Author Topic: Energy storage by moving concrete blocks  (Read 15825 times)

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Offline daqqTopic starter

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Energy storage by moving concrete blocks
« on: January 19, 2019, 05:52:19 pm »
The physics is sound and straightforward, the engineering, dunno, I guess that mechanical problems might arise:

https://energyvault.ch/

Any opinions?
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Offline Ice-Tea

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Re: Energy storage by moving concrete blocks
« Reply #1 on: January 19, 2019, 06:12:20 pm »
How is this better than pumped hydro storage?

Online coppice

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Re: Energy storage by moving concrete blocks
« Reply #2 on: January 19, 2019, 07:00:31 pm »
How is this better than pumped hydro storage?
They say the advantages are that smaller scale storage systems are feasible, and that the cost will be much lower. I see a number of problems, though.

There are only a limited number of locations where pumped storage will work well, because you need the high and low pools to be close together for the pipe resistance to be acceptable. For places with a lower gradient between the high and low locations, running large masses up and down rails might be a good choice. Rails can operate will pretty low rolling losses, so a rail based system to raise and lower cheap rough and ready blocks might work out well. The system Energy Vault is proposing goes to the opposite extreme - a 100% gradient, lifting blocks vertically, to build a tower, by stacking them. This looks nice in the video, but I suspect reality will bite. A practical system needs to work in strong winds, which will make it difficult to place blocks on long cables precisely. The system requires that many blocks be stacks up, because they won't get much potential energy stored in a low stack. Even with a really tall stack, the lower blocks in the stack won't be storing much energy. A tall stack would require precisely shaped blocks, precisely positioned, if the stack is to remain stable. Over time, how would they keep the blocks in pristine condition to fulfil this requirement?
 

Offline Twoflower

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Re: Energy storage by moving concrete blocks
« Reply #3 on: January 19, 2019, 07:40:21 pm »
Here's a podcast discussing an alternative to the concrete or to pumped hydro(Omega Tau – Gravity Storage). They say about the concrete-block approach that this potentially require much maintenance. Because lots of mechanics that could wear. One of the pro side is that even 'small' Installations seems to be possible.

If the Gravity Storage is a viable solution I'm not sure either. But it's an interesting approach as well.
 

Online tszaboo

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Re: Energy storage by moving concrete blocks
« Reply #4 on: January 19, 2019, 07:57:34 pm »
Let's do back of the envelope calculations:
Great Pyramid of Giza weights 500.000 tonnes. It is 146 meter high. It's center of gravity is at 1/4 of it's hight, 36m. It's potential energy is about 50 MWh.
These guys claim that they can store 35MWh in their tower. Basically claiming that they can build the pyramid in a day and take it apart at night.
 
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Offline Brutte

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Re: Energy storage by moving concrete blocks
« Reply #5 on: January 19, 2019, 08:01:20 pm »
Similar concept discussed on our forum, but railroad based instead of cranes.
 

Offline Yansi

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Re: Energy storage by moving concrete blocks
« Reply #6 on: January 19, 2019, 08:03:01 pm »
Let's do back of the envelope calculations:
Great Pyramid of Giza weights 500.000 tonnes. It is 146 meter high. It's center of gravity is at 1/4 of it's hight, 36m. It's potential energy is about 50 MWh.
These guys claim that they can store 35MWh in their tower. Basically claiming that they can build the pyramid in a day and take it apart at night.


Thought of exactly the same, but haven't bothered doing any ballpark maths.  Thanks for that, it is evident now ;)
 

Offline dmills

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Re: Energy storage by moving concrete blocks
« Reply #7 on: January 19, 2019, 09:25:34 pm »
Way back in the day, before electrical power of any scale was really practical, the dock at Liverpool had a clever hydraulic energy storage scheme for operating its cranes and winches.

It looked kind of like pumped storage writ small, but with the trick that the accumulator towers were really giant hydraulic rams that lifted large weights to allow high working pressures without needing the towers to be overly high... Prime power was steam plant in a few engine house locations around the dock.

Did it work? Yes, it did, but it was far more about peak power demand then bulk energy storage, and we have easier ways to do that today. 

Regards, Dan.
 

Offline Jeroen3

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Re: Energy storage by moving concrete blocks
« Reply #8 on: January 19, 2019, 10:37:20 pm »
One of the guys involved with this developed a system using gravel before.
 

Online coppice

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Re: Energy storage by moving concrete blocks
« Reply #9 on: January 19, 2019, 11:01:50 pm »
One of the guys involved with this developed a system using gravel before.

Do they give a round trip efficiency for that system? It looks like its burning through a lot of the generated power just shuffling the gravel around in the upper and lower storage areas.
 

