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Can we harness gravitational potential energy?
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$begingroup$
I'm following this question that was closed as unclear. I think the OP meant the potential energy.
There are skyscrapers sitting there and pushing on the ground with tremendous weight. Is it possible to convert this weight/force to harness energy to power the building?
Maybe, build the building on top of some type of pendulum that will rotate under the pressure and when one cycle of rotation reaches the equilibrium point we could give it a kick from the stored energy of the same source to continue rotation.
Was something like this created or tested and found useless?
Note: maybe my question should be is it possible to convert the potential energy of a building into a kinetic?
energy-conservation potential-energy perpetual-motion energy-storage
edited 1 hour ago
Qmechanic♦
105k121901203
asked 5 hours ago
GrasperGrasper
1425
$endgroup$
add a comment |
$begingroup$
I'm following this question that was closed as unclear. I think the OP meant the potential energy.
There are skyscrapers sitting there and pushing on the ground with tremendous weight. Is it possible to convert this weight/force to harness energy to power the building?
Maybe, build the building on top of some type of pendulum that will rotate under the pressure and when one cycle of rotation reaches the equilibrium point we could give it a kick from the stored energy of the same source to continue rotation.
Was something like this created or tested and found useless?
Note: maybe my question should be is it possible to convert the potential energy of a building into a kinetic?
energy-conservation potential-energy perpetual-motion energy-storage
edited 1 hour ago
Qmechanic♦
105k121901203
asked 5 hours ago
GrasperGrasper
1425
$endgroup$
$begingroup$
Potential energy IS stored mechanical energy. In the case of your pendulum, that stored mechanical energy gets transferred to kinetic energy as the pendulum moves... How do you "capture" the mechanical energy being transferred into kinetic energy?
$endgroup$
– N. Steinle
4 hours ago
$begingroup$
As others have said, you totally can extract electricity from gravitational potential energy, but you have to convert it to kinetic energy, as is done with the gravity light (deciwatt.global/gravitylight). You let a bag of rocks descend slowly that turns a generator, which produces electricity. But that energy isn't free, it comes from your muscles putting up the light, and it doesn't last forever, just until it turns back into kinetic and then electrical energy
$endgroup$
– Kevin Wells
7 mins ago
add a comment |
$begingroup$
I'm following this question that was closed as unclear. I think the OP meant the potential energy.
There are skyscrapers sitting there and pushing on the ground with tremendous weight. Is it possible to convert this weight/force to harness energy to power the building?
Maybe, build the building on top of some type of pendulum that will rotate under the pressure and when one cycle of rotation reaches the equilibrium point we could give it a kick from the stored energy of the same source to continue rotation.
Was something like this created or tested and found useless?
Note: maybe my question should be is it possible to convert the potential energy of a building into a kinetic?
energy-conservation potential-energy perpetual-motion energy-storage
edited 1 hour ago
Qmechanic♦
105k121901203
asked 5 hours ago
GrasperGrasper
1425
$endgroup$
I'm following this question that was closed as unclear. I think the OP meant the potential energy.
There are skyscrapers sitting there and pushing on the ground with tremendous weight. Is it possible to convert this weight/force to harness energy to power the building?
Maybe, build the building on top of some type of pendulum that will rotate under the pressure and when one cycle of rotation reaches the equilibrium point we could give it a kick from the stored energy of the same source to continue rotation.
Was something like this created or tested and found useless?
Note: maybe my question should be is it possible to convert the potential energy of a building into a kinetic?
energy-conservation potential-energy perpetual-motion energy-storage
energy-conservation potential-energy perpetual-motion energy-storage
edited 1 hour ago
Qmechanic♦
105k121901203
asked 5 hours ago
GrasperGrasper
1425
edited 1 hour ago
Qmechanic♦
105k121901203
asked 5 hours ago
GrasperGrasper
1425
edited 1 hour ago
Qmechanic♦
105k121901203
edited 1 hour ago
Qmechanic♦
105k121901203
edited 1 hour ago
Qmechanic♦
105k121901203
105k121901203
asked 5 hours ago
GrasperGrasper
1425
asked 5 hours ago
GrasperGrasper
1425
asked 5 hours ago
GrasperGrasper
1425
1425
$begingroup$
Potential energy IS stored mechanical energy. In the case of your pendulum, that stored mechanical energy gets transferred to kinetic energy as the pendulum moves... How do you "capture" the mechanical energy being transferred into kinetic energy?
$endgroup$
– N. Steinle
4 hours ago
$begingroup$
As others have said, you totally can extract electricity from gravitational potential energy, but you have to convert it to kinetic energy, as is done with the gravity light (deciwatt.global/gravitylight). You let a bag of rocks descend slowly that turns a generator, which produces electricity. But that energy isn't free, it comes from your muscles putting up the light, and it doesn't last forever, just until it turns back into kinetic and then electrical energy
$endgroup$
– Kevin Wells
7 mins ago
add a comment |
$begingroup$
Potential energy IS stored mechanical energy. In the case of your pendulum, that stored mechanical energy gets transferred to kinetic energy as the pendulum moves... How do you "capture" the mechanical energy being transferred into kinetic energy?
$endgroup$
– N. Steinle
4 hours ago
$begingroup$
As others have said, you totally can extract electricity from gravitational potential energy, but you have to convert it to kinetic energy, as is done with the gravity light (deciwatt.global/gravitylight). You let a bag of rocks descend slowly that turns a generator, which produces electricity. But that energy isn't free, it comes from your muscles putting up the light, and it doesn't last forever, just until it turns back into kinetic and then electrical energy
$endgroup$
– Kevin Wells
7 mins ago
$begingroup$
Potential energy IS stored mechanical energy. In the case of your pendulum, that stored mechanical energy gets transferred to kinetic energy as the pendulum moves... How do you "capture" the mechanical energy being transferred into kinetic energy?
$endgroup$
– N. Steinle
4 hours ago
$begingroup$
Potential energy IS stored mechanical energy. In the case of your pendulum, that stored mechanical energy gets transferred to kinetic energy as the pendulum moves... How do you "capture" the mechanical energy being transferred into kinetic energy?
