alt Hacker News> Not at all…
> The sun isn't just going up and down you know it also circles from east to West…
Over a narrow range in winter. You get good coverage from pointing very south and avoiding shade.
> I'm sorry but this is utter bullshit. The commercial plants do avoid shade as much as possible because shade destroy efficiency
They do not avoid it "as much as possible". The panels are shading each other in that very photo, and that photo wasn't taken at the crack of dawn.
It's basic trigonometry. Narrow spacing needs the sun to get pretty high before shading stops. A roof install never shades itself. The difference matters.
> They don't care about shade when the sun is low because when the sun is low the incidence angle is terrible in the first place.
Wrong answer. Those panels are plenty tilted for low incidence sunlight. The ones in front will make plenty of power in the winter. But the ones behind them won't.
The limiter is the price of land. If land was free I guarantee they would spread them out more.
And a home install doesn't have this specific issue.
> Yes, but that's over-paneling…
No it's not! If you need it for most of the year it's not "over"!
> Sigh… Over-paneling 10x isn't going to be more worth it just because in spring and winter you need 5x. That's a nonsensical argument…
If you need 5x or more for half the year, you calculated "x" wrong. Your math is what's nonsense here.
> They do not avoid it "as much as possible". The panels are shading each other in that very photo
You haven't linked the photo…
> It's basic trigonometry. Narrow spacing needs the sun to get pretty high before shading stops.
Of course it's “basic trigonometry”… It doesn't matter if the panels are shaded when the incidence angle is high anyway!
> The limiter is the price of land. If land was free I guarantee they would spread them out more.
They wouldn't, they'd just put more panels on a bigger surface. And again, industrial actors are maximizing the economic output they can make. Whatever decision you take at your level, it's going to be more expensive than what they are doing, and more efficient.
> No it's not! If you need it for most of the year it's not "over"
Yes it is… By definition you are over-paneling if your peak production is higher than what you use. This threshold is important because cost calculations only works when you haven't reached that yet!
> If you need 5x or more for half the year, you calculated "x" wrong. Your math is what's nonsense here.
X is the value for which the cost/MWh makes sense. The further you got from there, the bigger fraction of the power is unexploited and the higher the cost per unit of useful electricity rises.
I didn't invent these concepts or these calculations, those are standards when talking about solar.