How to Ensure Solar Module Reliability in Times of Massive Innovation and Supply Shortages
TaiyangNews Virtual Conference on Reliable PV Module Design
View the original recording with Taiyang News here.
The 2021 TaiyangNews Virtual Conference on Reliable PV Module Design concluded with a Panel Discussion. The discussion revolved around ensuring solar module reliability in times of massive innovation and supply shortages.
As a participant in the panel, CEA’s Director of Technology and Quality, George Touloupas, discussed rear materials (backsheet and glass), encapsulants (EVA and POE), and large format modules (M10 and G12).
Transcript
Michael Schmela:
Topic of the day is the panel, very much looking forward to that. It's a bit different than usual. So we have some slides also included into the panel. So you will simply see it very soon, which makes also the job for me somewhat easier.
Panel Introduction
Let me just briefly introduce my panelists. So we have with us George Touloupas, who is the Senior Director of Technology and Quality at Clean Energy Associates. If you’re in EPC development and are sourcing products from China, you will for sure know this company. If not, you will learn more about them now, because you should. We have with us also, again, Stephen Gong, the Senior Product Manager at Cybrid who just gave this presentation. We are also having with us, very happy to have Jorg Althaus, who is the Global Segment Manager for PV power plant services at TUV Rheinland for many, many years, the face of TUV Rheinland in the solar sector. Jorg, great to have you. And finally we have Evan Liu, who's a Senior R&D Director of Risen Energy, with Trina one of the two big proponents of the 210mm modules.
So what are we doing today? So, we want to reflect a bit of course, on what we learned during the conference and then sort of summarize that under the focus of how to ensure module reliability in times of massive innovation and supply shortage, and meaning also that we really take that into consideration. We will focus on four topics and for these four topics which are key for PV module reliability, George and Jorg have prepared a few slides. These are four topics. One is backsheets versus glass; encapsulants, EVA versus POE; large module format; and beyond standard testing. So the first three topics will be covered by George and then Jorg has some slides. And we will always do it this way. They will give a brief introduction, set the scene, and then we discuss it with the panel. So I would simply start with giving the first word to George, and present his first slide.
Rear Cover: Backsheet vs. Glass
George Touloupas:
So backsheet versus glass, I think you heard the backsheet side in great detail. But the truth is that in the last few years we've had the glass-glass gaining share. I think the main incentive was reliability. So there were more efficient glass projects, being developed a few years ago, but with bifacial it exploded. So it's a different world now because it's so much easier. At the same time, you know, it's considered more reliable, that's the general wisdom, but now there are transparent backsheet products as well. We also, everybody knows about backsheet troubles. The AAA disaster, PVDF cracking, that's fairly recent. Some PET failures, that Paul has done a great job in collecting free data. So very few materials have a long and solid track record, but that doesn't mean that the new ones that come up have this right, because there's so much innovation as we've seen both Cybrid and Jolywood.
Now, these questions in the centre, CEA has taken from investors because they're asking us these questions. 1) Do we choose glass-backsheet or glass-glass? Does location matter? That has to do with, of course, climate, temperature, things like that. 2) Is there a right test? What do you do to test bad backsheets? 3) When you have severe hail, is it good to use glass-glass? Because in that case you have to use 2mm glass, which is half-tempered. So it's not as strong as 3.2mm glass, which is full-tempered. 4) And in general, is it a better packaging material? Non-polymer is glass-glass better, or can also good polymers do the job? How about non-breathability? I saw some questions in the chat about acetic acid formation, rear side PID, the cooling, all this has been more or less touched.
So our take is that we've been working on reliability or studying reliability for a long time, we don’t have a lab, but we are looking at tons of reports every week. We believe that the new IEC technical specification is a good start. It does have a backsheet durability testing sequence, it's a good start. PVEL is also doing that with a bit more of damp heat, a thousand two hundred hours. So yeah, careful assessment on project conditions and testing are critical in screening unsuitable products. Although it's, it's not as it is, you need component testing. So a lot of things like you're not said testing, testing, testing, yeah. And screening by the simple physics and chemistry.
