My understanding is that the renewable energy target (RET)...

My understanding is that the renewable energy target (RET) dictates the requirement for users to buy LGC. As we reach the current target the need to buy LGC will trail off but if the target is increased that will mean LGC are required in greater number for longer. If the RET is increased as we expect will happen under Labor, the demand will again start to outstrip supply and trigger higher LGC prices until more LGC are available as additional renewables come online as has been happening recently. That is the current mechanism that has supported renewable investment to date. Unless it is dismantled a higher target will support LGC prices.

Can you explain what you mean by a Labor doing a reverse auction?