what happens to water when we use it to produce electricity

[Pradeepkumar]

when we use water to produce electricity(hydro-electricity)do water get exhausted. that is the quantity of water will change or not

[insane_alien]

the quantity of water will not change. it just gets slowed down a little.

[Mr Skeptic]

the quantity of water will not change. it just gets slowed down a little.

 

And generally you speed it up by building a big dam and letting the water fall from a distance, before slowing it down to extract the energy.

 

In a sense, it works much like wind power, except with water and dams instead of wind.

[insane_alien]

and water is effectively an incompressible fluid* while air is compressible.

 

*while water can actually be compressed, the ranges considered in hydroelectric power production allow this to be safely ignored as the effects are on the order of parts per billion.

[npts2020]

Hydroelectric power is usually from a dam with a turbine that is turned by water falling from the top to the bottom. This converts the potential energy of the water (at rest on top) to kinetic energy (water falling) to mechanical energy (turning the turbine which turns a generator) to electrical energy (output of the generator). I believe that is about as simple as I can state it.

[Martin]

what happens to water when we use it to produce electricity

 

it makes the water COLDER than it would otherwise be

 

(if we did not divert it and put it thru the turbine, but simply let it go roaring down the hill or falling down the cliff)

 

 

when we use water to produce electricity(hydro-electricity)... the quantity of water will change or not

 

Indeed, the quantity of water will change in the sense that the water downriver will have less MASS than it would have had if we had not diverted it thru the turbine.

 

The number of molecules of water is unchanged, but they have less heat-content---they are at a cooler temperature---and so they are not so massive.

==========================

 

This may seem confusing, Pradeep. the point is that when water falls off a cliff there is a big splashing agitation/commotion at the bottom of the cliff where the kinetic energy of falling is turned into the random motion of heat energy.

 

so in nature (without human intervention) the graviational potential energy of the water is converted to a very slight increase in the temperature of the water.

 

if we interfere in nature, and make the water pass thru a turbine, there is not so much commotion and wasted turbulence and kinetic energy, so the water is not warmed by that. so it will be slightly cooler than it would have been.

 

but heat energy contributes to the mass of water by the ususal connection between mass and energy. so the water is slightly less massive now, because it is cooler.

 

however this is not bad for the water or for the wild-life. it does not do anybody any harm. nobody loses anything by having the water be slightly cooler (by just a tiny fraction of a degree Celsius). so it is not to worry about.