What is considered to be a good $/watt OTD (with all taxes/fees minus the rebate)?

[solar pete]

Hi All,

These guys have been testing various makes and model panels for more than 10 years, https://www.dka.com.au/activities/dka-solar-centre they used to have a page somewhere that showed daily performance and performance over time of heaps of different panels. There website has changed but I am sure if someone is interested enough and has the time to poke around there website they will find that data. I haven't looked at it for many years now but last time I looked when the graphs were overlayed you couldn't tell which was which as production was so close, cheers.

[PugPower]

My cost $/Watt after federal and manufacturer rebates was $2.06. This was in 10/19 for a 6.7kW system installed by a professional solar company in San Diego and included a main panel upgrade, 20 LG panels, and a SolarEdge 6,000 inverter. Price before any rebates was approx. 20K including the main panel upgrade which was 2K.

[John_Dumke]

By rebate I meant the tax credit. Was your 14.5k price after subtracting the tax credit? or after tax credit you were down to ~10k spent?

14.5 is Total Cost, not including the credit.

While you take the time to choose the perfect panel, remember that a lower efficiency panel installed today will very likely gather more overall energy in your lifetime than a higher efficiency panel installed 6 months from now. IMHO, people make far too much of panel efficiencies and warranties (but marketing sure drill that into our heads).

After I made my home and lifestyle as efficient as possible, I purchased a 6.6kW turn-key grid-tie system from a trusted local installer and after all was said and done it came out to $1.68/W. With a few bonus incentives thrown in along the way by the local utility, I'll reach my break-even point this summer in under 6 years.

Yes, well said. Or said another way.... When I cleaned my panels I saw a 15% improvement. So several percentage points of efficiency is inconsequential compared to real world performance.

[azdave]

While you take the time to choose the perfect panel, remember that a lower efficiency panel installed today will very likely gather more overall energy in your lifetime than a higher efficiency panel installed 6 months from now. IMHO, people make far too much of panel efficiencies and warranties (but marketing sure drill that into our heads).

After I made my home and lifestyle as efficient as possible, I purchased a 6.6kW turn-key grid-tie system from a trusted local installer and after all was said and done it came out to $1.68/W. With a few bonus incentives thrown in along the way by the local utility, I'll reach my break-even point this summer in under 6 years.

[Duxa]

NEM - The meter was already NEM capable. I think they just "pinged" it and it then it had the capability. It was done in probably less than two weeks from the application being complete. They were very quick. The $14.5k included everything, permits, electrician, tools.... everything. Rebate???? There was no rebate. I did however take a 30% tax credit for 2019. This would have reduced my Federal tax bill by $4,350.

By rebate I meant the tax credit. Was your 14.5k price after subtracting the tax credit? or after tax credit you were down to ~10k spent?

[John_Dumke]

NEM - The meter was already NEM capable. I think they just "pinged" it and it then it had the capability. It was done in probably less than two weeks from the application being complete. They were very quick. The $14.5k included everything, permits, electrician, tools.... everything. Rebate???? There was no rebate. I did however take a 30% tax credit for 2019. This would have reduced my Federal tax bill by $4,350.

[Duxa]

Duxa,

FYI, my self install about one year ago in Long Beach, CA

https://www.solarpaneltalk.com/forum...system-success

Nice, how long did it take SCE to install the NEM meter and allow you to switch the system on? Also what was your final price per watt? Did you have to make panel changes (you mention the city didnt like that it was center fed). The $14.5k figure you give, does that include all permitting and also after the rebate or before the rebate?

[John_Dumke]

Duxa,

FYI, my self install about one year ago in Long Beach, CA

https://www.solarpaneltalk.com/forum...system-success

[PugPower]

This thread is getting a little heated.

Anywayz.... here's a short story on why I got LG panels. When my installer was designing my system he gave me the option between Panasonic, LG, and Hyundai panels. On paper the Panasonic had slightly better specs than the LG but they also cost a bit more, not much. The Hyundai was the cheapest of the bunch but had the worst specs of the three and would require additional panels be placed on my roof. While researching the different options I found a $250 rebate from LG. So that's what we went with. Also my installer was Korean and seemed to favor LG, I suspect for that reason.

[Duxa]

I'm not arguing anything either. Just sharing opinions arrived at over ~ 45 yrs. after changing careers to engineering as a result of getting the solar bug and then getting fed up with the B.S./lies I was told and then getting educated and possibly better able to find my own answers.

You are correct, I am approaching it from a different angle. I trust, but verify. Looks to me like you're one of the typical folks who sees what you want to see and read what you want to read and seem to have your mind made up based on incomplete information and ignorance of what's needed and how things work. So be it and hail the freedom to make the choice.

I'm also pretty sure that most residential panel systems I've been around probably exceed their warranted output and I know what's needed to measure it. You do not.

