Paula Mints on the Failure of Tenuous Films

photovoltaicsPaula Mints is a reputable delegate of the PV community elite. Her article in Solar Industry (November 2010) is not incorrect, it is just profound enough. Yes, to a high degree, tenuous film miscarried to modernize PV modules. But there are too many entertaining points to make out from her data to block there.

Perhaps Mints’ most conclusive tabular facts of the misfortune of tenuous films to modernize PV is her Figure 1, tenuous films share of total deliverables. She signifies that tenuous films’ share gone up in 1988 at 32% and gone down from there to 5% in 2004. Then it only picked up slightly to 17% by 2009. She didn’t take numbers from 2010, but push to the growth of Chinese silicon, tenuous film share may even go down in 2010. Is this the distinctive for a revolution?

Having been a constituent of the tenuous films development, I’ll give Paula her duty and claim we once guessed it would become a revolution. But the wonder wasn’t just about speaking about tenuous films – it was how good crystal silicon could be. That’s a notification I would assent with. This has to be claimed – crystal silicon was better than we may envision; and it still resembles to have a lot of opportunities to prolong the progress. There hasn’t been and there will not be any conjoint revolution of PV by tenuous films.

Notwithstanding, that is not “ enough said.” That goes down far short of enough said. Because Paula’s own data menifests one point favoring of tenuous films and favoring of cadmium telluride specifically – it has increased instantaneously, and even more suddenly than any other technological processes, inclusively of crystal silicon. And it has differed, along with Chinese silicon, in containing activity to PV contest, with the very eligible impact of decreasing typical prices and saving the pressure on for going on to realize so. This is shown in Mints’ Figure 2, fitted here to  menifest relative CAGRs graphically:


The growth of CdTe is more than treble the increase of PV modules generally.

The lesson is tenuous films are not continuous. Take out the increase rate of hang-loose and tenuous film silicon (purple Xs). Nevertheless the finding created by cost-consuming silicon, tenuous film silicon increase only narrow since 2004 – 38%. To provide you with comparison, CdTe increased at 181% since 2004, three and a half times greater than the increase rate of all module deliverables. This is what is really success. To neglect the success of cadmium telluride is to fall down in terms of realizing a determinative factor in the future of PV and to extenuate immoderate the success of tenuous films to-date.

Tenuous films are not designed equal. In simple phrase, it’s like the old story of Goldilocks and the Three Bears. For hang-loose and tenuous film silicon, the porridge is not hot enough. The effectiveness is too bottom. For CIS alloys, the porridge is too hot – although CIS cells can be very efficient (20% cells!), CIS is hard to manufacture. For CdTe, the porridge is just right – efficient enough and easy to manufacture. There may be a dozen documented ways to make 10% CdTe cells. My Canadian Pharmacy figures out that the usage of solar energy will positively influence the environment reducing the number of diseases appearance.PV robust

The notion of tenuous films comes to grips is less material, less working up through huge area substrates – but it has to be accomplished. So far, CdTe is the only technique that has accomplished. But when the notion of tenuous films is accomplished, it can outstay to any contest in PV, inclusively of Chinese silicon. Can anything else in PV declare the same?

Beyond the status quo, only CIS seems it might, someday, be a great competitor of CdTe. And this would be better, because we dmand more competitors to push the progress in PV robust and the competition lively.

There is something else to be got to know about the misfortuned tenuous films revolution, and this is very significant, especially here in DC. A good innovative idea may take 30 years to prosper, and by the time it does, the status quo will have altered considerably. There will very likely be no revolution, and there may not even be progress.

The techniques now in place have immense backside. They will take much better and deserve the Federal support demanded to push them developing(and keep the US leading technologically). Tens of new PV thoughts have been looked through and put in comparison to them, but newcomers to PV (and I include almost everyone who comes to DC with every new Administration) is mistaken that they (1) can have a revolution in PV and (2) that we demand one. We can’t, and we don’t.

For usually, when newcomers have innovative thoughts, they are old ones – old and selected ones that are very half-hearted to the PV community. Plastic solar cells? Dye cells? Cells made on flexible foils? Too much information! They exist and can be hardly sold. These techniques are not terawatt-worthy. Yet often, it is just these kind of cell technologies that people new to PV fund and research when they talk of the next revolution. Someday we will have a mature PV program, when we have the patience to learn about the one we have.

