The San Jose building, whose past occupants include IBM and a defunct solar startup, houses Hummingbird Energy Storage, part of an industry that barely existed 10 years ago but has become essential to keeping the lights on in California, Texas and other states, and that’s spreading around the world. The rapid growth of large-scale energy storage is driven by plunging battery prices, rising electricity demand and a recognition among operators, utilities and public officials that grids are less reliable than they once were.