The highest tides in the world occur in Minas Basin, in Nova Scotia. The total height difference is on average 12 meters (39 feet), but reach as high as or higher than 16 meters (52 feet). For those of you who don't know, that is very big. A lot of water can fit into something the size of the Minas Basin in that 52 feet different of tides.
Now, current tidal stations are passive; they only can collect worthwhile energy when the water is really moving. Plus, while tidal generators can tap the power of the tides, there is currently no really efficient way to store electricity. So enter the Minas Basin Tidal Power Generators.
Not specifically based in the Minas Basin, but possibly, these generators are built anywhere with high tides. What they do is something special. They store tidal energy at 100% efficiency. They are the perfect battery. It begins with a wall. It ends with a large flat place in the back, several intakes, and an ocean at the front.
When the tide is at its highest, the wall to this massive generator is lowered, allowing water to flow into the intakes, and raising the water level inside to rise. If built in the proper place (say, the Minas Basin) you can fill up the entire generator with 50 feet of water.
And considering that more water flows through the Minas Basin every tide than does water through every river on Earth each day, this is a lot of water to be talking about.
Let's pretend the generator covers a square mile of water. That means at 50 ft tides (Minas Basin...) we will get 1,449,676,800 cubic feet of water. In comparison, the Amazon River discharges about 408,240,000,000 cubic feet daily, and the Amazon is 20% of the world river output. And the Minas Basin tides happpen every 12.5 hours.
So, if we let the water flood inside and fill it to 50 ft, and close the intakes, what do you have? A square mile pool of water 50 feet above the ground. That is a LOT of potential energy.
Now to the flat area part. You have either a) Another mile square walled off area, on water, unaffected by tides, or b) behind another big wall, to the back, a large square-mile flat are walled off on land.
If in water, this unfilled part is where the water will go. Every low tide, the out-takes are opened, and the flat part is emptied of all water. And then the out-takes are closed.
What does this give you, you may ask? It gives you a way to control the trillion and a half cubic feet of water that is 50 feet above the surrounding area. Whenever you need energy, let some water from the high-tide trap trickle into the low-tide trap through some turbines. Every high-tide, the high-trap is filled, and every low-tide, the low-trap is filled.
Energy expense is neglidgeble, aside from building, and opening/closing intakes and outtakes.
So viola! Tidal energy, when you need it!-- DesertFox, Apr 19 2006 Minas Basin Tides http://www.valleyweb.com/fundytides/(They can't change meters to feet properly, they think it's 36 inches per meter, it is 39) [DesertFox, Apr 19 2006] Minas Tide Table http://www.mobilege...dar/month/3799.htmlShows around around 13 to 15m for April 2006 [Ling, Apr 20 2006] Two-basin power plants http://en.wikipedia...r#Two-basin_schemes [david_scothern, Apr 20 2006] Minas Basin Tides https://www.tidesch...County/Minas-Basin/Shows a 13m difference between high and low tides! [RyanJ, Jun 15 2019] Summary - a two mile square tidal trap split into two parts, the high-trap and the low trap; On high-tide, the high trap is filled, and on low-tide, the low-trap is emptied.
When water collects in the high-trap, and the tide lowers, the height of the water in the high-trap remains the same. To use the energy, let it flow through turbines into the low-trap, which is emptied every low-tide.
Constant, huge amounts of energy, if placed properly, in a place like Minas Basin, Nova Scotia with 50 ft tides.-- DesertFox, Apr 19 2006 100% efficiency? *Nothing* has that.
But if you're using tidal power to "charge" your battery, that doesn't really matter, since you've got plenty of energy to spare.-- DrCurry, Apr 19 2006 What I meant is it has 100% storage efficiency; <Zaphod-ish> gravitational potential doesn't change, baby! </Zaphod-ish> Well, actually, here it GAINS, because the moon swings around and add more during low tide.
Of course its not really 100% transfer, you have to take out energy for tidal to mechanical to electrical transformations, but for storage purposes, it is pretty durn close to 100 %. It's all gravitational potential, which doesn't wear down unless you remove part of the planet.
Oh, I forgot to say, if you want to calculate total gravitational potential energy, take the height and divide it by two, as it needs the average height.-- DesertFox, Apr 20 2006 Tidal power worries me. The energy has to come from somewhere. We could be storing up huge problems for our great great great...great grandkids by changing the mooon's orbit.
Aside: would taking energy from the moon increase or decrease its orbit?-- egbert, Apr 20 2006 //egbert// Earth's rotation is very slowly decelerating, the moon is picking up the energy, and slowly moving into a further orbit. Very, very, very slowly, mind you. I don't think you could mess with the tides enough to cause any trouble.-- sleeka, Apr 20 2006 Unless I am mistaken, messing with the tides would not change the mass of the Earth at all and shouldn't change the orbit of the moon one whit.-- 2 fries shy of a happy meal, Apr 20 2006 <Caused by the resonance effect of the cavity, played against the continental shelf.>
Would damming off some of the bay increase the resonant frequency, and change it from 13hrs to nearer 12hrs25mins? If so, the tidal change would be bigger.-- Ling, Apr 20 2006 This is baked (see link).-- david_scothern, Apr 20 2006 Hello, [RyanJ], I didn't see you come in (but situational awareness was never my strong point).-- pertinax, Jun 15 2019 So, maximum energy available per tide cycle is 1.4x10e9 cubic feet of water, over 25ft (the average height difference, with some juggling). In real units, that's 4 x 10e10 kg over 8m, so the available energy is mgh = 3.2 x 10^12 Joules.
Spread over 12 hours, that's only 74MW of continuous power.
I think the surface area is bigger than your estimate, but even if it's 10-fold bigger, that's still less than a GW continuous power output.-- MaxwellBuchanan, Jun 15 2019 random, halfbakery