camelot-forum.co.uk

Wonder if this actually gets built? Certainly seems like a deep mine with a 700m shaft, is 4MW (or is it 4MWh) good? I suppose better than not having it.

https://renews.biz/83986/gravitricty-pl ... zech-mine/

The agreement will see the two companies seek funding to transform the former decommissioned Darkov deep mine – which is located in the Moravian-Silesian region of the Czech Republic - into a 4MW / 2MWh energy store.
https://www.theengineer.co.uk/content/n ... ergy-store

Ever tried to maintain a crane winch? Ridiculous concept. Should just pump water.

Swwils wrote: ↑Wed Feb 22, 2023 7:37 pm Ever tried to maintain a crane winch? Ridiculous concept. Should just pump water.

They will be doing that anyway... most mines need perpetual pumping just to keep them useable. Maybe the droppers will be so dense that the buoyancy and viscosity - or corrosivity - of the (flood) water won't matter?

Back to the first point: there are precious few places where pumped hydro can be put. Which is why we haven't seen any for half a century or more now.

AE-NMidlands wrote: ↑Wed Feb 22, 2023 10:09 pm

Back to the first point: there are precious few places where pumped hydro can be put. Which is why we haven't seen any for half a century or more now.

Why not pump the bottom galleries dry, fit air tight bladders in them, allow them to flood a few hundred metres deep and use them to store compressed air at constant pressure?

openspaceman wrote: ↑Wed Feb 22, 2023 11:04 pm

AE-NMidlands wrote: ↑Wed Feb 22, 2023 10:09 pm Back to the first point: there are precious few places where pumped hydro can be put. Which is why we haven't seen any for half a century or more now.

Why not pump the bottom galleries dry, fit air tight bladders in them, allow them to flood a few hundred metres deep and use them to store compressed air at constant pressure?

That is a really good idea, as long as they are stable enough and not so rough (with steel support beams and suchlike) which would wreck the bladders.
I know a large part of coalmine work was keeping the roadways open and safe to use.

This is a specific solution that matches the topography and opportunities of the Czech Republic and they are trying to do something within that context, a bit like the UK opting primarily for wind (because we have so much of it) while trying, albeit at a small scale, for quite a few decades to harness the other great energy source we have in our coastal waters.

Given that largely untapped potential of tidal energy and the successful operational strides that have been made in that direction most recently the UK could be said to be less reliant on alternative types of stored energy options. That being said it is however an option that a few are pursuing in a number of countries and if it works as a private investment opportunity then all well and good - after all diversity is king when it comes to RE and energy storage.

I for one wish them good fortune and success.

Moxi

Exactly my point. They can't pump hydro since the geography needs to be just right and in any case takes years to build out. Once your done you can't dispatch all the energy quickly anyway.

Even if you make this magically almost free to operate it doesn't scale and costs too much. A simple exercise to imagine: test a cheaper version that mostly already exists e.g. a train on an existing trackside mountain. You still can't make the maths work even being given all those bits for free.

Would you put your own money into this? How about the classic "this will work but only if we raise 8x the funding!' pitch.

Yes it feels like something that should be a Government backed scheme of last resort and when placed in that camp there are arguably better options.

I liked your train analogy, here in North Wales we have a lot of slate workings where the old haul roads are still evident with slopes typically 1 in 3 - they would be very easy to re rail and install winches' and wights with a generator and you would have a reproducible small scale system that could address the Grids rapid response requirements.

As far as I can see no one is doing anything with this ideal infrastructure - most likely because its not profitable but the the opportunity is there should it become financially viable at a later date

Moxi

openspaceman wrote: ↑Wed Feb 22, 2023 11:04 pm

AE-NMidlands wrote: ↑Wed Feb 22, 2023 10:09 pm

Back to the first point: there are precious few places where pumped hydro can be put. Which is why we haven't seen any for half a century or more now.

Why not pump the bottom galleries dry, fit air tight bladders in them, allow them to flood a few hundred metres deep and use them to store compressed air at constant pressure?

Or airbags under the sea?