"The largest battery storage facility in the world, so far, was...

"The largest battery storage facility in the world, so far, was built in South Australia by Tesla Inc (NASDAQ:TSLA). The 100-MW plant works together with Neoen's 315-MW Hornsdale wind farm."

https://renewablesnow.com/news/aussie-battery-tender-attracts-19-cos-599610/

The winner of the tender in the Northern Territory will either have to build a renewable energy array (solar or wind?) or pair with an existing one  as a source of energy to store in the battery.  Tesla did this in South Australia, pairing with the Hornsdale Wind Farm.

I don't know that the Northern Territory has any big renewable energy assets at present, so building one would be necessary.

http://ecnt.org.au/renewable-energy/

I would expect that companies tendering for the battery storage system will be looking for strategic alliances from companies that specialise in large scale renewable energy arrays.