Effect of clouds on Solar Generation

[jboy210]

Hi all,

Today the SF East Bay we had a lot of clouds drifting across the sky. As a result, I was able to get this fun graph of the effect of clouds on solar production. We nominally generate up to 8.5 kW. But, you can really see the "cloud edge" effect that amplifies the solar generation as the sun comes out from behind a cloud. And how generation is crushed by clouds drifting by. The top row shows the generation at the time when I captured this screen, 3:40PM. Negative values in any amount mean current is flowing opposite of the legend.

 

[Silicon Desert]

Hi J, good to see you here again. Yup, I used to see that "Cloud Edge Effect" on my house in San Ramon. Sometimes it would increase the average output by 10% or more. I don't see it so much up here.
Thanks for the graph.

 

[jboy210]

Hi J, good to see you here again. Yup, I used to see that "Cloud Edge Effect" on my house in San Ramon. Sometimes it would increase the average output by 10% or more. I don't see it so much up here.
Thanks for the graph.

Thanks G. The cloud edge effect is definitely a strange magnifying effect.

So not rain/snow up there? The TV weather people were saying that might happen.

 

[Silicon Desert]

So not rain/snow up there? The TV weather people were saying that might happen.

I guess I should be more lucid by saying up here in this elevation, it seems to be either perfectly clear with no clouds or there are clouds covering everything. I don't often see the edge effect with those beautiful puffy clouds like you get down there.

 

[nwashin1]

Yes, clouds make a big difference.

At the moment it's midday here in the UK and I'm generating 0.5 Kw from my 5 Kw PV, yesterday it was ten times that!

Have you also noticed how you get the best PV output right after a rain storm - it seems to clear the air.

 

[jboy210]

Yes, clouds make a big difference.

At the moment it's midday here in the UK and I'm generating 0.5 Kw from my 5 Kw PV, yesterday it was ten times that!

Have you also noticed how you get the best PV output right after a rain storm - it seems to clear the air.

Rain? What is that? I think I sort of remember it. We have not seen rain since March/April and will not see any more until Oct/Nov. Where I am we can put a convertible car top down in May and not put it up until Oct/Nov.