UPDATE 27th August 2018: It has kindly been brought to my attention the warranty for SunPower’s P17 panels excludes normal residential installation. The SunPower P17 warranty says it does not apply to:
“PV Modules which have been installed on single-family homes or semi‐detached homes, including but not limited to duplexes and townhomes. For clarity, apartment and condominiums are not excluded.”
UPDATE 31st August 2018: P18 and P19 panels will be covered by SunPower’s warranty when installed on residential homes. Warranties for P-series panels can be downloaded from SunPower’s Australian site on this page.
SunPower Performance Series solar panel, or P-Series for short, are now available in Australia. These attractive panels aren’t available in a wide range of colours and are a lower efficiency but cheaper alternative to SunPower’s E-Series and X-Series panels. While sold overseas for more than a year, they’ve only been available Down Under for a few months and they’ve been on the down low, as their arrival was devoid of fanfare.
Their construction differs from most panels, as instead of being made from 60 or 72 separate solar cells, the P-series has 498 small overlapping silicon cell strips, each around the size that results from using a “laser” to cut a standard silicon wafer into 5 long pieces. This design improves efficiency by hiding electrical contacts under the overlapping part of the above cell so they can’t block sunlight.
The efficiency of the P-Series panels range from 16.0% to 17.0%. This is below SunPower’s other panels, but they come at a considerably lower price per watt. Despite the more competitive pricing, the P-series panel is still covered by SunPower’s 25 year full replacement product warranty.
What Is SunPower?
SunPower is an American solar company owned by a French oil company that makes high quality solar panels in China, Mexico, and the Philippines. They are ancient as far as solar panel companies go being founded way back in 1985. They make reliable panels and were the first company to introduce a 25 year product warranty.
SunPower’s X-Series And E-Series Panels
SunPower is well known for their X-Series panels which are the world’s most efficient, commercially available, solar panel. Their X-22 panel is available in Australia and has an efficiency of 22.2%. However, their high efficiency means you have to pay a hefty premium if you want to slap them on your roof.
If you don’t want to pay quite so much for roof slapping, but are still interested in a high efficiency panel, their lower priced E-Series is up to 20.4% efficient.
Cogenra Developed Them And Now SunPower Owns Cogenera
The overlapping solar cell technology used in the P-Series was developed by a Californian company called Cogenera which Sunpower bought in August 2015 as part of the vast ongoing soap opera that is capitalism. By absorbing their patents, knowledge, and people, SunPower added Cogenra’s technological and biological distinctiveness to their own.
“But I wanted to be an analogy for Communism!”
Where The P-Series Is Made
Currently SunPower produces most of their P-Series panels in Mexico, but they have also started production in China, where they plan to massively increase their manufacturing capacity to five gigawatts. For contact, that’s enough production to manufacture all the solar power ever installed in Australia in just 16 months.
Dense Cell Interconnect Technology, Shingles, Or Overlapping Cells
Cogenra, or just SunPower now that Cogenra has been well digested, called the method of overlapping solar cells used to make the P-Series Dense Cell Interconnect Technology. I think whoever came up with this name must have been a bit dense when they could have just called them “overlapping solar cells” and made everyone’s life just that little bit simpler.
Fortunately, someone realized they needed a better name. Unfortunately, this person was American and thought shingle solar panels was what they should they be called. This actually isn’t a bad name if you are American because they have a type of overlapping roofing material made of rocks called shingles, but here it’s a type of herpes. It’s caused by the chickenpox virus coming back for revenge after being suppressed by your immune system. Perhaps calling them chickenpox revenge panels would actually have been a good marketing move, as I’m sure it would get a lot of attention. But I think I’ll just call them overlapping solar cell panels for now and avoid the shingle association entirely.
Shady Busbars Are A Problem
Most solar cells have wires on their surface called busbars. A busbar is not a place where bus drivers knock back a few cold ones after a hard day’s work, or if you are a very unlucky passenger — a few cold ones before a hard day’s work. Instead, it is a method of gathering electrical energy from solar cells.
The drawback of having busbars on the surface is they shade the solar cell, blocking sunlight and reducing the amount of electricity generated. SunPower solves this problem with their E and X-Series panels by using “interdigitated back contact” which is a complicated set of words which means they don’t have to put busbars on the surface1. Unfortunately, this method increases the cost of solar cells, so most panels simply use cells with wires on top, despite the shading problem.