Michael Schmela:
Thanks, George. Yeah. Thanks for setting the scene. So let's maybe start with Stephen to kind of really take the case for the polymer side, and talk about, so when you are confronted with these glass module, glass versus backsheets topic, so what are you seeing actually, or what are your answers to the questions that George has actually just pinned down here?
Stephen Gong:
I agree with George, really some, some problems, more has been bonded during these years. People also find some bad PDVFs. It's true that some projects have got some problems, but, you know that today I had introduced the trend of a PVDF is developing. Because the first generation, second generation, third generation, there are some, suppliers already disappeared, but they are PVDF in terms of fluoro-content and also the performance, and also the reliability was not good. So, yeah, I also see some modules. But you start really, we were working with SKC also, we are doing ourselves PVDF. We had that basic knowledge and film makers, but they only produced films. They're selling every backsheet, they don't consider much about backsheet and also modules. So that's why in modules, Cybrid backsheet doesn't have any issues. Also, the other point is the customer is choosing the products from supplier. So, a customer should also learn more about the material science and also do more testing. Yes, it is better for everyone to find the failures at the laboratory stage. If you put the modules to the outside, the ground installation or roof installation, but you don't know what is the real environment that it should be put, which kind of aging, which kind of reliability issue, this is kind of what it should be. It shouldn't be used. So if you put a bad quality module to a harsh environment, for sure this module is cracking, is talking easier.
You cannot say that this is the problem of the material makers. I think mostly it is the case is you choose that you buy a cheap material. You buy not a reliable material. This is the most, because I was working in module makers some years ago. At that time, we don't know nothing about backsheet, EVA or even junction box, or many, many materials. The buyers always buy the cheapest one, the cheapest one. They ask the factory to use these kinds of material for manufacturing the modules. So what we do? Yeah, because you have to do nothing with these kind of actions. What we’re doing is to laminate to modules. This is from my point of view. Also, you need to also to look at the trend of the material development, because the material can solve the problem of the modules through the better material or higher performance tiers. That's why many big module players, they choose a hybrid material, a hybrid EVA. They do a module design, even the mechanical property, mechanical load.
Michael Schmela:
Okay. Let's maybe go to one client. So we have Evan Liu here from Risen, one of the biggest module manufacturers. So when you look at backsheet versus glass, Evan, so what's your take at, at Risen?
Evan Liu:
Hello, everyone, this is Evan from Risen Energy. From our opinion about the backsheet compared with glass, um, I think the market or the issue that, what they like about these two materials, I think that actually is an organic material. And, uh, as you know, the glass is an inorganic material, so the reliability is especially, and we can see. For the polymer material, which can be discouraging after some years, but for glass, as everyone knows no distortion, even 20 or 40 years. So for the material it's, so I think of course glass is better, but as you know, PV module only warranty 25 or 30 years. So, which means a polymer backsheet can guarantee 25 or 30 years, then the product quality is also okay for PV Modules, and then if we consider the economic consideration of the total product, I think also the backsheet is also a good consideration. But another one is for the bifacial module. Now that transparent backsheet is not so matter, so I think now for bifacial modules the glass-glass module is still a better choice, but it doesn’t mean that transparent backsheet is not good. Maybe after several years test, and we can confirm that a transparent backsheet is also quite okay, then maybe backsheet will come again. But we will need to know, which is related with a high, big size module. As everyone knows, big cell and the big modules will increase the total module size.
So for the transparent backsheet module, it's very challenging for these products, because as now, now for the backsheet modules, for the biggest modules, we use a support bar at the west side of module. But if we use the transparent backsheet, it will be challenging of the module if they, because everyone knows the support bar – we need to remove the support bar. So the mechanical loading is a very big challenge. So I think this is the most challenge of the backsheet, but for the backsheet itself, I think the quality should be okay if we design and manufacture very good.
