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Can Earth's rotation generate power? Physicists divided over controversial claim

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Re: Can Earth's rotation generate power? Physicists divided over controversial claim

#211

Post by bmm6o »

thaumasiotes wrote: post #189
kadoban wrote: post #141

Earlier quoted context omitted.

Ah I see, that makes sense. Thanks.

The mental model I was presented with is that the ocean bulges toward (and, on the other side of the earth, away from) the moon, and the earth spins within the ocean. If you take a perspective that is fixed to a particular point on the earth, you'll see the tides constantly moving past, but that's an illusion just like the rising and setting of the sun. They're both really the rotation of the earth.

Also relevant is that the oceanic bulge is along the elliptic, but the earth's axis of rotation is tilted. So the effect can vary by latitude.

Re: Can Earth's rotation generate power? Physicists divided over controversial claim

#212

Post by Nifty3929 »

Certhas wrote: post #203
Nifty3929 wrote: post #62

Earlier quoted context omitted.

I haven't seen any data that backs that up based on general principals. Most of the cost is in artificially-imposed operational requirements - however well founded. Also, remember that nuclear, unlike solar, has a lot of room for improvement still, both in how it's done, and how it's regulated. Solar has already been tremendously optimized, while nuclear has not. The cost argument seems to be advances by the same peo…

All I see is people with an aversion to solar and wind, that champion nuclear for purely ideological reasons. The aversion seems to be mostly driven by the fact that solar and wind were first championed by eco hippies, and some people seem to find it hard to bear that the eco hippies were right in this case. Nuclear has had tremendously more cumulative R+D spend than solar and wind. The notion that it's less optimize…

"All I see is people with..." - Maybe some do, but not me. I think solar is great, and wind too. I have solar panels on my roof that cover most of my family's usage. Geo would be awesome, and hydro can be great.

I'm all for doing more, and improving our lot incrementally over time. Let's focus on doing more wherever we can.

Why is nuclear getting more expensive over time? Are we forgetting how to produce it or something? Actually we've been finding more efficient and safer ways to produce nuclear for decades, but we impose - as I said - artificial burdens that make it more expensive, or simply don't allow it at all. At least in the US.

The operational requirements DON'T make it more safe though, they just add cost. Storing nuclear waste is also safe, easy and cheap - if we allow it to be so.

Re: Can Earth's rotation generate power? Physicists divided over controversial claim

#213

Post by mr_mitm »

aeternum wrote: post #200
mr_mitm wrote: post #148

Earlier quoted context omitted.

No, that's not possible due to conservation of angular momentum. Only tidal effects can transfer some of it to the sun.

Why would angular momentum be conserved? Rotation within an atmosphere should cause friction would should convert angular momentum into thermal loss. Interestingly, it looks like the upper atmosphere generally rotates faster than the planet, so it could be that the opposite effect actually dominates. IE the uneven heating causes a atmospheric bulge that actually pushes the atmosphere around slightly faster than the p…

Because the system exhibits rotational symmetry. It follows from Noether's theorem that angular momentum is conserved. Only when you include the interactions with other stellar bodies you lose the symmetry and you have an opportunity to shed angular momentum.

Re: Can Earth's rotation generate power? Physicists divided over controversial claim

#214

Post by triceratops »

veqq wrote: post #199
fsckboy wrote: post #142

Earlier quoted context omitted.

a substantial amount of wind is also caused by (differential) solar heating: that's why wind doesn't only go in one direction if you've ever spent time at the seashore, the wind comes in off the sea during the day (because of rising thermals on the land side) and blows back offshore at night (because the land cools and the sea is now warmer) that time in between the air is dead-still, and that's when the swarms of gn…

But the earth's rotation makes the solar heating _differential_

If the earth didn't rotate the differential would be permanent...and permanently in one direction

Re: Can Earth's rotation generate power? Physicists divided over controversial claim

#215

Post by bhk »

thayne wrote: post #196
bhk wrote: post #167

Earlier quoted context omitted.

None of the power comes from the Earth's rotation. Angular momentum is conserved in a closed system.

But it isn't a closed system. Tides transfer angular momentum from earth's rotation to the moon's orbit.

I was responding to a claim about wind. Yes, we can extract energy from tidal forces.

Re: Can Earth's rotation generate power? Physicists divided over controversial claim

#216

Post by aurizon »

ada1981 wrote: post #121
aurizon wrote: post #97

We could use this, by adding power, to fine tune the day to eliminate leap years...;)

Interesting. Yes could we put power into a similar system and accelerate the rotation?

turn fast enough = we can all fly... while we wear armor like a turtle...

