Water Battery Idea

[bstump]

I recently read about Switzerland's new "water battery" (https://electrek.co/2022/08/02/chec...ater-battery-that-can-power-up-to-900k-homes/) and had an idea.

I want to do a fish pond on my 12 acres. I was thinking about doing two ponds, one at the top of our hill and one at the bottom (about a 25-30 foot drop). If I an find a small hydro generator I could "drain" the upper pond into the bottom pond through it during the night to generate electricity and then use the extra solar during the day to pump that water back to the upper pond.

I will have to ask a fish pond expert if that would be too "bad" on the fish in the pond, but when I saw the idea it made me think.

Has anyone else done this? Does anyone here have a good source for the hydro generator?

Thank you ALL for ALL the help you've provided so far in my "green" journey!!!! This has been SO FUN as a tech nerd!!!!!!!

 

[sunshine_eggo]

Pretty sure the hydro turbine blades will kill them.

 

[RSahan]

I don't think it would be worth the time, headache, and money. Just buy some lifepo4's

 

[sirslayer]

I’ve seen this video on micro hydro and it’s possible!! I also own property that is empty in Colorado and I plan to build a ranch and of course it’s next to the Rio Grande river but check out this link

 

[Casteil]

I’ve seen this video on micro hydro and it’s possible!! I also own property that is empty in Colorado and I plan to build a ranch and of course it’s next to the Rio Grande river but check out this link

Of course it's possible... but there's a huge difference between a micro hydro setup with a continuous natural water source and attempting to make your own source by pumping it.

I'm with @ruchira88 on this one - for the cost, you could probably just add more panels and/or batteries and come out way better off in the end.

Here's one of the more interesting/creative hydro setups I've ever seen (takeaway here is that you could potentially repurpose that kind of washing machine to build a hydro turbine on the cheap):

Pretty sure the hydro turbine blades will kill them.

Not a hard problem to solve, just use mesh (or small holes or whatever) to keep larger objects out of the pump/turbine inlet/outlet.. and low/high water shutoffs to prevent either pond from being totally drained.

 

[sirslayer]

Overall going solar is cheaper, no mechanical devices to maintain but batteries storage is the high cost with a chance of failure in long term. The chance of failure with mechanical components is higher then storage batteries.

 

[bstump]

I don't think it would be worth the time, headache, and money. Just buy some lifepo4's

I have them already. Was just thinking this might be a cost effective way to supplement, adding a small turbine and a pump.

 

[OzSolar]

It's so fun to think about things like this!

My understanding is that Pumped storage , which has been around a long time, is very cost effective on a utility scale particularly when coupled with nuclear power. Pump up at night during off peak times then generate with hydro in the day during peak times.

I fear that it wouldn't scale down to a residential application very well.

Also I suspect you'd be looking at something far less than a 25% round trip efficiency. EG: You'd get less than 1 kWh of energy back for every 4 you used to pump to the upper pond.

edit: to fix typos

 

[Warpspeed]

Just buy some Lithium cells.
Pretty close to 100% efficiency, and no moving parts to go wrong.

 

[bstump]

Just buy some Lithium cells.
Pretty close to 100% efficiency, and no moving parts to go wrong.

I have them already. Was just thinking this might be a cost effective way to supplement, adding a small turbine and a pump.

 

[Warpspeed]

A small pumped hydro system has entertainment value only.
The time and money involved, would be much better spent elsewhere.

 

[time2roll]

I could see this as an excess load dump for all that excess solar power in the summer. I would assume less than 10% of the water would be used... are the ponds large enough that 10% would produce significant energy? 30' rise does not seem like much unless those ponds are borderline small lakes to get some real volume. Is there a combination pump-generator with enough efficiency or is this two pieces of equipment?

Just some random thoughts. Best of luck.

 

[bstump]

A small pumped hydro system has entertainment value only.
The time and money involved, would be much better spent elsewhere.

I think I could get the equipment for around $10K. While that would double my solar install, I'm still not sure if that would keep me above the water in winter. Looking to supplement that. I spent $196 in gasoline for my generator last month (propane is about 1/3 the cost and natural gas is about 1/10 the cost, but I don't have a generator for that yet - I did the math and I can generate electricity with a Generac cheaper than my local electric utility, even at current prices, which is pretty insane). I hate having to pull out the generator, especially in winter.

 

[OzSolar]

I did the math and I can generate electricity with a Generac cheaper than my local electric utility, even at current prices, which is pretty insane).

What cost per kWh from your generator did you come up with?

 

[Steve Fractals]

I like your idea, I guess you will need to calculate your water volume and fall in order to come up with how much you can store. Then you will need to calculate how much solar energy you will need to pump it up and if it makes sense with losses etc. I think it could work but only if you have really big almost lake sized ponds and the fall stores enough energy to make it worth it.

I know most will or have said batteries will be more cost effective in the long run but if you can make the numbers work for you then what a fun project it could be.

 

[kanelr]

SO THE LAKE IS YOUR "BATTERY"

 

[bstump]

SO THE LAKE IS YOUR "BATTERY"

Yep!

 

[45North]

A small pumped hydro system has entertainment value only.
The time and money involved, would be much better spent elsewhere.

Plus satisfaction and bragging rights if you can make it work.
Someone needs to think outside the box and try something new otherwise we'd all keep doing the same thing.
I assume water freezing is not a thing in your part of the world?

 

[Warpspeed]

In Australia, water is not allowed to freeze.

Sure, thinking outside the box is all part of the fun.
It can be pretty expensive fun though, unless the original concept is sound.

I frequently have off the wall ideas too, like this:
https://diysolarforum.com/threads/now-for-something-mini-hydro-a-little-bit-different.54131/

 

[Steve Fractals]

Gravity batteries of all sorts are making a come back so of course we have water like you are thinking but also lots of work around using blocks or crushed rock to store energy as heat or with gravity e.g. using old mine shafts, raise a big weight with solar/wind power and then lower it at night to release.

We have to keep trying things as energy storage needs sorting if we are ever to move largely to renewables.