solar and wind is only cheaper up to a certain percentage of total power due to its unreliability. Every watt of wind and solar is subsidized by another dispatchable source. As a sysadmin it seems very comparable to the need to essentially buy 2x and only run things at 50% capacity.

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spikels an hour ago | parent | next [-]

The US uses ~0.5 TW of electricity on average but to go 100% solar you would need ~3 TW of solar capacity (6X average usage) and ~30 TWh of battery storage, maybe lots more, plus a massive upgrade to the grid.

	▲	pepperoni_pizza 24 minutes ago \| parent [-]
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pydry 2 hours ago | parent | prev [-]

This is what the oil and nuclear industry propaganda says.

The reality is that solar and wind anticorrelate more than you think, demand shifting (e.g. charging the car when it's sunny) is easier than you think, batteries and pumped storage and power2gas are cheaper than you think and nuclear power is way, way, way, way more expensive than you think.

Weather based models with actual data say that in Australia you'd need 5 hours of storage to get to ~97% renewable: https://reneweconomy.com.au/a-near-100-per-cent-renewables-g...

In Europe or America you might need 7-8 while in carbon industry PR models (the same people who denied global warming) seem to think you need 300+.

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coryrc an hour ago | parent | next [-]

In January 2025, solar generated 1.5TWh of electricity in Germany (in June it generated 10TWh): https://www.energy-charts.info/downloads/electricity_generat...

In January 2025, Germany burned about 236 TWh of fossil fuels.

You cannot even mostly replace fossil fuels with solar.

	▲	tfourb 16 minutes ago \| parent [-]
		Germany will need a total of 1,867 TWh per year in 2030, so an average of 155 TWh/month. fossil fuels are very inefficient when used in most applications (especially ICE and oil for heating). As countries use more and more electricity instead of fossil fuels to generate motion and heat, total energy demand will decrease accordingly. Currently, Germany imports almost all of its fossil fuel from abroad. Mainly Norway, USA, Gulf countries, etc. Russia used to play an important role and we paid dearly for that. As we are for the reliance on the US, I guess. We could actually bring our energy dependence closer to home and make it cheaper by substituting fossil fuel imports with solar + battery with the PV part being distributed across northern African countries. But most likely it will be more convenient (if less efficient) and politically desirable to create a mix of domestic and souther European sources, with specialized stuff like H2/Green NG imports from Iceland and other energy rich places being mixed in. Also, Germany will (and does) a large share of it energy requirement not from solar, but from wind. Already, renewable energy has very much softened the effects of the Iran war on electricity prices. They never exceeded the highest levels of 2025, while fossil fuels jumped to levels last seen immediately after Russia's invasion of Ukraine and are still elevated over 2025 levels.

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Tuna-Fish 31 minutes ago | parent | prev [-]

> solar and wind anticorrelate more than you think

They anticorrelate in some locations. In others, they don't. Here in Finland in the winter you get effectively zero sun. We also get persistent stationary anticyclones. That means potentially over a month of temps in the -30°C region, and zero wind.

Australia is extremely sunny. California is even better, they are modeling that assuming they keep their current hydro capacity, they only need to add ~3h in batteries. Hot places also do better than cold places, because the usage peaks track the sun.

> In Europe or America you might need 7-8 while in carbon industry PR models (the same people who denied global warming) seem to think you need 300+.

How on earth do you expect 7-8 to be enough? 300 isn't enough either. The real number for a fully renewable-based grid here is somewhere north of 2000.

Renewables are great in some situations. There are places in the world that should go for 100% renewables as quickly as possible. It also makes sense to locate a lot of the high-consuming industry in such places. But before you hawk your solution everywhere, you need to actually study the local conditions, and not try to extrapolate anything from Australia.

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tfourb 4 minutes ago | parent | next [-]

> How on earth do you expect 7-8 to be enough? 300 isn't enough either. The real number for a fully renewable-based grid here is somewhere north of 2000.

2.000 hours of storage would equate to 83 full days of electricity demand. That's on its face absurd. Most models assume that a "Dunkelflaute" (span of time with significantly reduced solar and wind output) will last at most 10 days. Add a few days as a safety margin. And that is all of Europe becalmed and dark, as the entire European electricity net is synchronized and transfer capacity between various regional grids is continuously expanded.

Power transmission is a thing. And where you can't lay down a transmission line, you can convert electricity into h2 or methane and put it on ships, just like we do with dino juice.

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pepperoni_pizza 22 minutes ago | parent | prev [-]

I think it also depends on other stuff. Spain gets bunch of sun even when there's the deepest winter in Finland but even if they are technically part of the same grid, the challenge is getting the energy there.

	▲	Tuna-Fish 17 minutes ago \| parent [-]
		Spain and Finland are not part of the same grid. Spain is in the CESA, Finland is in the NSA.