Comparative Life Cycle Analysis of Nano and Bulk-materials in Photovoltaic Energy Generation
|Principal Investigator||Vasilis Fthenakis|
|Relevance to Implications||High|
|Class of Nanomaterial||Engineered Nanomaterials|
|Impact Sector||Human Health|
|Broad Research Categories||
Generation, Dispersion, Transformation etc.|
|Anticipated Total Funding||$200,000.00|
|Anticipated End Year||2008|
Life-cycle analysis (LCA) is used to assess potential environmental impacts from the rapidly growing implementation of photovoltaic (PV) systems. Nanomaterials are investigated for use in photovoltaic and other energy generation applications. The information derived from the LCA of bulk material based PV will be extrapolated to the processes used for their nanomaterial equivalents. For each of the life stages of PV (i.e., material production, cell/module manufacture, installation, operation/maintenance, recycling and disposal), resource utilization, process efficiencies, extra controls/steps, conversion efficiencies, recyclability and the environmental fate of the micro and the nonmaterial alternatives will be investigated. In this way, data and relationships will be built that will enable the quantification of the environmental effects of nanomaterials from existing micromaterial life-cycle inventory data.
The study aims to a) describe the life-cycle environmental profile of the main candidate nanomaterials for photovoltaic (PV) applications; b) compare these profiles with those of the micro-sized counterparts that they may replace, and, c) set out the elements of a process-based approach that will be valuable for comparing nano- to micro- materials within groups of thin-film materials (e.g., semiconductors and superconductors).
Life Cycle Analysis (LCA) studies have been carried out by the Pis of the proposed project on bulk materials and processes used for the deposition of silicon and cadmium telluride thin-film solar cells, their European collaborators and others. This work will comprise the baseline of the current analysis. Then, nanotechnology-based innovations that are being researched and tested by the U.S. manufacturers of thin-film PV will be described, mainly under the framework of process-based LCA. Process-specific data are essential for analyzing the subtleties of such emerging technologies. This analysis will be complemented by means of Input Output (ElO) LCA for some sub-stages (e.g., plant equipment, personnel supplies, and office commodities), and will guide us in selecting the systems boundaries for the main process-based analysis. The investigators and their graduate students at Columbia University (CU) will gather information on processes, materials, emissions, and energy requirements from established working relationships with U.S. PV companies and the National Renewable Energy Laboratory (NREL), covering two promising nano-material-based alternatives to existing commercial technologies, (i.e., a-Si and CdTe). We will focus on the effect of changing from the micro-scale to the nano-scale. The investigators have many years of experience with LCA studies and in particular with the environmental aspects of solar energy generation. This knowledge will be invaluable in defining the real issues and attributes of a nanotechnology-related lifecycle.
Comparisons will be made of the life cycle environmental profiles of micro materials with nanomaterial alternatives in the PV commercial technologies mentioned above. The following will be described quantitatively: 1) Amounts of materials required for the entire PV system; 2) Physical form of materials; 3) Required purity; 4) Material utilization rates; 5) Process efficiencies; 6) Life-time expectancy; 7) Electric-conversion efficiencies; 8) Recyclability. Energy payback time (EPBT), greenhouse gas (GHG) emissions, and human toxicity potentials (HTP) will be assessed. The life-cycle environmental profiles of the currently investigated options for nano-technology based photovoltaics will be presented. This LCA can be used as an analytical tool for pollution prevention, life cycle design, and life cycle management of nano-technology enabled photovoltaics. The applicability of the general conclusions of this study to other PV technologies and other thin-film deposition systems (e.g., semiconductors, superconductors) will be investigated. This project should result in conference papers and two peer review publications.