Daytime prices are supposed to reflect higher demand, when people are awake, office building are in use, factories are in production. That's when fossil fuel generators would normally be making most of their money.
The influx of rooftop solar has turned this model on its head. There is 1,100MW of it on more than 350,000 buildings in Queensland alone (3,400MW on 1.2m buildings across the country). It is producing electricity just at the time that coal generators used to make hay (while the sun shines).
The impact has been so profound, and wholesale prices pushed down so low, that few coal generators in Australia made a profit last year. Hardly any are making a profit this year. State-owned generators like Stanwell are specifically blaming rooftop solar.
Solar is now cheaper than network charges - meaning that it would be more economic even if coal was free. No wonder Tony Abbott hates it and wants to do away with it.
We could do this here too, with the right policies. The Greens have those policies. Labour backs them too. Only National supports the established electricity players. And as more people see how well these policies are working in Australia, Germany, and elsewhere, they'll be forced to grudgingly back them too - because the argument will have been won with the public.
This change can happen quickly. Making the coal-electricity industry uneconomic in Australia took only five years of good policy. One decent Green-Labour government is all it will take to put fossil fuel generators out of business here. And that will knock between 3 and 6 million tons of CO2 (4 - 8% of the total) off our annual emissions.
