[morsch]

My point was really only that neither is solar what I'd consider negligible in winter, nor are there really weeks with no wind. Other than that, my interpretation is pretty much the same as yours.

Above, I looked at the weekly min/max ratio. Of course the daily ratios are much higher, 1:60 for solar, and about 1:30 for wind. But wind and solar do have a useful anti-correlation: the ratio is "only" about 1:15 for combined solar+wind. Still high, but a huge improvement on both wind and solar individually.

https://www.energy-charts.info/charts/energy/chart.htm?l=en&...

In reality, the ratio is even higher since we routinely have to drop solar and turn off wind turbines when there is more production than demand (and I don't think that generation is reflected in the graph).

Ie. the max is already a representation more of grid and demand than of production, and it'd make more sense to use the ratio of min:mean, so comparing what we expect PV+wind to produce on average with what they give on the worst day. That gets us a different, more favorable ratio: 195 TWh produced in 2025 so far, let's call it 550 GWh/day, giving a ratio of about 1:6.

[adwn]

Thank you for actually running the numbers. I think the data is quite convincing that overprovisioning won't be the solution to the seasonal storage problem, or at least not the major factor in it.

Personally, I have high hopes for flow batteries. Increasing storage capacity is so easy with them, liquids can easily be stored for a long time, and it would even make long-distance transport by ship feasible. If only we can find a cheap, suitable electrolyte.