Last September, news broke that hackers had laid siege to the U.S. power grid, probing deep into dozens of energy firms, looking for weaknesses to exploit. The Department of Homeland Security issued a threat warning about an ongoing stream of malware attacks that could one day lead to a Black Sky event, crippling cellphones, erasing bank accounts, devastating hospitals, and disrupting every sector of the economy. Girding our grid (some of which dates back to 1917) could cost $500 billion—too pricey for the more than 3,200 private companies that own its hardware.