$endgroup$
– N. Steinle
4 hours ago
$begingroup$
As others have said, you totally can extract electricity from gravitational potential energy, but you have to convert it to kinetic energy, as is done with the gravity light (deciwatt.global/gravitylight). You let a bag of rocks descend slowly that turns a generator, which produces electricity. But that energy isn't free, it comes from your muscles putting up the light, and it doesn't last forever, just until it turns back into kinetic and then electrical energy
$endgroup$
– Kevin Wells
7 mins ago
$begingroup$
As others have said, you totally can extract electricity from gravitational potential energy, but you have to convert it to kinetic energy, as is done with the gravity light (deciwatt.global/gravitylight). You let a bag of rocks descend slowly that turns a generator, which produces electricity. But that energy isn't free, it comes from your muscles putting up the light, and it doesn't last forever, just until it turns back into kinetic and then electrical energy
$endgroup$
– Kevin Wells
7 mins ago
add a comment |
5 Answers
5
active
oldest
votes
$begingroup$
In classical mechanics, absolute values of potential energy are meaningless. In your case of a skyscraper just sitting there, we could say it has a large positive amount of potential energy, no potential energy, or even negative potential energy. It doesn't matter at all. What is important is a change in potential energy.
is it possible to convert the potential energy of a building into a kinetic?
Based on what is said above, you would need to decrease the potential energy of the building and find a way to harness that change in potential energy. The issue is that for gravity, the potential energy just depends on the distance from the Earth, so this would mean that you would have to move the building (or at least parts of the building) closer to the Earth. The utility of buildings is typically that they remain stationary so people can use them consistently and for a long time, so I don't see this being feasible.
To see how gravitational potential energy can be converted to other types of energy in other systems, see some of the other posted answers.
answered 4 hours ago
Aaron StevensAaron Stevens
11.5k31946
$endgroup$
10
$begingroup$
+1 for "The utility of buildings is typically that they remain stationary so people can use them consistently and for a long time".
$endgroup$
– dbmag9
3 hours ago
$begingroup$
There have been instances where a building's potential energy has been converted (briefly) into kinetic energy, but I'm not sure we care to repeat them.
$endgroup$
– Michael Seifert
51 mins ago
add a comment |
$begingroup$
An example of harnessing gravitational potential energy is a hydroelectric power plant which converts the potential energy of water falls, dams and the like into electrical energy.
As far as harnessing the potential energy of a building sitting on the ground, I suppose if you caused the building to topple you could harness the energy of the falling portions of the building. Obviously ridiculous.
All practical examples of harnessing potential energy involve its conversion to kinetic energy.Hope this helps.
answered 4 hours ago
Bob DBob D
3,2382215
$endgroup$
1
$begingroup$
If you want to describe hydroelectric power as "harnessing gravitational potential energy" then wouldn't it be more accurate to say that energy comes from the dammed lake or upriver water, rather than the dam itself or even the "waterfall" that moves the turbines?
$endgroup$
– talrnu
2 hours ago
$begingroup$
@talrnu The potential energy is the height of the water above the point where it drives a turbine. When it falls and reaches the turbine the potential energy has been converted to kinetic energy. Now the kinetic energy is converted to turbine work by the work energy principle.
$endgroup$
– Bob D
35 mins ago
$begingroup$
Or you could have a regenerative elevator: the car going down generates power to lift the car going up, so all you have to do is replace system losses.
$endgroup$
– jamesqf
22 mins ago
add a comment |
$begingroup$
Simply No. If you could generate energy simply from the potential energy of the building, induced by gravity, without somehow permanently decreasing that energy, you would build some sort of perpetuum mobile.
If you would gain usable energy (like an electrical current) out of the potential energy of the building, without reducing the mass of the building and without altering the gravitational field, you would have created energy out of nothing, but energy is conserved.
answered 5 hours ago
Patrik PuchertPatrik Puchert
112
$endgroup$
$begingroup$
Isn't gravitational force a perpetuum mobile? or at least it has the potential to be.
$endgroup$
– Grasper
4 hours ago
1
$begingroup$
@Grasper How so? You only get energy from the gravity by moving closer together. At some point, you can't get any closer and the energy doesn't increase.
$endgroup$
– JMac
4 hours ago
$begingroup$
@JMac because gravity is always there available?
$endgroup$
– Grasper
4 hours ago
$begingroup$
@Grasper But the objects aren't always apart. You can extract some energy from the system; but in extracting that energy you remove potential energy from the system; which you can only do a finite amount until there is no potential left. In a perfect isolated system with no loss, you in theory could have it move forever without energy exchange. Wikipedia calls that "perpetual motion of the third kind", and it's still not possible in practice. en.wikipedia.org/wiki/Perpetual_motion#Classification
$endgroup$
– JMac
4 hours ago
$begingroup$
@JMac Since the objects are still attracted to and exert force on each other when they meet, your explanation doesn't really address the source of Grasper's confusion. The question is about why we can't generate power from these forces when the objects are touching.
$endgroup$
– talrnu
25 mins ago
|
show 1 more comment
$begingroup$
By convention, potential energy (which can be mechanical, gravitational, chemical, electromagnetic or nuclear) refers to energy stored in a field (electromagnetic field, gravitational field, gluon field etc.). This energy must be converted into kinetic energy in order to be "harnessed" or do work. For example, you can convert potential energy into:
- kinetic energy of an arrow, a pendulum or a pipe full of water
- heat energy (which at a molecular scale is just kinetic energy again)
- an electric current (moving electrons, so kinetic energy again)
- energetic neutrons and other products of fission or fusion (kinetic energy again)
So you can harness potential energy, but only indirectly.
answered 4 hours ago
gandalf61gandalf61
29915
$endgroup$
$begingroup$
I understand this, maybe my question should be is it possible to convert the potential energy of a building into a kinetic?
$endgroup$
– Grasper
4 hours ago
1
$begingroup$
@Grasper Sure. A few well placed explosive charges will convert the potential energy of a building into kinetic energy for a short period, before this kinetic energy is used to break a lot of chemical bonds. I believe there are videos of the phenomena available on YouTube :) But if you want to convert some of the kinetic energy back to potential energy afterwards then you have to design a building that will bounce.
$endgroup$
– gandalf61
4 hours ago
$begingroup$
Speaking of bouncing, skyscrapers actually swing. There were strips created that generate electricity. They placed them under a bridge and anytime car passed it generated electricity. So if a very long string is attached this could work but in that case I think the wind energy would be more efficient but who knows.
$endgroup$
– Grasper
47 mins ago
$begingroup$
@Grasper In all of those cases the energy isn't coming from nowhere. For the strips that generate electricity from moving cars, that energy comes from reducing the speed of the cars as they pass through (even if only a tiny bit), meaning in aggregate you are reducing the mileage of those cars. It's basically an extremely inefficient generator that runs on gas. You could get energy from swaying buildings, but that energy is from the wind moving the building, and as you said, directly harnessing the wind is going to be far more efficient. In every case the energy has to come from somewhere
$endgroup$
– Kevin Wells
13 mins ago
add a comment |
$begingroup$
Yes, you can convert the potential energy of the skyscraper into useful work. But, to extract useful work from the potential energy, must reduce the potential energy, that is: you must reduce the height of the skyscraper. You must tear the skyscraper down to get its energy.
