Think about how much sun covers Australia and you're telling me there isn't enough sun? What about wind, uranium and gas? Look to the stars my friend.
To your point about the ratio of thermal to coking coal. What's your point? So Australia stops exporting thermal coal, and increases taxes on coking coal to pay for the transition to a renewable grid and support coal miners while they find other work in renewables (which they should've done 20 years ago). There's no problem with that plan.
And that is just in Australia. The customers of our coal markets will lose out as we unilaterally try to cut them off from the raw resources they need. That is probably a cost you are willing to bear, but it is still a problem.
There's also a massive backlog of green power efforts to connect to the grid, because the grid is badly designed. It was designed to take power directly from coal stations to cities, it wasn't designed to be an effective or efficient network.
Saying we need coal because we haven't upgraded the grid to meet modern demands is like saying someone with a broken arm needs a sling. It is true, but it isn't permanent, and the goal should be to get rid of it or you'll hurt yourself more in the long run.
We still don't have answers for relay desensitization and ferroresonance in particular.
The bigger renewable producing projects pose less problems, but still don't replace baseload in the grid or serve to stabilise the grid. They can only follow the grid within a given tolerance.
The worst part is that the powers that be are likely to ignore all of the above and roll out anyway. The grid will have already been syncronized by the things they turn off and things will for the most part roll along fine (service disruptions just becoming a part of daily life)... until something happens that requires a grid restart (think along the lines of a cyber attack or a natural disaster). That's when shit really hits the fans. Restarting the grid is a pretty manual and time consuming process, and renewables simply add too many variables to the equation to make this process possible. They would need to split the grid into lots of micro-grids, but then they would need interconnectors between each micro-grid that will be constantly tripping and incur substantial maintenance costs in normal operation.
I am aware that you are not the original commenter I was responding to, but I can't help noticing that you did not respond to the main thrust of my previous comment though, about metallurgical coal.
Has technology just blown your mind?
I've not heard a single reputable scientist or engineer claim this is such an impossible task as you. Yes it will take policy change [1], but honestly you sound like a defeatist and a denialist and really what is the alternative except for moving forwards? Australia just keep exporting thermal coal to Asia and not change our ways and die from famine, drought and heatwaves ?
Edit: I just want to say this whole argument you're making about "the grid not working without coal", just sounds like such a con. Just like the way the Government of Australia scares everyone with talk of a loss of jobs and growth whenever someone discussing stopping the Adani coal mine. It's just an unsubstantiated claim.
[1] https://www.theguardian.com/australia-news/2019/nov/06/ross-...
For some reason though, it's always lumped in with thermal coal by protesters and so-called environmental activists.
Also, you are massively kidding yourself if you think that Thermal Coal doesn't affect your everyday life in Australia. Enjoy no power and a collapsed grid if you remove most of the baseload power in the grid. The energy sector is forecasting an energy shortage in NSW and Vic due to them prematurely closing coal plants without adequately replacing that capacity.
South Australia may be "net green" or close-to if you are to believe headlines, but it would collapse instantly without the baseload of Victoria stabilising its grid and supplying power when required (and Vic later accepting power and lowering its coal output for the close to free useless power).
There is close to 0% chance that QLD alone will be able to supply the missing power that NSW and Vic will require.