Environmental Assessment of Dry Photovoltaic Etching
The report is summarizing the research contributions from VF as partner in the EU-project "Development of a competitive zero Global Warming Potential (GWP) dry process to reduce the dramatic water consumption in the ever expanding solar cell manufacturing industry – SOLNOWAT".
In the project a new etching method for silicon crystalline solar cell wafers was developed. VF was responsible for two main parts of the project: 1) Compiling an overview of laws and regulatory requirements relevant for the new etching process, and 2) Conducting simplified life cycle assessment (LCA) of the dry chemical etching in comparison with current state of the art wet chemical etching.
The overview of the regulatory framework was established through compiling up-to-date European and global emission regulations and requirements. This included a detailing of forthcoming regulations.
The simplified LCA of the dry process gave as result a potential for a substantial reduction in water consumption, i.e. 85 % reduction in comparison with the wet acidic etching, and 89 % reduction in comparison with the alkaline wet etching. The emissions of climate (green house) gases were also determined to be reduced, with 63 % and 20 % respectively, when compared with current state of the art wet acidic and alkaline chemical etching. The toxicity impacts were assessed to be lower for the dry chemical etching, compared to the wet process, allthough the uncertainty was quite high for that impact category.