[upsuper]

The regulation applies in the opposite side as well. I think the highest bid allowed is like A$16.8/kWh or something like that.

It's not fully clear to me how the market work as a whole. I learnt that generators may have swap contracts with retailers and big users, which, based on my understanding, can distort the price to arbitrarily low, because generators get paid for the difference from the other side regardless of spot price, so they can set the lowest possible to ensure they can dump their power to the grid.

Also when it's predicted to be this low (or that high), there is likely some operations (market or not) behind the scenes to level the price. Usually when it gets to the time, the actual spot price has been in a reasonable range.