You should note that skyscrapers aren't free and that someone used a crane powered by electricity or diesel to lift the parts of the skyscraper to their current positions. You are guaranteed to get less energy out of this process than was put in to build the skyscraper. You will waste a lot of energy in the process of converting energy from diesel or the electric grid into the potential energy of the skyscraper and then back into electricity. This would be a terribly inefficient way to store energy.
However, as noted by another answer, this is essentially what we do with hydroelectric dams. We move water from a high altitude to a lower altitude and extract useful work that is converted into electrical energy. This energy is free in the sense that the sun evaporated water somewhere and it rained down on the high altitude reservoir. So hydroelectric power is, at its core, solar power, because the sun effectively pumps the water uphill and we extract energy as it moves downhill.
Using actual electrically powered pumps, you can pump water uphill to store energy. You can use the energy later by allowing it to flow downhill.
answered 1 hour ago
WaterMoleculeWaterMolecule
21114
$endgroup$
add a comment |
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5 Answers
5
active
oldest
votes
5 Answers
5
active
oldest
votes
active
oldest
votes
active
oldest
votes
$begingroup$
In classical mechanics, absolute values of potential energy are meaningless. In your case of a skyscraper just sitting there, we could say it has a large positive amount of potential energy, no potential energy, or even negative potential energy. It doesn't matter at all. What is important is a change in potential energy.
is it possible to convert the potential energy of a building into a kinetic?
Based on what is said above, you would need to decrease the potential energy of the building and find a way to harness that change in potential energy. The issue is that for gravity, the potential energy just depends on the distance from the Earth, so this would mean that you would have to move the building (or at least parts of the building) closer to the Earth. The utility of buildings is typically that they remain stationary so people can use them consistently and for a long time, so I don't see this being feasible.
To see how gravitational potential energy can be converted to other types of energy in other systems, see some of the other posted answers.
answered 4 hours ago
Aaron StevensAaron Stevens
11.5k31946
$endgroup$
10
$begingroup$
+1 for "The utility of buildings is typically that they remain stationary so people can use them consistently and for a long time".
$endgroup$
– dbmag9
3 hours ago
$begingroup$
There have been instances where a building's potential energy has been converted (briefly) into kinetic energy, but I'm not sure we care to repeat them.
$endgroup$
– Michael Seifert
51 mins ago
add a comment |
$begingroup$
In classical mechanics, absolute values of potential energy are meaningless. In your case of a skyscraper just sitting there, we could say it has a large positive amount of potential energy, no potential energy, or even negative potential energy. It doesn't matter at all. What is important is a change in potential energy.
is it possible to convert the potential energy of a building into a kinetic?
Based on what is said above, you would need to decrease the potential energy of the building and find a way to harness that change in potential energy. The issue is that for gravity, the potential energy just depends on the distance from the Earth, so this would mean that you would have to move the building (or at least parts of the building) closer to the Earth. The utility of buildings is typically that they remain stationary so people can use them consistently and for a long time, so I don't see this being feasible.
To see how gravitational potential energy can be converted to other types of energy in other systems, see some of the other posted answers.
answered 4 hours ago
Aaron StevensAaron Stevens
11.5k31946
$endgroup$
10
$begingroup$
+1 for "The utility of buildings is typically that they remain stationary so people can use them consistently and for a long time".
$endgroup$
– dbmag9
3 hours ago
$begingroup$
There have been instances where a building's potential energy has been converted (briefly) into kinetic energy, but I'm not sure we care to repeat them.
$endgroup$
– Michael Seifert
51 mins ago
add a comment |
$begingroup$
In classical mechanics, absolute values of potential energy are meaningless. In your case of a skyscraper just sitting there, we could say it has a large positive amount of potential energy, no potential energy, or even negative potential energy. It doesn't matter at all. What is important is a change in potential energy.
is it possible to convert the potential energy of a building into a kinetic?
Based on what is said above, you would need to decrease the potential energy of the building and find a way to harness that change in potential energy. The issue is that for gravity, the potential energy just depends on the distance from the Earth, so this would mean that you would have to move the building (or at least parts of the building) closer to the Earth. The utility of buildings is typically that they remain stationary so people can use them consistently and for a long time, so I don't see this being feasible.
To see how gravitational potential energy can be converted to other types of energy in other systems, see some of the other posted answers.
answered 4 hours ago
Aaron StevensAaron Stevens
11.5k31946
$endgroup$
In classical mechanics, absolute values of potential energy are meaningless. In your case of a skyscraper just sitting there, we could say it has a large positive amount of potential energy, no potential energy, or even negative potential energy. It doesn't matter at all. What is important is a change in potential energy.
is it possible to convert the potential energy of a building into a kinetic?
Based on what is said above, you would need to decrease the potential energy of the building and find a way to harness that change in potential energy. The issue is that for gravity, the potential energy just depends on the distance from the Earth, so this would mean that you would have to move the building (or at least parts of the building) closer to the Earth. The utility of buildings is typically that they remain stationary so people can use them consistently and for a long time, so I don't see this being feasible.
To see how gravitational potential energy can be converted to other types of energy in other systems, see some of the other posted answers.
answered 4 hours ago
Aaron StevensAaron Stevens
11.5k31946
edited 2 hours ago
answered 4 hours ago
Aaron StevensAaron Stevens
11.5k31946
answered 4 hours ago
Aaron StevensAaron Stevens
11.5k31946
answered 4 hours ago
Aaron StevensAaron Stevens
11.5k31946
11.5k31946
10
$begingroup$
+1 for "The utility of buildings is typically that they remain stationary so people can use them consistently and for a long time".
$endgroup$
– dbmag9
3 hours ago
$begingroup$
There have been instances where a building's potential energy has been converted (briefly) into kinetic energy, but I'm not sure we care to repeat them.
$endgroup$
– Michael Seifert
51 mins ago
add a comment |
10
$begingroup$
+1 for "The utility of buildings is typically that they remain stationary so people can use them consistently and for a long time".
$endgroup$
– dbmag9
3 hours ago
$begingroup$
There have been instances where a building's potential energy has been converted (briefly) into kinetic energy, but I'm not sure we care to repeat them.
$endgroup$
– Michael Seifert
51 mins ago
10
10
$begingroup$
+1 for "The utility of buildings is typically that they remain stationary so people can use them consistently and for a long time".
