Tidal Generators

[Nick1911]

So, there are generators that make use of the tides in the ocean.

Question:  Where does the energy that is pulled out of this system originate from?

For example... if we pull out x megawatts from the tides, are we pulling that much energy out of the rotational velocity of the moon?  Are the two linked?  Why or why not?

 

[never_retreat]

I think it might me a moot point. I think there would be so much force exerted from the mood that we could not slow the effects.
Think about it, do PV panels let less of the sun hit the earth and change the climate?

[Tallpine]

So, there are generators that make use of the tides in the ocean.

Question:  Where does the energy that is pulled out of this system originate from?

For example... if we pull out x megawatts from the tides, are we pulling that much energy out of the rotational velocity of the moon?  Are the two linked?  Why or why not?

 

Probably.  TANSTAAFL, etc 

Actually, everytime that NASA "slingshots" one of its probes around a planet, they are stealing just a bit of orbital velocity from that planet. 

Keep it up long enough and the solar system will implode 

Actually, there will probably be a Society for the Conservation of Angular Momentum (SCAM) start protesting pretty soon.  I just hope they have ads and posters with naked girls 

[AJ Dual]

Yep, a tidal generator is robbing a teeny bit of the Earth's angular momentum, but so are the tides. Which is why we have those leap-seconds they add every few years, and the moon pulls away about an inch a year.

[RaspberrySurprise]

Better pulling away than plummeting in.

[Jim147]

I haven't seen too many tides in this part of the country.

jim

[MicroBalrog]

I don't believe this hasn't been posted yet.

[grampster]

Which brings us back to the notion of having everyone in the world jump as high as they can at the same time.  The resulting loss of planetary weight would lower the cholesteral of the Erf.  That would be good, yah.  Gaia could then eat bacon again.

[CNYCacher]

Which brings us back to the notion of having everyone in the world jump as high as they can at the same time.  The resulting loss of planetary weight would lower the cholesteral of the Erf.  That would be good, yah.  Gaia could then eat bacon again.

Massive Sinkhole destroys Farmville Pig Farm

Those poor piggies.

[MechAg94]

Which brings us back to the notion of having everyone in the world jump as high as they can at the same time.  The resulting loss of planetary weight would lower the cholesteral of the Erf.  That would be good, yah.  Gaia could then eat bacon again.

Didn't the Chinese try the "everyone jump" thing?

[AJ Dual]

Didn't the Chinese try the "everyone jump" thing?

The "Great Leap Forward"?

[Tallpine]

Better pulling away than plummeting in.

IIRC, the lunar tidal pull on the earth's core is one of the things that keeps producing the magnetosphere, which protects us from deadly solar radiation and keeps the atmo from blowing away.

The two little moons of Mars OTOH don't have enough mass to stir the planetary core and produce a magnetic field.  Hence, Mars does not and never will have much air.

In theory, at least, a planet without a significant moon could not support life (as we know it) which sorta knocks down the chances of finding potentially habital planets even in other solar systems.


I don't understand why they don't put in a water turbine generator in or near the ship channel at Corpus Christi...?  Because of the Laguna Madre, the channel runs like a river pretty much all the time - six hours one way, six hours the other.

[Jocassee]

The "Great Leap Forward"?

De Great Reap Frorard

[AZRedhawk44]

http://inventors.about.com/od/tstartinventions/a/tidal_power.htm

French engineers have noted that if the use of tidal power on a global level was brought to high enough levels, the Earth would slow its rotation by 24 hours every 2,000 years.

The Earth would stall in 2000 years of tidal generation if the coasts were lined with them, according to Frenchies.

I assume it would then start spinning backwards?

But, no one would be alive to see it.  I'm not sure if the Earth would cook from being exposed to a solar day that is the equivalent of 180 of our current days, but I'm sure the dark side would freeze to death in that matching 180 days.  The seas on the dark side would freeze, probably wrecking the tidal generators every six months and the planet would be forever stuck in a flat rotation.

I have no idea how that might destabilize our orbit around the Sun or the Moon's orbit around us.  I lack the math power to figure it out.

[CNYCacher]

The Earth would stall in 2000 years of tidal generation if the coasts were lined with them, according to Frenchies.

I think they are saying we would lose one day over 2000 years.

[Nick1911]

The earth would slow it's rotation by 24 hours.... to me this says that we would have a 48 hour day.

[AZRedhawk44]

OK, that makes sense, Nick.

[CNYCacher]

OK, that makes sense, Nick.

