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Old 09-11-2021, 01:30 PM   #3 (permalink)
JSH
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Quote:
Originally Posted by redpoint5 View Post
$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.
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