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General Overview
For a good general overview of the scientific research regarding cadmium, photovoltaics, and ES&H issues, please refer to the following materials:
Some of the following documents are available as Adobe Acrobat PDFs. Download Acrobat Reader
Fthenakis, V.M; Fuhrmann, M.; Heiser, J; Wang, W. (2004). "Experimental Investigation of Emissions and Redistribution of Elements in CdTe PV Modules During Fires." Prepared for the 19th European PV Solar Energy Conference, Paris, France, June 7-11, 2004. (PDF 244 KB)
Abstract: This study is based on glass-glass CdTe PV modules, which are the only ones in the market. Pieces of commercial CdTe photovoltaic (PV) modules, sizes 3.8 cm by 30.5 cm, were heated to temperatures up to 1100°C to simulate exposure to residential and commercial building fires. It was found that a small amount of cadmium compounds (0.4 to 0.6% of the Cd content) was carried to the edges by the flow of EVA decomposition products. The pathway for this loss was through the perimeter of the sample before the two sheets of glass fused together. In actual size PV modules, the ratio of perimeter to area is 13.5 times smaller; thus the actual Cd loss during fires would be insignificant (‹0.04% of the Cd content).
Fthenakis, V.M. (2004). "Life Cycle Impact Analysis of Cadmium in CdTe
PV Production." (PDF 700 KB)
Abstract: This paper describes the material flows and emissions in all the life stages of CdTe PV modules, from extracting refining and purifying raw materials through the production, use, and disposal or recycling of the modules. The prime focus is on cadmium flows and cadmium emissions into the environment. This assessment also compares the cadmium environmental inventories in CdTe PV modules with those of Ni-Cd batteries and of coal fuel in power plants. Previous studies are reviewed and their findings assessed in light of new data.
Eberspacher, C.; Fthenakis, V.M. (1997). "Disposal and Recycling of End-of-Life PV Modules." Prepared for the 26th IEEE PV Specialists Conference, October 1997.
Abstract: Recycling can be a cost-effective way to dispose of end-of-life PV modules. Recycling is economical if key components (e.g., Si wafers and/or glass sheets) can be salvaged intact or if the modules are classified as "hazardous" under existing environmental regulations. Recycling can simplify handling and disposal of end-of-life modules.
Fthenakis, V.M. (2000). "End-of-Life Management and Recycling of PV Modules," Energy Policy Journal, 28, pp. 1051-1058.
Abstract: Photovoltaics (PV) technology is undergoing a transition to a new generation of efficient, low-cost products based on thin films of photoactive materials. PV technology has definite environmental advantages over competing electricity generation technologies, and the PV industry follows a proactive life-cycle approach to prevent future environmental damage and to sustain these advantages. An issue with potential environmental implications is the decommissioning of solar cells at the end of their useful lives; a viable solution is recycling them when they are no longer useful. This paper presents a feasibility study for recycling thin-film solar cells and manufacturing waste, based on the current collection/recycling infrastructure and on current and emerging recycling technologies. It is shown that recycling is technically and economically feasible.
Fthenakis, V.M. (2002). "Could CdTe PV Modules Pollute the Environment?" Upton, NY: National Photovoltaic Environmental Health and Safety Assistance Center, Brookhaven National Laboratory.
Abstract: As CdTe PV modules reached commercialization, vocal opposition emerged based on concerns about potential emissions of cadmium. In this short article, I discuss the pertinent technical issues and conclude that CdTe PV modules do not present any risks to health and the environment during their use, and recycling the modules at the end of their useful life completely resolves any environmental issues.
Fthenakis, V.M.; Morris, S.C.; Moskowitz, P.D.; and Morgan, D. (1999). "Toxicity of CdTe, CIS and CGS." Progress in Photovoltaics, 7, pp. 489-497.
Abstract: The paper reviews recently derived toxicity data for cadmium telluride (CdTe), copper indium diselenide (CIS), and cadmium gallium diselenide (CGS), promising new materials on which a new generation of thin-film photovoltaic cells for generating electricity may be based. The new data deal with systemic and reproductive toxicity; acute pulmonary toxicity; and comparative pulmonary absorption, distribution, and toxicity of these materials in laboratory rats. CdTe is shown to have higher lung toxicity than CIS, with the CGS toxicity being the lowest in the group. These data are extended to human exposure levels, and exposure limits for CdTe are derived. The implications of these findings to the photovoltaic industry are also discussed.
Fthenakis, V.M.; Moskowitz, P.D. (2000). "Photovoltaics: Environmental, Safety and Health Issues and Perspectives," Progress in Photovoltaics, Millennium Issue, 8, pp. 27-38.
