> The horizontal angle doesn't change very much

Yes the range reduces in winter especially when you go north, but you still get at least 45° of incidence angle in the best case scenario.

> Winter sun is less than average but it's close to 50%, not 5%.

How can it be 50% when the sun is beyond the horizon for 17 hours straight?! For some reason you obsess with shade, but disregard the most important one: the one caused by earth moving in front of the sun (also called “night”)…

> That's so close to understanding my argument!

> Commercial plants don't bother. They're not optimal for winter

I see what you mean, but plants optimize for electricity value, not rough output, and electricity is more expensive in winter, if they could get good yields at that period, they would actually make more money than the one they get by selling excess electricity in summer…

> But it's not 2 hours of significant light, it's more than that. Clouds don't make the sun useless.

For regular solar panels, they pretty much do, especially in the north (because the cloud layer is effectively much thicker due to the high sunlight incidence angle). Amorphous panels have better performance in these scenarios but it's still far from good, especially if you tilt them heavily to face the sun as these panels need to be facing the sky to get as much diffuse daylight as possible.

As a result, the sunny hours, even though rare, are going to dwarf the others in electricity production, even if there's few of them.

But if you believe you can sustain 90% of your electricity consumption from solar in Denmark, go ahead, I'm not going to convince you otherwise and I'll have no guilt if you lose your shirt in the process.