You are probably looking at wholesale electricity production. At the retail end of the line things look different. But first a disclaimer: I'm an Australian, and we pay around AUD$0.27/kW hr. It varies a bit - one state it's closer to AU$0.36/kW hr.

Right now if you buy a PV + battery system that will cover all your usage, you are looking at $20K before rebates [0]. If that drops to $10K it becomes better for households to switch from being users to generators - where "better" means better than investing the cash and getting a 5% return after inflation over 10 years. In other words it's a no brainier. If a household doesn't choose to do it themselves, someone will come knocking on their door and pay them to do it.

For Australia that is the tipping point. Once we cross it the electricity market will change forever into something unrecognisable. There are 9M houses in Australia which when fitted with today "standard" 6.6 kW system with 5 kW inverter will generate 50% of our daily electricity usage. But it won't just be profitable for houses of course - it's not like businesses don't have roof space too. It's not too hard to see that other 50% disappearing too.

The thing preventing it from happening right now is battery prices. Battery are ignored as far too expensive by people looking at grid storage and right now they are too expensive for households too - but if that 8% per year improvement figure being bandied about is correct we will hit that $10k threshold in 10 years.

It won't suddenly happen in 10 years. We've are seeing close to EOL coal fired generators bought by purchasers saying they would squeeze another 20 or 30 years out them later shut down not long after. I'm not sure why, but the pattern has been repeated several times now. I do know in Australia the wholesale electricity price used to go negative most nights. Now we don't know if that still happens because our conservative government shut down the reporting of the wholesale price, however I suspect it's worse - not only does it go negative at night, it must also go negative at when the wind blows hard. Having to pay others to dig the coal out of the ground because you can't adjust quickly enough must be painful.

Regardless of why they're shut down, it's now pretty obvious every time a coal fired plant shuts down the prices go up the next year because it's happened several times. And so more people buy solar - we have the highest household solar penetration in the world. While the price goes does up less people pay it, overall less money comes in and around and around we go. The pace seems to be accelerating, and it will continue to accelerate until the wholesale price starts dropping. When most of your existing generation comes from coal, and coal generators are being retired every couple of years, it's hard to see that happening any time soon.

I don't know why the focus is always on the prices wholesale end of the chain. The big change isn't that renewables are slowly catching up to wholesale prices - the big change is they have already passed retail prices. While putting a coal fired generator or wind turbine in your back year was never feasible, throwing a few solar panels on your roof and installing a battery is feasible. Sure, the power generated costs 2x what a wholesaler can generate it for - but in Australia the price the wholesaler gets jumps by a factor of 3x to 4x. If battery prices keep dropping, there will be enough space for them to fit right in.

[0] It's actually used $20K for this type of system right now. After rebates it's about $13K right now, but when households are threatening to wipe out 50% of the generation market I expect the rebates will disappear.

[1] Average wholesale price: AUD$0.073 https://www.aemc.gov.au/energy-system/electricity/electricit...

[2] Average retail price: AUD$0.27 https://www.canstarblue.com.au/electricity/electricity-costs...