Michael Schmela:
Okay, thanks Evan. So Jorg, what are you seeing at TUV Rheinland when you're testing backsheet versus glass products?
Jorg Althaus:
Okay, Michael, thank you. First of all, I want to say that, the second point that George has on his slide - we see that a lot. I mean, in last years we have been involved in many claims from our field inspector portion and technical advisory part of our business where back sheets have failed, one or the other. And I really liked that George points out it's, it's not just AAA. PET has failed as well. PVDF has failed. So, um, that's something we're seeing. This is on modules that are fielded, of course. Then of course, there are things that, you know, somebody comes up with, an innovative new product and such new developments need their starting time, sometimes also fail in the lab. Luckily now we have an extensive durability test method. In the past, you know, organizations like TUV Rheinland or others would come up with test scenarios, but it was always, you know, one has this, one has that, and it’s hardly really meaningful in the end to compare products because everybody uses their own test scenario. It's hard to benchmark.
So that's one thing now we see, of course, also the question that George gets is, you know, the investors say, what should I do? Is it glass? What do you think about PVDF, what do you think about this or that? Of course, there is not always an easy answer. And if we are honest also, glass, the thin-film manufacturers have had extensive experience with glass and also would tell you a story that glass is not always reliable. It also has its issues, glass corrosion, or a sudden glass breakage due to tempering processes. And so on. Nevertheless, I would agree that glass as such, from the material point of view, of course, doesn't leave moisture through, let, let moisture through. It has a tendency to be more reliable, but it's a question about the application, where do you need, what sort of reliability?
And I think one thing you also should keep in mind is the temperature of the modules. If you have glass-glass modules, in some installations, they might run hotter. So it's a complex topic. I’m not trying to get away from giving a simple answer, but the thing is, there's a lot of new materials out there. And what I would advise is, you know, go through extensive testing, but also include some outdoor exposure. You know, if in the metal industry somebody brings out a new coating, they would make sure to have it tested for more than a year in very harsh environment. And the PV industry tends to bring out new materials with minimal testing times in advance.
Encapsulants: EVA vs. POE
Michael Schmela:
Okay. So I think maybe then let's move to the next topic. We don't have too much time, and I think we’re talking out, also now about the other packaging component encapsulants. We have EVA, and it is shown that EVA still has a huge market share, but of course we have POE and we have new materials coming also with bifacial. George, please.
George Touloupas:
Yeah. This is a topic that has been very well researched. I think it's pretty well known actually, and Gernot, I'm a great fan of his, and I learned a lot from his publications and his work. So definitely, EVA is very well known. Pros: 1) Low-cost - although that is not true at this moment. There is a pretty substantial price increase. 2) Ease of manufacturer. And cons: Because it decomposes, creates acetic acid which is not great for things, including corrosion, the conductive parts like long-term reliability, essentially.
Now POE is overall better because there's also bad POE. Yeah, can be, there is not one single formulation. These are complex materials. They have additives that have lots of UV blockers, etc. So we have POE gaining, it's been known for many years, it's gaining a lot of penetration acceptance because of the rear PID of bifacial modules. That's when we started seeing that three years ago, we had to do something, and POE is so much better at blocking the sodium ions, moving, destroying the passivation and having huge PID at rear. Right? So that's when it started being adopted, and it's a better material all over. However, it used to be a lot costlier than EVA, now the gap has shrunk. And also it has a lower yield because it shifts. So in the laminator, you have misalignment issues, you have bubble because of that as well. So the module drops and that's an extra cost, it's not only the material cost.
That's why we saw suppliers moving from double POE to EVA at the front, because you don't really need that for PID, and POE at the back, because you need it. Still the same yield problems and the cost. And that's why we have EPE, which is looks great, so I think it's going to be very popular,because it does the job. It has the POE layer to stop the migration, and it has good vision, good working conditions. But, it’s still worth asking - if POE is better, why not keep POE? I mean what is the price difference? It’s actually quite small. It's shockingly small. I'm not talking about material price, not extra cost caused by lower yield. And what is the risk of using mixed materials? These are not the same I feel anymore, front and back.
