Rebuilding Puerto Rico's Grid

Gary Soto was hunkering down on the outskirts of San Juan. Soto, the operations manager of Puerto Rico's state-run utility, faced a daunting task: to keep the grid running and minimize damage from the storm. In the windowless, wood-paneled control center at the Puerto Rico Electric Power Authority (PREPA), Soto and a dozen other engineers and supervisors worked at U-shaped desks littered with paper coffee cups, staring at computer monitors that displayed real-time conditions on the grid. One after another, transmission lines were failing, and the team hastily debated their course of action. In this fragile state, the network wouldn't be able to absorb an oversupply of power, excess voltages, or swings in frequency. They could inject test currents into the downed lines, to see which ones could be restored, or else reduce the level of electricity being put on the grid, to protect the remaining transmission system. Hour after hour, the team's chatter filled the room with rising urgency.