When U.S. officials warn about "attacks" on electric power facilities these days, the first thing that comes to mind is probably a computer hacker trying to shut the lights off in a city with malware. But a more traditional attack on a power station in California has U.S. officials puzzled and worried about the physical security of the the electrical grid--from attackers who come in with guns blazing. Around 1:00 AM on April 16, at least one individual (possibly two) entered two different manholes at the PG&E Metcalf power substation, southeast of San Jose, and cut fiber cables in the...