And the final question, it's a really hard one, and it applies to many materials. So if I want modules to last 35 or 40 years, a lot of projects where I assume these timelines, especially in the US should I insist in POE only? And you could ask the same for glass-backsheet versus just glass. So although we see that the PV industry is extremely cost sensitive to the point of a fraction of a cent, and also that suppliers dislike customization. They might say, okay, I can give you this option, but in practice it might be because of timeline, deliveries can be super hard, like material shortages.
So you can have really high premiums, not really related to the actual cost. So bottom line is that everything should be successfully screened and tested, appropriate testing. Then if we see the test results, that will take several months, then it should be considered suitable for designated application. Of course, we cannot answer the question about 30, 40 years because the tests do not, we don't really know the connection between testing in a chamber and years achieved in the field. Nobody knows that yet as of today.
Michael Schmela:
I think in the end, the answer is always test more, test better. I think we know that also from Corona these days. So Jorg, maybe you want to start first, so what are you seeing when you look at POE and look at EPE, which are now coming more and more, all these different combinations.
Jorg Althaus:
Yeah. I like it. George is saying test, test, test. So that's, that's okay. That's all business, but of course, there is, I would say, there are applications that EVA is still predominantly, also in our lab, also for the products being under certification for things to come now. But one thing of course, we see in particular in Europe, a big move also to develop modules for building integration. And then generally you have other encapsulation materials, which already have a good lifespan and good reliability. So in the past mainly process and existing production lines of large factories and the price, of course kept large manufacturers to stay away from alternatives to EVA. And we see that at least changing in parts. And I think that's good also for the competition.
Michael Schmela:
Okay. Comments from Evan?
Evan Liu:
Yeah. And I have some comments about the EVA and the POE. As you know, as everyone knows, several years ago, all PV modules are with EVA encapsulation. The POE encapsulation was very few, but now as you know all is changed to POE. Why? Because we can say that about the reliability. So not every innovation is to reduce the cost. Of course, we need to guarantee the module's reliability, but, not means that EVA reliability is not good. Because EVA usage already 30 or 40 years. Also, performance is good, but, POE is a trend of the module. I think it's not. Because, why we change the EVA to POE? It’s backside PID issues of the packed cells, but this PID exactly in the real plant, it won't happen. But if we want to pass the test of the IEC standard, then we need to use POE. That's why the POE manufacturer changes the EVA to POE. But from the reliability issues, EVA I think is still okay. So I think in the future to consider the reliability and the cost, the trend will be EPE. The EPE will increase the manufacture yield and also the production speed. And also there's reliability is also better compared with EVA. So I think the EPE will be the trend of the dual glass module. I think for the monofacial modules, the EVA plus EPE also a good solution.
Michael Schmela:
Okay, perfect. Then let's come to the third point, George.
Large Format Modules: M10 vs. G12
George Touloupas:
Yeah. This is the toughest; large format modules and then versus G12. Uh, so they’re gaining market share really quick. They’re all fairly new in the city, because they have obvious advantage for Balance of System savings with respect to G1 and also M6. M6 is now a transition format. It will be around for years, maybe even for residential, who knows, but definitely the future is M10 and G12. And the consensus is that bigger is better for balance of system savings. However, we have two major alliances, the M10 (182mm) camp that accuses the G12 camp of taking excessive risks, mainly stemming from, uh, like having the bigger sizes, higher current. And we saw Trina's very thorough and really impressive presentation countering exactly those arguments that are coming from a major player from the M10 camp, every single week in webinars and presentations.
