Contemplating Tree Removal

[brewbeer]

Hi all, I wanted to ask people's thoughts about when it makes sense to remove trees to decrease shading on their solar arrays.

My array consists of 27 roof mounted panels, azimuth of 162, tilt of approximately 25 degrees. 23 of the panels are on my main roof in two rows, and 4 are on my garage. See photo. Panels are equipped with SolarEdge optimizers and inverter.

Looking at the shading patterns, the panels on the west end of the house come out of shade at about 8:30 AM, and the panels on the east side are in full sun by about 10:45 AM. In the afternoon, the panels on the west side go into shade starting at 2:00 PM, and the last panels on east end go into shade by 4:15 PM.

I understand that as the sun gets higher in the sky, it has the ability to impart greater generation capability to the panels. However, it's not clear to me when it makes sense to remove trees that are shading the array. In the morning should I be aiming to have full sun by 10 AM? 9:30 AM? 9:00 AM? Conversely, in the afternoon, what time does "peak" power generation end? Are there "rules of thumb"?

In my case, the tree that shades in the morning is a huge maple, probably 100 feet tall, and I would more than likely need professional help to stop it from shading the array. The trees to the west (mix of deciduous and evergreen) are smaller, 60-70 feet, and I probably could take those down myself.

Thanks.

[SunEagle]

While I agree with you for the desire to get all you can out of your solar pv system I am sad it would be at the loss of a beautiful shade trees which only affects your panels for a short time each day.

And while I do not follow the "demands of others" with the need for humans to reduce CO2 output, it certainly would be a backward direction to take if it meant removing something that absorbs a lot of CO2 like those trees.

[ButchDeal]

So you have optimizers or micros?
have you looked at the monitoring to see the effect? I find the pvoutput Insolation curve to be fairly telling in this respect for calculating the area difference under the two curves ( at least visually)

[brewbeer]

SunEagle, the tree removal really doesn't bother me that much, I live on 4+ acres, 3+ of which are all woods with literally hundreds of trees. I'm not turning the area into grass or a parking lot, just removing the trees shading the array. If removed, the shorter trees will grow up. Also individual trees really aren't providing long-term sequestration of CO2; if the trees die naturally, they rot releasing their carbon to the atmosphere anyway. Once gone, smaller trees currently shaded by the large can grow up and take up the carbon released by the large trees being removed.

ButchDeal, I have optimizers, and yes, have looked at the monitoring to see the effect. One thing I've noticed is that now that the trees are leafed out, the shading effect and production reduction is more pronounced. I've looked at PVoutput but didn't see an insolation curve. Do I calculate the curve using downloaded data in a spreadsheet, or am I just missing something?

[ButchDeal]

ButchDeal, I have optimizers, and yes, have looked at the monitoring to see the effect. One thing I've noticed is that now that the trees are leafed out, the shading effect and production reduction is more pronounced. I've looked at PVoutput but didn't see an insolation curve. Do I calculate the curve using downloaded data in a spreadsheet, or am I just missing something?

if you have pvoutput configured with the correct pitch and azimuth then you should be able to click on "Live" to get to the live daily data view and then click on "Prev Day" till you get to a good day with no clouds. Then click on the word "Insolation" here is mine (we haven't had many sunny days) My system is south facing with no shadows (this is the most recent day with least clouds though )

[DanKegel]

Do you use air conditioning, btw? Shade from trees can save energy there.

[brewbeer]

I do use air conditioning, but not much, maybe 10 days per year when it's very humid out. Unfortunately, the solar panels are on the roof, so any tree shading of the house to keep it cool also shades the solar panels. The roof is white colored asphalt shingles. The house is well insulated, though, and we only need 2 modest window units to keep the entire house comfortable.

[silversaver]

If the shading isn't from 10 to 5 pm, then you don't really lose much of output. If you have optimizers on your panels, I don't think you need to really worry about it. If you are trimming the tree down, then why start off with optimizers?

[brewbeer]

If the shading isn't from 10 to 5 pm, then you don't really lose much of output.

There is shading before 10:45 and after 2:00. Given the 162 degree azimuth, isn't the morning more productive than the afternoon?

Butchdeal, I'm having a heck of a time trying to get my "live data" to upload to PVOutput using the CSV live loader. I can successfully transfer the data from the SolarEdge portal into a spreadsheet, and copy it into the live loader box, but when I ask for it to accept the data it only transfers the morning, then starts skipping entries, and then won't load any afternoon data.

I also have a Solar-Log revenue meter that tracks output in 5 minute intervals, but I cant figure out how to download data from that system.

[ButchDeal]

There is shading before 10:45 and after 2:00. Given the 162 degree azimuth, isn't the morning more productive than the afternoon?l

Butchdeal, I'm having a heck of a time trying to get my "live data" to upload to PVOutput using the CSV live loader. I can successfully transfer the data from the SolarEdge portal into a spreadsheet, and copy it into the live loader box, but when I ask for it to accept the data it only transfers the morning, then starts skipping entries, and then won't load any afternoon data.

I also have a Solar-Log revenue meter that tracks output in 5 minute intervals, but I cant figure out how to download data from that system.

Well if you have solarEdge then use the solarEdge logging. Get the API key and use that. All our solarEdge sites are uploaded directly to pvoutput via API.
You can also get daily graphs in solarEdge.

[brewbeer]

Well if you have solarEdge then use the solarEdge logging. Get the API key and use that. All our solarEdge sites are uploaded directly to pvoutput via API.
You can also get daily graphs in solarEdge.

I like the SolarEdge graphs, but how do you overlay the graphed production on a theoretical insolation graph for my system?

It's not clear to me how to get pvoutput to automatically acquire the SolarEdge data. Are there instructions you could point me to?

[ButchDeal]

http://pvoutput.org/help.html#autoupload-solaredge

[ButchDeal]

/pvoutput.org/help.html#autoupload-solaredge

[bcroe]

There is shading before 10:45 and after 2:00. Given the 162 degree azimuth, isn't the morning more productive than the afternoon?

I also have a Solar-Log revenue meter that tracks output in 5 minute intervals, but I cant figure out how to download data from that system.

A south facing system won't make much power at the more extreme hours, so you have little to gain. If you have a lot of east or
west facing panels, it would matter more. Another thing to consider; whatever shade you have will likely get worse every year
if you take no action. Bruce Roe

[ButchDeal]

I like the SolarEdge graphs, but how do you overlay the graphed production on a theoretical insolation graph for my system?

It's not clear to me how to get pvoutput to automatically acquire the SolarEdge data. Are there instructions you could point me to?

You will need the API key from solarEdge.
Then http://pvoutput.org/help.html#autoupload-solaredge

No solarEdge doesn't do the predictive model graph though

[DanKegel]

It's not clear to me how to get pvoutput to automatically acquire the SolarEdge data. Are there instructions you could point me to?

http://pvoutput.org/help.html#autoupload

[silversaver]

Depends on the shade area and time of shade, make your own decision (solar gain vs. cost)

I did trim down a tree on SW of my house...

[huge]

Your top row panel set up looks different in the 2 pictures. Did you change the set up after cutting the tree?

[silversaver]

For some reasons, I add 2 more panels to the arrays.