please evaluate this statement

electrofelon

Senior Member
Premium panel micro inverter systems produce 20% more energy than a central inverter system of the same size and offer by far the highest safety and reliability (99.7% up-time) and longest MTBF (Mean Time Between Failures) of any PV system on the market today. This 27.3 kW system is equivalent to a 32.8 kW central inverter system in annual energy harvest.
I havent heard the term "premium panel" before. Obviously micro inverters have some production advantages, but 20% more seems way high, even with a lot of differential shading. Thoughts?
 

jaggedben

Senior Member
Sounds like Sunpower BS.

I mean yes, micros will outperform old style string inverters, especially if there's shade issues. But not compared to optimizers, and not 20% when compared to a well designed string systen with more than one mppt and minimal shade. They are taking the best case and claiming it is average. They are also comparing their latest thing to what someone else was doing a decade ago. Classic Sunpower sales tactics.

There's no such thing as a premium panel. Nameplate is basically nameplate. See PTC rating if you want to know if the nameplate is being slightly oversold compared to another panel.
 

electrofelon

Senior Member
thanks, thats what I thought. I would guess if you are getting 20% gain from micros, you have so much shading there shouldnt really be a PV system there anyway.
 

jaggedben

Senior Member
I think that's an overstatement in general. I would probably guess 50% for that statement. But at a certain percentage for any given system, there would be a point that it would be true, or that the most shaded modules shouldn't be included.
 

pv_n00b

Senior Member
There has been a history of handwaving over the increase in output of a PV system using MLPE. Can it give a 20% boost over a non-MLPE system? Sure it can, if the array experiences a lot of partial shading, multiple module orientations, or other problematic problems. Will it provide a 20% boost over a PV system installed with quality modules, no shade, and everything perfect? Not a chance. It might give a few points boost just based on module mismatch.

This has been the problem with MLPE from the beginning, it can help but it can't promise that every install will get even a 5% boost the same install with a non-MLPE system, it's just too dependent on the site and the specific install.
 

pv_n00b

Senior Member
There's no such thing as a premium panel. Nameplate is basically nameplate. See PTC rating if you want to know if the nameplate is being slightly oversold compared to another panel.
There are definitely gradations in the quality of modules. Saying a cheap no-name module is the same as a Sunpower or other tier 1 module just defies reality. Modules might be commodity items but only if you are comparing quality modules to start with.
 

jaggedben

Senior Member
There are definitely gradations in the quality of modules. Saying a cheap no-name module is the same as a Sunpower or other tier 1 module just defies reality. Modules might be commodity items but only if you are comparing quality modules to start with.
Yes, there are some crap modules, probably especially in other countries. But there aren't premium ones, at least not in terms of production vs nameplate. You are correct to group Sunpower with 'other Tier 1 modules'. And practically nobody, to my knowledge, is trying to sell crap modules to residential customers in the US.

My point is basically that when it comes to energy production, all modules from reputable companies with 25 year performance guarantees can be assessed on a level playing field of nameplate, efficiency and price. Sunpower has over and over tried to claim to consumers that their product is somehow in a special category of its own and that it 'produces more energy', with the implication that it produces more for the same nameplate. What electrofelon quoted is a classic example, designed to mislead the less knowledgeable. It's just not true, and they don't even have higher nameplates than everyone else anymore.

To be fair, my company sells some higher efficiency lines as 'premium', based on appearance, fewer roof penetrations, company reputation, etc. ... but we don't make bogus claims about energy production vs nameplate.
 

GoldDigger

Moderator
Staff member
Yes, there are some crap modules, probably especially in other countries. But there aren't premium ones, at least not in terms of production vs nameplate. You are correct to group Sunpower with 'other Tier 1 modules'. And practically nobody, to my knowledge, is trying to sell crap modules to residential customers in the US.

My point is basically that when it comes to energy production, all modules from reputable companies with 25 year performance guarantees can be assessed on a level playing field of nameplate, efficiency and price. Sunpower has over and over tried to claim to consumers that their product is somehow in a special category of its own and that it 'produces more energy', with the implication that it produces more for the same nameplate. What electrofelon quoted is a classic example, designed to mislead the less knowledgeable. It's just not true, and they don't even have higher nameplates than everyone else anymore.

