You have only 30 million people, living on an island continent the size of the United States. And is the country with probably the longest warm water coastline on the planet.
Something to think about: with so few people we can only sustain a handful of metro centers, for many reasons metro centers need to be of a certain size to be effective as a hub for business, jobs, social aspects and policy making, so people gravitate to where the cities already are. So "property in a busy metro" is still a scarce resource in Australia.
Another aspect is we quite simply have an inflated market, driven by foreign investment, speculators, government policies and incentives that help investors at the expense of home buyers. We also have thousands of citizens with outsized investments in real estate, and the government is doing everything it can to make sure that house of cards doesn't topple down and cause a recession.
One of our last government's policies to "Help ease house prices" was to give grants to corporate investors, so that they could buy up land and rent it back to people. That's the kind of policy making we have here at the moment
South Australia is moving toward that, which is largely desert despite it's temperate climate south eastern region and coastlines.
They recently started putting together an interstate connector to other states, which allows the state to export excess power from renewables. In part to help offset grid reductions as NSW brings some of it's fossil fuel plants offline. They already have had some 100% renewable days, but plan to be 100% renewable by 2030.
Another quirk of SA's energy history was Elon Musk offering to help solve grid costly instability with a battery solution within 100 days or it was free. Odd tactic, but it happened and they have a 100MW battery reserve in Hornsdale that is set to expand to 150MW.
In order to crack water, you need water, which is in short supply in the desert. Desalination + massive pumps and pipelines from the ocean would soak up any increase you get in price efficiency compared to batteries or even compressed air.
Liquid hydrogen and liquid ammonia have almost 10x the energy density of current battery technology. If you could go all the way to synthesized hydrocarbons it's another 2x.
I'm not sure efficiency matters that much when you have far more energy production capacity than you need but it's concentrated in places and times where you can't use it.
As for costing more: compared to what ? Batteries don't seem like an economically effective option for storing solar energy at massive scale, do they ? And in any case they don't allow the stored energy to be shipped to other locations.
That might be useful for aircraft, but not cars or the grid. Batteries are already cost competitive with peaking power plants and prices just keep dropping.
Run some numbers and you find batteries are surprisingly cheap at grid scale. Grid solar is already tied into the grid and does DC>AC conversion anyway as part of it’s 2c/kWh pricing. So, rather than AC>DC>AC>DC you can just use solar panel’s AC power directly. Which means your just adding minimal cabling, batteries, some electronics, and a basic box for weather protection. So, ~100,000$ for 200kWh of storage x ~5,000 cycles that’s 10c/kWh for storage + (2c/kWh solar / 90% efficiency) = ~12.2c/kWh.
Granted that ignoring some real world costs like interest payments, but battery costs are also dropping so it’s a reasonable ballpark. Especially vs a theoretical system that’s never been scaled.
PS: By comparison if your at 50% efficiency to chemical storage and world record 63% thermal efficiency at combustion that’s 2 /.5 /.63 = ~6.3/kWh just for electricity plus the cost of your combined cycle gas turbine and chemical plant.
What about the cost of transporting the energy from where it's generated (say Nevada) to where it's needed (say New York) ?
EDIT: I think for that use case you'll find that a reasonable technology doesn't exist for transporting electrons over that distance (I don't think there are any superconducting transmission lines in actual use) but pipelines have been around for a long time.
Energy density is a mostly useless metric for grid storage. It's installed in a place where land is cheap so if its bulky who cares? Efficiency and simplicity are the main goals. You want something that doesn't waste much power and doesn't require a huge team of experts to keep running or cost an absolute fortune to install
Out of the 8 zones, zones 3 and 4 don't seem to inhabitable, they're probably the "outback" aka desert. 1 seems to be the subtropical jungle bits. They're huge, however doing a silly size comparison with Romania, which has around 20 million people ( https://thetruesize.com/#?borders=1~!NzkwMTU3Mg.NDI0MDg2OQ*M... ), it seems that even considering just the temperate zones, Australian population density is low.
I guess it's more an issue of bad urban planning because of economic pressures. Everyone bunches up in the same centers of population, which cover a very small area, in relative terms.
Probably the same as anywhere else. Many people want to live in a limited area, house prices go up. People who can afford them buy them, which keeps house prices there.
Something like 85% of the population lives within 50km of the coastline.