bhp executives support shale development, page-7

"2. Surely in the not too distant future with off shore gas coming on shore at Darwin the smidge needed for the power station could be diverted and possibly more cheaply than piping gas from Central Australia?"

I think the NT gov tried pinching some of that offshore gas for local use but to no avail. They fetch better price exporting. There is still a shortage of gas for local use, that's the same reason Rio Tinto wanted to shut their Gove refinery, unless the Gov can guarantee them 10 years supply.
Santos have indicated they're hunting for more gas in Central Australia.