by rstuart4133 | 2025-11-18 01:26:16+00:00
Sounds like you think renewables aren't cheaper. It is hard to tell, but we have a natural experiment going on in Australia that may shed some light.

The state of South Australia (SA) has no coal or gas, and is a long way from anywhere so importing those fuels are expensive. The eastern states live on a sea of coal and gas, exporting a huge amounts of it overseas.

Historically the price of electricity SA has always been more expensive than elsewhere. When renewables became an option, SA enthusiastically adopted them. Prices went up even more for a while presumable because of the CAPEX in building the renewable infrastructure. For a while SA, had the largest grid battery on the planet (others are now bigger), which is a little surprising for a place with a population of just 1.8M. Right over a year they average about 80% of renewable. From what I can tell the balance is supplied by gas peakers. They say they will be 100% renewable by 2027. SA is now paying about £0.20 / kWh retail.

SA transition happened over 2 decades. For the most of those two decades the eastern Australian states governments did mostly nothing, which is to say their coal fired power stations just kept chugging along. They couldn't do exactly nothing because the population is growing and they needed new supply. The cheapest way to add that was with renewables, filling in any gaps with more expensive gas peakers. The Federal government helped by subsidising solar. For the most of those 2 decades SA was transitioning impact of renewables in the eastern states was small, so their electricity prices remained stable while SA's went up. But it didn't stay that way.

Renewables contribution kept growing. Solar in particular accelerated. The Federal subsidies were designed to gradually reduce to 0 by 2030, but the impact of those reducing subsidies were more than offset by solar panel prices reducing. What those subsidies did do is train a generation of tradesmen on how to install them efficiently, and so Australia despite its high wages now has one of the cheapest installation costs for household solar. The end result of all that is now Australia has the highest penetration of household solar in the world, supplying well over 50% of demand when the sun is shining.

It turns out the renewables are free market poison for coal fired power plants. The coal plants were designed to make a profit by operating for 24 hours a day. Solar now reduces the wholesale price of electricity to $0 for 8 hours a day. Those wind installs intermittently rob them of income overnight. Compounding the problem is governments privatised the coal fired power plants while they were at mid life, priced on the basis of selling power for 24 hours. Presumably the logic was to sell them off while they were still making money, so the public purse could avoid shoulder the huge CAPEX of replacing them when the time came. But the introduction of renewables means they now aren't making money, so their private operators are shutting them down before their anticipated EOL has been reached, which has caused a mad scramble to replace the lost generation.

As the eastern states still have a low'ish penetration of renewables, the cheapest option to replace those coal fired generators is yet more renewables, supplemented with yet more gas peakers. The CAPEX needed to do that has created it's own crisis of sorts, so now the price of electricity in eastern states has reached parity with SA for the first time in history. Meanwhile the electricity produced by gas peakers is comparatively expensive, so expensive that with a little nudge it's cheaper for a household to buy a battery so they don't have to purchase gas electricity. The Federal government has just stepped in to provide that nudge, with a 30% subsidy (also gradually sun setting by 2030, I think). I'm not sure it was needed a wholesale battery prices dropped by 30% last year, but the publicity sure focused a lot of household owners minds on how to reduce their electricity bill. That has lead to an explosion of new battery installs and yet more solar, and a chronic shortage of installers which is amazing given the size of the solar industry in Australia.

If the price of solar and batteries keep dropping then the outcome looks to me that household solar + batteries will replace coal as the major supplier of electricity in Australia. Gas peakers will continue on for a while, but their high price means eventually renewables plus over provisioning plus storage will wipe them out. We've yet to figure out what we can do with all the excess but unreliable power that over provisioning will produce, but there are any number of entrepreneurs trying to figure out how they can make money out of it by producing ammonia, hydrogen and metallurgical refining.

SA will get there well before anyone else. If their own estimates are accurate, by 2028. Their continuing CAPEX will be mostly done at that point, and I guess their inflation adjusted electricity prices will start dropping. They may well have the lowest prices for electricity in mainland Australia for a while.