In Denmark, the spread of solar panels has become a divisive issue • Hacker News Board

Re: In Denmark, the spread of solar panels has become a divisive issue

#221

Post by rstuart4133 » Tue, Apr 14, 2026, 10:48 PM UTC

A quick calculation shows to supply all of Denmark's energy needs with solar, (assuming sufficient storage), they would need about 1,000 km² of solar panels. That's about 2% of their land area. That assumes a solar irradiation rate of 0.5 kWh / m² which is about what they get in winter. They get 6 kWh / m² in summer, so there would be 10 fold over production then. If they stored that by converting it to hydrogen, even if done very inefficiently, it would more than halve the land area required.

Given their solar irradiation is so poor they would be better off with wind. While 2% is big, it isn't inconceivable, particularly as solar panels don't prevent the land from being used for other things, such as transport, buildings, even some forms of agriculture. People will get comfortable with it over time, just as they did with destroying most natural ecosystems in Europe to turn the land over to agriculture. That horrifies me far more than covering 2% of land with solar panels.

Re: In Denmark, the spread of solar panels has become a divisive issue

#222

Post by nixpulvis » Wed, Apr 15, 2026, 1:05 AM UTC

JumpCrisscross wrote: post #189

nixpulvis wrote: post #188

Earlier quoted context omitted.

So extinctions, but not extinction?

> extinctions, but not extinction? Yes. Extinctions are horrible, but they aren’t an existential threat to us. Climate change simply isn’t an existential threat. That doesn’t mean it isn’t urgent. Like, the Bronze Age collapse and black plague and WWII weren’t existential, doesn’t mean they’re fine. But raising the stakes beyond what the science says like this undermines the credibility of the real warnings.

I think it's really naïve to realize that climate change is an existential threat to many species, but not connect that we are part of the ecosystem which is being put in danger. You are experiencing survivorship bias.

Even if we don't go extinct. It's still an existential threat to our way of life. Which is also a totally valid interpretation of the phrase.

Re: In Denmark, the spread of solar panels has become a divisive issue

#223

Post by JumpCrisscross » Wed, Apr 15, 2026, 4:43 AM UTC

nixpulvis wrote: post #222

JumpCrisscross wrote: post #189

Earlier quoted context omitted.

> extinctions, but not extinction? Yes. Extinctions are horrible, but they aren’t an existential threat to us. Climate change simply isn’t an existential threat. That doesn’t mean it isn’t urgent. Like, the Bronze Age collapse and black plague and WWII weren’t existential, doesn’t mean they’re fine. But raising the stakes beyond what the science says like this undermines the credibility of the real warnings.

I think it's really naïve to realize that climate change is an existential threat to many species, but not connect that we are part of the ecosystem which is being put in danger. You are experiencing survivorship bias. Even if we don't go extinct. It's still an existential threat to our way of life. Which is also a totally valid interpretation of the phrase.

> You are experiencing survivorship bias

Ex ante survivorship is literally the delineation between existential and not.

> Even if we don't go extinct. It's still an existential threat to our way of life

You see why this comes across as bullshit, though. It’s needlessly redefining a word to seem more punchy. We have plenty of perils we massively mobilize against without imagining they’ll exterminate the human species.

Re: In Denmark, the spread of solar panels has become a divisive issue

#224

Post by littlestymaar » Wed, Apr 15, 2026, 9:27 AM UTC

Dylan16807 wrote: post #220

littlestymaar wrote: post #215

Earlier quoted context omitted.

> They don't build them in deserts that far north, do they? I'm not aware of any desert in Denmark… But you say the design is driven by lack of space, then why do they use the same design in deserts?! That's my question. Denmark doesn't have much free space, but Sweden do, land is cheap in many places there, yet the Swede don't design their plant differently. > Normal commercial installs don't try to capture the morn…

> I'm not aware of any desert in Denmark… Right! A lack of places with such super free land that also have horrible sun angles. > But you say the design is driven by lack of space, then why do they use the same design in deserts?! The desert builds don't have to deal with the same horrible sun angles. But whatever, I might be wrong on what they would do with free land. That was a guess, I admit it. That guess was to…

> 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.