The rotational energy of the earth is estimated at 2.14 ×10²⁹ J

To reduce the earth's rotational speed by half, you would need to remove 3/4 of the rotational energy, which is approx 1.50 ×10²⁹ J

Spread that over 2000 years and we have 7.5 x 10²⁵ J per year generated.

Convert that to kilowatt-hours and we have 2.0833 × 10¹⁹ killowatt-hours

Which is what you get if you use 2.37687773 × 10¹⁵ watts constantly night and day all year

Of course, we should spread that out to the 6 billion people on the earth

Does anyone think that the French were talking about EACH PERSON on earth using 396,146 watts of power CONSTANTLY for the next 2000 years.

[AJ Dual]

Yes, we'd lose 24 hours, (one day) total over 2000 years if every coastline were extracting tidal energy at 100% effiency.

So instead of the rough 1/4 second we lose a year to normal tidal friction from the oceans, and the Moon/Sun, the day would grow roughly 43 seconds longer.

Solar and Lunar tides does help keep the Earth's mantle and core molten longer, however the main reason Earth maintains it's molten state and magnetosphere is our larger mass and volume, which meant more heat retained from Earth's accretion/formation, (which then reset and started all over again later than Mars did when Earth got blown apart to produce the Moon, then re-collapsed again...) and a larger proportion of radioactive elements/decay which also adds to the heat.

Mars cooled quicker and lost it's Magnetosphere because it's only about 10% the mass of the Earth. About half the diameter, at a lower average density, with a higher proportion of Silicates and less Iron, and presumably less Thorium/Uranium too.

All of which contributed it to it's mantle and core cooling much faster than Earth's did.

Due to it's smaller size, and quicker cooling, Mars had maybe a Billion year, to at least several hundred million year head start over Earth on forming an atmosphere and liquid water on it's surface. Meaning that the first microbes on Earth may actually have been transplants from Mars blasted off on rocks that achieved Martian escape velocity fropm comet and asteroid impacts.

[RevDisk]

Yes, we'd lose 24 hours, (one day) total over 2000 years if every coastline were extracting tidal energy at 100% effiency.

So instead of the rough 1/4 second we lose a year to normal tidal friction from the oceans, and the Moon/Sun, the day would grow roughly 43 seconds longer.

Am failing to see bad part.

Uh...  Negatives, negatives...   It's not nuclear power?

[MicroBalrog]

PACER is shinier.

[AJ Dual]

Am failing to see bad part.

Uh...  Negatives, negatives...   It's not nuclear power?

It's like the windmills. Net energy gain when you factor in ALL aspects of construction/erection of the system, and before mechanical breakdown/maintenance energy gets spent reducing your actual net gain... it's got to be BIG to get to that point quickly. So now you're building something mechanically complex like a windmill, but now you want it to operate underwater for years.. decades at a time with minimal maintenance. (Think about how often ships need maintenance/dry-dock on their keels and screws...)

It's like solar, most systems don't really start "earning", energy or economically, until 20-25 years have passed. At which point efficiency is starting to degrade, and odds of storm/hail damage approach better than 90%.

Pacer... That the underground h-bomb and molten (salt?) rock to make on-demand geothermal scheme? Is this around the time of "use nukes to dig Panama Canal II" or later?

The ability to mass produce kiloton-range fusion bombs cheaply is kind of scary in a geopolitical sense. Especially if you do so figuring out how to avoid using much in the way transuranics and tritium as your trigger. That might be a better use for Orion though, rather than just going all fission. The ability of third parties or rouge nations to make Lithium Deteuride is probably greater than it is to refine U-235 or Pu-239, so lowing the bar for the need of the heavy elements and tritium though economical H-bomb designs is probably not smart.

[CNYCacher]

Pacer... That the underground h-bomb and molten (salt?) rock to make on-demand geothermal scheme? Is this around the time of "use nukes to dig Panama Canal II" or later?

Maybe there's a way to control the nuclear explosion, maybe slow it down, and extract the heat from it to generate power.   

[Nick1911]

Maybe there's a way to control the nuclear explosion, maybe slow it down, and extract the heat from it to generate power.   

When you figure out how to make fusion do that, call me.   

[AJ Dual]

Maybe there's a way to control the nuclear explosion, maybe slow it down, and extract the heat from it to generate power.   

You could just gather a whole bunch of Hydrogen together until it collapses under it's own gravitation fusion is initiated, and then just receive the energy by orbiting about it.