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)

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.

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.

> 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.

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.

Yes, I was just suggesting that force times distance is not relevant to energy storage as gravitational potential unless the distance is vertical.

Gravitation is not the only force.

Even without local "freshman" classes, you may look it up in any dictionary. Or, just stop pretending.

I understand gravitation isn't the only force... how are you proposing to store energy? Other options (beside pumped hydro as gravitational potential energy storage) that come to mind are flywheels, springs, or batteries .... all of these technologies have existed for more than 100 years, and batteries are the only ones currently growing in usage - there's a good reason for that.

Batteries are being used primarily in electric vehicles, for, as you say, good reasons, and for domestic backup. For bulk utility storage, batteries are the most expensive choice, although battery cost is still falling fast and numerous utility-adapted chemistries are competing.

F may be water pressure, as in pumped hydro (which is growing) using elevated or underground reservoirs, or air pressure, as in CAES underground or underwater compressed air, or buoyancy using sea-floor pulleys and floats. No doubt as a soon-to-be Licensed Professional Engineer you will soon be able to think of other persistent forces.

Springs and flywheels will not be used for bulk utility-scale storage.

Generally, utilities will use what is cheap and reliable at the time they build it. Building storage before you have enough spare renewable capacity to charge it would be a bad misallocation of capital

Anhydrous ammonia will not be the cheapest medium, but has advantages of transportability and fantastic usefulness. Any unused overbuilt capacity will be put to work synthesizing for sale.

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%2...

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?

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?

You still fool no one.