Thin-film is apparently coming under pressure despite the knowledge is that modules made from thin-film silicon can be manufactured more cost-effectively than thick crystalline ones. It seems that the technology is trailing far behind its efficiency and cost objectives, whereas crystalline innovations are developing at a greater pace. PES investigates.
Sunfilm and Signet Solar have a lot in common, they have the “sun” in their names, were founded in 2006 and have succeeded in considerably reducing solar energy costs with their thin-film silicon modules. And, in spring this year, both companies experienced turbulent economic times.
Everything began with such promise. In 2006, classic silicon modules were still very expensive due to the high silicon costs and newcomers were apparently faced with a walkover; they only had to replace the solid semiconductors with a cheaper absorber. On the face of it, the silicon thin-film appeared perfect – it needed a hundred times less silicon than crystalline modules and could be manufactured far more cost-effectively as a result.
Amorphous silicon (a-Si) is applied at almost 200 degrees. For wafer-based cells on the other hand, ovens have to be fired to 1500 degrees for hours, which devours far more energy. Silicon thin-film attracted many newcomers for this reason. Mechanical engineering companies such as Oerlikon or Applied Materials offered completely equipped production lines for a-Si modules very early on. And they promised low production costs; on their lines, a watt could be produced for between just 0.70 and 0.85 dollars by 2010. With such attractive promises, creditors appeared generous and supported many new thin-film producers. Industry experts, such as Arnulf Jäger-Waldau, warned that due to a lack of expertise, capacities would be built-up which would be doomed to fail from the outset.