(You probably mean "geological" not " geopolitical".)
But what you're pointing out is why the IPCC and most climate scientists want nuclear as a stop gap. Because it's better than coal. But then the conversation becomes about nuclear vs renewables, which no one on the nuclear side wants to get rid or even slow the development of renewables.
Wide deployment & interconnection will also erase some of the local variability of, e.g. a cloud passing over.
> just build twice as much solar capacity
This would increase the land use from 1% to 2%. That's a huge amount of the country to give over to power production.
[1] https://www.solarpowerportal.co.uk/news/if_solar_covered_one...
But the real problem with the UK and solar is not nighttime but seasonality. No, we need to keep going with the wind buildout and not drop the tidal energy programme.
We're getting there: https://www.theguardian.com/business/2019/jun/21/zero-carbon...
Granted, half of that will be in Scotland and ideally your solar would be further south, but even then, you're probably talking about switching less than 5% of the arable land to solar.
There's also a saying "the wind is always blowing somewhere". A good grid reduces variability a lot.
Renewables are projected to get cheap enough that over provisioning can handle most, (but not all) of the stalls, drastically reducing the need for storage or peakers. For example, if you have enough solar to provide 3X as much power as you need on a sunny day, you get about 1X on a cloudy day.
Over-provisioning results in incredibly cheap power on sunny/windy days which can be a huge boon to industry.
In my city the electric scooter companies have carpet bombed the city centre with their vehicles. When I'm downtown can I be certain that one is available to take me from place A to B? I can't and in the worst case I'll have to walk a block to find one to ride on. Big deal.
The electricity grid works the same. It doesn't matter if one wind farm isn't producing because there are so many of them. As long as the total output from them is big enough. Think of it like a RAID system.
> what am I missing
Battery storage is a thing and will become much more of a thing
Looks delightful.
> What's the manufacturing breakeven in carbon costs for a windmill or a solar panel?
This questions feels like you mostly try to justify your otherwise preexisting preference. A proper system would have external costs factored into the price, by the way.
They don't for example, wonder if no one has thought to calculate the carbon impact of renewables, because they assume the scientists and other authority figures they trust who recommend it would have taken that into account. And if they did wonder, it's a short Google away, and their usual info sources would provide facts, not scaremongering propaganda.
That's why you'll rarely see a defence of nuclear that doesn't quickly degenerate into attacking Californian hippies, or government interference, or the collapse of Germany into a solar powered Islamic no-go-zone, or flat out denial that climate change is even a problem anyway" that they've read about in their highly reliable news sources. Generally they're more anti-renewable than pro-nuclear.
"Using Megapack, Tesla can deploy an emissions-free 250 MW, 1 GWh power plant in less than three months on a three-acre footprint – four times faster than a traditional fossil fuel power plant of that size. Megapack can also be DC-connected directly to solar, creating seamless renewable energy plants."
We need more Gigafactories (regardless of manufacturer/owner), which needs demand to be proven (contracts with utilities), which allows for more capital to be acquired from capital markets to build more battery factories. Batteries are a known quantity though, versus nuclear where you can spend billions and a decade and still not produce a kWh of power.
Tesla built Gigafactory 3 in Shanghai in 190 days, from breaking ground to manufacturing validation of a Model 3. These are tractable problems.
[1] https://www.tesla.com/blog/introducing-megapack-utility-scal...
Also does your figure of 6000 Megapacks derive from total electricity consumption in the US, or just base load?
Historical cost declines would agree with that thesis. Renewables will approach a price so close to 0 that the battery storage will be the dominate cost in supplying dispatchable energy (but still a lower cost than fossil fuels). Utility lithium battery storage is already cheaper than the most expensive peaking plants, and the cost model improves as costs continue to decline.
https://data.bloomberglp.com/professional/sites/24/Capture2....
https://about.bnef.com/blog/behind-scenes-take-lithium-ion-b... (A Behind the Scenes Take on Lithium-ion Battery Prices)
https://www.nrel.gov/docs/fy19osti/73222.pdf (PDF: NREL Cost Projections for Utility-Scale Battery Storage)
Unreasonable optimism about battery technology/cost.
These technologies are extremely sensitive to weather conditions which means that other, more stable sources must exist and have "stand by" production cap to produce all the energy these tech won't under bad conditions. If so, what's the point? (I mean in the grand, climate crisis, scheme of things) what am I missing?
Even in "green" countries, most of the green energy comes from bio fuel which is just burning young "soon to be coal".