Just a reminder that if a headline is a question, the answer to that question is no.
this post was submitted on 04 Dec 2024
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Full disclosure, I haven't watched the video, I'm just going off of the other comments. Mechanical energy storage is definitely already a thing. Flywheels are the past, present, and future of energy storage in certain niches. My dad was a PM for IBM for many years and told me all about installing them while building out datacenters in the 90s. They're great for powering large loads while a generator spins up. They're, uh, not really that great for multi-day storage. You're going to lose energy no matter what. Magnetic bearings won't help this, they still have something analogous to friction.
Anything other than batteries or pumped hydro is probably a fool's errand when it comes to grid-level storage. You're not going to make a crane big enough to compete with millions of gallons of water pumped up a hill. You're not going to be able to make a flywheel spin fast enough to compete with millions of gallons of water pumped up a hill. Do not try to compete with the water using your giant spinning death wheel or big dumb crane. Batteries get a pass because they're dense as fuck and very simple to deploy.
lol I mostly know flywheels as old rollercoaster launches before LSMs were a thing
Yep.
Caterpillar made/makes flywheel UPS systems, where the flywheel is in a vacuum and uses magnetic or air bearings.
It's much safer having 300 flywheel UPS racks than having 300 battery based systems. Also lifespan is much greater.
Yeah, the lifespan and ability to leave a flywheel "discharged" makes me wish I could have one for my homelab (as unrealistic as that might be). I have a solar generator as a battery backup, but it's not a true UPS with a fast transfer switch (I needed at least 3kWh of capacity for long power outages, my max draw is like 600 watts before I finish load shedding). Most of my servers can tolerate the brief voltage sag, but my R640 chokes and dies. My battery is hooked up to one of my PDUs, and I'd love to have a flywheel hooked up to the other PDU. The battery would be fully transitioned by the time the flywheel was discharged.
On the point of safety, I have a question. I feel like it's probably easier to prove that a flywheel system is deenergized, but there is the very slight risk of confinement loss. With a chemistry like Lithium Iron Phosphate that can't sustain a flame and doesn't produce flammable gasses, do you feel that batteries might begin to approach the safety of flywheels? It sounds like you have actual experience with flywheel systems, so I'm quite curious.
EDIT: holy shit, someone is actually selling a 300 KVA flywheel system on eBay for $30,000. I wonder who the hell would buy something like that used.
EDIT: I said "very slight risk" of confinement loss, and I should probably correct myself. The risk is ridiculously, stupidly small for a system like I linked above. Maybe the bigger systems that get buried and have concrete poured on them are riskier, but I don't know if people even do that anymore for datacenters.
These are pumped hydro, but with extra steps, more expense, and less mass stored (read: less energy storage). ThunderFoot did a video going through this in detail, he even used the crane-based one in his examples.
This is the question you always need to ask: is this new mass-based storage better than pumped hydro?
We already have gravity batteries. This "block tower" type doesn't work in practice (no matter how many times they try it), because as they grow in size, they are subject to natural forces like wind, and that makes stacking the blocks safely a big challenge.
I'll be happy to eat my words if somebody can make this a viable solution, but this isn't a new concept, and this particular style has never worked so far.
They did test those block towers to see if they were resistant to earthquakes, and they were still standing after a test comparable to the strongest earthquake in California. Though I agree that compared to the other options available it does look way more unsafe and inefficient.
I do hope they get somewhere with this idea, because novel energy storage that's clean is always a good thing to pursue, but ever since I first saw this idea back in the mid-2010s, it's never materialized due to unforseen issues when it scales up to real-world use.
Is there a TL;DW for that?
When I think of mechanical batteries, I think of flywheel energy storage. Those can deliver a lot of power, but for a short period of time. Is this describing something similar, or something more novel?