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.