Sorry, did I say bigger? I meant biggest. The town of Presidio, Texas has built the biggest NaS battery in the US, capable of storing up to four megawatts of power for up to eight hours. They even nicknamed it.
Big Old Battery (or BOB, as it's affectionately referred to by locals, to the extent that one can refer with affection to a sodium sulfur battery) began charging this week. Before BOB, Presidio's only link to the US power grid was a transmission line built in 1948, which meant fairly frequent stretches with no electricity. Now, they've got a backup plan that can power the entire town.
The project cost about $25 million to complete, which is a little over half as much as the $50 million required to build a second transmission line. A battery obviously can't power a town indefinitely, so they'll be adding that second line soon. But in the meantime, they've got a fail safe and a tourist attraction—for fans of batteries and gigantism, anyway—all in one. [NPR via PopSci]