Abstract: The photovoltaic (PV) industry must continue its proactive approach to prevent accidents and environmental damage, and to sustain PV's inherent environmental, health, and safety (EHS) advantages. This paper presents an overview of EHS issues related to current and emerging PV technologies and gives examples of this proactive approach. We summarize the hazards related to potential accidental releases of toxic or flammable gases used in photovoltaic cell production and strategies for reducing such risks (e.g., choosing material and process options that inherently have small risks and preventing accident-initiating events). Other issues discussed herein include reducing the use of toxic or carcinogenic materials in powder form, managing liquid hazardous waste, and recycling solid waste and spent modules. As the PV industry approaches these issues and mitigation strategies in a vigilant, systematic way, the risk to the industry, the workers, and the public will become minimal. The potential of PV in reducing carbon dioxide emissions is also discussed.
Fthenakis, V.M.; Moskowitz, P.D. (1997). "Thin-Film PV Cells: Health and Environmental Issues in Their Manufacture, Use, and Disposal." Progress in Photovoltaics, Vol. 3, pp. 295-306.
Abstract: The large-scale manufacture of thin-film photovoltaic cells may present health and safety hazards if adequate precautions are not taken. In this paper, we examine the hazards associated with producing and using Si, CdTe, and CIS thin-film photovoltaic modules. We focus especially on the potential of workers in manufacturing facilities to be exposed to chronic, low levels of Cd. Pertinent regulations are reviewed and control options are presented which can minimize the risks to workers. Also, we investigate occupational safety hazards and the associated engineering and administrative options related to using pyrophoric silane in making amorphous silicon cells. Finally, recycling and disposal options for spent photovoltaic modules are discussed.
Fthenakis, V.; Zweibel, K. (2003). "CdTe PV: Real and Perceived EHS Risks." Prepared for the NCPV and Solar Program Review Meeting 2003 (PDF 170 KB) (Download Acrobat Reader).
Abstract: As CdTe photovoltaics reached commercialization, questions were raised about potential cadmium emissions from CdTe PV modules. This paper gives an overview of the technical issues pertinent to these questions and further explores the potential of environmental, health, and safety (EHS) risks during production, use, and decommissioning of CdTe PV modules. The following issues are discussed: (a) the physical and toxicological properties of CdTe, (b) comparisons of Cd use in CdTe PV with its use in other technologies and products, and (c) the possibility of CdTe releases from PV modules.
Spiegel, R.J. (1995). "Demonstrating Pollution Reduction Capability of Photovoltaic Systems." Presented at the Solar World Congress/International Solar Energy Society Conference, September 9-18, 1995.
Abstract: The paper discusses a program to demonstrate the capability and potential of photovoltaic (PV) systems as a pollution-mitigating energy replacement for fossil fuels. The approach has been to install and monitor PV systems located on rooftops of residential, commercial, and military buildings across the United States. The economic value of the PV systems is enhanced by this approach because they compete with the retail price of electric power rather than the utility-avoided cost price. Participating utilities provide hourly records indicating which load-following power plants (marginal or 'swing' plants) are operating, as well as total utility system load. On a site-by-site basis, the project tracks carbon dioxide (CO2), nitrogen oxides (NOx), sulfur dioxide (SO2), and particulate-avoided emissions.
More Information
Agency for Toxic Substances and Disease Registry (ATSDR). 1999. "Toxicological profile for cadmium." Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service.
Alsema, E.A.; van Engelenburg, B.C.W. (1992). "Environmental Risks of CdTe and CIS Solar Cell Modules." Prepared for the 11th European Solar Energy Conference, Montreux, 1992, pp.12-16.
Anderson, B. A. (2000). "Materials availability for large-scale thin film photovoltaics." Progress in Photovoltaics, 8, pp. 61-76.
Drysdale, D. (1985). An Introduction to Fire Dynamics, pp. 329-330, Wiley, NY.
Environmental Resources Limited (ERL). (1990). Evaluation of the Sources of Human and Environmental Contamination by Cadmium. Prepared for the Commission of the European Community; Directorate General for Environment, Consumer Protection and Nuclear Safety; London, February 1990.
Fthenakis, V.M.; Eberspacher, C.; Moskowitz P.D. (1998). "The Feasibility of Recycling Solar Cells." Prepared for IEEE Spectrum.
Moskowitz, P.D.; Bernholc, N.; Fthenakis, V.M.; Pardi, R.M.; Steinberger, H.; and Thumm, W. (1995). "Environmental, Health and Safety Issues Related to the Production and Use of Cadmium Telluride Photovoltaic Modules," Chapter 4. Boer, K.W., ed. Advances in Solar Energy: An Annual Review of Research and Development, Vol. 10, Boulder, CO.: American Solar Energy Society, Inc.; pp. 211-245.
