[tpmx]

What happens if the grid frequency disagrees too much with the rotation frequency of the flywheel, too quickly?

The flywheel disintegrates and turns into a massive spherical weapon of mass distruction?

Like this, but 20x worse?

https://www.youtube.com/watch?v=bdcE3VyKv5U

[msandford]

The spinning flywheel doesn't just spin on its own. It gets spun up and kept spinning by an electric motor/generator I have to imagine. So you're limited as to how much power can go in or out by the size of that motor/generator.

If it's a 100kw peak electrical machine then it can provide at most 100kw of instantaneous power to the grid while at the same time slowing down by however much is required to deliver that power.

If I understand correctly the idea is a lot like capacitors for DC voltage. The DC voltage has to go down in order for the capacitor to supply current, but the capacitor ensures that the voltage can't go down as quickly as it would otherwise.

[MrBuddyCasino]

Thats not the theoretical limit though. This is a physical device with moving parts. What if the bearing fails? What if the weight disintegrates due to a manufacturing fault?

Suddenly all that stored energy wants to go somewhere.

[opwieurposiu]

The flywheel will have breakers to prevent excessive inflow or outflow of power.

In a conventional plant, the spinning machinery is monitored by vibration sensors. If the vibration exceeds some threshold, a "Turbine Trip" occurs and the offending generator is disconnected from the grid. It then slowly spins down, dissipating energy via it's own friction.

https://en.wikipedia.org/wiki/Turbine_trip

[Johnythree]

No.

It's a synchronous motor which normally idles at the Mains frequency, but if the Mains frequency attempts to change, the rotor inputs massive amount of current (leading or lagging) into the mains which prevents the change.

There is no need for a drive motor.

In the industry they are known as a "Synchronous Condenser" or Syncom. They have been in use for a long time.

https://www.pv-magazine-australia.com/2019/04/06/long-read-b...

[msandford]

So are you saying that the entire mass of the whole flywheel is all the synchronous motor?

I guess I had assumed -- especially based on the picture and description -- that a portion of the mass of the device was the synchronous motor and that a portion of the mass of the device is just "dead weight" whose purpose is just to act as energy storage via rotational inertia.

The parallels to the steam turbine would seem apt; the turbine end of a generator has a lot of mass relative to the electrical end. Isn't that a part of the point? Or did I miss something?

[tpmx]

Sorry, but this comment shows that you don't understand the physics that would be involved in something like this.

[ladberg]

I think you're misunderstanding how this flywheel operates. It doesn't provide 50hz AC in the same way the grid operates, it just is attached to a DC motor that provides electricity which can then be converted into AC to power the grid.

That means it can spin at any frequency and it doesn't really matter what state the grid is in.

[Johnythree]

Completely wrong.

It's a synchronous rotor which is spun by the mains. When the mains frequency tries to change, the momentum of the flywheel supplies massive leading or lagging current to prevent the change.

It behaves exactly as an un-powered generator idling on the mains.

There is no DC motor.

In the industry they are known as a "Synchronous Condenser" or Syncom. They have been in use for a long time.

https://www.pv-magazine-australia.com/2019/04/06/long-read-b...

[phtevus]

The article states the flywheel will not be used to provide electricity to the grid.

[URSpider94]

Of course it provides electricity to the grid. It doesn't provide any NET energy to the grid, since it's not a generator. It will pull and push energy to the grid in small amounts as needed to regulate the frequency, which is directly related to the voltage of the grid.