Questions about Solar Installation (Orlando, FL - 11.6 kw)

[Dan Long]

I trying to decide on solar and I have questions about costs and equipment. And while being technically mind, I know nothing useful about solar with regards to practical application. Below is the scenario.


The price to install a 40 panel system system totaling 11.6 kw DC is $26,026. This 11.6 kw system installed on the southwest roof assuming very minimal shade will generate approximately on average 1300-1400 kWH per month depending on the time of year (summer or winter), which will offset approximately 80% (normally $200/month avg.) of the energy bill based on the past 12 months of energy usage data.
The system consists of the following components:

* REC solar TwinPeak 2 290 Watt panels (http://www.recgroup.com/sites/default/files/documents/ds_rec_twinpeak_2_series_rev_e_eng.pdf)
* Power Optimizer P-300 DC (https://www.solaredge.com/us/products/power-optimizer#/) at each panel.
* SolarEdge 10000 inverter (https://www.solaredge.com/sites/default/files/se-single-phase-us-inverter-datasheet.pdf)

Rendering showing the maximum amount of panels that will fit on the roof based on Helioscope software.
PHOTO: drive.google.com/file/d/1Ecetu20V-Uevtt4TLfidGx9Ulj0na8gd/view?usp=sharing
(ignore the 4 panels on the side).


+ ~$67/panel SolarWorld's Panels SW300 (https://www.solarworld-usa.com/~/media/www/files/datasheets/temp/sw-01-7506us-plus-mono-wob-290-295-300-prior-9-1-17.pdf)
+ ~$67/panel Mission Solar Energy Panels 300W 60-cell Mono (http://www.missionsolar.com/wp-content/uploads/2017/08/MSE-PERC-60_v2.pdf)


The increased price to install SolarWorld or Mission Solar panels would cost $28,694 (= 26,026 + (40 * $66.7))

The whole complete solar package is eligible for a 30% Federal tax credit.

The payment terms are as follows:
25% deposit
50% payment due upon ordering equipment before installation
15% upon inspection with building department
10% Duke Energy interconnection




These are my questions:
Price, how is it? Expensive? Cheap? Middle of the road?
How are the panels compared to? REC vs SolarWorld vs Mission Energy. Are they three junk? Information regarding the specific modules listed would be great.
How are the SolarEdge Power Optimizers?
How is the SolarEdge inverter rated?
Anyone have Duke Energy I know Duke has Net Metering in Florida and it is 12-months rolling - Is Duke is it a continuous rolling credit or is it a 12-month reset at an some anniversary date or calendar date?
Anyone have Amica Insurance -- Does their typical home insurance include solar? Or is a Special provision needed/required?
While this system does not provide 100% of the energy needed, but if it did and I never owe Duke any money, with Net Metering does Duke still charge the 'Customer Charge' ($8.76) or 'Asset Securitization Charge' ($4.00) per month?

Let me know if any additional information is needed.

[Rob Beckers]

Dan, first of all, welcome to the forum!
I'm a little short on time, but wanted to get this in: Solarworld is bankrupt. Any warranty on those panels is likely not worth the virtual paper it's written on. Possibly, just possibly, they'll emerge from bankruptcy as a viable company again, especially in light of the suit they brought (and so far won) before the ITC claiming unfair competition. But even if they continue there is a good chance they'll disavow any prior warranty liabilities.

Just so you know...

-RoB-

[Dan Long]

Dan, first of all, welcome to the forum!
I'm a little short on time, but wanted to get this in: Solarworld is bankrupt. Any warranty on those panels is likely not worth the virtual paper it's written on. Possibly, just possibly, they'll emerge from bankruptcy as a viable company again, especially in light of the suit they brought (and so far won) before the ITC claiming unfair competition. But even if they continue there is a good chance they'll disavow any prior warranty liabilities.


Thanks Rob, for the welcome, glad to be here! Yes, I am aware of SolarWorld's financial filings. As stated, I really don't understand real world applications or performance of solar panels. I wasn't sure if you really even needed the "25 year" warranty. Do panels go bad? How often? Are there performance/failure data for panels? If so, where to find them?

w/r/t Duke's Net Metering (https://www.duke-energy.com/_/media/pdfs/rates/peratesrulesandregs.pdf?la=en), I did find some additional information: It looks like at the end of the calendar year they buy any credits at COG-1 tariff rate. From energysage.com (https://www.energysage.com/net-metering/duke-energy/) it states, "The current rate for COG-1 is 6.310 cents/kWh". While, it isn't great, it's not terrible either.

Any other ideas on the other "questions" ?

