Shading: Conflicting results

[J.P.M.]

JPM, that is the same info I gleaned from this site and took it to the bank. This site is also full of info (including this thread) that anything more than a tiny bit of shade is a no go for solar.

Do and think as you please, and I wish you the all best and good luck, but from someone (like Butch BTW) with no skin in the game and maybe a smattering of knowledge and experience, IMO, your solar ignorance and what seems to be hoping against hope optimism are going to lead to some disappointments. Read Butch's last post a few times and think realistically.

[Sunking]

JPM encourage him to spend his money. No better teacher than loosing a lot of money.

[J.P.M.]

JPM encourage him to spend his money. No better teacher than loosing a lot of money.

Believe me, wasted money is a great learning experience. Done it more than most, usually, as I've come to conclude, out of ignorance with a lot of that from a mixture of pride and arrogance. I think get and understand what you're writing, but that method seems a bit and unnecessarily mean spirited to me, at least until other methods that aren't as costly, wasteful, and produce less collateral damage have been tried and exhausted.

Besides, it runs counter to my libertarian sensibilities that folks ought to be free to do want while some sense of my "we're all in this together" attitude is a part of why I (and I suspect maybe you and others) try to offer opinions based on experience and training. I know: yea me and yea us.

Additionally, While I'm not a crusader, at least not any more, I still thing R.E. has a contribution to make, and if I can help someone avoid installing what I honestly believe to be a bad solar application, I may be helping to avoid another blackeye solar installation of the type that won't help solar acceptance.

That battle is mostly against ignorance, and letting what I believe to be a mistake while keeping my pie hole shut doesn't seem to help much of anyone or anything.

When I was a peddler, it didn't take me long to learn you get more flies with honey or sugar than vinegar, and it's almost always easier to convince people of the rightness of your cause (or the greater worth of your product) by, first of all, honesty and also by not insulting them. Still, some folks you just can't and never will reach. So, I wish them the best and move on as I've done here.

Respectfully,

[Sunking]

Believe me, wasted money is a great learning experience. Done it more than most, usually, as I've come to conclude, out of ignorance with a lot of that from a mixture of pride and arrogance. I think get and understand what you're writing, but that method seems a bit and unnecessarily mean spirited to me,

Perhaps, but after 6 or 7 years here I have learned what has always been known. A fool and their money will soon part. You cannot save people from themselves. Like you I have made my share of mistakes and lost money. I learned and never repeated those mistakes. When a person decides to do something stupid, there is no stopping them. Once in a while you can shine the light and help someone from doing something stupid, but that is the exception to the rule. I give it one shot, but after that I will help them load the gun so they can shoot themselves. In my business I turned a lot of clients away for that exact reason. I don't want any part of it. I send them to my competition to be robbed. My clients come back.

[rscott]

The way I look at this is that it boils down to 1 number: dividing the cost by the expected annual output to get the cost per MWh. If it costs $30,000 to produce 10,000kWh/year, that's $3 per MWh/year. If it costs $60,000 to get the same result, it's $6 per MWh/year. It's different than the normal $/kW, since you have to rely on estimated production.

Company 1 says "The south-facing side isn't worth doing. We expect the north-facing side will be $5.44/MWh/year." From that, it is impossible to say if the south-facing side is worth it. And the north-facing side, if their numbers are accurate, *might* justify the expense.

Company 2 says "We expect the south-facing side will cost you $2.78/MWh/year." If accurate, that's a much better deal. If they wildly overestimated product, and it generates half of what they expect, the number now becomes $5.56/MWh/year. That would be a bit worse than Company 1's north-facing option, but I've still got the option to see about getting the trees cut -- in which case the numbers would likely improve (but I would have to factor in the cost/hassle of getting the trees cut).

And even if the numbers don't quite make sense financially, we're still getting some renewable energy to replace non-renewable energy.

I certainly respect what people have posted -- it is clear that some (or perhaps all) people posting have much more knowledge than I do, and quite likely more than the people that have looked at my house. But what I need to be convinced that it is a bad deal is information suggesting that the numbers won't work. What I have seen so far is that my house is far from an ideal candidate for solar with (and some saying without) the trees. And that is very helpful information. But it is hard for me to reconcile something like "It looks like it is going to be a bad installation" with "We expect it is going to cost $X/MWh/year" along with educated (but perhaps naive) guesses as to how far off the estimate could be.

[J.P.M.]

The way I look at this is that it boils down to 1 number: dividing the cost by the expected annual output to get the cost per MWh. If it costs $30,000 to produce 10,000kWh/year, that's $3 per MWh/year. If it costs $60,000 to get the same result, it's $6 per MWh/year. It's different than the normal $/kW, since you have to rely on estimated production.

Company 1 says "The south-facing side isn't worth doing. We expect the north-facing side will be $5.44/MWh/year." From that, it is impossible to say if the south-facing side is worth it. And the north-facing side, if their numbers are accurate, *might* justify the expense.

Company 2 says "We expect the south-facing side will cost you $2.78/MWh/year." If accurate, that's a much better deal. If they wildly overestimated product, and it generates half of what they expect, the number now becomes $5.56/MWh/year. That would be a bit worse than Company 1's north-facing option, but I've still got the option to see about getting the trees cut -- in which case the numbers would likely improve (but I would have to factor in the cost/hassle of getting the trees cut).

