Yet there's a heavily invested private venture to sell Australian solar energy to Singapore. If private investors think it's viable and think they can send the power to Singapore, then surely the technology is there to overcome all of your above blockers.
A$20 billion for 3 gigawatts of power. Battery storage. Transmitted over 3800kms. No problems generating it, but I'd like to see the transmission losses. It would be interesting to see the concept in full detail.
Just an aside, In 2018, Australia generated 261,405 GWh. Renewables contributed 49!339 (19%). There's a. fair bit of investment required here. No doubt it would need major private investors, what would be the cost I wonder, both in investment and what would the average consumer have to pay?