What happens when tidal power runs out?

In summary, tidal power plants are a thing. They harvest the energy from water moving around. That energy comes from somewhere, specifically the moon, right? So does harvesting tidal power (very very very) slowly degrade the moon's orbit? Does liquid's existence on Earth deteriorate the orbit to begin with? I mean, perpetual energy is not a thing, right, so the system has to deteriorate somehow... How does a tidal energy system deteriorate? How long would that take?Harvesting tidal power does not degrade the moon's orbit. The water flow is more obstructed, but the moon's orbit is not depleted. Harvesting tidal power does slow down Earth's rotation, but it is not possible to
  • #1
Simoyd
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So tidal power plants are a thing. They harvest the energy from water moving around. That energy comes from somewhere, specifically the moon, right? So does harvesting tidal power (very very very) slowly degrade the moon's orbit? Does liquid's existence on Earth deteriorate the orbit to begin with? I mean, perpetual energy is not a thing, right, so the system has to deteriorate somehow... How does a tidal energy system deteriorate? How long would that take?
 
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  • #2
By adding a tidal power-harvesting plant you're effectively adding extra resistance to the motion of water, which leads to a tiny bit more efficient tidal braking - the slowing down of Earth's rotation and a recession of Moon's orbit. The flow of water is more obstructed, so it does a bit better job at dragging on the surface.

This is, however, a minuscule amount when compared to the braking the regular motion of water exerts due to the way the ocean beds and continents are structured, which in turn is not enough to tidally lock (i.e. deplete the potential for extracting tidal energy) the Earth to the Moon over the lifetime of the Sun.

Additionally, even in principle, full tidal lock of Earth and Moon is not possible, as at some point tidal forces from the Sun would take over, disrupting the system. That is, you can't have a situation where our planet is locked both to the Sun and the Moon, so some tidal interaction is ensured for as long as the Moon remains in the system as a freely orbiting body.
There will be a gradual reduction in efficiency of tidal power as the Moon recedes and Earth slows its rotation, though. But again, gradual enough so as not to be a practical worry for millions of years, if ever at all.

If you're still concerned about the effect of human activities on the process, I suggest the following exercise: estimate the current energy consumption of the human race, assume it's all produced by tidal power plants at typical efficiency, and compare it to the energy required to completely stop the rotation of the Earth (which is an o.k. approximation of a tidal lock).
 
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  • #3
We switch back to coal.
 
  • #4
Simoyd said:
How long would that take?
zillions of years, nothing mankind has to worry about
 
Last edited:
  • #5
davenn said:
zillions of years, nothing mankind has to worry about
About 390 million years, actually.
 
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  • #6
D H said:
About 390 million years, actually.

not as long as I expected, but mankind isn't likely to be around to worry about it :wink:Dave
 

1. What is tidal power?

Tidal power is a form of renewable energy that harnesses the energy of the tides to generate electricity. It works by using the natural movement of the ocean to turn turbines, which then convert the energy into electricity.

2. How does tidal power work?

Tidal power works by using the rise and fall of the tides to turn turbines, which are connected to generators that produce electricity. This process is similar to how a hydroelectric dam works, but instead of using the flow of a river, tidal power uses the movement of the ocean.

3. What happens when tidal power runs out?

Unlike non-renewable sources of energy, tidal power will never run out. The tides are driven by the gravitational pull of the moon and the sun, which will continue to occur as long as these celestial bodies exist. This makes tidal power a reliable and sustainable source of energy.

4. Are there any environmental concerns with tidal power?

While tidal power is a renewable energy source, it can still have some negative impacts on the environment. The construction of tidal power facilities can disrupt marine life and habitats, and the turbines can also pose a danger to aquatic animals. However, with proper planning and mitigation measures, these impacts can be minimized.

5. Is tidal power cost-effective?

The cost-effectiveness of tidal power depends on various factors, such as location and technology used. In some areas, tidal power can be more expensive than other forms of renewable energy. However, as technology advances and more tidal power facilities are built, the cost of tidal power is expected to decrease and become more competitive with other energy sources.

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