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Tidal energy is not renewable

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Re: Tidal energy is not renewable

#71

Post by btilly »

jval43 wrote: post #5
uoaei wrote: 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?

Isn't wind created by temperature and pressure differentials between regions? How much is due to earth's rotation?

A lot.

Look up Hadley cells. https://groups.seas.harvard.edu/climate/eli/research/equable...

Warm air rises near the tropics, rotating with the Earth. It then goes towards the temperate zone, still rotating with the Earth to form the jet stream. It then falls, creating the trade winds as it slows down. It then is sucked back towards the tropics, creating a reverse trade wind because it is only going as fast as the temperate zone. And then it rises, completing the cycle.

The prevailing wind in both temperate zones and the tropics is therefore due to the Earth's rotation.

Re: Tidal energy is not renewable

#72

Post by bbor »

toomuchtodo wrote: post #34
JumpinJack_Cash wrote: post #26

Earlier quoted context omitted.

That better be the case , we are already seeing that if the pie can't grow then we start fighting each other violently to enlarge one's piece of it.

Conflict over scarce resources is inevitable. When the violence starts, you should be prepared to win (from a nation state perspective). https://news.ycombinator.com/item?id=37122796 | https://www.mdpi.com/2673-4060/4/3/32 https://news.ycombinator.com/item?id=37313586 | https://medium.com/@samyoureyes/the-busy-workers-handbook-to... https://overshoot.footprintnetwork.org/newsroom/country-over... https://en.wikipedia.…

Jesus fucking Christ this is depressing. You just brought up how you think genocide inevitable, and you imply that we should start it so that we’ll win?

I don’t think there’s any reason we should take “let’s kill everyone else so we can keep our nice stuff” should make any more sense in 2023 than it has over the last… well, such arguments pop up in all of human history, I guess.

To answer your question: i think it’s more likely that we build an egalitarian global society, or at least continue on the path.

Re: Tidal energy is not renewable

#73

Post by qayxc »

octacat wrote: post #60

Solar energy is not renewable too in the long run (very long run).

That's not what renewable means. Renewable energy means that the source is naturally replenished within a human lifetime. In other words, the source isn't permanently depleted by tapping into it.

This is the case with solar energy: the Sun's energy output doesn't change depending on whether we use it or not. Renewable doesn't mean perpetual - that'd be physically impossible for all we know.

Re: Tidal energy is not renewable

#74

Post by bbor »

adventured wrote: post #68
toomuchtodo wrote: post #34

Earlier quoted context omitted.

Conflict over scarce resources is inevitable. When the violence starts, you should be prepared to win (from a nation state perspective). https://news.ycombinator.com/item?id=37122796 | https://www.mdpi.com/2673-4060/4/3/32 https://news.ycombinator.com/item?id=37313586 | https://medium.com/@samyoureyes/the-busy-workers-handbook-to... https://overshoot.footprintnetwork.org/newsroom/country-over... https://en.wikipedia.…

> Which is more likely? Everyone lives like a European (from a consumption perspective)? Or a bunch of people don’t or die while some do? There are no systems that can ever be created to actually balance out / eliminate inequality, outside of very small communities operated via extreme authoritarianism. See: modern Sweden. A formerly highly effective welfare state, increasingly brought to its knees by poor immigrants…

You have some sources for “Sweden and France are failed countries”? Something tells me that’s not quite an objective take. “Inequality exists now so it will always” is also not the objective scientific take I think you’re implying it to be

Re: Tidal energy is not renewable

#75

Post by paulmd »

popol12 wrote: post #65
coldcode wrote: post #53

Earlier quoted context omitted.

More countries are now sub-2.0 replacement, China is down to 1.09 so the peak is unlikely to get much more than that.

A Google search for “china children per woman” gives me 1.705 Are you talking about something else ?

Leave it to HN to be unaware of the physical or social mechanics of reproduction

Re: Tidal energy is not renewable

#76

Post by qayxc »

Rantenki wrote: post #48

It's a neat thought experiment, but the underlying assumption: The world's energy consumption was about 5.67x1020 Joules in 2013.[18] This number has increased by more than 2% per year on average in the last 50 years. The average world economic growth rate in the last 50 years is about 3%, which requires a corresponding increase in the energy supply. So, the 2% growth rate for world energy consumption should be a con…

Not only that. The paper is only even remotely plausible if the author assumes 100% efficiency. Otherwise waste heat alone would turn Earth into Venus long before any tidal locking could take effect.