So both camps claim victory of balance of system savings, however, from an analysis that we have performed, we couldn't be conclusive. The data are not really transparent and they are very sensitive to project specifics. They're also price bidding, et cetera. So I don't think there is a clear winner between M10 and G12 to date, or clear, not in my personal opinion, as it appears to our clients as well. So our clients and investors are asked, what is the best choice: M10 or G12? And are the wide and long variants posing reliability concerns? Will the modules bend more, cells crack faster? Mechanical loads, junction boxes. I think Trina's day-to-day like answered every single one of these, quite convincingly to be honest. But that needs to be verified by testing and testing and more testing.
So this is a race towards lower LCOE. And that's not the first time that we've done radical changes in a very short time. So we have a much better tool kit now than the older years, overall the industry’s way more sophisticated. So investors should definitely thoroughly check the balance of systems savings claims and consider all kinds of contingencies. Some examples like the mechanical load test must be performed for the specific project tracker rail length and configuration, not taking like a test that has been done on an irrelevant mounting structure. Very important detail because you might have the module completely break down. This isn’t great, we've seen lab results like that.
Also, the third party extended reliability test must be completed before the investors commit orders. And the technical advisors must ensure that everything - reports, BOMs – check out, that everything matches. So not a different BOM order, different BOM tested. Also robust quality assurance must be performed, especially for the new lines and products that take a long time to ramp up and I don't know at all, all the issues and problems. So these are a lot of steps that have to be taken. We need to be very, very careful and the price will be a lower LCOE.
Michael Schmela:
Thanks, George, let's start with Evan, although we know which direction that you will probably argue.
Evan Liu:
Okay. So from our opinion, I think everyone, I think I need to pose one point. Why or what we do, why we do the M10 or G12? As we know with the wafer size, from M2, M6 and M10 and now G12, everyone knows big cells, well, you decrease the total manufacturing cost of the wafer and the cells. But M10 or G12 is not a final product. The final product is a module. Exactly module, like good or not, is not related with the cell itself. Cell is different of the module. So I think what is the best choice? Of course, the low cost choice, low cost wafers or cells is better because then we can decrease the total cost. Of course G12 is better.
And, because now everyone knows that the M10, and they said that the G12 module is not good. But I think this point is not the right point because the module, good or not, is based on the design of the module. The structure, inside the interconnection of the cells, and also other design of the products, you can see that G12 module is not good because G12 module, which can pass all the test. And even though we can use the 63209, and the 63126, even with the increased peel test of the new tests of the IEC 63397, all these increase the IEC test. The G12 and the M10, I think if you use this right design, the right material, all module can be made very good.
So if someone said that module is not good, I think this very not correct point, and not a right one to say that. Another one is asking questions about reliability, if the module size to be changed to wider, the module mechanical loading will be poor. Is that right? I think if we don't change the design of the module frame and the glass, yes, it's correct. But if we change the design of the module and the mechanical loading it’s not a problem. And also for the junction box, if we keep the same material, the junction box and the design, of course there are some issues. But if we change the design, this is not an issue. So I think that when technology or product is good or not is based on the design. You can see when a product is good or not. You need to check the details inside, that’s my opinion.
And then also, I want to say another opinion. Why somebody now likes the M10, not the G12? Because they have a lot of old capacity of the equipment and the manufacturing capacity. If you want to prolong this capacity of the equipment to be used longer, you must try some, try to pretend, uh, the old product to be used for a long time. Then the capacity can be used more time. But as you can see, for the new player of the market of the PV module, they all invest G12, not M10 and M6, because which have the best LCOE. That's the difference. If you have lower padding of the load capacity you will use G12. If you have a lot of padding you will use M10 or M6. This is logic. Okay.
Michael Schmela:
Thanks, Evan. So maybe Stephen, one sentence, then Jorg, one sentence, and then Jorg, you can directly start with the final topic when we really talk about beyond the standard testing. Stephen?
