Kinetic Energy Storage
 

Energy Vault is going public on the NYSE. They are a new company building grid level energy storage using mechanical instead of chemical means. When there is surplus energy a crane stacks concrete blocks. When energy is needed the crane unstacks the blocks and recovers the potential energy stored in the block. Pretty cheap ($150 / kWh) and simple and they claim 85% efficiency. Same concept as pumped hydro but much smaller and not dependent on geography.

https://www.lifechange.at/wp-content...psh3onzibt.jpg

https://www.wsj.com/articles/renewab...ic-11631136600

(Print Friendly will get you past the paywall)

$150/kWh is more expensive than battery solutions. Seems like a decent amount of maintenance too with bearings and cables that will need replacement.

What if towns just built twice as many water towers as they need and use half of the capacity as an electricity buffer? If adverse weather is likely, they could fill them to full and have double the water capacity they would otherwise have. Kill 2 stones with 1 bird.

The problem with water is the volume required. Water has a density of 1000 kg/m^3. Concrete has a density of 2400 kg/m^3 so you are getting 2.4 x more energy per volume with concrete. Pumped storage is about $260 per kWh for 100 MW.

Yes, this system is more expensive than just the batteries in a grid storage system but when you add the rest of the components you are double the cost of stacking concrete. LFP is about $350 / kWh for a 100 MW system battery system. Batteries also steadily degrade over time and have about a 20 year life before needed to be replaced.

https://www.pnnl.gov/sites/default/f...12-11-2020.pdf

No, replacing components on the crane system isn't free but they are using pretty standard off-the-shelf components from construction cranes.

Time will tell, Energy Vault is building some full size units now.

I wonder if anyone at home could just use water or concrete storage and how that would compare to battery.

The hard part would probably be the electronics required to control the thing.

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There are many different ways to mechanically store energy using weights.

Here’s one I’ve posted before.

https://aresnorthamerica.com/


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We need a space elevator, and when there is excess power the occupants travel up faster, and when there is a lack of power, they have to cut their space vacation short.

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Here’s another one.

Low cost per kWh.

https://www.gravitypower.net/


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I've had that thought, second-hand weight lifting weights on a flagpole.

First time I saw that proposed, the rock piston was to be laser cut out of the hole itself. :thumbup:

And another one.... Same concept but a single big weight in a mine shaft

https://gravitricity.com/

https://www.nsenergybusiness.com/wp-...ty-concept.png

It's the wall building machine.

I realize that this is simplified for explanation - but - you would actually use a PUMP to pump the water and TURBINE to generate the power. The pump would only move high pressure water under the piston, and the turbine would be used to generate power from the water moving out from under the piston.

I see a problem with maintaining those seals? There does not appear to be access to them.

I'm sure the design has progressed from there!

Sounds like it belongs to the unicorn corral.

Why couldn't the turbine and pump be the same thing?

Otherwise you'd need a valve.

This kind of reminds be off the hydraulic hybrid, only the use and scale is much different. But on a hydraulic hybrid the pump-motors both convert hydraulic energy into some other form or vice-versa.

Modern pumped hydro uses reversible turbines. No separate pumping system is used.

https://voith.com/corp-en/11_06_Bros...ge_einzeln.pdf

Pretty much every system mentioned is this thread has been built and shown to work. Very different than the HHO generators and magnets in the unicorn corral.

The question is if they are economically viable compared to other grid storage systems.

Has anyone tried a rack railroad on a mountainside?

Wouldn't water require variable pitch blades or the Wells_turbine?

With the winches, using the four cables to keep it centered in the bore sounds like a loser.

redneck linked one in this thread

ARES Nevada is developing a 50MW GravityLineTM merchant energy storage facility on approximately 20 acres at Gamebird Pit, a working gravel mine in Pahrump, Nevada. This project will employ a fleet of 210 mass cars, weighing a combined 75,000 tons, operating on a closed set of 10 multi-rail tracks.

I looked again:
Sounds more like a cable car, but close enough. I was thinking about minimizing the length of the road.

en.wikipedia.org/wiki/Rack_railway#Locher_(1889)

Oregon City, OR, would be my candidate. They have one of the eight municipal elevators in the world. en.wikipedia.org/wiki/Oregon_City_Municipal_Elevator

Sounds like a job for the Boring Company. :)

And this is why those concrete blocks and that crane seem to not be so efficient at all.

The question of economic viability depends on certain assumptions.

Could papermill landfill waste pave our highways?

What happened to the guy doing energy storage on the abandoned rail line in Tehachapi?

We had a discussion here a while back

Why? If (yes that is an unknown) Energy Vault can built full size units at the quoted cost they are far cheaper than any other grid storage technology listed in the Dec 2020 Department of Energy report I linked above.

It's not so clear how lowering the blocks with a crane could effectively provide electric power. Would it require a special crane with some feature similar to the regenerative braking featured on hybrid cars?

This was Thunder Busted a couple years ago:
https://www.youtube.com/watch?v=mfms4h2YAA0

Edit: Sorry wrong video, I meant this one:
https://www.youtube.com/watch?v=NIhCuzxNvv0

Engineering is all about trade-offs. It appears that the costs of doing separate pumps and turbines on very large systems out-weigh the increased efficiencies (from the graphs in the link)

I am guilty (again) of ASSUMING and being too LAZY to look it up :(

That is exactly how it works. When the grid has surplus electricity you use it to run the electric motors on the crane and stack blocks. When the grid needs electricity you unstack blocks, gravity turns the electric motor which acts as a generator and produces electricity. Just like an electric motor in an EV or hybrid.

Energy Vault's key innovation is stacking lots of smaller blocks with an autonomous crane. By using small weights the lifting structure can be built with inexpensive off-the-shelf construction crane components.

Wow, that is an annoying bad video full of useless filler. I notice it is from 2019 - before Energy Vault built their 1/4 scale demo unit which was finished a little more than a year ago.

I really got a laugh when he said "there is absolutely no reason to have bricks on the bottom" (of the stack) because "The bricks on the bottom store zero energy" Why are there bricks there at all? LOL! Maybe because you can't have a stack of bricks without one of the bricks being on the bottom.

His basic argument is the pump storage is better and makes up 95% of grid storage. He seems to fail to see that we will need to add a huge amount of grid storage if we switch to renewable energy at scale and we are about out of places to put huge reservoirs of water.

That's the reason I didn't watch it. Well actually it's his annoying voice crack on 'Welll...."

Joey Salads was on Tim Pool and when he wanted to slag on Elon Musk, he quoted Thunderfoot. I burst out laughing.

edit: I just realized where the idea for my 3D round house printer (with yards and booms) came from. It has a print head for pumped concrete, a pick-and-place arm for placing blocks and an impactor for a rammed earth floor.

Seems reasonable, yet I believe it would still need some chemical storage, either a battery pack or some capacitors which might be better suited to the quick discharge cycles.

Yep, no getting around the need for instantaneous buffer to allow the continuous supply to ramp up. Fortunately that shouldn't need to be that extensive. 10 minutes tops?

Most likely it would be OK with a 10-minute buffering.

Software Define Power responds in milliseconds.