5 ms·

It can work, it's just a cost equation. You need a large amount of mass to get meaningful amounts of energy stored. So pumped hydro is nice because you are basi

It can work, it's just a cost equation. You need a large amount of mass to get meaningful amounts of energy stored. So pumped hydro is nice because you are basically using natural reservoirs and some cheap pumps and pipes. A water tower needs to be built first and only stores a limited amount of potential energy. The problem is not the efficiencies but the cost of building a big enough tower. A tower with the same capacity of a pumped hydro reservoir would be insanely expensive. Or alternatively building many thousands of smaller towers that add up to the same capacity would also not be cheap. There are a few alternative gravity systems being tested out in the form of e.g. big cranes with weights that drive generators, mine shafts with similar systems, etc. Proving they work efficiently is not the issue. It's just scaling their deployment cost effectively.

killjoywashere 4y ago
Why would you need a water tower? If you're in flat geography at sea level, you could probably access tidal energy to drive generators. If you're flat and far from water, couldn't you dig a shallow hole and a deeper hole, and put the generator and pumps in between? I mean, even in Kansas it's not that hard to find an elevation difference of 50 feet.
- Sakos 4y ago
  > If you're in flat geography at sea level, you could probably access tidal energy to drive generators There are projects testing this, but ocean water is highly corrosive and maintenance is a nightmare.
- jillesvangurp 4y ago
  It's just an example from the comment I replied to was using; I agree it's not a very feasible thing to do. But I used it to illustrate the difference in cost between that and pumped hydro using natural reservoirs. The point being here that you'd need a stupidly large amount of water towers to come close to the amount of energy you can store in a pumped hydro reservoir Whether it's a water tower, a big crane, or whatever that holds the mass that you then use to drive a generator. You have to build it or use nature to have some natural height difference. Building infrastructure like that is expensive. So nature is preferable and way cheaper. I come from a relatively flat part of the world; so that's not really an option there. Gravity based batteries are nice where they can be done cheaply. But otherwise probably not ideal.
- Schroedingersat 4y ago
  Digging 100m deep holes isn't cheap.

killjoywashere 4y ago

Why would you need a water tower? If you're in flat geography at sea level, you could probably access tidal energy to drive generators. If you're flat and far from water, couldn't you dig a shallow hole and a deeper hole, and put the generator and pumps in between? I mean, even in Kansas it's not that hard to find an elevation difference of 50 feet.

Sakos 4y ago
> If you're in flat geography at sea level, you could probably access tidal energy to drive generators There are projects testing this, but ocean water is highly corrosive and maintenance is a nightmare.
jillesvangurp 4y ago
It's just an example from the comment I replied to was using; I agree it's not a very feasible thing to do. But I used it to illustrate the difference in cost between that and pumped hydro using natural reservoirs. The point being here that you'd need a stupidly large amount of water towers to come close to the amount of energy you can store in a pumped hydro reservoir Whether it's a water tower, a big crane, or whatever that holds the mass that you then use to drive a generator. You have to build it or use nature to have some natural height difference. Building infrastructure like that is expensive. So nature is preferable and way cheaper. I come from a relatively flat part of the world; so that's not really an option there. Gravity based batteries are nice where they can be done cheaply. But otherwise probably not ideal.
Schroedingersat 4y ago
Digging 100m deep holes isn't cheap.