Stephen Gong:
The story was like this before for M10, last year was a problem of a PET shortage. Because the PET is full with, they cut one meter, one meter like this, then selling to us, and they rely on that to backsheet. They don't prefer to do the M10 because they waste with the PET, and they need to recycle. So they prefer to do G12 because all the five meter PET, can sell to all the backsheet makers without any waste. But this year they improved, they changed the line, and now they can do both. They can do M10 and G12, they can do both. For EVA, always no problem because EVA, we can do 2 meters, 3 meters, so this can cover every size of modules. No problem from Cybrid.
Michael Schmela:
Okay, perfect.
Jorg Althaus:
Uh, one sentence. Well, I would say about 15, 20 years ago, we already had eight installer sales by a company called AstroPower. And now deceased as many. And also we used to have Gen 8.2 modules of 2 meters 60 by 2 meter 40 by a company called Applied Materials. Um, none of that went so well, I'm not saying this is the same story. I'm just saying new things take their time and we have to be cautious, but definitely there's a big movement at the moment.
Michael Schmela:
Okay, super.
Beyond Standard Type Approval Testing
Jorg Althaus:
Okay. So I'm trying to share my screen, but I think George is still hosting. Okay. Thanks.
Real quick, going into reliability testing a little bit, a lot of that was said already now. So, basically, the story is we have, of course the qualification standards, 1215 and 1730 that are however written for a milder environment, they were never written for a hot climate or a tropical climate or whatever. And originally, that didn't incorporate bifacial modules, that was amended beginning of this year. So important to look out when you buy bifacial modules that they adhere to the newest standard. But that's more or less the simple thing, then since last year there is a standard or a technical specification out there for a higher temperature environment. Highly needed, basically that standard refers to which kind of tests from the previous mentioned standards should be done at different temperature levels.
I will come into that little bit, and then George stated in his slides, the reliability standard 63209, which of course is, again, as any standard, a compromise between trying to do something in a feasible budget, feasible time, but having a long term meaning. So not an easy task, that standardization committees took I think 10 years to come up with, but at least it's something now.
Looking at the IEC 63126, it basically differentiates also module installation methods on a ground mount roof parallel or roof integrated or insulated basically. And then states a couple of tests that have temperature influences in there and basically the original requirement for a typical max temperature or a 98% of 70 degrees. That's what IEC 61215, 61646, 61730 are okay with, but the question is, is that true for your site, that 70 degrees, or do you have a risk of running higher? And secondly, of course, if you have roof integration or something like that, then you might look at temperatures going well above that. And you could see that the different standards, test methods, hotspot testing, or bypass thermal test, thermal cycling, get additions to the temperature, which makes it much more meaningful for the end use.
A bit of wild picture, not going to go into detail. So those of you who have looked at testing know some of those tests and what I've highlighted here, the reliability test standard basically is taking IEC, 61215 requirements and extending them. So instead of doing 200 cycles, you're doing 600 cycles. Instead of 1000 damp heat, you’re doing 2000 damp heat. But there are other tests that are on top, and one I would like to highlight is the cyclical or dynamic mechanical load test, which is also known as a typical failure for larger modules, because it's much higher stress on the modules. So that's something to look out for. And the sequence in the middle with UV and repeating temperature cycles is certainly something that is really good for testing back sheets. This is running several times, UV, thermal cycling, humidity freeze, and those backsheets who failed in the field also fail this test miserably. So, good points to look out for.
As I stated, of course, testing is always a compromise. We don't have that one chamber that has every climate in parallel on the modules. Otherwise, we would have to test for 25 years. So always have to take some compromise, but, what the community came up with is what I'm showing you on the right, is a best match. However, any new design, any new material coming to the market also potentially brings new uncovered relevant design risks. So I can't say this is the method for the next 25 years. Whatever new materials come up, we will have to do a lot of research before as well. Yeah, that's basically all I wanted to share with you for now, but certainly we can discuss.
