The control room for the Texas electric grid is dominated by a Cineplex-sized screen along one wall. As outdoor temperatures plunged to Arctic levels around the low-slung building 30 miles from Austin last Sunday night, all eyes were on it. The news wasn’t good.

Electric demand for heat across the state was soaring, as expected, but green dots on the corner state map started flipping to red. Each was a regional power generator, and they were spontaneously shutting down — three coal plants followed quickly by a gas plant in Corpus Christi.

Then another metric began to flash: frequency, a measure of electricity flow on the grid. The 60 hertz needed for stability fell to 59.93.