$endgroup$
– dbmag9
3 hours ago
$begingroup$
+1 for "The utility of buildings is typically that they remain stationary so people can use them consistently and for a long time".
$endgroup$
– dbmag9
3 hours ago
$begingroup$
There have been instances where a building's potential energy has been converted (briefly) into kinetic energy, but I'm not sure we care to repeat them.
$endgroup$
– Michael Seifert
51 mins ago
$begingroup$
There have been instances where a building's potential energy has been converted (briefly) into kinetic energy, but I'm not sure we care to repeat them.
$endgroup$
– Michael Seifert
51 mins ago
add a comment |
$begingroup$
An example of harnessing gravitational potential energy is a hydroelectric power plant which converts the potential energy of water falls, dams and the like into electrical energy.
As far as harnessing the potential energy of a building sitting on the ground, I suppose if you caused the building to topple you could harness the energy of the falling portions of the building. Obviously ridiculous.
All practical examples of harnessing potential energy involve its conversion to kinetic energy.Hope this helps.
answered 4 hours ago
Bob DBob D
3,2382215
$endgroup$
1
$begingroup$
If you want to describe hydroelectric power as "harnessing gravitational potential energy" then wouldn't it be more accurate to say that energy comes from the dammed lake or upriver water, rather than the dam itself or even the "waterfall" that moves the turbines?
$endgroup$
– talrnu
2 hours ago
$begingroup$
@talrnu The potential energy is the height of the water above the point where it drives a turbine. When it falls and reaches the turbine the potential energy has been converted to kinetic energy. Now the kinetic energy is converted to turbine work by the work energy principle.
$endgroup$
– Bob D
35 mins ago
$begingroup$
Or you could have a regenerative elevator: the car going down generates power to lift the car going up, so all you have to do is replace system losses.
$endgroup$
– jamesqf
22 mins ago
add a comment |
$begingroup$
An example of harnessing gravitational potential energy is a hydroelectric power plant which converts the potential energy of water falls, dams and the like into electrical energy.
As far as harnessing the potential energy of a building sitting on the ground, I suppose if you caused the building to topple you could harness the energy of the falling portions of the building. Obviously ridiculous.
All practical examples of harnessing potential energy involve its conversion to kinetic energy.Hope this helps.
answered 4 hours ago
Bob DBob D
3,2382215
$endgroup$
1
$begingroup$
If you want to describe hydroelectric power as "harnessing gravitational potential energy" then wouldn't it be more accurate to say that energy comes from the dammed lake or upriver water, rather than the dam itself or even the "waterfall" that moves the turbines?
$endgroup$
– talrnu
2 hours ago
$begingroup$
@talrnu The potential energy is the height of the water above the point where it drives a turbine. When it falls and reaches the turbine the potential energy has been converted to kinetic energy. Now the kinetic energy is converted to turbine work by the work energy principle.
$endgroup$
– Bob D
35 mins ago
$begingroup$
Or you could have a regenerative elevator: the car going down generates power to lift the car going up, so all you have to do is replace system losses.
$endgroup$
– jamesqf
22 mins ago
add a comment |
$begingroup$
An example of harnessing gravitational potential energy is a hydroelectric power plant which converts the potential energy of water falls, dams and the like into electrical energy.
As far as harnessing the potential energy of a building sitting on the ground, I suppose if you caused the building to topple you could harness the energy of the falling portions of the building. Obviously ridiculous.
All practical examples of harnessing potential energy involve its conversion to kinetic energy.Hope this helps.
answered 4 hours ago
Bob DBob D
3,2382215
$endgroup$
An example of harnessing gravitational potential energy is a hydroelectric power plant which converts the potential energy of water falls, dams and the like into electrical energy.
As far as harnessing the potential energy of a building sitting on the ground, I suppose if you caused the building to topple you could harness the energy of the falling portions of the building. Obviously ridiculous.
All practical examples of harnessing potential energy involve its conversion to kinetic energy.Hope this helps.
answered 4 hours ago
Bob DBob D
3,2382215
edited 4 hours ago
answered 4 hours ago
Bob DBob D
3,2382215
answered 4 hours ago
Bob DBob D
3,2382215
answered 4 hours ago
Bob DBob D
3,2382215
3,2382215
1
$begingroup$
If you want to describe hydroelectric power as "harnessing gravitational potential energy" then wouldn't it be more accurate to say that energy comes from the dammed lake or upriver water, rather than the dam itself or even the "waterfall" that moves the turbines?
$endgroup$
– talrnu
2 hours ago
$begingroup$
@talrnu The potential energy is the height of the water above the point where it drives a turbine. When it falls and reaches the turbine the potential energy has been converted to kinetic energy. Now the kinetic energy is converted to turbine work by the work energy principle.
$endgroup$
– Bob D
35 mins ago
$begingroup$
Or you could have a regenerative elevator: the car going down generates power to lift the car going up, so all you have to do is replace system losses.
$endgroup$
– jamesqf
22 mins ago
add a comment |
1
$begingroup$
If you want to describe hydroelectric power as "harnessing gravitational potential energy" then wouldn't it be more accurate to say that energy comes from the dammed lake or upriver water, rather than the dam itself or even the "waterfall" that moves the turbines?
$endgroup$
– talrnu
2 hours ago
$begingroup$
@talrnu The potential energy is the height of the water above the point where it drives a turbine. When it falls and reaches the turbine the potential energy has been converted to kinetic energy. Now the kinetic energy is converted to turbine work by the work energy principle.
$endgroup$
– Bob D
35 mins ago
$begingroup$
Or you could have a regenerative elevator: the car going down generates power to lift the car going up, so all you have to do is replace system losses.
$endgroup$
– jamesqf
22 mins ago
1
1
$begingroup$
If you want to describe hydroelectric power as "harnessing gravitational potential energy" then wouldn't it be more accurate to say that energy comes from the dammed lake or upriver water, rather than the dam itself or even the "waterfall" that moves the turbines?
$endgroup$
– talrnu
2 hours ago
$begingroup$
If you want to describe hydroelectric power as "harnessing gravitational potential energy" then wouldn't it be more accurate to say that energy comes from the dammed lake or upriver water, rather than the dam itself or even the "waterfall" that moves the turbines?
$endgroup$
– talrnu
2 hours ago
$begingroup$
@talrnu The potential energy is the height of the water above the point where it drives a turbine. When it falls and reaches the turbine the potential energy has been converted to kinetic energy. Now the kinetic energy is converted to turbine work by the work energy principle.
