Critical Infrastructure Protection: Electricity Suppliers Have Taken Actions to Address Electromagnetic Risks, and Additional Research is Ongoing, Report to Congressional Requesters   [open pdf - 3MB]

"GAO [Government Accountability Office] examined government and industry studies and interviewed federal and industry officials about potential GMD [geomagnetic disturbance] and HEMP [high-altitude electromagnetic pulse] effects on grid infrastructure; reviewed regulatory standards, monitoring processes, and NERC [North American Electric Reliability Corporation] compliance audit data from April 2015 through August 2017; reviewed federal regulations and interviewed state regulators on cost recovery issues; and interviewed officials from a nongeneralizable sample of 13 U.S. and Canada electricity suppliers, selected based on factors such as GMD experience and preparation for GMD and HEMP events."