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Nanosolar remastered: An interview with company boss Martin Roscheisen

09 September 2009 | By Tom Cheyney | Chip Shots

On the ninth day of the ninth month of the ninth year, a fortuitous string of the second-luckiest number in Chinese lore, the day that President Obama addresses the U.S. Congress about health care, Apple unveils iTunes 9.0, and the Beatles’ remastered album catalog hits the retail world, Nanosolar has come out with some remastering of its own. The copper-indium-gallium-(di)selenide thin-film PV company hasn’t had much to say lately, but chose this day full of nines to release a torrent of news that it hopes will improve its signal-to-noise ratio and put it squarely back in the serious conversation about ultra-low-cost cell/module manufacturing and utility-scale PV power.

nanosolar_roscheisen1

Rather than go into granular detail on the implications of Nanosolar’s news burst or comb through the details of the company’s two new white papers on its cell and panel technologies—you can check the revamped Website for that and more—I’d like the man himself, chairman/CEO Martin Roscheisen, to have his say.

Martin and I met in person for the first time at the recent Intersolar North America trade show in San Francisco. Our conversation was off the record, although some of the information that he shared with me has appeared among the day’s news announcements and technology revelations.

I came away from our July cup of coffee a little less skeptical about Nanosolar, believing that the company’s well-funded efforts to perfect a low-cost, printed-ink CIGS TFPV roll-to-roll volume-manufacturing approach—a paradigm shifter, to say the least—might just be bearing fruit. The details of the “glass/glass with flex cell” panel technology that he described also intrigued.

Although my skepticism may have eased, I was still not totally convinced. Show me the factories, tell me about installations, my inner voice cried!

We were scheduled to have an early-morning, on-the-record phone chat this past Tuesday, but Martin's schedule got too hectic, so plan B kicked in: an email interview. Not my favorite approach to the Q’s and A’s—doesn’t allow for spontaneity, follow-up questions, etc., though it removes the burden of transcription—but still a method that’s become a key part of the journalistic toolkit.

So here is my complete interview with Martin, raw and unfiltered except for one deleted Q&A (because there was no A) and some minor edits.

Nanosolar has been quiet for awhile, so why did you choose this particular timing to come out with these announcements?

Because we completed the construction of our panel factory and got it up and running. Plus because we realized that a lot of significant news had piled up without our announcing them.

Over the past 18-24 months, what have been the most challenging aspects of making the cell and panel/module lines commercial-production worthy? Any specific process steps or tooling which were trickier to perfect than others, and that have been modified over the past few generations?

We have surely learned more about all sorts of things than we ever meant to learn about. The bar on product quality and performance from the existing volume manufacturers in the industry is very high in the meantime. 2009 is very different than 2005 in this way. Meeting and exceeding that bar with a product out of the gate takes a big and sustained effort.

Specifically, we have been hugely paranoid and obsessed on reliability and gone to extra lengths to ensure it. This took a substantial team and millions in investment.

As far as process complexity, we almost never ever had a problem with the nanoparticle printing process. This process basically always works. High-vacuum tools, which we still use for the electrodes, turned out [to be] more hassle than we wished for. So in a curious way, this surely validated our business plan.

Are there further modifications (for example, going to a dry CdS step, eliminating the remaining high-vacuum steps to be 100% nonvacuum) that could make the process even better?

Yes, there’s a host of R&D activities to continue to drive the agenda we have had of simplifying the manufacturing of thin-film solar cells. In fact, through the five generations of pilot tools we have developed, we have basically reinvented many processes more than once already.

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What web width and speed are you running at on the cell line now, and what is the line capable of running? What kind of across- and down-web film uniformities do you see, at least in terms of percentage? What kind of yields are you getting on the lines, and what can be done to improve them?

We are up to 1500mm in width and up to 40m/min in speed on certain process steps. We see excellent down-web uniformity almost naturally. We have also achieved sufficient cross-web uniformity but only after some tooling modifications.

What level of advanced process control, inline metrology, yield enhancement, etc. do you have in place on the production lines? Please offer some examples.

We have a huge amount of inline metrology in place, including things that are unprecedented. It’s been a huge effort and investment area of ours. According to engineers on our team who have worked at First Solar and other leading manufacturers, what we have on that is on a completely different level. I cannot comment further as this is a very proprietary area.

Can you talk more about Nano’s work with the leading lamination toolmaker in the panel factory, and provide more details on what “stack lamination” is and how it’s done? Also, can you talk about other modifications/improvements/unique aspects of the overall panel design and panel factory?

I can’t talk about details except to say that we were surprised that we ended up spearheading this area too. We thought there must be some process step–lamination being a good candidate–which we do not reinvent.

What are some other examples where your equipment and materials suppliers provided key expertise in achieving your goals? Do you have any specific areas of concern where you would like to see some improvements from those suppliers, a wish list of sorts? Are there areas where today you do the work internally that you might consider outsourcing to a supplier at some point?

We work strategically with production tooling partners on each tool. We only build pilot tools in-house. We do not find it scalable to build production tools ourselves, so we have a best-of-breed partner in each category.

What kind of R&D work is going on, at least that you can talk about? Are you working on flexible panels, multijunction devices, etc.? Do you have ongoing collaborative research programs with the national labs, universities, etc.? Is there a general theme or themes to the research/development work?

I’m afraid I cannot discuss. We are very open to university collaborations though.

As for conversion efficiencies, how far do you believe they can be pushed, and why? Which engineering pathways—optical, contact, grain boundary, band, and dopant—offer the most opportunity for pushing cell performance and efficiency, and why?

We obviously have some rather detailed plans and models on this. We believe we can gain a few more points within the existing framework through a number of known knobs.

