Comparative life‐cycle energy payback analysis of multi‐junction a‐SiGe and nanocrystalline/a‐Si modules

Despite the publicity of nanotechnologies in high tech industries including the photovoltaic sector, their life-cycle energy use and related environmental impacts are understood only to a limited degree as their production is mostly immature. We investigated the life-cycle energy implications of amorphous silicon (a-Si) PV designs using a nanocrystalline silicon (nc-Si) bottom layer in the context of a comparative, prospective life-cycle analysis framework. Three R&D options using nc-Si bottom layer were evaluated and compared to the current triple-junction a-Si design, i.e., a-Si/a-SiGe/a-SiGe. The life-cycle energy demand to deposit nc-Si was estimated from parametric analyses of film thickness, deposition rate, precursor gas usage, and power for generating gas plasma. We found that extended deposition time and increased gas usages associated to the relatively high thickness of nc-Si lead to a larger primary energy demand for the nc-Si bottom layer designs, than the current triple-junction a-Si. Assuming an 8% conversion efficiency, the energy payback time of those R&D designs will be 0.7–0.9 years, close to that of currently commercial triple-junction a-Si design, 0.8 years. Future scenario analyses show that if nc-Si film is deposited at a higher rate (i.e., 2–3 nm/s), and at the same time the conversion efficiency reaches 10%, the energy-payback time could drop by 30%. Copyright # 2010 John Wiley & Sons, Ltd.

[1]  Ray,et al.  Amorphous-silicon formation by rapid quenching: A molecular-dynamics study. , 1987, Physical review. B, Condensed matter.

[2]  Lester B Lave,et al.  Life cycle economic and environmental implications of using nanocomposites in automobiles. , 2003, Environmental science & technology.

[3]  Witold-Roger Poganietz,et al.  Towards a framework for life cycle thinking in the assessment of nanotechnology , 2008 .

[4]  D. Carlson,et al.  Amorphous silicon solar cells , 1977, IEEE Transactions on Electron Devices.

[5]  Gregory A. Keoleian,et al.  Modeling the life cycle energy and environmental performance of amorphous silicon BIPV roofing in the US , 2003 .

[6]  Nicolas Wyrsch,et al.  Microcrystalline silicon and ‘micromorph’ tandem solar cells , 2002 .

[7]  S. Guha,et al.  Triple-junction amorphous silicon alloy solar cell with 14.6% initial and 13.0% stable conversion efficiencies , 1997 .

[8]  Vikas Khanna,et al.  Carbon Nanofiber Production , 2008 .

[9]  S. Guha,et al.  Hydrogenated amorphous silicon and silicon germanium triple-junction solar cells at high rate using RF and VHF glow discharges , 2008, 2008 33rd IEEE Photovoltaic Specialists Conference.

[10]  Vikas Khanna,et al.  Life Cycle Energy Consumption and Environmental Impact , 2008 .

[11]  Mary Ann Curran,et al.  An examination of existing data for the industrial manufacture and use of nanocomponents and their role in the life cycle impact of nanoproducts. , 2009, Environmental science & technology.

[12]  S. Guha,et al.  Study of Large Area a-Si:H and nc-Si:H Based Multijunction Solar Cells and Materials , 2008 .

[13]  Martin Kumar Patel,et al.  Environmental and Cost Assessment of a Polypropylene Nanocomposite , 2007 .

[14]  A. Howling,et al.  Plasma silane concentration as a determining factor for the transition from amorphous to microcrystalline silicon in SiH4/H2 discharges , 2007 .

[15]  Christophe Ballif,et al.  TCOs for nip thin film silicon solar cells , 2009 .

[16]  S. Guha,et al.  Status of nc-Si:H Solar Cells at United Solar and Roadmap for Manufacturing a-Si:H and nc-Si:H Based Solar Panels , 2007 .

[17]  D. Staebler,et al.  Reversible conductivity changes in discharge‐produced amorphous Si , 1977 .

[18]  Bernd Rech,et al.  Intrinsic microcrystalline silicon: A new material for photovoltaics , 2000 .

[19]  Vasilis Fthenakis,et al.  Update of PV Energy Payback Times and Life-Cycle Greenhouse Gas Emissions , 2009 .

[20]  A. Howling,et al.  Optimization of the microcrystalline silicon deposition efficiency , 2007 .