Moskowitz, P; Fthenakis, V. (1990). "Toxic Materials Released from Photovoltaic Modules during Fires: Health Risks." Solar Cells, 29; pp. 63-71.
Moskowitz, P.D.; Fthenakis, V.M.; Hamilton, L.D.; Lee, J.C. (1987). "Public Health Issues in PV Energy Systems: an Overview of Concerns." Sol. Cells, 19, pp. 287-299.
Moskowitz, P.D.; Fthenakis, V.M.; Zweibel, K. (1990). "Health and Safety Issues Related to the Production, Use, and Disposal of Cd-Based PV Modules." Prepared for the 21st IEEE PV Specialists Conference, 21-25 May 1990.
Moskowitz, P.D.; Hamilton, L.D.; Morris, S.C.; Novak, K.M.; Rowe, M.D. (1990). "Photovoltaic Energy Technologies: Health and Environmental Effects Document." BNL-51284. Upton, New York: Brookhaven National Laboratory.
Moskowitz, P.D.; Zweibel, K. (eds). (1992). "Recycling of Cadmium and Selenium from PV Modules and Manufacturing Wastes: a Workshop Report." BNL-47787. Upton, New York: Brookhaven National Laboratory.
Moskowitz, P.D.; Zweibel, K.; Fthenakis, V.M. (1990). "Health, Safety, and Environmental Issues Relating to Cadmium Usage in PV Energy Systems." SERI/TR-211-3621, DE90000310. Golden, CO: National Renewable Energy Laboratory.
Organization for Economic Co-operation and Development (OECD). (1994). Risk Reduction Monograph No. 5: Cadmium OECD Environment Directorate, Paris, France.
Patterson, M.; Turner, A.; Sadeghi, M.; Marshall, R. (1994). "HSE aspects of the production and use of CdTe thin film modules." Presented at the 12th European PV Solar Energy Conference, Amsterdam.
Plachy, J. (2002). "Cadmium." USGS Minerals Yearbook: Metals and Minerals, Vol. 1, available online from the U.S. Geological Survey, (PDF 185 KB)
(Download Acrobat Reader).
Last modified December 26, 2002; accessed January 9, 2003.
Steinberger, H. (1997). HSE for CdTe and CIS thin film module operation, IEA expert workshop "Environmental aspects of PV power systems," May 23, 1997, Report No. 97072, Niewlaar E. and Alsema E. (ed.), Utrecht University, The Netherlands.
Thumm, W.; Finke, A.; Nuemeier, B.; Beck, B.; Kettrup, A.; Steinberger, H.; Moskowitz, P. (1994). "Environmental and health aspects of CIS-module production, use, and disposal." Presented at the First World Conference on Photovoltaic Energy Conversion, Waikoloa, Hawaii, 5-9 December 1994.
Tolley, W.K.; Palmer, G.R. (1991). "Recovering Cadmium and Tellurium from CdTe Manufacturing Scrap." 1991 AIME Annual Meeting, New Orleans, LA, February 1991, Bureau of Mines, Salt Lake City.
Van Assche, F. J.; Ciarletta, P. (1993). "Environmental Exposure to Cadmium in Belgium: Decreasing Trends during the 1980s." Heavy Metals in the Environment, Volume 1, pps. 34-37. Toronto, September 1993.
Van Assche, F. J. (1998). "A Stepwise Model to Quantify the Relative Contribution of Different Environmental Sources to Human Cadmium Exposure." NiCad '98, Prague, Czech Republic, September 21-22, 1998.
Zweibel, K. (1995). "Thin Films: Past, Present, Future." Progress in Photovoltaics, Vol. 3, pp. 279-293.
Zweibel, K. (1997). "Reducing ES&H impacts from thin film PV." Environmental Aspects of PV Power Systems, Utrecht University, The Netherlands.
Zweibel, K. (1999). "Issues in thin film PV manufacturing cost reduction." Solar Energy Materials and Solar Cells, 59, pp. 1-18.
Zweibel, K.; Chu, T.L. (1993). "Cadmium Telluride Photovoltaics," Advances in Solar Energy, Vol. 8, ed. by M. Prince, American Solar Energy Society, Boulder, CO.
Zweibel, K.; Moskowitz, P.; Fthenakis, V. (1998). "Thin-Film Cadmium Telluride Photovoltaics: ES&H Issues, Solutions, and Perspectives." NREL/TP-520-24057, DE-AC36-99-GO10337. Golden, Colorado: National Renewable Energy Laboratory.
For further reading on the subject, please refer to the Brookhaven National Laboratory Environmental, Health and Safety Assistance Center Bibliography.
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