Hurricane Katrina humbled U.S. military bases in 2005, cutting power at air towers, training facilities and command centers just as it did everywhere else along the Gulf Coast. The Naval Construction Battalion Center in Gulfport, Miss., for example, a staging ground for regional relief operations after the storm, needed relief itself after running for two weeks on backup power systems. And Keesler Air Force Base near Biloxi, Miss., lost its airfield lights and had to scramble to keep its hospital running after a generator was swamped. While diesel generators kept critical missions going during Katrina, the storm provided a wakeup call for Pentagon leaders concerned about terror attacks on the electric grid, which provides 99 percent of the energy that bases consume. Could bases withstand a power outage that outlasts their three-to-seven-days' supply of diesel for backup systems? Is it wise for the military to rely on the same power plants and transmission lines that feed homes and businesses?