I thought the trend in flywheels was magnetic suspension and removing mechanical linkages? Admittedly I haven't kept up.
What gives you that impression? Seems to me that it explodes if you contain it, and if you don't contain it, it can spout jets of thermal energy at virtually any angle. With flywheels you need to arrest it in bulk heavy objects that don't tend to sustain fire. That seems a lot simpler to me.
The bigger problems with flywheels are cost of manufacture and (depending on the technology used) efficiency for overnight storage.
> I thought the trend in flywheels was magnetic suspension and removing mechanical linkages? Admittedly I haven't kept up.
IIRC flywheels with limited motion gimbals (to reduce the tolerances on the wheel) are becoming more popular, still magnetic bearings.
Insulation is cheap, effective, and very compact. And it's easy to transfer heat quickly, also (either via injecting lots of cold extinguisher or flush lots of hot oxidizing gas)?
Cool, thanks for the update on flywheels. I ... am not trying to create a false dilemna, here. Fuel cells for stranded methane deposits are great. Flywheels have outstanding responsiveness and energy density. Li / compressed air / pumped water et al scale well. They all fit into a more resilient grid storage strategy that permits a transition to periodic sources of input from non-renewable base load.
And anyway, you tried to be too clever. I said "non-renewable" and not "carbon free" just to avoid this conversation. Unless you can start synthesizing utility grade quantities of well-behaved fissile material at a net energy surplus then it's not renewable even if we have decades/centuries of supply.
Someday, even the Sun will run out of fuel. In the long run, we are all dead - unless someone figures out how to reverse entropy.
edit: Love reading that short story, it somehow never gets old.
Humans are plenty smart and the people of tomorrow will be better equipped to solve tomorrow's problems.
It's not even a matter of "ripping off a band aid" and paneling up the planet - solar panels aren't going to last hundreds of years either, we will be lucky to get 30 years out of them. Can we make more, sure, but we could also do nuclear and then make solar panels in 500 years when we're running out of fuel.
The biggest problems are that we need to come up with the political will to reprocess waste (extracting additional usable fuel and compacting the amount of true waste that needs to be disposed of) and then dispose of it in a proper repository rather than just letting it sit around on-site indefinitely Fukushima-style.
Which is itself a good thermal-runaway damper, to speak to the second sentence of your second paragraph.
Having witnesses a corn silo explosion, I was unprepared for the ferocity of that ignition.
>So is a wind turbine explosion
Off to YouTube...
[1] https://en.wikipedia.org/wiki/Hornslet_wind-turbine_collapse
Assuming the flywheel keeps its integrity it's much harder to predict the "blast radius" of where that thing is going to go.
Not AFAIK for the last, though precessional torque bearing load is a nontrivial consideration.
Wikipedia claims flywheel loss rate circa 2013 of 5% per day. https://en.wikipedia.org/wiki/Flywheel_storage_power_system
That compares to recent estimates of Tesla li-ion loss rates at under 5% per month -- 0.16% per day.
Amber Kinetics is one company building fixed flywheel storage products. http://amberkinetics.com/
They have one 32 kWh, 5-ton, 98% steel flywheel installation on Oahu; pictures here: http://amberkinetics.com/hawaiian-electric-and-amber-kinetic...
Angular momentum in 100 kWh - multi MWh rotational systems is large.
No, they're not all the same.
Compressed air, flywheel, flour mill - very dramatic events.
Lithium battery - much more mild, typically.
Gasoline - it depends.
So is a lithium battery explosion. So is a gasoline explosion. So is a flour mill explosion. So is a wind turbine explosion.
Energy is energy, and losing control of energy is never great, no matter where it comes from. So while I catch your meaning, it might be better to phrase it with respect to how controllable that energy is.
From what I know of flywheel storage, the problem mostly comes down to keeping the wheel from coming apart, and containing it when it does. The nice thing about using flywheels for grid storage is that you can bury them and make them large. The earth contains your explosion risk and the lack of jostling means that your bearings don't need to take as much stress and limits that failure risk.