A U.S. Air Force official leaked a briefing to the Washington Examiner, March 2016, to warn Americans of the growing threat to our power grid. The briefing indicates that the military is taking the threat to the grid seriously.
The leaked slide below is titled Our grids have become vulnerable. It catalogued potential threats to the grid including aging infrastructure, determined adversaries and severe natural disasters.
The briefing emphasized that there were a "growing number of cyber incidents" on the grid, "coordinated physical attacks on key grid components" and "risks from state and non-state actors," presumably the Islamic State and North Korea.