And even if the numbers don't quite make sense financially, we're still getting some renewable energy to replace non-renewable energy.

I certainly respect what people have posted -- it is clear that some (or perhaps all) people posting have much more knowledge than I do, and quite likely more than the people that have looked at my house. But what I need to be convinced that it is a bad deal is information suggesting that the numbers won't work. What I have seen so far is that my house is far from an ideal candidate for solar with (and some saying without) the trees. And that is very helpful information. But it is hard for me to reconcile something like "It looks like it is going to be a bad installation" with "We expect it is going to cost $X/MWh/year" along with educated (but perhaps naive) guesses as to how far off the estimate could be.

Amen to the ability to choose.

One last comment and I'm outa' here: If you knew some of what I think I might know, you'd not be doing what you're considering.

[Sunking]

Amen to the ability to choose.

One last comment and I'm outa' here: If you knew some of what I think I might know, you'd not be doing what you're considering.

Ditto JPM. The OP just proved you cannot save people from themselves. Out of here.

[rscott]

Please help educate me. Are you saying that I shouldn't be focusing on the cost for the electricity generated (something that I haven't heard here yet, maybe just because I haven't been listening), or that the production estimate I got from Company 2 is more than double what I could actually expect, or something else? And are you saying that even with the trees cut down, this isn't worth pursuing?

I get that the shade is a big, big problem, and will cut the production of the system compared to not having shade, and likely by quite a bit more than I originally expected.

I'm trying to learn here, but feel like I'm being mocked and patronized. Yes, I really want this to work. But honestly I feel like I'm being told to give up without a reason.

[SunEagle]

Please help educate me. Are you saying that I shouldn't be focusing on the cost for the electricity generated (something that I haven't heard here yet, maybe just because I haven't been listening), or that the production estimate I got from Company 2 is more than double what I could actually expect, or something else? And are you saying that even with the trees cut down, this isn't worth pursuing?

I get that the shade is a big, big problem, and will cut the production of the system compared to not having shade, and likely by quite a bit more than I originally expected.

I'm trying to learn here, but feel like I'm being mocked and patronized. Yes, I really want this to work. But honestly I feel like I'm being told to give up without a reason.

The problem with using the generated power values to compare systems is that your kWh output varies a lot over the lifetime of the system and is affected by bad weather along with shade or blockage. Production estimates are just a "guess" on what a system may do.

It is better to compare systems by using the installed $/ DC wattage of the system. Everything else is speculative.

[solarix]

How about using the NW facing roof and tilt the panels toward the Southwest?

[rscott]

These photos are taken at different times and different years. You can see massive tree size difference in some of them and some are completely leaf off (Winter)
The first and third look like they were taken a long time ago, while the fifth is more recent with more trees.
...

Thank you very much for taking the time to analyze those images; it is greatly appreciated.

In this day and age, the benefits of solar production to the planet are important enough that old "rules of thumb" ("Never install if there is much shade" and "Never install on north-facing roofs" that J.P.M. and Sunking seem to be going by) often need to be examined. If you're discussing with someone on an airplane, it's fine ("I doubt it would work for your roof"). But data like you provide is VERY helpful. It makes it clear that this is nowhere near an optimal situation, and that Company 2's estimated production is likely quite a bit off the mark, and is going to have me re-thinking things.

[ButchDeal]

How about using the NW facing roof and tilt the panels toward the Southwest?

could be code issues in many places for reverse tilt installs.
Also this is drastically higher up lift issues and requires much more engineering and connection points.
still has some shadow issues.

[Mike90250]

If you have a shaded roof, solar is futile, and it's unlikely you will realize any net gains. Till the trees go (and the thin shadows from branches) it's pointless.

But you can spend a bunch of $$ and prove me wrong, and then I'd eat a slice of pizza.

[FFE]

If you have a shaded roof, solar is futile, and it's unlikely you will realize any net gains. Till the trees go (and the thin shadows from branches) it's pointless.

But you can spend a bunch of $$ and prove me wrong, and then I'd eat a slice of pizza.

The above is absolutely wrong. I have over two years of data proving it is wrong. I would gladly invite you over to see my shade situation, see my Electric bills for the last three years and my solar production for the last two plus years. I could post pictures and video but it would not do it justice. I am not willing to spend the time to post all my bills, spread sheets, production, videos and pictures since it could easily be denied or argued. I will even buy the pizza.

[SunEagle]

The above is absolutely wrong. I have over two years of data proving it is wrong. I would gladly invite you over to see my shade situation, see my Electric bills for the last three years and my solar production for the last two plus years. I could post pictures and video but it would not do it justice. I am not willing to spend the time to post all my bills, spread sheets, production, videos and pictures since it could easily be denied or argued. I will even buy the pizza.

@ FFE. You may have different results based on where you live, the size of your pv system and the amount of shade you get.

It is all relative to how much "shading" your panels gets. IMO if you get it every day and it covers a larger percentage of the panels your kWh output is greatly reduced making it much harder to justify using solar to save on your electric bill.