[Rob Beckers]

Alright, let me tackle some of your other questions:

Price you quoted is very similar to the going rate over here (after I convert the currency). So, this wouldn't be a bad price here. I don't know if in your neck of the woods things are generally cheaper or not, so that's something to consider.

If you have a choice of panels REC is not a bad one. They have great future prospects and should be around for a while to honor warranty.

You are correct though that it is very rare for a panel to be or go bad. I've seen a few, but those were all issues right at the start. I've also heard about panels that did go bad in other countries, mainly snail-trail issues, but have not seen that happen over here. It's just that if you're going to buy panels from a chapter-11 corporation they should come at a steep discount, knowing that their warranty won't likely be there, and if so I'd buy a couple extra panels as spares.

SolarEdge is great stuff. It comes at quite the surcharge though vs. a string inverter. Personally I'm also no great fan of sticking optimizers or micro-inverters behind panels, where they are in a very harsh environment. I can pretty well guarantee that at least one will break over the next 20 years, and while you may get a free replacement it's a real pain to pull panels to get to the broken one, and reinstall them again.

If you think my worries are purely theoretical, consider that Enphase's (THE most popular micro-inverter brand) M190 micros either have failed or will fail. Every single one of them.

The beauty of solar is that there are no moving parts, panels rarely if ever fail, they'll likely live for 30-plus years without issue, there's really no maintenance (if you're in a dusty climate you have to hose them off but that's it). Adding complex electronics behind each panel undoes that reliability in a big way! That's why I like to stick to a string inverter unless there's a compelling reason to go with optimizers or micros.

I don't like the payment term about "50% when ordering equipment". It should be 50% when DELIVERING the equipment to site, even if it's not installed yet. If anything happens to the installer you don't want to be out 50% without having equipment to show for it, and they really should have the cash-flow to be able to order stuff for you before it's paid.

These days many/most home-owner's insurance will cover solar panels as well. You have to tell them about it though. Generally they don't charge extra but I've heard from some customers their insurance wanted to jack the rates after they declared the solar panels. In that case it's time to shop around for another insurance company.

Can't speak to the rest of your questions. While I went to Duke University's grad school, I know nothing about Duke Power!

Cheers,

-RoB-

[Dan Long]

> SolarEdge is great stuff.

How are their inverters compared to other brands? Although, I do not think that I have a choice. The installer quoted SA10000A-US. I installed System Advisor Model (SAM) from National Renewable Energy Laboratory (NREL). And in the Inverter section, it lists multiple SA1000A-US each with different voltages, 208, 240, and 227. Trying to understand the field but so many terms -- I can't even match what is in the PDF (from the manufacture's website) with what is in the SAM database.

> Price you quoted is very similar to the going rate over here

Supposedly, I am getting up to a 25% discount because this purchase would be part of a co-op (bulk purchase/install). So if the US$26K is comparable with CAD, I may not have gotten a discount at all, assuming that prices between CAD and US are similar. Currently, in the US we get a 30% federal tax credit, at least until 2019, at which point it then drops down. So, the US$26,026 is really US$18,218.

> I'd buy a couple extra panels as spares

Even if the company wasn't going out of business. Would you suggest purchasing an extra panel or two?


> I like to stick to a string inverter unless there's a compelling reason to go with optimizers or micros.

To be honest, I didn't ask about optimizers/micros vs string. So either, this was a silent upsell, standard for all installs, or they have a reason and just didn't tell me. As it is roof mounted, there will be little, if any shading and so only from clouds. I am told the system generates power even when it's raining during the day. I guess the question here would be, how much more efficient would the system be with the optimizer vs without. Any general rule of thumb numbers?


> payment terms

I agree with you. However, in this case, I am okay since the company has been in business for at least 7 years (maybe longer, 7 ago years is when I first heard their name). And being part a co-op, I am hoping the group has done some financial vetting from the installers.


I have an additional new question. So, for no-fee, my power company limits the system to 10kwAC, so the 11.6kwDC (my installer said 11.6 * .85% ... I don't get this.). Anyway, to go higher, there is an application fee of ~ US$250 plus they require a US$1 million general liability insurance policy. For an additional side, a fee of $300 + panels + labor; I can add 4 additional panels (290 W) southeast facing (see photo (https://drive.google.com/file/d/1Ecetu20V-Uevtt4TLfidGx9Ulj0na8gd/view?usp=sharing) https://drive.google.com/file/d/1Ecetu20V-Uevtt4TLfidGx9Ulj0na8gd/view?usp=sharing). The question is, if the $300 + $250 +panel + labor is worth the additional 4 panels over the lifetime of the system? I am not including the US$1Mil policy because that is something that we plan on getting anyway. I will get the cost of the additional panel + install tomorrow.