Re: In Denmark, the spread of solar panels has become a divisive issue

#225

Post by ben_w » Wed, Apr 15, 2026, 10:12 AM UTC

hbogert wrote: post #208

ZeroGravitas wrote: post #46

Earlier quoted context omitted.

Far north places have long summer days. This doesn't align well with the winter heating needs but it does balance really well with wind generation which peaks in winter.

It would make even more sense if we can synthesize fuels

We've been able to do that since at least 1897. It just wasn't important enough to bother with for a lot of the intervening time. It may still not be, we'll find out by people doing it or not doing it.

Re: In Denmark, the spread of solar panels has become a divisive issue

#226

Post by Dylan16807 » Wed, Apr 15, 2026, 9:34 PM UTC

littlestymaar wrote: post #224

Dylan16807 wrote: post #220

Earlier quoted context omitted.

> I'm not aware of any desert in Denmark… Right! A lack of places with such super free land that also have horrible sun angles. > But you say the design is driven by lack of space, then why do they use the same design in deserts?! The desert builds don't have to deal with the same horrible sun angles. But whatever, I might be wrong on what they would do with free land. That was a guess, I admit it. That guess was to…

> 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…

> How can it be 50% when the sun is beyond the horizon for 17 hours straight?!

50% of the average. The average being a day with something like 12 hours of sunlight. Sorry to be unclear.

> 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…

One important factor is that they're not optimizing for power per panel. Panels are pretty cheap, and filling the land with panels makes sense as an overall decision.

Let me reframe things. For a commercial plant it's not that they could get significantly more power in deep winter, it's that they could get the same power with 20% as many panels. But spreading panels out that far would be worse the rest of the year.

Many home installs can get that "spreading" for free.

So to redo my claim from earlier, if there was a magic button to put 50 feet between each row of panels with no downside, I strongly bet commercial installs would pay to press it. And it should take the winter output up from "useless" to "bad".

It's possible I'm still severely underestimating the clouds. But when there is light, there's this interesting advantage small/widely-spaced installs get in winter. Or rather, they have a much smaller disadvantage.

Re: In Denmark, the spread of solar panels has become a divisive issue

#227

Post by perilunar » Thu, Apr 16, 2026, 2:25 AM UTC

amarant wrote: post #202

marssaxman wrote: post #198

Earlier quoted context omitted.

Whether you store it or not, getting free energy from the sun for half the year is better than getting no energy from the sun. Every marginal reduction in fossil fuel usage helps.

Scandinavia is actually seeing a pattern where in the summer, there is so much electricity produced that it's approximately free, and in the winters, when solar panels produce nothing, there's not enough to go around so prices are sky high. It's a very weird situation where it's financially difficult to build new power because you'll be doing it entirely for free half the year, but then you get 4-5 months that are an…

Free electricity in summer and high prices in winter is not a bad place to be really — it provides a good incentive to develop long-term storage. Batteries are probably not it. Pumped hydro is good — not in Denmark (too flat), but maybe in nearby Norway. Maybe synthetic fuels could be produced and stored economically?

Re: In Denmark, the spread of solar panels has become a divisive issue

#228

Post by teamonkey » Thu, Apr 16, 2026, 7:37 AM UTC

cjrp wrote: post #200

teamonkey wrote: post #59

Earlier quoted context omitted.

Are you sure it’s arable land? The majority of solar farms in the UK are built on low-grade land that aren’t suitable for growing food.

I wonder if that will remain the case. The input costs for farming are increasing (seed, fertiliser, energy), the output is becoming less predictable (flood, drought) and the grants from DEFRA which are meant to smooth things out have dried up somewhat since Brexit. If farmers are offered a guaranteed income for a field, I suspect they'd take it.

See the adjacent link I posted about projected land use.