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posted by Fostertom, Tony, DJH and Ed Davies on another thread[the Moon causes tides by] maintaining a standing wave as Earth rotates under it.
By increasing friction via tidal turbines, letting water in and out of barages out of sync etc we are leveraging the mass of the moon to slow down Earth's rotation.
Now we think that wind tide and waves are harmlessly 'renewable' infinite resources that we can harness forever, but ultimately what we're depleting is the planet's rotational momentum.
Not in any meaningful sense.
It would be measurable, though
tidal has adverse impact orbital taking energy out of the moon eventually it will get further away and take longer to go round the earth.
tide is mostly due to the influence of the moon
https://en.wikipedia.org/wiki/Tidal_acceleration#Angular_momentum_and_energy
Posted By: WillInAberdeenI find the 'standing wave' idea a bit theoretical, because it ignores all the continents, which would stop such a wave running constantly round the Earth at 1000mph. That could only work in a belt around the Antarctic, or under the Arctic Ocean.
There's also a very finite number of good sites, and a Betz limit how much energy you can get from each site.
They transfer energy to speed up the Moon, so it slingshots to a higher orbit above Earth.
The [tides] transfer energy to speed up the Moon, so it slingshots to a higher orbit above Earth.Exactly as written, but maybe too condensed to be clear:
Posted By: WillInAberdeenIf only!
I don’t agree with the idea of energy being transferred to or from the moon.Since this effect has been directly measured in the form of both the slowing of the Earth's rotation and the increased distance of the Moon your agreement on this, as with other subjects, is rather moot.
Posted By: Jeff BRe moon getting further away etc... what time frame are we talking here chaps before this has some dramatic influence on life as we know it?A long time. We'll have other problems before that. First the increased heat of the Sun increasing weathering so removing COâ‚‚ from the atmosphere resulting in the death of all the plants then the expansion of the Sun to a red giant which will likely engulf the Earth. So beyond the term of this parliament.
Posted By: Jeff B
A quick skirmish on the Internet found this article: https://www.sciencedirect.com/science/article/pii/S1364032115016676
It seems there is a lot of work to be done yet!
Posted By: philedgePosted By: Jeff B
A quick skirmish on the Internet found this article: https://www.sciencedirect.com/science/article/pii/S1364032115016676
It seems there is a lot of work to be done yet!
The article seems to be from 2016 and I think things have moved on a bit. I think theres already operational turbines installed in the channel and in scotland with more coming into operation soon. Google Orbital Marine Power and Atlantis Ocean Energy.
Posted By: Ed DaviesPosted By: Jeff BRe moon getting further away etc... what time frame are we talking here chaps before this has some dramatic influence on life as we know it?A long time. We'll have other problems before that. First the increased heat of the Sun increasing weathering so removing COâ‚‚ from the atmosphere resulting in the death of all the plants then the expansion of the Sun to a red giant which will likely engulf the Earth. So beyond the term of this parliament.
Posted By: Jeff BPosted By: djhFWIW, there's a list of existing tidal power stations athttps://en.wikipedia.org/wiki/List_of_tidal_power_stations" rel="nofollow" >http:////en.wikipedia.org/wiki/List_of_tidal_power_stations" rel="nofollow">https://en.wikipedia.org/wiki/List_of_tidal_power_stations
The Rance Barrage is pretty nearby and has a lot of experience.
Thanks. The Swansea Bay scheme is dead of course and the SeaGen operation has been decommissioned.
Posted By: Jeff BThe Swansea Bay scheme is dead of course
Posted By: Ed DaviesAIUI the efficiency of pumped-storage schemes increases with height though I'm not really clear on why. Anybody?
Posted By: Mike1Fortunately not - they've done some site clearance work, which is enough to have secured the planning permission in perpetuity - so it's effectively 'shovel ready'
Posted By: djhAh, so the distinction is between 'efficiency' and 'effectiveness'? You'd need to define both those terms for me; I'm just thinking in terms of energy out over energy in.