[morsch]

Here are some numbers: January 2025, the output of solar was ~1500 GWh, it peaked in June at 10500 GWh. So the lowest output was about 15% of the maximum, this year.

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

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

Looking at wind, the ratio between min and max per week is about 1:5 (~1200 vs ~6000 GWh). Just as there is always some solar power generation, there is never no wind, though looking at those charts there were 4 weeks in the late summer of 2023 when production was low consecutively, between 700 and 1000 GWh.

[adwn]

How do you interpret these numbers? If your point is that we can simply overprovision photovoltaik arrays by a factor of 6.67, then that would make solar the most expensive power generation method by far.

And it only gets worse the more households transition to heatpumps, because the consumption in winter is so lopsided. For example, I heat my home with a heatpump, and I have 10 kWp of solar arrays on my roof. In the last week of July, we consumed 84 kWh and generated 230 kWh (273 %). In the last week of November, we consumed 341 khW and generated 40 kWh (11 %). This means we'd need roughly 10 times as much PV area to match demand (10 roofs?), and huge batteries because most of that consumption is in the evening, at night, and in the morning.

Of course, utility-scale and residential solar behave a bit differently, and it becomes more complicated if wind is factored in. But it shows that you can't just overprovision PV a little to fix the main problem of solar power: that it is most abundant in summer, and most in demand in winter.

[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.

[ZeroGravitas]

This is just a slighty more sophisticated version of the "solar doesn't work at night" trope.

The implications of bringing it up is that these silly hippies haven't even thought of this basic fact so how can we trust them with our energy system.

Meanwhile, actual energy experts have been aware of the concept of winter for at least a few years now.

If you want to critique their plans for dealing with it, you'd need to do more than point out the existence of winter as a gotcha.

[coryrc]

And this also leaves out all the heating power still consumed directly from fossil fuels. The gap is much larger.

This doesn't have have to be by switching consumption; using less is possible: Passivhaus is from Germany, after all. However, you can't do that and keep all your historical protections on buildings and layers-upon-layers of red tape on renovations.

[gpm]

> it peaked in June at 10500 GWh

And 8280 GWh the previous June for those wondering roughly how much of this was due to more solar panels being deployed.

[toomuchtodo]

For reference, Germany has ~101GW of solar capacity installed as of this comment (and is deploying ~2GW/month). 59% of Germany's electricity in 2024 came from renewable sources, up from 56% in 2023. I am curious to see how 2025 turns out, and therefore predict 2026 from planned renewables and battery storage projects.