Offline Domagoj T

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Re: Energy storage by moving concrete blocks
« Reply #10 on: January 21, 2019, 07:06:39 am »
Honestly, that conveyor thing looks like it's decently built. Yeah, plenty of losses in the mechanical gravel shuffle system, but it looks solid.
I still like the rail system better.
 

Offline ebastler

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Re: Energy storage by moving concrete blocks
« Reply #11 on: January 21, 2019, 03:06:10 pm »
Honestly, that conveyor thing looks like it's decently built. Yeah, plenty of losses in the mechanical gravel shuffle system, but it looks solid.
I still like the rail system better.

Hmm... Looks like this storage technology is best combined with solar power generation? I am not convinced how well that tower would hold up in strong wind...
 

Offline Mr. Scram

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Re: Energy storage by moving concrete blocks
« Reply #12 on: January 21, 2019, 03:26:15 pm »
Let's do back of the envelope calculations:
Great Pyramid of Giza weights 500.000 tonnes. It is 146 meter high. It's center of gravity is at 1/4 of it's hight, 36m. It's potential energy is about 50 MWh.
These guys claim that they can store 35MWh in their tower. Basically claiming that they can build the pyramid in a day and take it apart at night.
A pyramid has an centre of gravity which is intentionally low. This is evidenced by it only being at a quarter height. I'm not saying there aren't issues with the technology, but it's not the best example.
 

Online coppice

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Re: Energy storage by moving concrete blocks
« Reply #13 on: January 21, 2019, 03:49:41 pm »
Let's do back of the envelope calculations:
Great Pyramid of Giza weights 500.000 tonnes. It is 146 meter high. It's center of gravity is at 1/4 of it's hight, 36m. It's potential energy is about 50 MWh.
These guys claim that they can store 35MWh in their tower. Basically claiming that they can build the pyramid in a day and take it apart at night.
A pyramid has an centre of gravity which is intentionally low. This is evidenced by it only being at a quarter height. I'm not saying there aren't issues with the technology, but it's not the best example.
So, you think the pyramid designers thought "let's make a monument with a really low C of G"? :-\

It would be easier to assemble and disassemble a pyramid every day, as its shape greatly eases the precision requirements for the blocks and their placement.

I saw someone call into question the wear and tear of the cables hauling the blocks. That's not a factor I had considered, since many elevators are used continuously through the waking hours, and the cables seem to last for years.
 

Offline Mr. Scram

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Re: Energy storage by moving concrete blocks
« Reply #14 on: January 21, 2019, 03:58:08 pm »
So, you think the pyramid designers thought "let's make a monument with a really low C of G"? :-\

It would be easier to assemble and disassemble a pyramid every day, as its shape greatly eases the precision requirements for the blocks and their placement.

I saw someone call into question the wear and tear of the cables hauling the blocks. That's not a factor I had considered, since many elevators are used continuously through the waking hours, and the cables seem to last for years.
A pyramid is a relatively stable shape. The Egyptians were a fairly clever lot, so you can bet they realized a pile of sand settles in pretty much that shape because it's quite stable.

A pyramid wouldn't be a good shape to use for this, exactly because its centre of gravity is too low. You'd be moving around a huge pile of material for not that much energy stored. That's not what you want. I don't see how the shape eases requirements. Interlocking blocks should be self centring when they're placed with a modicum of precision. You can basically build any shape you like, but getting more blocks high up increases the energy stored. This means you probably want to build as high as you can without things becoming too unstable.
 

Offline jmelson

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Re: Energy storage by moving concrete blocks
« Reply #15 on: January 21, 2019, 04:32:27 pm »
How is this better than pumped hydro storage?
Right, the Taum Sauk plant in central Missouri puts 1.5 billion gallons (12 billion Lbs or 6 million tons) of water up on an 800 foot mountain.  Because the pipes are small, and the reservoir is big, basically all the water starts at the 800 foot elevation.  This tower scheme seems to waste a lot of the blocks building the BOTTOM of the tower, where the potential energy is low.

Jon
 

Online coppice

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Re: Energy storage by moving concrete blocks
« Reply #16 on: January 21, 2019, 04:32:55 pm »
A pyramid is a relatively stable shape. The Egyptians were a fairly clever lot, so you can bet they realized a pile of sand settles in pretty much that shape because it's quite stable.

