Ocean-Powered Electricity?

It all boils down to economics. There are two components to the cost which have to be considered: The cost of the energy itself (fuel, sunlight, tide, etc.) and the amortized cost of the plant necessary to derive this energy.

In the case of solar and tidal, the energy is free, but there is still the cost of building and maintaining a windmill or a tidal power system. You have to look at the total cost to compare the alternatives.

There's also the economics of the delivery systems if the infrastructure isn't already established, like the running of power lines and other things that come with it.

No we don't. Often due diligence is a hindrance to progress. If nobody tries new technology then stagnation will happen.

Don't get me wrong. Small scale, test projects with no expectation of profit should blaze the trail for expansion, miniaturization or scraping an idea as a noble failure.

I like that idea Red. Who would fund a small scale test project with no expectation of profit except the government or an educational institution, which is synonomous with government funding? I believe in that premise, I am just wondering why it is acceptable to you in this guise?

Oh I see, a bias is showing. While there are about four times more public than private K-12 schools in the US they certainly are not all government funded institutions. I hope I don't need to post a citation to persuade you that there are many privately funded colleges. As for who would fund a small scale test project, why any business that wants to stay ahead of the competition will want to fund a small research project. (Isn't that right Mr. Musk and Mr. Branson.)

As for myself, I find it very odd you believe my premise but want me to explain my reasons for believing my premise. I don't know how to answer that contrary paradox with anything but dismay.

The paradox you present is there for anyone to see. You find it odd that I would want you to explain the reason you believe in a particular premise? It happens a lot in my company; I believe it is common among excellent organizations.

I will start. Mr Musk and Mr. Branson have committed significant funds to research, that is true. They are exemplary, especially because space exploration is so exciting. The research they performed cannot hold a candle, however, to the amount and quality of work that NASA has completed. It is therefore, an inferior methodology, if your goal is progress. If your goal is to let billionaires run the research zoo, you get what you get, and what made us so great ain't happening nearly as often.

So you propose that only the majority methodology should be attempted. But a majority of anything implies that there should be a minority approach. You cannot have Yin without Yang.

Besides that bit of Zen, the paradox that stuns me is asking why I believe my premise exists when I already offered two examples.

If you refuse to listen, I will be silent.

Good Bye

I never proposed that only the majority methodology should be attempted. That logic is a bit sophmoric. We do not get to where I want to be by condemning government roles to trash collection, or scientific development to billionaires. I don't know if you and I want to get to the same place. I think we do.

OK, I'll give you that. Sometimes you have to gamble, especially if you're rich, on an idea that may or may not work. You can analyze just so much, but when you try it out, it may be better or worse than your analysis showed. There's nothing wrong with test projects in the name of research.

I realize it is of no practical consequence, but purely from a theoretical point of view, I'm curious about the statement that tidal turbines would eventually slow the rotation of the earth. My question is whether we would be increasing the energy transfer from the earth's rotation with the tidal turbines, or would that energy, if not captured, just be dissipated elsewhere from the tides pushing against a shoreline. (It's possible that the energy transfer would be less "efficient", and so would slow the earth's rotation less, i.e., energy removal at the tidal station would result in even more energy not being removed at the shoreline.)

If the earth were completely inflexible, or if it were made of a frictionless fluid, there would be no tidal drag to slow it down. (Energy = displacement x force.) Somewhere between these two extremes there is a maximum energy transfer. Also somewhere between these two extremes is the current reality, and the question is whether the tidal power plants would shift that reality in the direction of the maximum or away from it.

It's somewhat analogous to capturing sunlight with solar panels and using the energy that will eventually turn to heat, or just letting the light hit the ground and turn to heat immediately. The amount of energy derived from the sunlight would depend on how much the solar panels absorbed compared to the ground underneath. (In this case, it's a simple matter of measuring the reflectance, much easier than analyzing the tidal problem.)

I agree. This is an inaccurate theoretical extrapolation from the author. I believe the point they were trying to make was the magnitude of the energy taken by this process is minimal compared to how this energy naturally gets dissipated.

As for the theoretical question, will this energy harvest produce a net speed up or slow down of the Earth's rotation? I believe the unknown orientation of the shore line will determine this. The magnitude of the effect will be many orders of magnitude smaller than any measurement uncertainty that I'll be amazed if anyone can measure it.

Slowing of the Earth's rotation adds 2 ms to each day every century. (Source)

The Earth suffers from tidal braking due to mechanical losses in the Earth-Moon system. Significant energy harvested from tides would increase this effect, however unlikely or unnoticeable. (Source, Source)

Tides on the earth are composed of two components, due to the moon's gravity and the sun's gravity, with the moon's gravity causing the majority. (The tidal attraction falls off as the cube of the distance, giving the moon more influence.)

Tidal friction due to the moon's gravity increases the length of the day and lengthens the lunar month. Tidal friction due to the sun's tide increases the length of the day and increases the length of the year.

Angular momentum is conserved. The angular momentum of the earth's rotation is being transferred to the angular momentum of the earth-moon system (raising the moon's orbit, increasing its period) and to the sun-earth system (raising the earth's orbit, increasing the length of year).

Would it be possible to have forward-reverse flow turbine but with a single angular direction? Has anyone seen such?

The problem with air is, it damps more than water--> this is true if no one opposes.

You might want to check to see if a valve could be made that allows a flow in only one direction.

I mean that one. You see, air move forward and reverse. I wonder how they manage to get one shaft direction in the turbine.