When there is a voltage or frequency disturbance on the grid, caused by lightning strikes or equipment failures, ERCOT expects power generators to “ride through” the disturbances and continue producing power. But inverter-based resources such as wind, solar and batteries — especially the oldest ones — may sometimes not be able to ride through the disturbance and could “trip” > offline and disconnect from the grid. This could lead to a domino effect of other generators tripping offline, which could in a worst-case scenario result in the “rapid collapse of part of or all the ERCOT system,” according to ERCOT.
ERCOT has experienced a growing number of these inverter-based resource failures, particularly in West Texas. In 2021 and again in 2022, more than 1,000 megawatts of solar resources tripped offline near Odessa, prompting the North American Electric Reliability Corp. (NERC), an international regulatory authority, to recommend ERCOT rectify the risk.
Interesting read: Inverters don’t have spinning mass like turbines that can deal with fluctuations in the grid (simplified) (as we learned from Grady’s Practical Engineering) and they follow the grid, but can’t build a grid. But we also learned from him that modern inverters can actually build a grid and behave like a “mechanical generator”.
So as I understand it, a lot of existing renewable suppliers have to do some retrofitting, which is probably expensive, so now we are here.