[21]  Influence of Pressure and Plasma Potential on High Growth Rate Microcrystalline Silicon Grown by Vhf Pecvd , 2005 .

[22]  Steve Hegedus,et al.  Thin film solar modules: the low cost, high throughput and versatile alternative to Si wafers , 2006 .

[23]  Michio Kondo,et al.  High-rate deposition of microcrystalline silicon p-i-n solar cells in the high pressure depletion regime , 2008 .

[24]  G. Keoleian,et al.  Application of life‐cycle energy analysis to photovoltaic module design , 1997 .

[25]  Thomas Huang.  Strategies for energy reduction in semiconductor manufacturing , 2008 .

[26]  S. Guha,et al.  Optimization of high efficiency amorphous silicon alloy based triple-junction modules , 1999 .

[27]  Harin S. Ullal,et al.  “The role of polycrystalline thin-film PV technologies in competitive PV module markets” , 2008, 2008 33rd IEEE Photovoltaic Specialists Conference.

[28]  H Scott Matthews,et al.  Life cycle benefits of using nanotechnology to stabilize platinum-group metal particles in automotive catalysts. , 2005, Environmental science & technology.

[29]  S. Guha,et al.  HIGH-EFFICIENCY AMORPHOUS SILICON ALLOY BASED SOLAR CELLS AND MODULES , 2004 .

[30]  A. Nozik.  Quantum dot solar cells , 2002 .

[31]  Eric A. Schiff,et al.  Amorphous Silicon-Based Solar Cells , 2011 .

[32]  Arvind Shah,et al.  Towards Very Low-Cost Mass Production of Thin-film Silicon Photovoltaic (PV) Solar Modules on Glass , 2006 .

[33]  Gregory A. Keoleian,et al.  Parameters affecting the life cycle performance of PV technologies and systems , 2007 .

[34]  Christian Capello,et al.  Energy Consumption During Nanoparticle Production: How Economic is Dry Synthesis? , 2006 .

[35]  B. von Roedern,et al.  Thin-Film Si:H-Based Solar Cells , 2008, Renewable Energy.

[36]  Arvind Shah,et al.  From amorphous to microcrystalline silicon films prepared by / hydrogen dilution using the VHF 70 MHz GD technique , 1998 .

[37]  Vikas Khanna,et al.  Carbon nanofiber polymer composites: evaluation of life cycle energy use. , 2009, Environmental science & technology.

[38]  Masat Izu,et al.  Roll-to-roll manufacturing of amorphous silicon alloy solar cells with in situ cell performance diagnostics , 2003 .

[39]  A. Matsuda,et al.  High-rate microcrystalline silicon deposition for p–i–n junction solar cells , 2006 .

[40]  Bernd Stannowski,et al.  Helianthos : Roll-to-Roll deposition of flexible solar cell modules , 2007 .

[41]  Martin A. Green,et al.  Solar cell efficiency tables (Version 34) , 2009 .

[42]  Margaret R. Taylor,et al.  Environmental risks of nanotechnology: National Nanotechnology Initiative funding, 2000-2004. , 2006, Environmental science & technology.

[43]  Subhendu Guha,et al.  Multijunction Solar Cells and Modules , 2000 .

[44]  Erik Alsema,et al.  Energy requirements of thin-film solar cell modules—a review , 1998 .

[45]  Jeffrey B Dahmus,et al.  Thermodynamic analysis of resources used in manufacturing processes. , 2009, Environmental science & technology.

[46]  S. Guha,et al.  Amorphous silicon alloy photovoltaic research—present and future , 2000 .

[47]  M. Sano,et al.  Microcrystalline silicon solar cells fabricated by VHF plasma CVD method , 2005 .

[48]  Nikhil Krishnan,et al.  A hybrid life cycle inventory of nano-scale semiconductor manufacturing. , 2008, Environmental science & technology.

[49]  A. Matsuda,et al.  High-Rate Plasma Process for Microcrystalline Silicon: Over 9% Efficiency Single Junction Solar Cells , 2004 .

[50]  J. Müller,et al.  Amorphous and microcrystalline silicon solar cells prepared at high deposition rates using RF (13.56 MHz) plasma excitation frequencies , 2001 .

[51]  R. Collins,et al.  Phase engineering of a-Si:H solar cells for optimized performance , 2004 .