4 ms·

> The key principle of bulk energy storage is E = Fx, applied liberally worldwide for centuries. It is taught to every freshman engineering student Hi there, I

> The key principle of bulk energy storage is E = Fx, applied liberally worldwide for centuries. It is taught to every freshman engineering student Hi there, I graduated engineering and am currently applying for professional licensure. I took only one course focused on energy, but I've never heard of E=Fx. Googling it brought up no relevant results. Could you expand on what it is?

ncmncm 4y ago
You may go back to your freshman physics textbook. If you get a professional engineering license without recalling basic Newtonian physics, that just tells us the licensing process has utterly failed us.
- Manuel_D 4y ago
  What do the values of E, F, and x even stand for? Googling this yields no related results [1]. Presumably F and x stand for the energy output of a storage system and the duration that system is online, respectively. But simply stating that equation is pointless, unless you actually give a plan to deliver on appropriate values of F and x. It's about as inane as saying "E + MC^2 so let's just build fusion and be done with it." 1. https://google.gprivate.com/search.php?search?q=E%20=%20Fx%20energy%20storage https://google.gprivate.com/search.php?search?q=E%20=%20Fx%2...
  - ncmncm 4y ago
    You really are fooling no one. Why maintain the imposture? Are you not embarrassed at being called out on falsehoods each time you trot them out again?
    - Manuel_D 4y ago
      For the third time, what do F, E, and x stand for? Are you not embarrassed about telling people to go back to their physics textbook when the equation you're writing has nothing to do with energy storage?
      - ncmncm 4y ago
        You still fool no one.
- SECProto 4y ago
  > You may go back to your freshman physics textbook. I may, but I live in a country that doesn't use the word freshman, so I don't know which year physics text that would be. I assume from context you were meaning to refer to gravitational potential energy, which is generally represented as ∆U=mg∆h (change in gravitational potential energy equals mass times gravity times change in height). The variables you used (E=Fx) would mean energy equals force times (variable). From dimensional analysis the variable would have to be units of length (m), however it clearly only applies in the vertical dimension so it's better to use a specific variable like ∆h Regardless, energy storage via gravitational potential energy (i.e. pumped storage) has been in use for about a century, and still makes up a rsmall proportion of grid operations. It has very specific requirements that aren't available everywhere. It's not an end-all solution for energy storage.
  - lumost 4y ago
    Not the parent, but feel compelled to clarify the physics here. Delta E= force * distance always holds. This is the same physics of a car breaking or a jet accelerating. However a more general formula would be the integral of net force over distance.
    - SECProto 4y ago
      Yes, I was just suggesting that force times distance is not relevant to energy storage as gravitational potential unless the distance is vertical.
      - deleted 4y ago
        [deleted]
      - ncmncm 4y ago
        Gravitation is not the only force. Even without local "freshman" classes, you may look it up in any dictionary. Or, just stop pretending.
        SECProto 4y ago
lumost 4y ago
They are likely referring to force * distance = energy. Which in context is a pitch for pumped hydro storage. This all sounds well and good, however it’s highly unclear that utility scale pumped hydro is viable. To make it work you need to have plentiful water, limited evaporative loss/other losses, and two large basins to store both the charge, and discharge of water. In the event of drought, these facilities could become impractical. Hydro facilities have their own environmental concerns. Combined with shifting climates and rainfall patterns there are many challenges to be solved. (some of which go away if the hydro storage is in underground ceiled chambers… which also has a cost associated)
- ncmncm 4y ago
  Pumped hydro is not the only storage; otherwise I would have said E = mgh. Pumped hydro is practical in many, many more places than have hydro generation today, because unlike those, it does not need a watershed. It can use a deep underground cavity where a hill is not forthcoming. Where water is scarce, other methods will be used. Other applications of Fx include (but are not limited to) compressed air, and buoyancy. Places that run low on storage resource can import and burn fuel, as they do now, or schedule power from a transmission line, where they have one. Soon, liquified anhydrous ammonia will be cheapest and most practical, but liquified hydrogen may be cheaper and sufficiently practical for bigger utilities. Ammonia has the advantage that it does not need cryogenic treatment. These will be available from numerous tropical sources.

ncmncm 4y ago

You may go back to your freshman physics textbook. If you get a professional engineering license without recalling basic Newtonian physics, that just tells us the licensing process has utterly failed us.