$endgroup$
– Bob D
35 mins ago
$begingroup$
@talrnu The potential energy is the height of the water above the point where it drives a turbine. When it falls and reaches the turbine the potential energy has been converted to kinetic energy. Now the kinetic energy is converted to turbine work by the work energy principle.
$endgroup$
– Bob D
35 mins ago
$begingroup$
Or you could have a regenerative elevator: the car going down generates power to lift the car going up, so all you have to do is replace system losses.
$endgroup$
– jamesqf
22 mins ago
$begingroup$
Or you could have a regenerative elevator: the car going down generates power to lift the car going up, so all you have to do is replace system losses.
$endgroup$
– jamesqf
22 mins ago
add a comment |
$begingroup$
Simply No. If you could generate energy simply from the potential energy of the building, induced by gravity, without somehow permanently decreasing that energy, you would build some sort of perpetuum mobile.
If you would gain usable energy (like an electrical current) out of the potential energy of the building, without reducing the mass of the building and without altering the gravitational field, you would have created energy out of nothing, but energy is conserved.
answered 5 hours ago
Patrik PuchertPatrik Puchert
112
$endgroup$
$begingroup$
Isn't gravitational force a perpetuum mobile? or at least it has the potential to be.
$endgroup$
– Grasper
4 hours ago
1
$begingroup$
@Grasper How so? You only get energy from the gravity by moving closer together. At some point, you can't get any closer and the energy doesn't increase.
$endgroup$
– JMac
4 hours ago
$begingroup$
@JMac because gravity is always there available?
$endgroup$
– Grasper
4 hours ago
$begingroup$
@Grasper But the objects aren't always apart. You can extract some energy from the system; but in extracting that energy you remove potential energy from the system; which you can only do a finite amount until there is no potential left. In a perfect isolated system with no loss, you in theory could have it move forever without energy exchange. Wikipedia calls that "perpetual motion of the third kind", and it's still not possible in practice. en.wikipedia.org/wiki/Perpetual_motion#Classification
$endgroup$
– JMac
4 hours ago
$begingroup$
@JMac Since the objects are still attracted to and exert force on each other when they meet, your explanation doesn't really address the source of Grasper's confusion. The question is about why we can't generate power from these forces when the objects are touching.
$endgroup$
– talrnu
25 mins ago
|
show 1 more comment
$begingroup$
Simply No. If you could generate energy simply from the potential energy of the building, induced by gravity, without somehow permanently decreasing that energy, you would build some sort of perpetuum mobile.
If you would gain usable energy (like an electrical current) out of the potential energy of the building, without reducing the mass of the building and without altering the gravitational field, you would have created energy out of nothing, but energy is conserved.
answered 5 hours ago
Patrik PuchertPatrik Puchert
112
$endgroup$
$begingroup$
Isn't gravitational force a perpetuum mobile? or at least it has the potential to be.
$endgroup$
– Grasper
4 hours ago
1
$begingroup$
@Grasper How so? You only get energy from the gravity by moving closer together. At some point, you can't get any closer and the energy doesn't increase.
$endgroup$
– JMac
4 hours ago
$begingroup$
@JMac because gravity is always there available?
$endgroup$
– Grasper
4 hours ago
$begingroup$
@Grasper But the objects aren't always apart. You can extract some energy from the system; but in extracting that energy you remove potential energy from the system; which you can only do a finite amount until there is no potential left. In a perfect isolated system with no loss, you in theory could have it move forever without energy exchange. Wikipedia calls that "perpetual motion of the third kind", and it's still not possible in practice. en.wikipedia.org/wiki/Perpetual_motion#Classification
$endgroup$
– JMac
4 hours ago
$begingroup$
@JMac Since the objects are still attracted to and exert force on each other when they meet, your explanation doesn't really address the source of Grasper's confusion. The question is about why we can't generate power from these forces when the objects are touching.
$endgroup$
– talrnu
25 mins ago
|
show 1 more comment
$begingroup$
Simply No. If you could generate energy simply from the potential energy of the building, induced by gravity, without somehow permanently decreasing that energy, you would build some sort of perpetuum mobile.
If you would gain usable energy (like an electrical current) out of the potential energy of the building, without reducing the mass of the building and without altering the gravitational field, you would have created energy out of nothing, but energy is conserved.
answered 5 hours ago
Patrik PuchertPatrik Puchert
112
$endgroup$
Simply No. If you could generate energy simply from the potential energy of the building, induced by gravity, without somehow permanently decreasing that energy, you would build some sort of perpetuum mobile.
If you would gain usable energy (like an electrical current) out of the potential energy of the building, without reducing the mass of the building and without altering the gravitational field, you would have created energy out of nothing, but energy is conserved.
answered 5 hours ago
Patrik PuchertPatrik Puchert
112
answered 5 hours ago
Patrik PuchertPatrik Puchert
112
answered 5 hours ago
Patrik PuchertPatrik Puchert
112
answered 5 hours ago
Patrik PuchertPatrik Puchert
112
112
$begingroup$
Isn't gravitational force a perpetuum mobile? or at least it has the potential to be.
$endgroup$
– Grasper
4 hours ago
1
$begingroup$
@Grasper How so? You only get energy from the gravity by moving closer together. At some point, you can't get any closer and the energy doesn't increase.
$endgroup$
– JMac
4 hours ago
$begingroup$
@JMac because gravity is always there available?
$endgroup$
– Grasper
4 hours ago
$begingroup$
@Grasper But the objects aren't always apart. You can extract some energy from the system; but in extracting that energy you remove potential energy from the system; which you can only do a finite amount until there is no potential left. In a perfect isolated system with no loss, you in theory could have it move forever without energy exchange. Wikipedia calls that "perpetual motion of the third kind", and it's still not possible in practice. en.wikipedia.org/wiki/Perpetual_motion#Classification
$endgroup$
– JMac
4 hours ago
$begingroup$
@JMac Since the objects are still attracted to and exert force on each other when they meet, your explanation doesn't really address the source of Grasper's confusion. The question is about why we can't generate power from these forces when the objects are touching.
$endgroup$
– talrnu
25 mins ago
|
show 1 more comment
$begingroup$
Isn't gravitational force a perpetuum mobile? or at least it has the potential to be.
$endgroup$
– Grasper
4 hours ago
1
$begingroup$
@Grasper How so? You only get energy from the gravity by moving closer together. At some point, you can't get any closer and the energy doesn't increase.
$endgroup$
– JMac
4 hours ago
$begingroup$
@JMac because gravity is always there available?
