SHORTLY AFTER noon on Monday April 28th, Spain’s electricity grid suddenly and unexpectedly lost 15 gigawatts of power—equivalent to 60% of its national demand. The massive drop caused most of the country’s electricity system to shut down, followed by much of neighbouring Portugal’s. Trains and metros ground to a halt and 35,000 passengers across Spain had to be evacuated. Traffic lights stopped working; hospitals cancelled all non-essential operations; and mobile phone and internet networks went dark.