Take a close look at your own statement. I'll even bold it for you.
Japanese energy companies pay $7 per gigajoule of Aussie gas....
Australian citizens must pay about $21 per gigajoule
I'm not sure why you're surprised. Energy companies buy gas literally by the shipload; of course they're going to get a cheaper rate. Buy in bulk and save etc. But then of course they will onsell that gas to the Japanese consumer, who will probably pay as much or more than we do.
