3 ms·

I've never understood the concept of something like this. Isn't the energy generated canceled out with power expended to pump it through? I feel like friction

I've never understood the concept of something like this. Isn't the energy generated canceled out with power expended to pump it through? I feel like friction would never make something like this useful. Can someone explain how this kind of generation is beneficial?

csense 11y ago
The energy is input by the sun which turns sea water (at sea level) into water vapor, which then moves to higher elevation due to weather patterns (also caused by sun's energy input) and falls as rain into a reservoir at higher elevation than the locations it serves.
- jamesrom 11y ago
  All energy on earth is solar energy.
  - onion2k 11y ago
    Apart from nuclear power. Even that is technically 'solar' in the sense that the elements necessary were made in a star, but not our sun.
    - jholman 11y ago
      You're right about nuclear (though, if we can get hydrogen fusion to be profitable, that won't even be stellar in the way that fission is). Tidal energy isn't solar in any sense. It's harvesting momentum which in turn is generated by some combination of gravity and the Big Bang. Geothermal energy isn't solar. It's harvesting heat, which apparently comes from three sources: heat from the planet's formation, caused by gravity, heat from friction from deep-interior motion, and heat from radioactive decay. Only the last of these is even stellar, and none are solar.
      - jamesrom 11y ago
        Moon (and Earth) were given their momentum during the formation of the solar system. I'd say that's solar. And if you want to make a distinction about which star forged the heavy elements required for radioactive decay, then I'll agree it's 'stellar' energy not so much 'solar'.
viraptor 11y ago
Asked the same thing the last time this was posted. There's a good answer: https://news.ycombinator.com/item?id=9835804 https://news.ycombinator.com/item?id=9835804 (in short, you already have too much pressure being relieved using valves along the way with the extra energy wasted)
MLR 11y ago
This comment explains it pretty well I think. https://news.ycombinator.com/item?id=9838012 https://news.ycombinator.com/item?id=9838012 It's the same idea behind regenerative braking.
latch 11y ago
"The pipes can't generate power in every location; they only work in places where water is naturally flowing downward with gravity (if water is being pumped, the system would waste energy)."

csense 11y ago

The energy is input by the sun which turns sea water (at sea level) into water vapor, which then moves to higher elevation due to weather patterns (also caused by sun's energy input) and falls as rain into a reservoir at higher elevation than the locations it serves.

jamesrom 11y ago
All energy on earth is solar energy.
- onion2k 11y ago
  Apart from nuclear power. Even that is technically 'solar' in the sense that the elements necessary were made in a star, but not our sun.
  - jholman 11y ago
    You're right about nuclear (though, if we can get hydrogen fusion to be profitable, that won't even be stellar in the way that fission is). Tidal energy isn't solar in any sense. It's harvesting momentum which in turn is generated by some combination of gravity and the Big Bang. Geothermal energy isn't solar. It's harvesting heat, which apparently comes from three sources: heat from the planet's formation, caused by gravity, heat from friction from deep-interior motion, and heat from radioactive decay. Only the last of these is even stellar, and none are solar.
    - jamesrom 11y ago
      Moon (and Earth) were given their momentum during the formation of the solar system. I'd say that's solar. And if you want to make a distinction about which star forged the heavy elements required for radioactive decay, then I'll agree it's 'stellar' energy not so much 'solar'.

viraptor 11y ago

Asked the same thing the last time this was posted. There's a good answer: https://news.ycombinator.com/item?id=9835804 https://news.ycombinator.com/item?id=9835804 (in short, you already have too much pressure being relieved using valves along the way with the extra energy wasted)

MLR 11y ago

This comment explains it pretty well I think. https://news.ycombinator.com/item?id=9838012 https://news.ycombinator.com/item?id=9838012 It's the same idea behind regenerative braking.

latch 11y ago

"The pipes can't generate power in every location; they only work in places where water is naturally flowing downward with gravity (if water is being pumped, the system would waste energy)."