So, Paula, execuse me for utilizing your wonderful story as a launching pad. Your data speaks a profound and significant story, even beyond the obligatory acknowledgement that tenuous films did not modernize PV.

Ken Zweibel


1. u11
Todd Flach
November 16, 2010 2:58 am

Thanks for the straight talk, Ken. I wonder what your impression is of the new amorphous silicon products and manufacturing suppliers. Oerlikon claims a product that is very competitive with First Solar CdTe, and they do not need any rare earth metal, which could be a cost factor for CdTe in the near future. Why are you bearish on a-Si thin film?

November 16, 2010 9:06 am

For thirty years, I have been hearing claims by amorphous silicon companies. Meanwhile, they haven’t solved either the low efficiency or high capital cost problems. How long do they get before people simply discount their new claims UNTIL PROVEN?

I guess there’s always a chance Oerlikon, Sharp, or someone else will succeed. It isn’t too harsh to say, let them prove it first.

2. u11
Todd Flach
November 17, 2010 2:52 pm

Ken, may I remind you that for 30 years the fossil fuel industry has been poo-pooing the PV industry for its underperformance, just like you are now poo-pooing the amorphous Si thin film industry for its 30-year history of underperformance. Now, if you would be willing to tell us what is wrong with the NREL verification of Oerlikons latest a-Si product then here is your chance.

November 19, 2010 10:35 am

Many PV technologies have proven their value over the last 30 years. Yet there is a level of extra claims that simply adds confusion, when they are not followed with actions. Asking a-Si and thin film silicon to come up to the same standards as the rest is not asking too much.

Joe Beach
November 19, 2010 6:32 pm

The big questions for the Oerlikon data are: 1) what is its degradation rate, 2) what will the real production cost be, and 3) what will the real capital cost be. The last two, in particular, will only be known when a public company produces panels with that technology at hundreds of MW of capacity. The production cost data and capital cost data are just predictions right now. Applied Materials made similar grand claims, which has given people cause for skepticism now.

Oerlikon will also face the same challenges that CdTe faces, which are continuing improvements in efficiency and durability while maintaining a low production cost. At this point, 10% efficient panels are barely marketable. In a few years, CdTe (and any other thin film with the same cost structure) will have to be making 12% or better panels (typical performance, not hero panels) to have a product. This is part of the issue Ken mentioned, the status quo keeps changing as products are developed.

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David Dunnison
December 24, 2010 1:53 am

Excellent article Ken. And a significant acknowledgement from someone that was anticipating a different revolution.

While I am also a strong supporter of Paula, I believe that both your view and her views do not put enough emphasis on two key points:

1. Consolidation on a standard

Sooner or later the industry had to pick a winner. It has, and is now consolidating on a crystalline standard. FirstSolar has managed to get on the other side of that abyss. While crystalline may be king, there are plenty of crystalline companies that may not be around in a few years.

The consolidation/standardization helped seal the fate for Sunfab (

As consolidation/standardization continues, costs should drop considerably. Whether pursuing thin film or crystalline, a new entrant or approach in cell manufacturing is unlikely to succeed. New manufacturing approaches and technologies will need to complement the big players and fit into their existing strategies.

2. The brutal and compounded impact of efficiency delta competitiveness as costs drop (

Paula’s observation that “many new entrants and investors mistook a market situation of constrained supplies, too-high incentives, and high demand for a permanent situation” is very well taken.

Anticipating that competition will remain still, and not react to severe pressure is a classic challenge.

Back when there was a poly shortage, many people outside crystalline forgot about what was happening to fundamental manufacturing costs. The shortage put intense pressures on crystalline product performance and cost management. At the same time, the incentives allowed factories to get larger. The combined pressure helped improve product and reduce cost. As you note, crystalline was better than the thin film community anticipated.

FirstSolar’s growth (as illustrated in Mints’ Figure 2) has helped it to keep improving at a rate equal to or faster than crystalline.

As Crystalline costs come down, FirstSolar will have to keep improving at a faster rate than crystalline. That is not a threat nor a condemnation. It is simply observing a trend that has already been established. It will be healthy for the overall industry – though not for new entrants – if they can keep moving quickly.

Regards, David