1.21 gigawatts? Do you have any idea how much energy that is? The only power source capable triggering that kind of energy is a bolt of lightning. It would have to be a real wall-shaker, big enough to stop a clock!
(I mean this as purely a bit of comic relief. Texas is in dire straits right now, and I wish the people and infrastructure all the best in this time.)
I suspect the person you're responding to is using the featured link (real-time conditions) and looking at the diff between system capacity and current demand, which doesn't match the current operating reserves on the ercot homepage.
