Synthetic inertia created by inverters can maintain grid frequency, but they cannot handle fault current. Without the ability to ride through disturbances, downstream protection equipment will fail to work correctly. If you hit a semiconductor with 10x its rated load, it needs to shut down immediately or it will be destroyed. The turbine at a nuclear or coal plant can take a serious beating for several cycles before it would be forced to trip offline. The machine is massive enough to absorb any damage without losing its overall functionality.
We need actual synchronous machines spinning with heavy masses. They don't need a carbon-emitting prime mover on the other side. They just need to be connected to the grid. They also need to be placed relatively close to the inverters (same plant/substation) or they won't provide the desired support.
[–] eigenspace 2 days ago
[–] alibarber 3 days ago
[–] perilunar 2 days ago
I wish someone would pay me to supply inertia. I'm quite good at it too.
[–] raverbashing 2 days ago
I'd prefer to think someday supercapacitors before the inverters can take that inertial need, but in the meanwhile the spinning heavy thing solution works
Tier 1 is flywheels because they have the fastest response, and then response isn't regulated by software but instead is purely mechanical
Tier 2 is batteries, they can be made to respond to current or frequency faults in a response time on the order of miliseconds, and the flywheels give you plenty more time than that to make grid-wide orders for the batteries to respond
Tier 3 is gas peaker plants. The batteries are able to buy enough time that if there's a serious fault that could last multiple hours, you're able to spin up (or down) a gas peaker plant to adjust the grid frequency / current.