Manuel_D 4y ago
What do the values of E, F, and x even stand for? Googling this yields no related results [1]. Presumably F and x stand for the energy output of a storage system and the duration that system is online, respectively. But simply stating that equation is pointless, unless you actually give a plan to deliver on appropriate values of F and x. It's about as inane as saying "E + MC^2 so let's just build fusion and be done with it." 1. https://google.gprivate.com/search.php?search?q=E%20=%20Fx%20energy%20storage https://google.gprivate.com/search.php?search?q=E%20=%20Fx%2...
- ncmncm 4y ago
  You really are fooling no one. Why maintain the imposture? Are you not embarrassed at being called out on falsehoods each time you trot them out again?
  - Manuel_D 4y ago
    For the third time, what do F, E, and x stand for? Are you not embarrassed about telling people to go back to their physics textbook when the equation you're writing has nothing to do with energy storage?
    - ncmncm 4y ago
      You still fool no one.
SECProto 4y ago
> You may go back to your freshman physics textbook. I may, but I live in a country that doesn't use the word freshman, so I don't know which year physics text that would be. I assume from context you were meaning to refer to gravitational potential energy, which is generally represented as ∆U=mg∆h (change in gravitational potential energy equals mass times gravity times change in height). The variables you used (E=Fx) would mean energy equals force times (variable). From dimensional analysis the variable would have to be units of length (m), however it clearly only applies in the vertical dimension so it's better to use a specific variable like ∆h Regardless, energy storage via gravitational potential energy (i.e. pumped storage) has been in use for about a century, and still makes up a rsmall proportion of grid operations. It has very specific requirements that aren't available everywhere. It's not an end-all solution for energy storage.
- lumost 4y ago
  Not the parent, but feel compelled to clarify the physics here. Delta E= force * distance always holds. This is the same physics of a car breaking or a jet accelerating. However a more general formula would be the integral of net force over distance.
  - SECProto 4y ago
    Yes, I was just suggesting that force times distance is not relevant to energy storage as gravitational potential unless the distance is vertical.
    - deleted 4y ago
      [deleted]
    - ncmncm 4y ago
      Gravitation is not the only force. Even without local "freshman" classes, you may look it up in any dictionary. Or, just stop pretending.
      - SECProto 4y ago

lumost 4y ago

They are likely referring to force * distance = energy. Which in context is a pitch for pumped hydro storage. This all sounds well and good, however it’s highly unclear that utility scale pumped hydro is viable. To make it work you need to have plentiful water, limited evaporative loss/other losses, and two large basins to store both the charge, and discharge of water. In the event of drought, these facilities could become impractical. Hydro facilities have their own environmental concerns. Combined with shifting climates and rainfall patterns there are many challenges to be solved. (some of which go away if the hydro storage is in underground ceiled chambers… which also has a cost associated)

ncmncm 4y ago
Pumped hydro is not the only storage; otherwise I would have said E = mgh. Pumped hydro is practical in many, many more places than have hydro generation today, because unlike those, it does not need a watershed. It can use a deep underground cavity where a hill is not forthcoming. Where water is scarce, other methods will be used. Other applications of Fx include (but are not limited to) compressed air, and buoyancy. Places that run low on storage resource can import and burn fuel, as they do now, or schedule power from a transmission line, where they have one. Soon, liquified anhydrous ammonia will be cheapest and most practical, but liquified hydrogen may be cheaper and sufficiently practical for bigger utilities. Ammonia has the advantage that it does not need cryogenic treatment. These will be available from numerous tropical sources.