2m (up) = 40,000J

40,000J =  11.11 Watthours

It might cost billions of dollars but I believe most damns pay themselves off in the first few years. Also, where I live it averages 6+ feet up and down a day and in Alaska some places have 50ft tides twice a day.

Tim

Fritznien, so it would really have to be 100 million cubic meters of tidal water movement needed to equal a Nuclear power plant?

no it would take many many times that. i forgot to divide for 24 hours in a day and you have conversion lose in making electricityand a nuke plant runs 24/7. so your customers have to use something else
when your system resets or changes direction. don't forget dams are used for peaking power and thus get top dollar. also most dams also double as flood control and irrigation not just power.
to pay for itself yours would have to produce enough power to pay the interest on the money to build it
its an old old idea that was used to mill grain in the past..
fritz

[nwman]

I have seen that article about the largest tidal generator. Clever, but it doesn't seem that effect and has large environmental impact. It would be almost better if they were to just build a man made pond and keep fish and what not from entering it. There are a lot of places that have land that is only a few feet above sea level.

I really have no reason to keep my design secret. Its probably already been done. What gave me the idea is years ago in High school was seeing these large cargo ships and aircraft carriers being tossed up and down by the tides as if they are not even there. That's millions of pounds of steel just being tossed up and down.

The idea is to simple make a large water displacement vessel that is anchored to the sea floor with large pillions and then attach large hydraulic rams from the vessel to the pillions. With hydraulic ratios you can relatively gear it down so that you can utilize every ounce of potential energy possible. You can harness both the up and down motion. There would be no moving parts in contact with the salt water. It could be made of concrete or steel. Which ever is cheaper. And you could possibly make lots of small ones or one large one that looks like an island (even plant trees on top).

Environmental problem would be limited. The biggest problems would be the drilling into the bay or ocean floor which is only a temporary problems because it would create a large reef, and the light displacement onto the sea floor below it. If this is a big enough problem then it would be possible to redirect the sunlight through the floor of the vessel. It really shouldn't be too large of an impact on the current flow which if it did could cause large environmental impact.

Now the other problem proposed is that it would be limited to the tide movements and not on demand. Well yes and no. There are some days when there is little tidal movement but most days there is a lot. You could actually calculate exactly how much power will be produced every day for the next several hundred years because they can calculate with in inches the tidal heights. Also, how said the vessel would have to move with the tides. If the tide is low and is starting to rise then simply don't let the vessel rise as fast as the tide until you need the power. It will relatively hold the potential energy until you need it or until the tide starts to move in the opposite direction. Also, by prolonging the movement slower then the tides you can produce power even during the time the tides are changing direction. Besides days that don't have a lot of tidal movement this design should be able to produce consistently on demand.

My state (WA) is mostly powered by one damn. The grand coolie. Though it would me massive it seems you could build a simple water displacement vessel equivalent in ratio to the water that flows though the grand coolie every day. Not to mention again that in Alaska the tides can move 50 up and down twice a day.

The real question is simple the cost and environmental impact compared to other power production. Nuclear is the best idea but its still creating a long term problem (waist). It doesn't effect us now and my not for hundreds of years but what will happen in a few hundreds years?

Anyways, it just an idea.

Tim