The bet is on. South Australia will work with Tesla and renewable energy provider Neoen to install the world's biggest lithium-ion battery, in a bid to curb energy concerns that have plagued the state. The announcement was made on Friday months after Tesla founder Elon Musk made a Twitter bet in March that he could fix the state's energy problems by installing its Powerpack system with 100MW of capacity "within 100 days or it's free.