$endgroup$
– Grasper
4 hours ago
$begingroup$
@Grasper But the objects aren't always apart. You can extract some energy from the system; but in extracting that energy you remove potential energy from the system; which you can only do a finite amount until there is no potential left. In a perfect isolated system with no loss, you in theory could have it move forever without energy exchange. Wikipedia calls that "perpetual motion of the third kind", and it's still not possible in practice. en.wikipedia.org/wiki/Perpetual_motion#Classification
$endgroup$
– JMac
4 hours ago
$begingroup$
@JMac Since the objects are still attracted to and exert force on each other when they meet, your explanation doesn't really address the source of Grasper's confusion. The question is about why we can't generate power from these forces when the objects are touching.
$endgroup$
– talrnu
25 mins ago
$begingroup$
Isn't gravitational force a perpetuum mobile? or at least it has the potential to be.
$endgroup$
– Grasper
4 hours ago
$begingroup$
Isn't gravitational force a perpetuum mobile? or at least it has the potential to be.
$endgroup$
– Grasper
4 hours ago
1
1
$begingroup$
@Grasper How so? You only get energy from the gravity by moving closer together. At some point, you can't get any closer and the energy doesn't increase.
$endgroup$
– JMac
4 hours ago
$begingroup$
@Grasper How so? You only get energy from the gravity by moving closer together. At some point, you can't get any closer and the energy doesn't increase.
$endgroup$
– JMac
4 hours ago
$begingroup$
@JMac because gravity is always there available?
$endgroup$
– Grasper
4 hours ago
$begingroup$
@JMac because gravity is always there available?
$endgroup$
– Grasper
4 hours ago
$begingroup$
@Grasper But the objects aren't always apart. You can extract some energy from the system; but in extracting that energy you remove potential energy from the system; which you can only do a finite amount until there is no potential left. In a perfect isolated system with no loss, you in theory could have it move forever without energy exchange. Wikipedia calls that "perpetual motion of the third kind", and it's still not possible in practice. en.wikipedia.org/wiki/Perpetual_motion#Classification
$endgroup$
– JMac
4 hours ago
$begingroup$
@Grasper But the objects aren't always apart. You can extract some energy from the system; but in extracting that energy you remove potential energy from the system; which you can only do a finite amount until there is no potential left. In a perfect isolated system with no loss, you in theory could have it move forever without energy exchange. Wikipedia calls that "perpetual motion of the third kind", and it's still not possible in practice. en.wikipedia.org/wiki/Perpetual_motion#Classification
$endgroup$
– JMac
4 hours ago
$begingroup$
@JMac Since the objects are still attracted to and exert force on each other when they meet, your explanation doesn't really address the source of Grasper's confusion. The question is about why we can't generate power from these forces when the objects are touching.
$endgroup$
– talrnu
25 mins ago
$begingroup$
@JMac Since the objects are still attracted to and exert force on each other when they meet, your explanation doesn't really address the source of Grasper's confusion. The question is about why we can't generate power from these forces when the objects are touching.
$endgroup$
– talrnu
25 mins ago
|
show 1 more comment
$begingroup$
By convention, potential energy (which can be mechanical, gravitational, chemical, electromagnetic or nuclear) refers to energy stored in a field (electromagnetic field, gravitational field, gluon field etc.). This energy must be converted into kinetic energy in order to be "harnessed" or do work. For example, you can convert potential energy into:
- kinetic energy of an arrow, a pendulum or a pipe full of water
- heat energy (which at a molecular scale is just kinetic energy again)
- an electric current (moving electrons, so kinetic energy again)
- energetic neutrons and other products of fission or fusion (kinetic energy again)
So you can harness potential energy, but only indirectly.
answered 4 hours ago
gandalf61gandalf61
29915
$endgroup$
$begingroup$
I understand this, maybe my question should be is it possible to convert the potential energy of a building into a kinetic?
$endgroup$
– Grasper
4 hours ago
1
$begingroup$
@Grasper Sure. A few well placed explosive charges will convert the potential energy of a building into kinetic energy for a short period, before this kinetic energy is used to break a lot of chemical bonds. I believe there are videos of the phenomena available on YouTube :) But if you want to convert some of the kinetic energy back to potential energy afterwards then you have to design a building that will bounce.
$endgroup$
– gandalf61
4 hours ago
$begingroup$
Speaking of bouncing, skyscrapers actually swing. There were strips created that generate electricity. They placed them under a bridge and anytime car passed it generated electricity. So if a very long string is attached this could work but in that case I think the wind energy would be more efficient but who knows.
$endgroup$
– Grasper
47 mins ago
$begingroup$
@Grasper In all of those cases the energy isn't coming from nowhere. For the strips that generate electricity from moving cars, that energy comes from reducing the speed of the cars as they pass through (even if only a tiny bit), meaning in aggregate you are reducing the mileage of those cars. It's basically an extremely inefficient generator that runs on gas. You could get energy from swaying buildings, but that energy is from the wind moving the building, and as you said, directly harnessing the wind is going to be far more efficient. In every case the energy has to come from somewhere
$endgroup$
– Kevin Wells
13 mins ago
add a comment |
$begingroup$
By convention, potential energy (which can be mechanical, gravitational, chemical, electromagnetic or nuclear) refers to energy stored in a field (electromagnetic field, gravitational field, gluon field etc.). This energy must be converted into kinetic energy in order to be "harnessed" or do work. For example, you can convert potential energy into:
- kinetic energy of an arrow, a pendulum or a pipe full of water
- heat energy (which at a molecular scale is just kinetic energy again)
- an electric current (moving electrons, so kinetic energy again)
- energetic neutrons and other products of fission or fusion (kinetic energy again)
So you can harness potential energy, but only indirectly.
answered 4 hours ago
gandalf61gandalf61
29915
$endgroup$
$begingroup$
I understand this, maybe my question should be is it possible to convert the potential energy of a building into a kinetic?
$endgroup$
– Grasper
4 hours ago
1
$begingroup$
@Grasper Sure. A few well placed explosive charges will convert the potential energy of a building into kinetic energy for a short period, before this kinetic energy is used to break a lot of chemical bonds. I believe there are videos of the phenomena available on YouTube :) But if you want to convert some of the kinetic energy back to potential energy afterwards then you have to design a building that will bounce.
$endgroup$
– gandalf61
4 hours ago
$begingroup$
Speaking of bouncing, skyscrapers actually swing. There were strips created that generate electricity. They placed them under a bridge and anytime car passed it generated electricity. So if a very long string is attached this could work but in that case I think the wind energy would be more efficient but who knows.