Thanks!

[Dave Schwartz]

My 18 SolarWorld 230's (installed in 2010) are all still going like champs and that includes having dealt with the occasional heavy snow load and me running a roof rake over them to clear the snow.

My panels are on the garage roof oriented pretty much exactly due south. I do not have any other electronics other than a Solectria 3.9kW GT inverter in the garage (pretty much on the other side of the wall from the utility meters). Its been completely reliable for over 7 years and is already well past the financial break-even point).

Your 11.6kWDC/10kWAC configuration means that you are "overpanelled" by a small amount. This is often a good idea these days when panels are cheap. Your inverter will clip the output power so that no more than its nameplate rating will go out to the utility. While the panels may be capable of more power (even after losses), the inverter's MPPT (maximum power point tracking) algorithm will not ask any more of them than it needs to produce that 10kW output. The panels will only be capable of outputting their maximum power when the unobstructed sun is directly above (and within, say, +/-10 degrees of that). What overpanelling does is to extend that angle range so that, because the inverter won't have to be calling for maximum power from every panel to achieve its desired input when they aren't capable of it, it will spend more time at the maximum rated output.

As to the 'power on a rainy day', that is true - but it won't be the maximum power. You generally get some output any time the sun is up, clouds or not. With a clear sky, my system will actually go on-grid a few minutes before sunrise and stay on-grid a few minutes after sunset. However, on a cloudy day you may be only putting out a few hundred watts even at solar noon. I've actually seen mine drop off the grid during the heaviest cloud of a rainstorm.

That breakpoint at 10kW is about what we have here in Ontario in the microFIT and FIT programs. 10kW or less and you are considered an amateur and go into the microFIT program. Above 10kW you are considered a commercial generator and the rules are much more cumbersome and the rates lower... just go read Rob's trials and tribulations of getting his 100kW system going on the roof of his new office/warehouse.

[Dan Long]

Another point is the direction of the panel. The installer did not talk about installation angles and such. However, when I asked about putting additional panels on the north facing roof and angling it south, he stated that they generally mounted flat so that they don't have to to deal with wind load.... My south facing roof is really 240 degrees azimuth, no not really south by more south-west. I may have to push the point and see if they will mount it with more optimal facing.

Is there any power output calculation on 240 vs 180 degrees azimuth? I want to say that my roof pitch is 25-28 degrees.

[Dan Long]

I ran some number through SAM:

1) Panels without Power Optimizers (DC-DC converters @ each panel), mounted flat (25-28 degree slope) on my roof (240 degrees azimuth) vs panels mounted 180 degrees azimuth, the payback went from Year 12 down to Year 11.

2) Again, panels mounted 240 vs 180 (25-28 degree slope), but this time with Power Optimizers at each panel, the payback went from Year 11 down to Year 10.

Also, someone on reddit suggested that instead of using a SE 10000, use two SE 6000 instead. Reasoning was that the 10000 has a fan ("user replaceable") whereas the 6000 are passively cooled. Comparing the two status, it's interesting that the stated CEC Weighted efficiency for the 10000 is between 97.0-97.5, where as the 6000 is 99. *not that I know what CEC Weighted Efficiency means as I type this but will google when done typing. :)

[Dave Schwartz]

240 azimuth is a bit less than optimal. Your peak generation will be less than if you faced due south and it will occur later in the day, which is actually of benefit to the grid as a whole. I think you'll find that your payback will not be improve to that degree (ha!... a pun!) if you install them on a wedge to get them to 180 degrees because a) the racking will be much more expensive, b) the installation likewise and c) the probability that you will lose them all to tropical storm (or higher) winds in Florida will rise markedly.

Are you in a part of Florida which has a daily cloud/haze cycle? I've heard of some locations nearer the water (this might not describe Orlando) that have morning sea haze where a southwest orientation actually is the best (its better to directly face a clear, lower sun than an overcast, higher sun).

I have a neighbor down the road with a 24-panel system on his garage roof that is pointing dead east and I do wonder why he chose to do that when there is a due south face (not square and above living space though) immediately adjacent.

My garage roof is also 28 degrees, which is not optimal for my 43 degree latitude, but when I talked to my installer about tilting the rows to get a better angle he quickly talked me out of it for reasons a and b (and partly c because we do get 50mph storms in our area in the winter). If you have a flat roof (like Rob's building) or ground mount you have no choice but on a pitched roof facing generally south you'll almost always be better off to lay them flat to the roof (just add more panels to be even more overpanelled to make up the difference).

