"I see no reason why the NEM should have either a price cap or a price floor (negative or not). If we're trying to balance demand and supply power quantities, why not let unfettered bidding prices reveal them? That's a question for another day."
No it's a question for now, because if you're going to write about SA's power, it's best to understand the context in which the cap was introduced:

'Twas the summer of 2000–01, before SA had all those wind turbines and solar panels. SA's electricity supply was at its most unreliable. It had just been privatised, and the electricity companies were using Enron style tactics to maximise their profits. Introducing a price cap was one of the things that was done in response to prevent those companies from holding back supply to increase the price.

I don't know about the floor price, but ISTM it would be better to ask why we don't have the infrastructure to make use of excess electricity when its price falls below zero?

Now common sense and many years of experience tells me that to every advantage there's a corresponding disadvantage....so when some one tells me they have the solution then I ask as to the cost....not so much the financial, but the consequential. If I am told there is non then I know I'm likely talking to a half wit who wants me to be a nitwit.
When one thing is changed a corresponding other is also changed, intentional or otherwise

IF we had a government that believed in the free market and open competition, we'd have policies that didn't try to pick winners, didn't offer subsidies to the most expensive forms of energy and did allow the cheapest to flourish.

It takes a special genius to take a country with one of the lowest energy costs and abundant resources and, within a decade, turn it into a country with one of the highest energy costs which ignores and vilifies its abundant resources. And then having done so, convince the people (and themselves) that the causes were other than their policies. Truly we deserve the leadership we get.

I'm completely on board with Alan B on this one. If only we had the right pollies we could start installing thorium reactors and all our problems would be solved within six months of next Tuesday week.

What's that you say?....commercial thorium reactors don't exist.

Please don't bother me with frivolous detail.