Considerations on PV Module Reliability as Installations Grow to Meet Climate Goals
Michael Schmela:
Okay, perfect. But I think we are running out of time. So I think I would like to have that set. I would like to rather ask to everyone, and I think you maybe also can of course reflect on testing and that final question, everyone. So we're installing this year around 160 GW. Bloomberg New Energy Finance came recently out with their new energy report. And they said in that if we want to go to net zero in 2050, we have to install worldwide an average 632 GW of solar until 2050, as of now. So it means if we have to go to a completely different scale very, very soon, what has to be taken into consideration most from your perspective, when it comes to solar module reliability? Everyone, two sentences as a final words.
Jorg Althaus:
So I mean, since you just quoted Bloomberg, I would like to quote Bloomberg back. I think it was 2017 in their report where they were saying, don’t rely on tier ratings alone, take technical due diligence from a third party into account. And I think that's key, in particular if we want to go large scale everywhere. There is no off-the-shelf go everywhere. The due diligence is key to look and get those massive amount of gigawatts installed, and don't have miserable failure because that would backfire on all of us.
Michael Schmela:
Okay. Yep. George?
George Touloupas:
Yeah. So my personal opinion is that we'll have to do it and the risks are huge. And just imagine having this discussion years ahead talking about perovskites and encapsulation, for example. Because they are very good, very cheap, like the lowest LCOE and people want to buy them. So it's going to get more complicated. And so our duty would be to combine expertise, testing, quality assurance, different evaluation techniques, and it's all about risk mitigation. So there will always be some risk. Let's make it as little as possible, but we cannot wait.
Michael Schmela:
Thanks. Evan?
Evan Liu:
Yeah. For the module reliability testing and now for the module become bigger and bigger, I think the most what we need to pay attention is the mechanical loading and the hotspot, and also, if we change new material, we also need to pay attention to the weather and conditions test, like damp heat and thermal cycle. But I think that is not a big problem now, because now the material is being better and better. But some of the tests, such as hotspot tests and also mechanical loading, this may be, maybe if you're not doing the module good, maybe there are some issues. But I think the good modules can pass all the tests. So we need to pay attention to the choosing of the product.
Michael Schmela:
Okay, thanks. Stephen?
Stephen Gong:
My point of view is, the module is developing, also the material is developing. We have the traditional one that is on the market and we have the new one will be putting it in the market. So, the so large quantity of the module you need to put outdoor, we need to find, base price and performance ratio products. This is what we are always, always looking for from the past till now, and also in the future. Such large quantity of the module installation, for sure need material to be guaranteed module safety – hotspot, reliability issues. This is what we really need to do. Not only the size of the wafers, this is the power of the module, but the power of the module needs to be guaranteed by the polymers. Yeah, this is my point of view.
Michael Schmela:
Okay, thanks. So takeaways, first of all, we have to think big. Although, a lot of people are telling us, many analysts have been always too conservative, so industry must think big, otherwise we would have not this silicon shortage that we have at the moment. So, and at the same time, quality matters. You get what you pay for and due diligence is important.
Just a few words from me, as an ending, as a closing for the conference. So there's the latest reports that we still have for downloads, if you're interested and haven't downloaded them yet, please go to our website. It’s available for free. The upcoming reports that we publish is our market survey on backsheets and encapsulation. This will be available end of September. So again, if anyone is interested in advertising, you're welcome. If we are missing anyone. So if you were not mentioned in this presentation, please get in touch, we would try to get you in. We will also have a couple of more reports and conferences. The next conference that we're having in October will be a first. We are constantly working on a market survey on inverters. It's our first inverter survey and we are focusing on smaller inverters. So that means we look just at the solar rooftop segments, so there will be no central inverters. That’s the next term conference. So again, if there's anyone interested, please get in touch. That’s it from our side. Thanks again to everyone for staying with us. Thanks to the presenters. Thanks a lot to the panelists. Thanks again to the sponsors and see you soon again in October for the next event. Thanks so much and have a great day or evening.
