Calls grew on Saturday for greater security for Germany’s energy grids after an arson attack on the power supply to the giant Tesla factory near Berlin. “The incident emphasizes the need for resilient energy supply structures,” said a spokeswoman for the Federal Network Agency, responsible for regulating energy and telecommunications infrastructure. The government is now working on the security requirements for critical infrastructure, including how to protect it against physical threats. “The aim is to further raise the level of security.” Specific requirements should be tailored to actual fa…