Besides being impossible to verify, that most panels exceed their published output as modified by conditions of operation is one reason of several why I'm of the opinion that believing in degradation numbers and basing an equipment buying decision on such things is mostly a waste of time and spending $$.

As for your "you could just" dream of how to make a claim, it's an example of your ignorance of the subject. How you imagine you'd spot a problem simply will not yield anything of use. What you think will work to verify output, will not - if for no other reason than weather and irradiance variation - which, in spite of your aversion to gathering data, will be necessary to know and, known or not will have a high probability of making system output different by about the same amount as that weather and irradiance variation - probably something like 5-10 % yr/yr. You're looking at finding a 1 % diff. ? Good luck. Also, has the state of your array's cleanliness been documented and also temporally correlated with irradiance ? Whether or not you care about instruments, precision or otherwise, you'll need some data to back up your method.

As for the vendor doing what's necessary to find an alleged problem, how many times do you thing vendors/mfg. get calls from users who think their system is underperforming ? If the traffic around here is any indication, probably a lot. Also looking at such posts leads me to think there's a lot of solar ignorance on the part of users or potential users that's the cause of most of the confusion. Looks to me like you may be one of that group.

Look, I don't have a hardon for you or what you want. NOMB or concern. I simply see you spinning your wheels, ignorantly going down roads that don't matter and don't get you a better system or installation. IMO only, you'd be better off with more education before you go further.

In that education, since I've seen no mention of what usage (annual electrical demand) you have or how much of that load you want to offset with a PV system. I'm wondering if you've done that bit of necessary basic analysis yet. If not, I'd suggest that might be a good place to start.

Please clarify something for us. Are you saying that marketing material provided by Panasonic, LG and other top brands is a blatant lie? If so, then we are in Alex Jones territory here.

And let me clarify, for like the third time. I do not make my decisions based purely on marketing material, but you seem to keep hammering that point, as if that is how it is. You cant argue with brand reputation built up over decades by millions of customers who would crap all over Panasonic, LG at the first opportunity they can get.

Did you personally have a bad experience with these brands? Well then enlighten us on what happened and how you analyzed the problem, used your sophisticated measuring equipment (which you keep insisting you "know" how to use). Id love to hear this story. And dont worry, I have multiple engineering degrees, Ill understand it But so far you have been all huffing and puffing and no substance.

[Duxa]

If you blindly believe everything you read and are told, yes.

Duxa is a neophyte who, like many others, including me many years ago, buys into the hype that solar can save the world.

Those who don't get informed and educate themselves before the commit resources to a project or lifestyle usually waste time, $$ and effort by their persistent ignorance of what's required and the bullheadedness of having their minds made up and not wanting to be confused by reality and the facts as seen by others who have gone down the same path and learned.

I am a neophyte in what? solar? sure. But I am an engineer and work in a field where precision, accuracy etc etc is important. We go through the same processes as these manufacturers. Subject of marketing claims, company reputations etc, span far beyond solar, and this being solar has little to do with it. Panasonic is not a solar company, neither is LG. They have a small division that makes those products. But these companies have good reputation for a reason. Its not something they branded themselves with, its something their customers (you and I and millions of other neophytes) have labeled them. Reputation is hard to earn, but easy to lose.

I am starting to get a feeling that you have convinced yourself that any panel is as good as any other, made your purchasing decision based on that conviction, feeling good about the money you saved, and are now trying to convince others (and yourself), that you made a good purchasing decision. If your goal is to convince us that a panel from an unknown Chinese manufacturer is as good as a Panasonic or LG panel, well then everyone that has chimed in so far in this discussion begs to differ.

I dont blindly buy a top brand or whatever of any product, I look at reviews, user opinions, and yes marketing material, then I make my purchasing decision based on that. And as we have already established, marketing material from big companies that are always under a microscope (like LG or Panasonic) can be trusted. Marketing material from some company that spun up within last few years in rural China that claims they are just as good as the top brands. Well, thats a red flag. But even if you put a tin foil hat on and throw all that out, sheer number of satisfied customers who at the first chance would crap all over these top brands tells you that they are good products. You literally have zero reason to think otherwise. We have decades of satisfied customers that feel that the performance of the products they bought matched the product that the marketing material sold them.

I have a feeling you are not an engineer.

[J.P.M.]

First of, I want to say that Im not trying to argue anything. I am just trying to participate in a discussion and share my own opinion about things.

Now. I think you are approaching this from a completely different angle than I am. I do not care at all about precision measurements, they are unnecessary in this case. Things like this have a +- margin of error, always. All you have to do, as a consumer is to look at your yearly production during year 1, then if at any point in the future your year over year is significantly lower than the advertised rates you call up the warranty, its up to them to measure and prove to you that the degradation is within the expected range. Otherwise you get a new panel.

Additionally there is such thing as false advertising. And I do not think top end brands would be advertising something that was blatantly false, especially when it is so easily checked.