Re: Can Earth's rotation generate power? Physicists divided over controversial claim

#217

Post by whutsurnaym »

pavel_lishin wrote: post #185
Hyperboreanal wrote: post #115

Earlier quoted context omitted.

Saying what book you're talking about is kind of a spoiler now for anyone that happens to be reading its series. Are there spoiler tags on HN? The Long Utopia, book 4/5 of the Long Earth series by Pratchett and Baxter. The series has very meh characters/dialogue, excellent ideas and sense of nearly possibility-unlimited discovery that's executed very well, highly recommend if that's your cup of tea. Ended up skipping…

I was wildly disappointed in that series. A great premise that fizzled out about 3/4ths of the way through the first book. I powered through, and started the second, and gave up maybe five chapters in. If the concept of world-hopping intrigues you, Charles Stross's "Merchant Princes" series does it better.

I'm really glad to see this wasn't just my experience.

I absolutely loved the premise of the first book. Every time I think about it I get the same kind of excitement I feel when I come up with the perfect idea for a D&D campaign.

But the second book gathers dust on my shelf, and no matter how many times I think "I should get back into these!" I just can't. The first book ended in a fizzle and the second completely failed to keep my attention.

I'll take a look at Merchant Princes and see if that's more to my liking!

Re: Can Earth's rotation generate power? Physicists divided over controversial claim

#218

Post by Certhas »

SecretDreams wrote: post #209
Certhas wrote: post #204

Earlier quoted context omitted.

You seem to think this contradicts my statement somehow? Obviously you want a tech mix, and obviously anyone working in the field is taking the dunkelflaute or other extreme events very seriously. That's where storage comes in, and that's where the biggest unknowns and needs for future development are (e.g. is seasonal H2 storage really feasible). But to pretend like nuclear can magically become cheaper through techn…

> But to pretend like nuclear can magically become cheaper through technical breakthroughs, while storage is an unsolvable problem is disingenuous. I didn't say storage was not solvable and I even gave a better storage solution than your silly "batteries" example. > Based on the projections for adopted climate scenarios, the average annual energy loss of the global nuclear fleet is estimated to range between 0.8% and…

What silly batteries example?

If seasonal storage is solvable, solar + wind is not unreliable.

And no, I don't have an anti nuclear agenda. But I know the energy system models and the results, and just how difficult integrating nuclear into the mix is.

https://nworbmot.org/blog/burden-of-proof.html

Finally, I know exactly what the paper says but maybe you don't: the problem with Dunkelflaute events is correlation. If it's cloudy somewhere and the sun is shining elsewhere, then no problem. These problematic conditions for nuclear are the same: large scale spatial correlated.

Re: Can Earth's rotation generate power? Physicists divided over controversial claim

#219

Post by Certhas »

Nifty3929 wrote: post #212
Certhas wrote: post #203

Earlier quoted context omitted.

All I see is people with an aversion to solar and wind, that champion nuclear for purely ideological reasons. The aversion seems to be mostly driven by the fact that solar and wind were first championed by eco hippies, and some people seem to find it hard to bear that the eco hippies were right in this case. Nuclear has had tremendously more cumulative R+D spend than solar and wind. The notion that it's less optimize…

"All I see is people with..." - Maybe some do, but not me. I think solar is great, and wind too. I have solar panels on my roof that cover most of my family's usage. Geo would be awesome, and hydro can be great. I'm all for doing more, and improving our lot incrementally over time. Let's focus on doing more wherever we can. Why is nuclear getting more expensive over time? Are we forgetting how to produce it or someth…

Seriously, that's good to hear. I really often encounter arguments that seem heavily ideology driven.

Do you have some sources for operational requirements not making things safer? And as far as I know there are plenty of fusion concepts in the lab, but very few that have actually been explored at the full reactor scale. If you have any pointers on recent developments in that direction I would also be curious to take a look.

But then I also have to ask why nuclear? Why not methanation (or hydrogen if storage becomes feasible) and gas power plants or some more sophisticated version of that? That has much better complementarity to solar. And it typically is preferred to nuclear by energy system models wherever seasonality is strong.

Also I haven't really seen any proposals discussing long term waste storage. Again do you have any sources that discuss this?

Re: Can Earth's rotation generate power? Physicists divided over controversial claim

#220

Post by MaxikCZ »

Rygian wrote: post #73
deadbabe wrote: post #69

Suggest a hard sci-fi story where humans abuse this so much the Earth basically stops rotating.

I've already read one where some weird alien ants hollow out the earth to make it spin faster, and take advantage of the increase in speed to generate power somehow (maybe by building a geostationary conductive belt around the planet, that acts as the "stator"?)

Wouldnt hollowing the earth not change its rotation speed? And if the hollowed material would be deposited on surface, wouldnt the speed actually decrease?
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