I've never understood the need for optimizers if you don't have differential shading issues to compensate for... maybe someone can educate me but it just seems like you can't get any more optimal than an unshaded string. Certainly the installer won't mind the higher profit of selling (and servicing, as Rob's already pointed out) you more gear but I don't understand what the benefit is going to be to you.

I don't know how to compare the one- v.s. two- inverter scheme but I will say that the two-inverter scheme, combined with your overpanelling will push you over the 10kW nameplate rating class and that may bring more expensive baggage down on you.

[Dan Long]

240 azimuth is a bit less than optimal. Your peak generation will be less than if you faced due south and it will occur later in the day, which is actually of benefit to the grid as a whole. I think you'll find that your payback will not be improve to that degree (ha!... a pun!) if you install them on a wedge to get them to 180 degrees because a) the racking will be much more expensive, b) the installation likewise and c) the probability that you will lose them all to tropical storm (or higher) winds in Florida will rise markedly.

My garage roof is also 28 degrees, which is not optimal for my 43 degree latitude, but when I talked to my installer about tilting the rows to get a better angle he quickly talked me out of it for reasons a and b (and partly c because we do get 50mph storms in our area in the winter). If you have a flat roof (like Rob's building) or ground mount you have no choice but on a pitched roof facing generally south you'll almost always be better off to lay them flat to the roof (just add more panels to be even more overpanelled to make up the difference).


This is what Superior Solar said, "Both your front and side roofs have south in the orientation and are both considered good for solar photovoltaics. I cannot tilt, elevate, or angle that panels to face 180 degrees due to the wind loading requirements with the Florida Building Code. It has to anchor into the trusses mounted flush to withstand hurricane force winds. The system mounted flush at the same angle of the roofs will perform well. Ideally 180 degrees South is optimal, but an azimuth between 120 and 240 is great at our latitude of 29 degrees in Central Florida."

Are you in a part of Florida which has a daily cloud/haze cycle? I've heard of some locations nearer the water (this might not describe Orlando) that have morning sea haze where a southwest orientation actually is the best (its better to directly face a clear, lower sun than an overcast, higher sun).

No, we don't get daily cloud/haze in CFL (Central FL). I'm about 25 miles north of Orlando in Lake Mary, FL.


I've never understood the need for optimizers if you don't have differential shading issues to compensate for... maybe someone can educate me but it just seems like you can't get any more optimal than an unshaded string. Certainly the installer won't mind the higher profit of selling (and servicing, as Rob's already pointed out) you more gear but I don't understand what the benefit is going to be to you.

I don't know how to compare the one- v.s. two- inverter scheme but I will say that the two-inverter scheme, combined with your overpanelling will push you over the 10kW nameplate rating class and that may bring more expensive baggage down on you.

Apparently SAM can run the simulation. Which I ran last night, the payback was slightly better, but I am wondering if the payback is better only because the CEC weighted averaged efficiency of the SolarEdge 6000 (99.2%) is higher than then SolarEdge 10000 (97-97.5%). The payback period was still 10 years but the dollar amount was different in that 10th year. Less than a $1000 and more than $100 on the 10 year. Unfortunately, Superior Solar currently does not offer the SolarEdge HD 6000, but they will in the future.


Superior Solar said, "The power optimizers are required for the SolarEdge inverter system to perform properly. The SolarEdge inverter will not work without the DC optimizers. " I asked them if I am there is a different option than SolarEdge inverter.

[Dave Schwartz]

Superior Solar said, "The power optimizers are required for the SolarEdge inverter system to perform properly. The SolarEdge inverter will not work without the DC optimizers. " I asked them if I am there is a different option than SolarEdge inverter.

I haven't looked into the SolarEdge hardware but if the two are linked such that one won't work without the other then they must have some funky split to the electronics. That would make me cautious.

For our microFIT program, the contracts run 20 years and everyone says you should plan for replacement of the inverter during that period. If that is true and there's no possible way to guarantee SolarEdge will still be in business by then, what happens if you can't get an inverter that will work with their optimizers? Also, what happens if an optimizer fails and you can't get a replacement compatible with a SolarEdge inverter? Does just one panel drop out? A whole string?

That's why when looking at a system that should be expected to run for 20 or 30 years you are best to stick with industry standards at the interface points. Manufacturers come and go but the industry standards last a lot longer.

Of course you may not stay in that house that long in which case you don't care if it becomes someone else's problem.