It takes 13,760 individual nickel-cadmium cells, each about the size of a desktop PC and weighing about as much as a full-grown adult, to create the world’s largest battery. Vice’s Motherboard column has more:
On August 27, 2003, the Golden Valley Electric Association (GVEA), the cooperative that provides power to the Fairbanks area, powered up BESS, aka the Battery Energy Storage System. Larger than a football field and weighing 1,500 tons, BESS exists to ensure continuity of electric service. If the supply of electricity coming in from relatively distant coal plants to the south is interrupted, BESS kicks in until local power plants can be put online.
BESS can hold things down powerwise for all of seven minutes. It functions as what’s known as a spinning reserve. It’s a bridge between primary and backup power and is generally taken to mean some amount of excess generating capacity that is at any given time pre-synchronized to the grid. If power goes down, switching the spinning reserve on should be seamless.