$endgroup$
– Grasper
47 mins ago
$begingroup$
@Grasper In all of those cases the energy isn't coming from nowhere. For the strips that generate electricity from moving cars, that energy comes from reducing the speed of the cars as they pass through (even if only a tiny bit), meaning in aggregate you are reducing the mileage of those cars. It's basically an extremely inefficient generator that runs on gas. You could get energy from swaying buildings, but that energy is from the wind moving the building, and as you said, directly harnessing the wind is going to be far more efficient. In every case the energy has to come from somewhere
$endgroup$
– Kevin Wells
13 mins ago
add a comment |
$begingroup$
By convention, potential energy (which can be mechanical, gravitational, chemical, electromagnetic or nuclear) refers to energy stored in a field (electromagnetic field, gravitational field, gluon field etc.). This energy must be converted into kinetic energy in order to be "harnessed" or do work. For example, you can convert potential energy into:
- kinetic energy of an arrow, a pendulum or a pipe full of water
- heat energy (which at a molecular scale is just kinetic energy again)
- an electric current (moving electrons, so kinetic energy again)
- energetic neutrons and other products of fission or fusion (kinetic energy again)
So you can harness potential energy, but only indirectly.
answered 4 hours ago
gandalf61gandalf61
29915
$endgroup$
By convention, potential energy (which can be mechanical, gravitational, chemical, electromagnetic or nuclear) refers to energy stored in a field (electromagnetic field, gravitational field, gluon field etc.). This energy must be converted into kinetic energy in order to be "harnessed" or do work. For example, you can convert potential energy into:
- kinetic energy of an arrow, a pendulum or a pipe full of water
- heat energy (which at a molecular scale is just kinetic energy again)
- an electric current (moving electrons, so kinetic energy again)
- energetic neutrons and other products of fission or fusion (kinetic energy again)
So you can harness potential energy, but only indirectly.
answered 4 hours ago
gandalf61gandalf61
29915
answered 4 hours ago
gandalf61gandalf61
29915
answered 4 hours ago
gandalf61gandalf61
29915
answered 4 hours ago
gandalf61gandalf61
29915
29915
$begingroup$
I understand this, maybe my question should be is it possible to convert the potential energy of a building into a kinetic?
$endgroup$
– Grasper
4 hours ago
1
$begingroup$
@Grasper Sure. A few well placed explosive charges will convert the potential energy of a building into kinetic energy for a short period, before this kinetic energy is used to break a lot of chemical bonds. I believe there are videos of the phenomena available on YouTube :) But if you want to convert some of the kinetic energy back to potential energy afterwards then you have to design a building that will bounce.
$endgroup$
– gandalf61
4 hours ago
$begingroup$
Speaking of bouncing, skyscrapers actually swing. There were strips created that generate electricity. They placed them under a bridge and anytime car passed it generated electricity. So if a very long string is attached this could work but in that case I think the wind energy would be more efficient but who knows.
$endgroup$
– Grasper
47 mins ago
$begingroup$
@Grasper In all of those cases the energy isn't coming from nowhere. For the strips that generate electricity from moving cars, that energy comes from reducing the speed of the cars as they pass through (even if only a tiny bit), meaning in aggregate you are reducing the mileage of those cars. It's basically an extremely inefficient generator that runs on gas. You could get energy from swaying buildings, but that energy is from the wind moving the building, and as you said, directly harnessing the wind is going to be far more efficient. In every case the energy has to come from somewhere
$endgroup$
– Kevin Wells
13 mins ago
add a comment |
$begingroup$
I understand this, maybe my question should be is it possible to convert the potential energy of a building into a kinetic?
$endgroup$
– Grasper
4 hours ago
1
$begingroup$
@Grasper Sure. A few well placed explosive charges will convert the potential energy of a building into kinetic energy for a short period, before this kinetic energy is used to break a lot of chemical bonds. I believe there are videos of the phenomena available on YouTube :) But if you want to convert some of the kinetic energy back to potential energy afterwards then you have to design a building that will bounce.
$endgroup$
– gandalf61
4 hours ago
$begingroup$
Speaking of bouncing, skyscrapers actually swing. There were strips created that generate electricity. They placed them under a bridge and anytime car passed it generated electricity. So if a very long string is attached this could work but in that case I think the wind energy would be more efficient but who knows.
$endgroup$
– Grasper
47 mins ago
$begingroup$
@Grasper In all of those cases the energy isn't coming from nowhere. For the strips that generate electricity from moving cars, that energy comes from reducing the speed of the cars as they pass through (even if only a tiny bit), meaning in aggregate you are reducing the mileage of those cars. It's basically an extremely inefficient generator that runs on gas. You could get energy from swaying buildings, but that energy is from the wind moving the building, and as you said, directly harnessing the wind is going to be far more efficient. In every case the energy has to come from somewhere
$endgroup$
– Kevin Wells
13 mins ago
$begingroup$
I understand this, maybe my question should be is it possible to convert the potential energy of a building into a kinetic?
$endgroup$
– Grasper
4 hours ago
$begingroup$
I understand this, maybe my question should be is it possible to convert the potential energy of a building into a kinetic?
$endgroup$
– Grasper
4 hours ago
1
1
$begingroup$
@Grasper Sure. A few well placed explosive charges will convert the potential energy of a building into kinetic energy for a short period, before this kinetic energy is used to break a lot of chemical bonds. I believe there are videos of the phenomena available on YouTube :) But if you want to convert some of the kinetic energy back to potential energy afterwards then you have to design a building that will bounce.
$endgroup$
– gandalf61
4 hours ago
$begingroup$
@Grasper Sure. A few well placed explosive charges will convert the potential energy of a building into kinetic energy for a short period, before this kinetic energy is used to break a lot of chemical bonds. I believe there are videos of the phenomena available on YouTube :) But if you want to convert some of the kinetic energy back to potential energy afterwards then you have to design a building that will bounce.
$endgroup$
– gandalf61
4 hours ago
$begingroup$
Speaking of bouncing, skyscrapers actually swing. There were strips created that generate electricity. They placed them under a bridge and anytime car passed it generated electricity. So if a very long string is attached this could work but in that case I think the wind energy would be more efficient but who knows.
$endgroup$
– Grasper
47 mins ago
$begingroup$
Speaking of bouncing, skyscrapers actually swing. There were strips created that generate electricity. They placed them under a bridge and anytime car passed it generated electricity. So if a very long string is attached this could work but in that case I think the wind energy would be more efficient but who knows.
