3 ms·

But don't the tides naturally dissipate a lot of that energy anyway? E.g. whenever you go to the beach and see waves crash upon the shore, that's tidal energy b

But don't the tides naturally dissipate a lot of that energy anyway? E.g. whenever you go to the beach and see waves crash upon the shore, that's tidal energy being dissipated as heat. If you stick a turbine in the mix to extract useful work before it turns into heat, isn't it still turned into heat regardless?

hollerith 3y ago
Quoting from the OP: >it will take about 10.468 billion years for Earth to lock to the Moon naturally.
dre85 3y ago
That's exactly what I was wondering as well. I didn't really understand how tapping into the power source could possibly cause an additional loss that wouldn't otherwise happen.
timmaxw 3y ago
Yes, tides do naturally dissipate energy. The main source of tidal dissipation is friction between the moving seawater and the seabed. [1] Current tidal generators work either by inserting a turbine into the moving water; or by a dam that captures the high tide, then releases it through a turbine at low tide. Depending on the exact details, it could slow down the rate at which the current later flows over the seabed, which would reduce the energy dissipated from friction with the seabed. But, there's no guarantee that this would compensate for the energy taken by the tidal power generator. You could imagine a different type of tidal power generator: covering the seabed with a giant treadmill. As water flows past, it drags the surface of the treadmill, generating power. My guess is this would dissipate less total energy than the natural friction of the seabed does. But, it doesn't sound very practical. (Anyway, all of this is a moot point. As other commenters have noted, if human energy consumption actually were to grow 2% annually for 1000 years, we'd have way bigger problems than the moon becoming tidally locked.) [1] https://en.wikipedia.org/wiki/Tidal_acceleration#Angular_momentum_and_energy https://en.wikipedia.org/wiki/Tidal_acceleration#Angular_mom...

hollerith 3y ago

Quoting from the OP: >it will take about 10.468 billion years for Earth to lock to the Moon naturally.

dre85 3y ago

That's exactly what I was wondering as well. I didn't really understand how tapping into the power source could possibly cause an additional loss that wouldn't otherwise happen.

timmaxw 3y ago

Yes, tides do naturally dissipate energy. The main source of tidal dissipation is friction between the moving seawater and the seabed. [1] Current tidal generators work either by inserting a turbine into the moving water; or by a dam that captures the high tide, then releases it through a turbine at low tide. Depending on the exact details, it could slow down the rate at which the current later flows over the seabed, which would reduce the energy dissipated from friction with the seabed. But, there's no guarantee that this would compensate for the energy taken by the tidal power generator. You could imagine a different type of tidal power generator: covering the seabed with a giant treadmill. As water flows past, it drags the surface of the treadmill, generating power. My guess is this would dissipate less total energy than the natural friction of the seabed does. But, it doesn't sound very practical. (Anyway, all of this is a moot point. As other commenters have noted, if human energy consumption actually were to grow 2% annually for 1000 years, we'd have way bigger problems than the moon becoming tidally locked.) [1] https://en.wikipedia.org/wiki/Tidal_acceleration#Angular_momentum_and_energy https://en.wikipedia.org/wiki/Tidal_acceleration#Angular_mom...