Considering going Solar - AM shade issues

[Ne0eN]

Hello all,

New to the forum, hope one of you pros can share your infinite wisdom. So I've been contemplating a 10kW Solar system on my house in northern VA, but I'm a bit concerned about the shading from near-by trees that may impact my AM production. (my house is bordering a county park.) Using a time-lapse photography I can see significant shading on my south facing roof (170 azimuth) before 10am. How significant is this for a typical installation? I'm guessing a lot of installations have some sort of shading issues. My overall plan is to install 28 SolarWorld 285W panels on this side, plus 6 more panels facing west (260 azimuth) which would help in late afternoon production. I'm considerting SolarEdge optimizers to reduce the impact of shading and different roof faces. I also realize that winter shading will be much worse, so does the overall system even make economic sense? Are there any other panels that may be more efficient at lower irradiance levels (Canadian Solar?)

Thanks!

[ButchDeal]

If those are the only shadows, it would be little effect assuming optimizers or micros

[Mike90250]

Sum before 10am has low solar energy. So it would effect the output, but not as bad as10am - 11am would

[Engineer]

Agree that early morning shading will lave low impact - depending on area there may be morning fog/cloud cover anyhow, and even if not the panels are at a low incidence angle. OTOH that roof will be oriented quite well for the early morning since its so steep.

[DanKegel]

Check out nearby systems on Pvoutput.org and see how much they generate before 10.

Looks like about one sixth of my output in LA?

[Ne0eN]

Check out nearby systems on Pvoutput.org and see how much they generate before 10.

Looks like about one sixth of my output in LA?

Good point. A comparable system near by is generating 9.7 out of 58.5 kWh (17%) - so exactly the same result.

What gives me hope is that at 9:15am about 50% of the panels on that roof will be getting sun.

[Ne0eN]

If those are the only shadows, it would be little effect assuming optimizers or micros

These are the only shadows that I'm really concerned with. I will be removing the outdoor antenna, and relocating the plumbing vents. There will be other shadows - roughly after 4:30pm from the roof gables and the chimney. By 5:30 that roof will be 75% shaded. The west roof will continue getting sun till about 6:45.

[DanKegel]

FWIW microinverters / solaredge will probably improve output during that transition period when some of your panels are shaded, which might matter if it happens during a relatively bright period.

PVWATTS and looking at neighboring systems in pvoutput ought to help you decide how much energy you'd get. You'd have to combine that with your current and estimated future bills to figure out the payback time for a solar system.

Nice job using time-lapse to quantify your shading, btw!

[FFE]

I have worse shade than that with a dual MPPT string inverter. I lose slightly more output than the shade covers. It just means I get less output. That mainly effects the financial aspect in my opinion. Panel level optimization will get that extra 10% when there is shade if you prefer that route. Not worth the 10% in my opinion if you prefer a MPPT string inverter.

[DanKegel]

Panel level optimization will get that extra 10% when there is shade if you prefer that route. Not worth the 10% in my opinion if you prefer a MPPT string inverter.

Is your preference based on cost, on perceived reliability, or something else?

[J.P.M.]

These are the only shadows that I'm really concerned with. I will be removing the outdoor antenna, and relocating the plumbing vents. There will be other shadows - roughly after 4:30pm from the roof gables and the chimney. By 5:30 that roof will be 75% shaded. The west roof will continue getting sun till about 6:45.

FWIW, I've got shade after about 4 P.M. in the summer and after about 3 P.M. in the winter. Annual output is decreased about 3-5 % from daylong unobstructed insolation as a result.