You are or have engaged in a wide variety of standard and nonstandard testing, and have had the panels certified by the usual groups. What kind of testing is going on now, are there any other tests that need to be performed or certifications to be obtained, and will you be expanding the number of test locations?

We have a huge effort on testing and are in fact expanding this even further. We believe the standard tests are limited in some ways. We are interested in looking at combination of stresses as well as various forms of dynamic behavior.

We have all of the certifications we require. We obviously need to resubmit panels on an ongoing basis for recertification as we change process or components or power ratings.

In the Utility Panel white paper, mention is made of a special thermal freeze stress test, and how that test led your team to make changes in the panel materials in order to optimize the coefficients of thermal expansion across all layers. Can you provide more details on that test and examples of changes made in the materials? What other “customized” tests are needed, and why?

The white paper describes the test fairly specifically already I believe. We don’t mind others copying this test, in fact would suggest so. Our attitude is that if others’ panels fail in the field, this only hurts everyone else too.

What are the optimal performance conditions for the Utility Panel, in terms of climate, geographies, size of installation, etc.?

Cold and sunny is optimal–for every PV panel though. Our panels are relatively standard in this regard.

What are some key results from side-by-side comparisons with both First Solar and crystalline panels that have been done? For example, the kilowatt-hour energy delivery performance and normalized kilowatt-hour per watt-peak energy harvest info, where the data show Nano competitive with First’s panels.

It’s the usual thing one would expect: First Solar has atypically good low-low-light efficiency, which is in part an artifact of their semiconductor and their cell series resistance not being optimized for full-sun irradiation. But given that 0.1 suns only contribute a tenth of the kWh’s as a full sun, this is of limited impact. The critical zone is at 0.3 to 0.4 suns, where it gets more interesting.

Nano’s gameplan includes taking on thin-film market leader First Solar. There is a fair amount of information in the white papers about how you stack up against First, plus you have mentioned that the due diligence experts agree that you have a process that is intrinsically—and significantly--more cost and capital efficient than First’s. Can you provide some detail about what the experts say about those cost and capital efficiencies (cost/W, COGS, etc.) as well as other competitive advantages/First’s vulnerabilities?

We are planning to demonstrate that we are three times as capital efficient as First Solar. By depositing thin films directly onto glass, First Solar is limited in the types and sizes of glass it can use with existing cell production investment. We believe this will be limiting.

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What do you see as some of the key differences between Nano’s approach to CIGS and the other CIGS companies out there, both technically and economically, and what competitive advantages do they provide you? (monolithic vs. discrete, materials utilization, vacuum vs. nonvacuum, aluminum foil w/ metal wrap through, etc.)

Lowest-cost foil substrate, MWT architecture, high materials utilization, mostly nonvacuum.

Among the other CIGS companies, which ones do you see as having a good chance of making an impact on the marketplace, and why?

Just because it’s CIGS does not mean it’s lower-cost than CdTe and First Solar specifically. In fact, according to our cost models, it takes quite a lot of innovation and effort to make CIGS actually come in at lower cost than the FSLR baseline. People at times forget that FSLR does have a very high throughput semiconductor deposition process–more economic than any high-vacuum process as typically required for CIGS. I personally don’t see how high-vacuum CIGS can compete with FSLR.

How much Nano PV (Utility Panel or otherwise) has been installed/activated so far, is in the process of being installed, and is in the pipeline for future deployment (in MW)?

Our past installations were more focused on the quality with which we obtain accurate and independently verified data from them than their quantity and size. So in terms of watts, this doesn’t add up to all that much. But it’s very accurate data in many different locations.

We are presently completing a first megawatt-scale project and have several further ones in the pipeline.

With the introduction of the Edge Connector, the development of panel array length and other things, Nano has entered the balance-of-systems component realm. When did you realize that you needed to do more work on the panel’s installability, costs, etc., and do you see the company getting more involved in BOS, or possibly getting more involved in the engineering-procurement-construction side of the business?

We have been focused on systems perspective pretty much from day one. We were fortunate to find partners with whom we could work through the detailed constraints and requirements of the systems business.

Nano has a strategy of assembling panels regionally/locally near to where they will be deployed. The first factory will mostly serve the European market; when will you know it is time to build factories in the North America and Asia? Also, at your current sites in San Jose and Luckenwalde, can you add production lines/manufacturing capacity?

We will build additional regional panel-assembly factories as soon as we know that a multi-100MW market exists for ourselves in this region. We expect there to be a ready market, i.e., we don’t like to do market development.

Do you have any plans for entering the residential and/or commercial/industrial market segments?

Yes, we have a solution for commercial rooftops using our Utility Panel and we are planning to offer a solution for the residential market.

Over the past few years, many have been skeptical of Nanosolar’s claims. Now that you have your production up and running and your partner/customers’ projects are in various stages of installation or development, what would you like to say to those skeptics now?

We didn’t offer our skeptics a lot of information not to be skeptical, so they had good reason to be so.

First Solar and others have talked about what it means to be a gigawatt-scale company, a 2GW, 5GW, 10GW company and beyond, in terms of the ultimate potential for solar to scale to planetary levels. What’s your vision of Nano’s future and its ability to meet the challenges of solar’s multigigawatt and even terawatt era?

I’m not an economist; I like to stay focused on shipping the next 10 MW. Plus once we have shipped multiple 100MWs, we will still have plenty of time to think of multiple GWs.

That said, for solar to go to big scale at low price points, there is no way of doing so without supreme capital efficiency of production. If your price point to capex ratio is one, you can’t grow even at 30% a year without being an eternal black hole for cash flows. We are quite pleased about the extent to which we are beating our original business plan on capital efficiency; we are on a very good track there and have many more things in the pipeline along these lines.