3 ms·

> Thermoelectric power plants: 41% of total US water use I did some research on this statistic. More than 90% of this is returned to source. So if the power

by throwaway2037 2mo ago

> Thermoelectric power plants: 41% of total US water use I did some research on this statistic. More than 90% of this is returned to source. So if the power plant is drawing water from a river (or aquifer), it is returned after being used to generate electricity (create steam, turn turbines). For example, if you have a 1GW coal powerplant on a river, it might draw 4 billion liters of water per day, but will only evaporate about 5-10% of that amount. The rest is returned to the river. Of course, this is much less exciting (click-baity) than writing "41% of US water use is for thermoelectric power plants".

tesnorindian 2mo ago
Most rivers drain into Oceans while some do drain into inland lakes.
yreg 2mo ago
Is it different with data centers?
- consp 2mo ago
  Depends on if they use evaporative cooling or not. But the water returned is warmer which can harm the ecosystem quite a bit, both for power plants and data centers.
  - deleted 2mo ago
    [deleted]
  - AnthonyMouse 2mo ago
    Water which is evaporated is also returned to the ecosystem. It falls back out as rain. The heat issue is also widely misunderstood. The state of California gets on the order of a PWh of heat every day from the sun. A million GWh. Even a large nuclear plant doesn't make a dent in that. The issue is localized to the immediate area at the outlet, because the water temperature directly at the outlet is going to be higher than it is at the inlet, before it diffuses back into the background. Naturally the way to mitigate this is to pull more water through the cooling system, all of which you're still returning, but then you raise the temperature of twice as much water by half as much temperature, which is what you want since the temperature delta is the concern. Of course, doing this will cause people to accuse you of using more water, even though you're neither consuming the water nor modifying the amount of heat being transferred to the environment. In addition to that, water has extremely different levels of scarcity depending on what region you're in. Parts of California and Texas have arid climates and extremely limited economical means to source additional fresh water. Areas like the Midwest get dramatically more rainfall and as a result fresh water is not meaningfully scarce there.
    - lesostep 2mo ago
      >> Water which is evaporated is also returned to the ecosystem. It falls back out as rain. No, not necessary to the same one. Every body of water has a catchment area, and through the bottom parts of some lakes/rivers water sips into the earth, filling underground water levels. Now, let's say you life on a coast with a regular winds in the ocean direction. You basin fills with water evaporated by you, your neighbors catchments and – sometimes – ocean (wind doesn't always blow in one direction). But the large percentage of the water you evaporate goes into the ocean. Let's say 90 percent falls again on your catchment area, 10 percent falls in ocean but is regained through neighbors basins evaporation. Now, if you increase your evaporation, you could easily drain a lot of water from your land.
      - yreg 2mo ago
        Why can't they condense the vapor on site? Or simply use closed cooling loops? Would it be that much more expensive?
        AnthonyMouse 2mo ago
        The premise of evaporative cooling is that the phase change absorbs an enormous amount of heat and carries it away. The heat is returned when it condenses back into water, so doing it on-site would defeat the purpose. Hypothetically you could recondense it somewhere else, i.e. get a large land area and then capture the rainfall. Probably the big win there would be to take the water which is currently routed into the ocean from storm drains and recover it instead of doing that with it.
      - AnthonyMouse 2mo ago
        > Now, if you increase your evaporation, you could easily drain a lot of water from your land. At which point we're back to the quadrillion watt hours of sunlight you get a day, which evaporates such a large amount of water that you have to be doing something pretty dramatic to move the needle. Which thermal power plants and data centers don't, but agriculture? It's pumping trillions of gallons of water out of the ground and into fields in that sun.
- throwaway2037 2mo ago
  I did some research on this matter. There are (at least) two uses for water by data centers. (1) If the data center is in a very low humidity environment, the data center is artificially humidified (is this a real English word?) to reduce the effects of static electricty. (2) Almost all data centers outside of cold regions (northern Europe, etc.) use water for evaporative cooling.
  - dredmorbius 2mo ago
    humidified Yes, a real English word. Machines that humidify air are called ... humidifiers. (There are also dehumidifiers.)

tesnorindian 2mo ago

Most rivers drain into Oceans while some do drain into inland lakes.

yreg 2mo ago

Is it different with data centers?

consp 2mo ago
Depends on if they use evaporative cooling or not. But the water returned is warmer which can harm the ecosystem quite a bit, both for power plants and data centers.
- deleted 2mo ago
  [deleted]
- AnthonyMouse 2mo ago
  Water which is evaporated is also returned to the ecosystem. It falls back out as rain. The heat issue is also widely misunderstood. The state of California gets on the order of a PWh of heat every day from the sun. A million GWh. Even a large nuclear plant doesn't make a dent in that. The issue is localized to the immediate area at the outlet, because the water temperature directly at the outlet is going to be higher than it is at the inlet, before it diffuses back into the background. Naturally the way to mitigate this is to pull more water through the cooling system, all of which you're still returning, but then you raise the temperature of twice as much water by half as much temperature, which is what you want since the temperature delta is the concern. Of course, doing this will cause people to accuse you of using more water, even though you're neither consuming the water nor modifying the amount of heat being transferred to the environment. In addition to that, water has extremely different levels of scarcity depending on what region you're in. Parts of California and Texas have arid climates and extremely limited economical means to source additional fresh water. Areas like the Midwest get dramatically more rainfall and as a result fresh water is not meaningfully scarce there.
  - lesostep 2mo ago
    >> Water which is evaporated is also returned to the ecosystem. It falls back out as rain. No, not necessary to the same one. Every body of water has a catchment area, and through the bottom parts of some lakes/rivers water sips into the earth, filling underground water levels. Now, let's say you life on a coast with a regular winds in the ocean direction. You basin fills with water evaporated by you, your neighbors catchments and – sometimes – ocean (wind doesn't always blow in one direction). But the large percentage of the water you evaporate goes into the ocean. Let's say 90 percent falls again on your catchment area, 10 percent falls in ocean but is regained through neighbors basins evaporation. Now, if you increase your evaporation, you could easily drain a lot of water from your land.
    - yreg 2mo ago
      Why can't they condense the vapor on site? Or simply use closed cooling loops? Would it be that much more expensive?
      - AnthonyMouse 2mo ago
        The premise of evaporative cooling is that the phase change absorbs an enormous amount of heat and carries it away. The heat is returned when it condenses back into water, so doing it on-site would defeat the purpose. Hypothetically you could recondense it somewhere else, i.e. get a large land area and then capture the rainfall. Probably the big win there would be to take the water which is currently routed into the ocean from storm drains and recover it instead of doing that with it.
    - AnthonyMouse 2mo ago
      > Now, if you increase your evaporation, you could easily drain a lot of water from your land. At which point we're back to the quadrillion watt hours of sunlight you get a day, which evaporates such a large amount of water that you have to be doing something pretty dramatic to move the needle. Which thermal power plants and data centers don't, but agriculture? It's pumping trillions of gallons of water out of the ground and into fields in that sun.
throwaway2037 2mo ago
I did some research on this matter. There are (at least) two uses for water by data centers. (1) If the data center is in a very low humidity environment, the data center is artificially humidified (is this a real English word?) to reduce the effects of static electricty. (2) Almost all data centers outside of cold regions (northern Europe, etc.) use water for evaporative cooling.
- dredmorbius 2mo ago
  humidified Yes, a real English word. Machines that humidify air are called ... humidifiers. (There are also dehumidifiers.)