Re: Tidal energy is not renewable

#77

Post by qayxc »

pdonis wrote: post #15
josephcsible wrote: post #9

Where is the angular momentum going?

To the Moon's orbital angular momentum. As the Earth's spin slows, the Moon moves further away and its orbital angular momentum increases.

Incidentally, this also causes the tidal effects to weaken to a point where calculations show that tidal locking will actually never happen.

Re: Tidal energy is not renewable

#78

Post by Nition »

wcoenen wrote: post #27

I'm not sure the author realized this, but they're actually making a statement about how crazy exponential growth is. Not about the sustainability of tidal power. This becomes obvious once you look closer at what that 2% growth rate (as assumed in the post) implies. Our global energy consumption in 2008 was estimated to be 474 exajoules. The total energy received by the earth from the sun during a year is about 5 mil…

Humanity needing that amount of energy seems obviously absurd, but then I suppose a CPU with 100 billion transistors seemed clearly impossible in 1960.

Maybe a few hundred years from now, Internet archaeologists will find your comment as one of the first harbingers of the coming World Energy Crisis, much as we see the 1912 Rodney & Otamatea Times "Coal Consumption Affecting Climate" snippet today.[0]

Then they'll find this comment...

----

[0] https://paperspast.natlib.govt.nz/newspapers/rodney-and-otam...

Re: Tidal energy is not renewable

#79

Post by eldaisfish »

WillPostForFood wrote: post #63
wcoenen wrote: post #27

I'm not sure the author realized this, but they're actually making a statement about how crazy exponential growth is. Not about the sustainability of tidal power. This becomes obvious once you look closer at what that 2% growth rate (as assumed in the post) implies. Our global energy consumption in 2008 was estimated to be 474 exajoules. The total energy received by the earth from the sun during a year is about 5 mil…

Any sort of straight line extrapolation is useless. Look at the US energy consumed per capita, flat or declining for the last 50 years. Other parts of the world will follow as they develop. Likely the same for population growth. http://insideenergy.org/wp-content/uploads//2017/01/historic... from: https://insideenergy.org/2017/01/12/energy-explained/

the rest of the world still has to catch up to these levels. Granted, they won't get to the absurd wastage levels of north america but they will continue to consume more energy. Just looking at the energy levels in one country doesn't tell you much.

Re: Tidal energy is not renewable

#80

Post by toomuchtodo »

bbor wrote: post #72
toomuchtodo wrote: post #34

Earlier quoted context omitted.

Conflict over scarce resources is inevitable. When the violence starts, you should be prepared to win (from a nation state perspective). https://news.ycombinator.com/item?id=37122796 | https://www.mdpi.com/2673-4060/4/3/32 https://news.ycombinator.com/item?id=37313586 | https://medium.com/@samyoureyes/the-busy-workers-handbook-to... https://overshoot.footprintnetwork.org/newsroom/country-over... https://en.wikipedia.…

Jesus fucking Christ this is depressing. You just brought up how you think genocide inevitable, and you imply that we should start it so that we’ll win? I don’t think there’s any reason we should take “let’s kill everyone else so we can keep our nice stuff” should make any more sense in 2023 than it has over the last… well, such arguments pop up in all of human history, I guess. To answer your question: i think it’s…

I didn’t say genocide, I said violence over scarce resources. They are distinct motivators. I also didn’t say to start it, I said to win.

> To answer your question: i think it’s more likely that we build an egalitarian global society, or at least continue on the path.

Good luck with that. Hope is not a strategy, but hopefully the future is not as bleak as the current data predicts. Show me a voter cohort that will willingly give up substantial go forward energy or resource quality of life for people on the other side of the world who they have not nor will never meet. Do you know how many people are dying right now at this moment because their basic needs are not being met? One every 4 seconds per Oxfam. This is before more frequent heat events, crop failures, aquifers reaching terminal depletion, etc.

https://www.oxfam.org/en/press-releases/humanitarian-organiz...

Agreed it’s (extremely!) depressing, but facts are different than a reality based on feelings. Finding truth is following the facts to the (sometimes) unpleasant places it takes us.

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