“Less obvious is the Army’s reliance on the electrical grid. According to the Defense Science Board, ‘About 85% of the energy infrastructure upon which DoD depends is commercially owned, and 99% of the electrical energy DoD installations consume originates outside the fence.’ U.S. forces also rely on foreign utilities for power on overseas bases. Backup electrical power for the DoD isn’t very different than corporate or municipal actors, i.e. via an onsite generator.”
Source: Hacks on Gas (and the Grid): Cybersecurity, Energy and National Defense – Forbes