$endgroup$
– Grasper
47 mins ago
$begingroup$
@Grasper In all of those cases the energy isn't coming from nowhere. For the strips that generate electricity from moving cars, that energy comes from reducing the speed of the cars as they pass through (even if only a tiny bit), meaning in aggregate you are reducing the mileage of those cars. It's basically an extremely inefficient generator that runs on gas. You could get energy from swaying buildings, but that energy is from the wind moving the building, and as you said, directly harnessing the wind is going to be far more efficient. In every case the energy has to come from somewhere
$endgroup$
– Kevin Wells
13 mins ago
$begingroup$
@Grasper In all of those cases the energy isn't coming from nowhere. For the strips that generate electricity from moving cars, that energy comes from reducing the speed of the cars as they pass through (even if only a tiny bit), meaning in aggregate you are reducing the mileage of those cars. It's basically an extremely inefficient generator that runs on gas. You could get energy from swaying buildings, but that energy is from the wind moving the building, and as you said, directly harnessing the wind is going to be far more efficient. In every case the energy has to come from somewhere
$endgroup$
– Kevin Wells
13 mins ago
add a comment |
$begingroup$
Yes, you can convert the potential energy of the skyscraper into useful work. But, to extract useful work from the potential energy, must reduce the potential energy, that is: you must reduce the height of the skyscraper. You must tear the skyscraper down to get its energy.
You should note that skyscrapers aren't free and that someone used a crane powered by electricity or diesel to lift the parts of the skyscraper to their current positions. You are guaranteed to get less energy out of this process than was put in to build the skyscraper. You will waste a lot of energy in the process of converting energy from diesel or the electric grid into the potential energy of the skyscraper and then back into electricity. This would be a terribly inefficient way to store energy.
However, as noted by another answer, this is essentially what we do with hydroelectric dams. We move water from a high altitude to a lower altitude and extract useful work that is converted into electrical energy. This energy is free in the sense that the sun evaporated water somewhere and it rained down on the high altitude reservoir. So hydroelectric power is, at its core, solar power, because the sun effectively pumps the water uphill and we extract energy as it moves downhill.
Using actual electrically powered pumps, you can pump water uphill to store energy. You can use the energy later by allowing it to flow downhill.
answered 1 hour ago
WaterMoleculeWaterMolecule
21114
$endgroup$
add a comment |
$begingroup$
Yes, you can convert the potential energy of the skyscraper into useful work. But, to extract useful work from the potential energy, must reduce the potential energy, that is: you must reduce the height of the skyscraper. You must tear the skyscraper down to get its energy.
You should note that skyscrapers aren't free and that someone used a crane powered by electricity or diesel to lift the parts of the skyscraper to their current positions. You are guaranteed to get less energy out of this process than was put in to build the skyscraper. You will waste a lot of energy in the process of converting energy from diesel or the electric grid into the potential energy of the skyscraper and then back into electricity. This would be a terribly inefficient way to store energy.
However, as noted by another answer, this is essentially what we do with hydroelectric dams. We move water from a high altitude to a lower altitude and extract useful work that is converted into electrical energy. This energy is free in the sense that the sun evaporated water somewhere and it rained down on the high altitude reservoir. So hydroelectric power is, at its core, solar power, because the sun effectively pumps the water uphill and we extract energy as it moves downhill.
Using actual electrically powered pumps, you can pump water uphill to store energy. You can use the energy later by allowing it to flow downhill.
answered 1 hour ago
WaterMoleculeWaterMolecule
21114
$endgroup$
add a comment |
$begingroup$
Yes, you can convert the potential energy of the skyscraper into useful work. But, to extract useful work from the potential energy, must reduce the potential energy, that is: you must reduce the height of the skyscraper. You must tear the skyscraper down to get its energy.
You should note that skyscrapers aren't free and that someone used a crane powered by electricity or diesel to lift the parts of the skyscraper to their current positions. You are guaranteed to get less energy out of this process than was put in to build the skyscraper. You will waste a lot of energy in the process of converting energy from diesel or the electric grid into the potential energy of the skyscraper and then back into electricity. This would be a terribly inefficient way to store energy.
However, as noted by another answer, this is essentially what we do with hydroelectric dams. We move water from a high altitude to a lower altitude and extract useful work that is converted into electrical energy. This energy is free in the sense that the sun evaporated water somewhere and it rained down on the high altitude reservoir. So hydroelectric power is, at its core, solar power, because the sun effectively pumps the water uphill and we extract energy as it moves downhill.
Using actual electrically powered pumps, you can pump water uphill to store energy. You can use the energy later by allowing it to flow downhill.
answered 1 hour ago
WaterMoleculeWaterMolecule
21114
$endgroup$
Yes, you can convert the potential energy of the skyscraper into useful work. But, to extract useful work from the potential energy, must reduce the potential energy, that is: you must reduce the height of the skyscraper. You must tear the skyscraper down to get its energy.
You should note that skyscrapers aren't free and that someone used a crane powered by electricity or diesel to lift the parts of the skyscraper to their current positions. You are guaranteed to get less energy out of this process than was put in to build the skyscraper. You will waste a lot of energy in the process of converting energy from diesel or the electric grid into the potential energy of the skyscraper and then back into electricity. This would be a terribly inefficient way to store energy.
However, as noted by another answer, this is essentially what we do with hydroelectric dams. We move water from a high altitude to a lower altitude and extract useful work that is converted into electrical energy. This energy is free in the sense that the sun evaporated water somewhere and it rained down on the high altitude reservoir. So hydroelectric power is, at its core, solar power, because the sun effectively pumps the water uphill and we extract energy as it moves downhill.
Using actual electrically powered pumps, you can pump water uphill to store energy. You can use the energy later by allowing it to flow downhill.
answered 1 hour ago
WaterMoleculeWaterMolecule
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answered 1 hour ago
WaterMoleculeWaterMolecule
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answered 1 hour ago
WaterMoleculeWaterMolecule
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answered 1 hour ago
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$begingroup$
Potential energy IS stored mechanical energy. In the case of your pendulum, that stored mechanical energy gets transferred to kinetic energy as the pendulum moves... How do you "capture" the mechanical energy being transferred into kinetic energy?
$endgroup$
– N. Steinle
4 hours ago
$begingroup$
As others have said, you totally can extract electricity from gravitational potential energy, but you have to convert it to kinetic energy, as is done with the gravity light (deciwatt.global/gravitylight). You let a bag of rocks descend slowly that turns a generator, which produces electricity. But that energy isn't free, it comes from your muscles putting up the light, and it doesn't last forever, just until it turns back into kinetic and then electrical energy
$endgroup$
– Kevin Wells
7 mins ago