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Tidal energy is not renewable

cs.stanford.edu

11–20 of 350 posts

Re: Tidal energy is not renewable

#11
post #2

> ... if we were to extract the rotational energy just to supply 1% of the world's energy consumption, the rotation of the Earth would lock to the Moon in about 1000 years ... and most life on Earth could be wiped out. Important safety tip.

But is it possible to extract that much energy from the tides with current techniques? That starting point in their math may be invalid. But it is good to know that not very much energy is available from the tides.

Re: Tidal energy is not renewable

#13
post #3

Then technically neither is wind, since it slows down surface air currents and widens the effective boundary layer of the atmosphere. Technically-technically, no forms of energy "generation" (technically just conversion) are 100% efficient so something is always lost to heat. I guess the important question is, what is the net effect in changing that kind of energy into purely thermal energy?

Air currents have a purpose, and I actually believe large scale wind farming will have negative impacts on climate. Not to mention the impact on birds killed by the things. I would even go as far to say nuclear energy has less of an impact (as long as all goes well).

The question few seem to ask is should we be this (literally) power hungry in the first place?

Re: Tidal energy is not renewable

#16
> So, the 2% growth rate for world energy consumption should be a conservative assumption.

An important caveat: this article assumes that energy consumption will continue to increase exponentially to get the 1000 year timeline of draining the rotational energy of the Earth.

Re: Tidal energy is not renewable

#18

Neither is fission.

How is fission not renewable, when one can literally make more of the material in the right type of reactor?

> one can literally make more of the material in the right type of reactor?

Until one runs out of the feedstock one is using to make more fissionable material. You're not recycling actually burned fission fuel. You're making more fission fuel out of isotopes that don't fission at all.

Re: Tidal energy is not renewable

#19
post #2

> ... if we were to extract the rotational energy just to supply 1% of the world's energy consumption, the rotation of the Earth would lock to the Moon in about 1000 years ... and most life on Earth could be wiped out. Important safety tip.

But is it possible to extract that much energy from the tides with current techniques? That starting point in their math may be invalid. But it is good to know that not very much energy is available from the tides.

If its not possible then we really shouldn't be very interested in it because it can't get us very far, 1% is a rounding error towards solving the CO2 PPM causing climate change.

Re: Tidal energy is not renewable

#20
Can someone with more experience in the field comment on whether this paper is well founded or off base?

The abstract sounds... lets go with "not completely implausible" but the assertion that extracting 1% of the Earth's energy from the tidal sloshing would slow the earth and tidally lock it in 1000 years feels extreme. Of the extreme assertions require extreme evidence variety.

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