Thin-film PV solutions differ based on the type of semiconductor material chosen to act as a sunlight absorbing layer, and also on the type of substrate on which the sunlight absorbing layer is affixed.

There are several approaches which are currently being deployed by thin-film PV manufacturers aiming to make their offering successful in this sector.

For instance, there are companies which are focusing on the choice of substrate material to differentiate themselves from other thin-film PV manufacturers.
A section of the industry believes that the use of a flexible, lightweight substrate which is easier to install provides clear advantages for commercial rooftops, higher value-added BIPV and other markets, where rigid substrates are unsuitable for many applications. Plus, such flexible, plastic substrate provides significant cost advantages because it enables companies to employ monolithic integration techniques that may not be available to manufacturers who use flexible, metal substrates.
Commenting on market segments that are most promising for thin film PV applications and how they will develop in Europe, Daniela Schreiber, Head of Research Operations, EuPD Research, is of the opinion that flexible substrates in the segment of commercial rooftop and building integrated PV may increase.
"Both technologies are increasing market segments in Europe. C-Si and CIS/ CIGS are the technologies with the highest efficiency. But on the other hand they have a high temperature coefficient. That means that energy yield decreases by rising temperatures. In countries with comparatively temperatures like Germany, the focus is on technologies like that. Technologies like a-Si or CdTe with a low temperature co-efficient are profitable in countries with a high temperature just like in Australia, India or Mexico as the lower efficiency may be outpaced by the temperature coefficient. The future for technologies like this is in such countries," said Daniela, who is scheduled to speak during Thin Film Solar Summit Europe, scheduled to take place on 19-20 May in Berlin this year.
Daniela also spoke about some interesting and relevant issues in an interview with thinfilmtoday.com. Excerpts:
thinfilmtoday.com: According to a company like Applied Materials, cost per watt is driving the industry, especially for large scale solar farms and commercial rooftop applications. Given the cost advantage for thin film technologies, the adoption is expected to grow rapidly for these applications. However, the macroeconomic liquidity issues and weakening global economy are likely to delay some projects and impact end-use demand. How do you assess the current situation in Europe as far as growth of thin-film business is concerned?
Daniela Schreiber: The project financing is secured by the KfW (Kreditanstalt für Wiederaubau) in Germany - in comparison with other countries. On the contrary to capital market investments, PV is a well secured financial investment - particularly in the face of the current finance crisis. In addition to that it is assumed that prices for PV plants play an increasing role in the purchase decision - for example caused by oversupply and increasing degression. Thin film has advantages compared to crystalline technologies due to the lower manufacturing costs.
thinfilmtoday.com: Most technologies are challenged by crossing over form low volume performance to creating a robust technology that drives down cost per watt on a large commercial scale basis. Specifically, efficiency is a huge lever but is also one of the most difficult to achieve in high volumes. Do you think efficiencies in the range of 11% - 12% can be achieved in the future in high volume manufacturing?
Daniela Schreiber: Efficiencies of 11%-12% with CdTe and CIGS-technologies are nearly reached...technically feasible until 2010. The circumstances silicon thin film technologies like tandem are more difficult. Highest efficiencies are currently at 8.5 %. But through considerable investments in the field of research and development of a couple of companies like Applied Materials, Oerlikon, Mitsubishi Heavy or Sharp, it is to be expected that efficiencies over 10% are possible in the middle-term caused by innovations.
thinfilmtoday.com: Do you believe that the use of a flexible, lightweight substrate which is easier to install provides clear advantages for commercial rooftops, higher value-added BIPV and other markets, where rigid substrates are unsuitable for many applications?
Daniela Schreiber: The technology is in competition with other roofing coverage technologies. For further market development, flexible and lightweight substrates are important innovations and provide new market segments. But the mass production is currently carried out only by Uni Solar.
thinfilmtoday.com: A company like First Solar says the advantage about efficiency, of course, is that as it drives its costs down, those costs also are - there's some level of cost that's passed along to the system installers as well, and they gain additional benefits through increased efficiency as well. But an expert pointed out that cost and price are not connected in all cases -- lower cost gives more cushion in the margin, but the market drives price. A module that costs $1.00 to produce can still sell (in an elastic market if demand is strong) for >$3.00. Higher efficiency goes right to lower manufacturing and installation costs. How do you assess the situation?
Daniela Schreiber: I can agree to this thought. Referring to our PV price index module prices of installers decreasing intensively - in the contrary to system prices that only keep track with the degression in Germany. Decline in prices of system prices is recognised within the scope of legal degression.
thinfilmtoday.com: With the right market structures in place, thin film companies say they are capable of significantly expanding their annual production capacity and during this scale up, manufacturing costs declined by two-thirds. How do you assess the situation?
Daniela Schreiber: In emerging industrial sectors like photovoltaic, the starting years are very capital intensive. A lot of money has to be invested in research and development as well as for the development of the new production processes. If the know-how matures and manufacturing processes change to mass production, economies of scale could be reached. That means that synergy effects as well as spreading of fixed costs at the production could be achieved. Besides effects of the learning curve is higher in the initial few years. Later effects of the learning curve fall and "fine tuning" is more important. First Solar reached the manufacturing costs decline of two-thirds between 2004 and 2008. In the future, a lot is to be expected as far as the cost reduction is concerned.
thinfilmtoday.com: In recognition of the role that renewable and solar will play in the coming low carbon energy infrastructure, and the need to immediately develop and scale the enabling technologies, the EU recently reinforced its commitment to renewable energy with an EU-wide directive that commits the EU to 20% renewable energy targets by 2020. What major developments do you foresee for thin-film business in Europe in the time to come?
Daniela Schreiber: Rooftop plants are the most important market segment in the EU. The directive efforts demand particularly for countries with a low level of renewable energies and which are not willing to invest a lot in that segment. If it is to be assumed that thin film will be adopted for plants, the relevance of the technology will increase.

Thin Film Solar Summit Europe 2009
Daniela Schreiber, Head of Research Operations, EuPD Research is scheduled to speak during Thin Film Solar Summit Europe, scheduled to take place on 19-20 May in Berlin this year.
For information, click here: http://www.thinfilmtoday.com/eu/agenda.shtml
Or Contact: Joshua Bull at +44 (0) 207 3757227 or email josh@cpvtoday.com