To be fair, my company sells some higher efficiency lines as 'premium', based on appearance, fewer roof penetrations, company reputation, etc. ... but we don't make bogus claims about energy production vs nameplate.
IMHO the only claim to measurable superiority that Sunpower can offer is a higher energy production per unit area of panel. And it is not impossible (although hard) to imagine an installation where mounting space is at a premium and a specific total energy target must be met. That would be the only case in in which the Sunpower "superiority" would have a direct benefit that could influence the panel choice.
 

jaggedben

Senior Member
IMHO the only claim to measurable superiority that Sunpower can offer is a higher energy production per unit area of panel. And it is not impossible (although hard) to imagine an installation where mounting space is at a premium and a specific total energy target must be met. That would be the only case in in which the Sunpower "superiority" would have a direct benefit that could influence the panel choice.
They don't have much of an edge left. LG and Solaria are gonna be close enough for most projects.
 

electrofelon

Senior Member
IMHO the only claim to measurable superiority that Sunpower can offer is a higher energy production per unit area of panel. And it is not impossible (although hard) to imagine an installation where mounting space is at a premium and a specific total energy target must be met. That would be the only case in in which the Sunpower "superiority" would have a direct benefit that could influence the panel choice.
I agree that efficiency is a reason one could claim "premium" panels. That is probably often used as a marketing ploy, since many consumers dont understand that "watts are watts"

I just wasnt sure if maybe there were some panels that did a little better in low light for example, for the same max power rating.
 

GoldDigger

Moderator
Staff member
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I just wasnt sure if maybe there were some panels that did a little better in low light for example, for the same max power rating.
Not that I am aware of.
Some claims have been made for thin panels (amorphous active ingredient) being better in low light, but I suspect what is being anecdotally reported as better in low light may actually be better in partial shade.
 

pv_n00b

Senior Member
Yes, there are some crap modules, probably especially in other countries. But there aren't premium ones, at least not in terms of production vs nameplate. You are correct to group Sunpower with 'other Tier 1 modules'. And practically nobody, to my knowledge, is trying to sell crap modules to residential customers in the US.

My point is basically that when it comes to energy production, all modules from reputable companies with 25 year performance guarantees can be assessed on a level playing field of nameplate, efficiency and price. Sunpower has over and over tried to claim to consumers that their product is somehow in a special category of its own and that it 'produces more energy', with the implication that it produces more for the same nameplate. What electrofelon quoted is a classic example, designed to mislead the less knowledgeable. It's just not true, and they don't even have higher nameplates than everyone else anymore.

To be fair, my company sells some higher efficiency lines as 'premium', based on appearance, fewer roof penetrations, company reputation, etc. ... but we don't make bogus claims about energy production vs nameplate.
I definitely agree, the term "premium" has no legal definition and can mean anything a marketer wants it to mean. It's like the term "fresh" when applied to produce, it has no legal definition. Unlike "organic" which has a legal definition and if the producer does not meet the requirments, they can't use the term.
 

pv_n00b

Senior Member
I agree that efficiency is a reason one could claim "premium" panels. That is probably often used as a marketing ploy, since many consumers dont understand that "watts are watts"

I just wasnt sure if maybe there were some panels that did a little better in low light for example, for the same max power rating.

Thin film cells have a different response to insolation than crystalline cells. They can produce more energy in diffuse and low lighting conditions and they tend to have better temperature response. This has been validated. Whether this will produce more annual energy depends on the conditions at the site.

Keep in mind that STC is a specific set of test conditions. The amount of isolation, temperature, flash time, etc. It provides comparable results for only those specific conditions, same for PTC. Different cell types might have very different responses over the range of conditions they are exposed to in the field that might result in modules with the exact same STC power rating producing different amounts of energy over the year. Don't make the mistake of assuming that an STC rating is also a rating for annual energy production.
 

electrofelon

Senior Member
Its frustrating how every solar proposal I have seen is skewed to the optimistic side. This one I was looking over for a friend: 1) Looks like the annual production is 10-15% high based on a quick PV watts run through 2) they claimed 20% more production because of micro inverters and "premium panels" (and #1 is after correcting for this) 3) They did 'ye old "electricity prices rise x% every year lie" (electricty prices have in fact not kept up with inflation over the last several decades). Just annoys me, I like solar but I hate this lying.
 

ggunn

PE (Electrical), NABCEP certified
One thing about SunPower modules that I think is unique to them is that they make electrical contact with the front surface of the module through what we used to refer to in the semiconductor bidness as "buried contacts" from the back side, so there is no shading from conductors running across the front of the module.

Full disclosure: the company I work for is a SunPower dealer. I won't get onto either side of a SunPower bashing debate.
 

jaggedben

Senior Member
One thing about SunPower modules that I think is unique to them is that they make electrical contact with the front surface of the module through what we used to refer to in the semiconductor bidness as "buried contacts" from the back side, so there is no shading from conductors running across the front of the module.

Full disclosure: the company I work for is a SunPower dealer. I won't get onto either side of a SunPower bashing debate.
It's no longer unique. LG is doing it now, too.
 
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