A pyramid wouldn't be a good shape to use for this, exactly because its centre of gravity is too low. You'd be moving around a huge pile of material for not that much energy stored. That's not what you want. I don't see how the shape eases requirements. Interlocking blocks should be self centring when they're placed with a modicum of precision. You can basically build any shape you like, but getting more blocks high up increases the energy stored. This means you probably want to build as high as you can without things becoming too unstable.
The pyramid shape eases requirements, because any old blocks will stack up to make a stable pyramid. They don't need to be made very precisely, and as they suffer bumps and bruises they would still be just fine for the job. To make a tall, narrow, and not very stable tower the blocks need to be precise, and even small amounts of wear and tear will be problematic.
 

Offline jmelson

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Re: Energy storage by moving concrete blocks
« Reply #17 on: January 21, 2019, 04:35:05 pm »
I saw someone call into question the wear and tear of the cables hauling the blocks. That's not a factor I had considered, since many elevators are used continuously through the waking hours, and the cables seem to last for years.
Nope, they have to be replaced annually in anything that lifts people, or lifts things that could conceivably go over people's heads (cranes, etc.)  At least that's true in the US.

Jon
 

Offline Yansi

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Re: Energy storage by moving concrete blocks
« Reply #18 on: January 21, 2019, 04:50:12 pm »
I doubt lift ropes are replaced annually. In fact I have never seen any mentioning of any lift being out of service due to rope change out. I am pretty sure they does not have to be replaced annually.  The wear on them is quite minimal I'd guess and there are humongous safety margins in place.

But there may be different standards in place in different countries. Maybe in the US, when they go on cheap, lifts aren't designed with such brutal safety margins and hence why the replacements required.  :-//

 

Offline Mr. Scram

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Re: Energy storage by moving concrete blocks
« Reply #19 on: January 21, 2019, 04:50:43 pm »
The pyramid shape eases requirements, because any old blocks will stack up to make a stable pyramid. They don't need to be made very precisely, and as they suffer bumps and bruises they would still be just fine for the job. To make a tall, narrow, and not very stable tower the blocks need to be precise, and even small amounts of wear and tear will be problematic.
Again, with a minimum of thought you can make blocks that can be banged up quite a bit before that start being an issue. You don't want to throw away half of the power potentially stored because you're worried about wear. Modern technology should be able to place them accurately enough for that not to be an issue, even if the blocks aren't shaped to prevent the issue.
« Last Edit: January 21, 2019, 05:16:59 pm by Mr. Scram »
 

Online coppice

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Re: Energy storage by moving concrete blocks
« Reply #20 on: January 21, 2019, 04:56:42 pm »
The pyramid shape eases requirements, because any old blocks will stack up to make a stable pyramid. They don't need to be made very precisely, and as they suffer bumps and bruises they would still be just fine for the job. To make a tall, narrow, and not very stable tower the blocks need to be precise, and even small amounts of wear and tear will be problematic.
Again, with a minimum of though you can make blocks that can be banged up quite a bit before that start being an issue. You don't want to throw away half of the power potentially stored because you're worried about wear. Modern technology should be able to place them accurately enough for that not to be an issue, even if the blocks aren't shaped to prevent the issue.
OK. Apply a minimum of "though" and see if you can propose a design that might work.
 

Offline Mr. Scram

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Re: Energy storage by moving concrete blocks
« Reply #21 on: January 21, 2019, 05:16:46 pm »
OK. Apply a minimum of "thought" and see if you can propose a design that might work.
This or a variant of it self centres when roughly placed and is already designed to be hard to break and fit while worn.
 

Online coppice

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Re: Energy storage by moving concrete blocks
« Reply #22 on: January 21, 2019, 05:20:12 pm »
OK. Apply a minimum of "thought" and see if you can propose a design that might work.
This or a variant of it self centres when roughly placed and is already designed to be hard to break and fit while worn.
Try stacking those 150m high, when they start to get beaten up a bit, and see how far the stack tilts.
 

Offline Mr. Scram

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Re: Energy storage by moving concrete blocks
« Reply #23 on: January 21, 2019, 05:25:38 pm »
Try stacking those 150m high, when they start to get beaten up a bit, and see how far the stack tilts.
You only need to get to 75 metres for the same amount of energy stored, as the centre of mass is in a much more favourable position. As long as they're somewhat clean there shouldn't be tilting issues. If it somehow does turn out to be an issue, automated compensation isn't beyond today's technology.
 

Online coppice

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Re: Energy storage by moving concrete blocks
« Reply #24 on: January 21, 2019, 05:42:11 pm »
Try stacking those 150m high, when they start to get beaten up a bit, and see how far the stack tilts.
You only need to get to 75 metres for the same amount of energy stored, as the centre of mass is in a much more favourable position. As long as they're somewhat clean there shouldn't be tilting issues. If it somehow does turn out to be an issue, automated compensation isn't beyond today's technology.
The proposed design that started this discussion has towers at least 150m tall.
 


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