No Visible Busbar – No Problem
Cogenra solves the problem of the busbar shading solar cells by making them overlap. Each cell is long and narrow which means one busbar at the top is enough to gather the current it generates. This busbar is covered by the lower edge of the cell above it. This means the only thing blocking light from hitting a solar cell is another solar cell and that’s not a bad thing.
The Extra Silicon Required Is Not A Problem
This process requires extra silicon and 10 years ago when silicon cost over 20 times as much as it does now it the idea would have seemed insane. But silicon is far cheaper now and much less is required to make solar cells. Today one gram of polysilicon, the most commonly used sort, only costs around 1.9 cents which is quite a contrast to that terrible time back in 2008 when the price of silicon rose to 67 cents a gram and we were all convinced the world was running out of sand.
To make one watt of solar cell only requires around one gram or less of silicon. There is about half a gram in the cell itself and about half a gram is lost in sawing silicon ingots into wafers and random breakage. So a 350 watt panel will require around $6.65 worth of silicon ingot to make. If overlapping the cells increases the amount needed by 20% that comes to around $1.30 more.
But looking at the cost of a big hunk of silicon is the wrong way to go about it. Sawing a polysilicon ingot into wafers is an expensive process and so they cost about 15 cents a watt. This means there is around $53 dollars worth in a 350 watt panel. Increasing that by 20% will cost $11, which is well worth it if it makes for a high quality panel, which it apparently does.
Because using very thin solar cells can simplify some steps of the overlapping process, it is possible these panels may contain considerably less than half a gram of silicon per watt. But I’m afraid I don’t know the actual thickness of the cells in these panels.
They Handle Shade Well
Almost all solar panels have difficulty handling shade. Just a small amount from a TV aerial, some leaves, or a single splat of bird poo, can greatly reduce their output. A small amount of soiling, say the result of one poorly digested bird breakfast, will reduce the output of a typical panel by 33%. But SunPower says it will only reduce the output of one of their panels, including the P-series, by around 11%.
They Are A Large Panel
The most common type of panel installed on Australian roofs has 60 solar cells and is typically 1.65 m by 0.99 m. But the P-Series panels are 2.067 m by 0.998 m making them just over one-quarter larger in area. This extra size is a consideration when it comes to determining how many can fit on a roof.
P-Series Price
SunPower Australia has said the Performance series panels will be priced lower than their other two series. Unfortunately, they haven’t said just how much lower. So I went and asked an installer and he said the P-Series is likely to cost households at least 20% less than an E-Series panel and over 35% less than their most expensive X-Series panel. But these comparisons are very rough, so don’t rely on them too much.
If you like the reliability of SunPower panels and the peace of mind that comes from their 25 year fully replacement product warranty, but you don’t have a shortage of roof space that requires you to get the most efficient panels possible, then the P-Series could be exactly what you want. A reliable SunPower panel without a hefty premium.
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- I touch upon the topic of interdigitated back contact in my article on P and N junction solar cells and completely fail to describe what it is. ↩
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Why is it that no manufacturer or importer will tell us the price of their different panels on their websites? Makes it very hard to do comparison shopping but then again I guess that is the idea.
The bottom line for most households is the total installed cost per watt, so knowing the panel prices alone generally won’t be that useful. But if you go to our Solar 101 guide:
https://www.solarquotes.com.au/solar101.html
You can see panels roughly ordered from most affordable to top end.
Thanks Ronald.
I also followed your blog on optimisers and micro inverters. Looking at your chart for value and manufacturers I see JA towards the left but when I click on their website they have smart panels with inbuilt optimisers. Have you been able to compare them to the more expensive panels. I need something because I have shade problems.
Doug
For reducing the effects of panel shading on panels for part of the day the options are:
(1) Use DC optimizers
(2) Use microinverters
(3) Use panels with panel string optimization.
Using panels that handle shading well, such as the SunPower ones mentioned in this article, can be part of a solution, but a way will generally be needed to prevent one shaded panel reducing the output of others on a string.
Because DC optimizers and microinverters prevent one shaded panel bringing down the performance of others, they can’t improve the performance of the shaded panel. Panel string optimization can and so should give slightly better results. I wrote about it here:
https://www.solarquotes.com.au/blog/maxim-just-killed-microinverter-dc-optimiser/
Ronald Brakels.
