Activated with ~40 days to spare; also see Elon Musk's Battery Boast Will Be Short-Lived (Bloomberg)
"When fully charged, the battery can power up to 30,000 homes for an hour. However, it will mostly be used to support and stabilise existing electricity supplies.Tesla mega-battery in Australia activated - BBC News
The battery is comprised of a grid system that runs on the same technology that powers Tesla's cars.
In a statement, the company said the completion of the battery "shows that a sustainable, effective energy solution is possible"."