Now, personally, all these things aside, I would trust Panasonic, LG, and other brands that have been doing this stuff for decades, and their advertisements than some random hole in the wall place in China. Why? Well because they are operating 50 years later either because they make good products, or not one of the millions of their customers (including businesses with the proper equipment to check their claims) has ever called them out. And I find it extremely unlikely that their product doesnt match the advertisements, as it is extremely unlikely that over 50 years not one in many millions has called them out on it.

When you are buying into a company like LG or Panasonic or any other major brand, you are also buying into their warranty, guarantee that they will be around to honor that warranty, access to their service centers etc etc...

Thats just my personal opinion... participating in conversation. Not trying to prove anything. As with everything in life, you get what you pay for. There is a reason some panels are cheaper and others are more expensive. If the cheap panel could sell itself for more, then it would. Solar panels arent some new unknown technology, its older than cell phones.

I'm not arguing anything either. Just sharing opinions arrived at over ~ 45 yrs. after changing careers to engineering as a result of getting the solar bug and then getting fed up with the B.S./lies I was told and then getting educated and possibly better able to find my own answers.

You are correct, I am approaching it from a different angle. I trust, but verify. Looks to me like you're one of the typical folks who sees what you want to see and read what you want to read and seem to have your mind made up based on incomplete information and ignorance of what's needed and how things work. So be it and hail the freedom to make the choice.

I'm also pretty sure that most residential panel systems I've been around probably exceed their warranted output and I know what's needed to measure it. You do not.

Besides being impossible to verify, that most panels exceed their published output as modified by conditions of operation is one reason of several why I'm of the opinion that believing in degradation numbers and basing an equipment buying decision on such things is mostly a waste of time and spending $$.

As for your "you could just" dream of how to make a claim, it's an example of your ignorance of the subject. How you imagine you'd spot a problem simply will not yield anything of use. What you think will work to verify output, will not - if for no other reason than weather and irradiance variation - which, in spite of your aversion to gathering data, will be necessary to know and, known or not will have a high probability of making system output different by about the same amount as that weather and irradiance variation - probably something like 5-10 % yr/yr. You're looking at finding a 1 % diff. ? Good luck. Also, has the state of your array's cleanliness been documented and also temporally correlated with irradiance ? Whether or not you care about instruments, precision or otherwise, you'll need some data to back up your method.

As for the vendor doing what's necessary to find an alleged problem, how many times do you thing vendors/mfg. get calls from users who think their system is underperforming ? If the traffic around here is any indication, probably a lot. Also looking at such posts leads me to think there's a lot of solar ignorance on the part of users or potential users that's the cause of most of the confusion. Looks to me like you may be one of that group.

Look, I don't have a hardon for you or what you want. NOMB or concern. I simply see you spinning your wheels, ignorantly going down roads that don't matter and don't get you a better system or installation. IMO only, you'd be better off with more education before you go further.

In that education, since I've seen no mention of what usage (annual electrical demand) you have or how much of that load you want to offset with a PV system. I'm wondering if you've done that bit of necessary basic analysis yet. If not, I'd suggest that might be a good place to start.

[bob-n]

In my company, field failure rate is critical, but also impossible to get accurately. We report customer return rate and also failure statistics from our own standardized reliability testing..

I'm guessing that it's even harder for solar.

Panels can have failure due to abuse, storm damage, transportation damage, mis-installation, and perhaps even inverter failure (although not likely). They can also have true manufacturing defects, wearouts and the other issues we want to track. Can we accurately separate these? It's even harder to get accurate when dealing with small numbers, because one or two errors grossly skews the statistics.

How many panels fail in the field but are not sent back? How many are sent back to the distributor but never make it back to the factory? How many of those sent back are dissected to find root cause of failure? That work is expensive. How many reported failures are mis-categorized? How many reported failures are intentionally mis-reported (fraud)? Who knows?

My opinion is that the best statistics come from large installations where there is relatively little variation in environment and reporting. Second best would be the accelerated reliability studies done by manufacturers.

[bcroe]

Considering which panel to buy, efficiency is a factor mfrs can check. I would like to know the
field failure/replacement rate. The aging rate is low enough to not be much of a factor. AND
it almost surely varies with average sun intensity at the installation, not ever mentioned.

It would be interesting to find out how long panels actually are kept in service after setup. My
guess is, it is a lot less than 20 years at this point. I have seen arrays much newer, which have
not been kept up. Like a small tree growing a couple feet in front, maybe the original owner
lost interest/moved/passed away. Bruce Roe

[J.P.M.]

Are we kidding ourselves?

If you blindly believe everything you read and are told, yes.

Duxa is a neophyte who, like many others, including me many years ago, buys into the hype that solar can save the world.

Those who don't get informed and educate themselves before the commit resources to a project or lifestyle usually waste time, $$ and effort by their persistent ignorance of what's required and the bullheadedness of having their minds made up and not wanting to be confused by reality and the facts as seen by others who have gone down the same path and learned.