Consider the following drawing:
I take it that solar panel’s generated electricity would be the same whether it’s installed in scandinavia or africa, as long as it faces in the same direction? or am i stupid
i’m asking this because everywhere i hear how “solar panels have higher efficiency near the equator”, but that’s just not true. Maps such as these are common on the internet:
And they suggest that solar energy around the equator would be twice as available as on northern latitudes, but actually that’s just the solar irradiation if the panels weren’t inclined, but in practice, they were likely will be. So they receive similar amounts of power.
edit: so, it’s the cloud cover. got it; thanks :D
The suns rays go through less atmosphere near the
polesequator. Not to scale, but should show the overall concept.
“The sun rays go through less atmosphere near the poles”?
I think you meant to say sunlight goes through more atmosphere near the poles, but otherwise nice quick sketch diagram 👍
I had so much fun making the image I totally the words
You can actually see this in action. At sunrise or sunset, it is possible to look directly toward the sun. That’s because more light is scattered at that angle and so it is less direct. At noon, the same sun will sear your eyes.
Helpful diagram. Thank you!
isn’t the atmosphere transparent for most of the light, though? (except UV, but that gets filtered out even at the equator, so it’s the same everywhere again)
It isn’t perfectly transparent. It has dust, moisture, and other particles in the air that block or deflect a portion of the light.
thank you, i’ll consider this the best answer as it names both dust and moisture as reasons why sunlight is blocked.
There’s several factors here.
The most important probably being the energy per square meter. Higher latitudes gets less energy per square meter than equatorial latitudes.
There’s also the mentioned cloud cover and atmosphere density.
The climate it’s also important. As higher latitudes tends to be more cloudy.
And sun hours, here is not about the total energy but how it’s distributed. As sun hours are more estable near the equator (12 hours light 12 hours dark) while in higher latitudes you can get 4 hours light some times of the year that can’t amount to nothing, and 20 hours of day other times of the year which are nice, but there’s no way to store that energy for the winter lack of sunlight.
Lie on the beach in winter: the sun is pathetically un-warm.
Adjusting the angle at which you recline won’t make the sun any warmer.
So your intuition is off here.
Imagine someone puts an opaque shell around the earth at cruising altitude, and cuts a metre-square window in it.
Put that window directly over the equator, wait for noon. You will have a metre-square patch of sunlight on the ground.
As the sun heads towards the horizon, the patch of sunlight stretches into a long east-west tail, just like a long shadow.
The same amount of energy is coming through the window, but it’s spread over a much larger area on the surface, so there’s fewer watts-per-square-cm hitting the ground.
Now move that window north 30 degrees. Wait until noon, and the patch is already smeared into a long tail north-south, and that’s before applying any east-west smear. As the sun heads for the horizon, it’s going to be even more spread out into a great big enormous oblong, extended in both directions.
Now, entirely replace that shell with windows, and through the raytracing gets more involved, the same principles are at work.
That’s why mornings and evenings are cold, that’s why winter is cold, that’s why it gets colder towards the poles. You’re getting a smaller and smaller share of the sunlight hitting the area where the earth is.
Really great visuals.
This covers much of it. Also inderect sunlight matters too. So any percentage non sky (groud/horizon) the panel “sees” wil have less indirect sunlight than the (blue or even cloudy) sky going towards the panel.
I see what you’re getting at here. The solar constant is the solar constant. If you’ve got a perfect angle to the sun, you should be getting the same amount of power regardless of latitude. I mean I suppose it’s possible there might be a slight attenuation with the sun at a lower angle due to there being more atmosphere to traverse? Otoh solar panels don’t function as efficiently at high temperatures, so it’s possible they may be more efficient in some cases.
But you have to consider that averaged out, you’re looking at shorter daylight hours overall at high latitudes, even if there are periods in mid-summer when days can be super long, so that’s a consideration. So yes, the panels should pull in similar amounts of power while the sun is up, but it’s not up as much.
Solar panels are more efficient closer to the equator because of the most direct light from the sun. At higher or lower latitudes, there is more atmosphere for the light to pass through. The actual distance from the sun is basically irrelevant without an atmosphere. There might be a measurable difference based on distance alone but not much.
Efficiency does not generally equate to optimal power generation. There are probably hundreds of other variables that directly translate to maximum power production.
Assuming an ideal mounting angle…
Near the equator, sunlight has less distance of atmosphere to travel through than at higher or lower latitudes, generally speaking.
Then there’s also the average of the weather patterns for different areas, like some areas get way more cloud cover and rain than others.
And then there’s also the air pollution factor, and since significantly more people live in the northern hemisphere than the southern, of course the northern hemisphere has more air pollution.
I hope my insight on this has been helpful.