In your opinion as of todays date, based on the information you have at hand; what is the best value solar module available ?
Hi Leon.
I’m afraid that’s an impossible question to answer as it will depend on the buyer’s goals and personal values.
If someone is just looking for the fastest payback time possible then a lower end tier one panel with a 10 year product warranty is likely to meet that goal. But someone who is after hassle free reliable operation with minimal decline in output over decades is only likely to get that if they pay extra for solar panels with an above average performance warranty.
Let’s look at those figures:
X E P
1 Area in square metres (m2) 1.634 1.634 2.063
2 Efficiency % 22.2% 20.4% 16.5%
Relative output per m2 (line 2 / line 1) 136 125 80
Relative price 100 80% 65%
Price per unit output per m2 136 156 123
Conclusion
Series E costs most per output per square metre
Series P costs least per output per square metre, even allowing for the low efficiency
If you have a big, big roof then that’s attractive; but the more use you intend to make of your PV output (charging your Powerwall, charging your EV, heating your hot water etc) the more the size of the roof becomes a limiting factor. So you’re best advised to ignore Series P and buy Series X
Ronald
I tried to get the figures lined up, but the app doesn’t want to know.
Can you either clean it up at your end, or scrub the comment, please Thanks
I’m afraid I can’t line them up as intended, but I think people can still follow your point, so if you want me to publish it as is, just let me know.
Wasn’t an Australian company making a panel which was supposed to handle partial shade very well? Sliver panels?
I think it was about 10 years ago and they got some hype and then seemed to disappear.
http://reneweconomy.com.au/origin-energy-closes-sliver-solar-factory-flags-writedown-93369/
This is the panel that was supposed to be more shade tolerant.
I note the article says it would use lots less silicon.
Hi Ronald,
Is Sunpower Series P really available in Australia? Can you let me know which solar company install them as I have asked for quotes form several without any success?
I am told that Sunpower Series E cost around $500 per panel? How much is the cost of the P Series?
Thanks
Hello Stephen
I don’t know where you are, but MC Electrical, which is based in Brisbane, has them.
I don’t know just what P series panels cost households at the moment, at the current exchange rate, but I assume you will pay under $1 a watt. So if you were looking at a 350 watt panel maybe you’d pay $300 for it.
Hi Stephen,
SAE Group can also quote you on the P Series SunPower Panel.
Thanks, James
Hi James
Will SunPower warrant P-series panels you install residentially or will they only warrant those that are installed commercially?
Hi Ronald,
We are selling the P19, the P17 is only for commercial use as you have mentioned. The P19 is a much smaller 320w panel with a black frame, and yes, SunPower will honour the 25 year product warranty residentially.
Thanks, James Fulleylove
SAE Group
Thank you very much for clearing that up, James. I was on the phone with SunPower a few days ago to ask about warranties and they didn’t mention the difference between the P17 and the P18 and P19 panels. To be fair, that may have been because I didn’t ask the right questions.
ps. I didn’t realise how old this thread was haha the P19 is only available in October and is very competitively priced. Not long now!
Hi Ronald,
Just a quick comment on residential properties and the p17 series. Unfortunately, Sunpower has informed us that they will not provide any warranty on the p17 panels if they are installed on a residential property.
It is outlined in their warranty document for the panel, I was disappointed to learn of this fact myself.
You say it’s 17% efficiency on this article but their own spec sheet for the P19 says 19% efficiency. Is that just a typo on your article?
I think at the time the article was written only the P17 was available.
Yes I believe that was the reason but I was just confused as the P19 is also mentioned in the article
Well, it is only mentioned in the update. I can’t remember, but my guess is it wasn’t out when I wrote the original article.
Hi Ronald,
I can confirm that SunPowers standard 25 year warranty covers the P19 Performance (72 cell) module for commercial installations only. Being a large format panel (2067 x 998mm) they really aren’t suitable for residential installations anyway. SunPower currently have 390W & 395W in Australia. The specs for the commercial P19 are;
390W – (18.9% (eff)
395W – (19.1% (eff)
The residential P19 is a standard (1690 x 998mm) footprint in a ‘shingle’ format, which is covered under their standard 25 year warranty for residential installtions.
SunPower have very limited stock of the all black backsheet 320W in AU. We are holding some stock
Thanks for that.
I’m due to have 32 x all black P320 (BLK) installed in a few weeks. Very excited as they look amazing and still 19% efficiency.