This is the literature review and project information page of the Appropedia user Vishal Arya performing a project on Environmental effects of monocrystalline and multicrystalline Silicon-based solar cells as part of the MSE 5490 course by Prof. Dr. Joshua Pearce. It will primarily be updated by this User and if you wish to add to or collaborate on this project, feel free to discuss and add relevant pages and sources to the appropriate sections in chronological order. Thank you.

Lifecycle and Economic Assessment of Standard texturized Czochralski Silicon and Black Multicrystalline Silicon PERC cells[edit | edit source]

Source paper[edit | edit source]

Abstract[edit | edit source]

Industrial Czochralski silicon (Cz-Si) photovoltaic (PV) efficiencies have routinely reached >20% with the passivated emitter rear cell (PERC) design. Nanostructuring silicon (black-Si) by dry-etching decreases surface reflectance, allows diamond saw wafering, enhances metal gettering, and may prevent power conversion efficiency degradation under light exposure. Black-Si allows a potential for >20% PERC cells using cheaper multicrystalline silicon (mc-Si) materials, although dry-etching is widely considered too expensive for industrial application. This study analyzes this economic potential by comparing costs of standard texturized Cz-Si and black mc-Si PERC cells. Manufacturing sequences are divided into steps, and costs per unit power are individually calculated for all different steps. Baseline costs for each step are calculated and a sensitivity analysis run for a theoretical 1 GW/year manufacturing plant, combining data from literature and industry. The results show an increase in the overall cell processing costs between 15.8% and 25.1% due to the combination of black-Si etching and passivation by double-sided atomic layer deposition. Despite this increase, the cost per unit power of the overall PERC cell drops by 10.8%. This is a significant cost saving and thus energy policies are reviewed to overcome challenges to accelerating deployment of black mc-Si PERC across the PV industry.

Keywords[edit | edit source]

  • black silicon; economics; manufacturing costs; multicrystalline silicon; passivated emitter rear cell; PERC; silicon solar cells; photovoltaic; photovoltaic manufacturing

Background[edit | edit source]

Journals[edit | edit source]

  • Energy
  • Solar Energy
  • Renewable and Sustainable Energy Reviews

Searches[edit | edit source]

Literature Review[edit | edit source]

1. What is Lifecycle assessment?[edit | edit source]

Economic Input-Output Lifecycle Assessment Life Cycle Analysis

2. Why Lifecycle assessment?[edit | edit source]

J. B. Guinée, R. Heijungs, G. Huppes, A. Zamagni, P. Masoni, R. Buonamici, T. Ekvall, T. Rydberg, Life Cycle Assessment: Past, Present, and Future, Environmental Science & Technology 2011 45 (1), 90-96 DOI: http://dx.doi.org/10.1021/es101316v/

3. History of Silicon Cell's Evolution[edit | edit source]

M. A. Green, The path to 25% silicon solar cell efficiency: History of silicon cell evolution, Progress in Photovoltaics: Research and Applications 2009 Volume 17, 183-189 DOI: https://doi.org/10.1002/pip.892 Open Access

Abstract[edit | edit source]

The first silicon solar cell was reported in 1941 and had less than 1% energy conversion efficiency compared to the 25% efficiency milestone reported in this paper. Standardization of past measurements shows there has been a 57% improvement between confirmed results in 1983 and the present result. The features of the cell structure responsible for the most recent performance increase are described and the history of crystalline and multicrystalline silicon cell efficiency evolution is documented.

3. What are the methods of Lifecycle assessment in the PV industry?[edit | edit source]

Methodologies and Guidelines on Life Cycle Assessment of Photovoltaic Electricity

4. J. Kim., J. Rivera, T. Y. Meng, B. Laratte, S. Chen, Review of life cycle assessment of nanomaterials in photovoltaics, Solar Energy August 2016 Volume 133, 249-258[edit | edit source]

DOI: https://doi.org/10.1016/j.solener.2016.03.060

Abstract[edit | edit source]

Photovoltaic (PV) technologies are gaining a share in the renewable energy production market. Recently nanomaterials have been used by researchers to improve the performance and efficiency of PVs. Consideration to the environmental aspects of nanomaterials infused PVs is a growing area of interest. Therefore, the objective of this paper is to investigate the application of LCA to PV technology. Particularly, the authors are interested in scrutinizing the application of LCA to PV systems infused with nanomaterials. In this paper, a literature review was performed to describe and assess the limitations of current research on the usage of life cycle assessment (LCA) methodologies to predict the environmental impact of nanomaterials usage on PVs. The approach to this review focuses on two sub-categories: production and/or use of PVs, and end-of-life of PVs. Following this approach the context and progress of LCA is described. Research gaps and opportunities for improved environmental performance throughout the life cycle of nano-infused PVs are identified and discussed. This work provides a basis for the continue analysis of emerging nanomaterials and PV technologies.

5. N. A. Ludin, N. I. Mustafa, Marlia M. Hanafiah, M. A. Ibrahim, M. A. M. Teridi, S. Sepeai, A. Zharim, K. Sopian, Prospects of life cycle assessment of renewable energy from solar photovoltaic technologies: A review, Renewable and Sustainable Energy Reviews November 2018 Volume 96, 11-28[edit | edit source]

DOI: https://doi.org/10.1016/j.rser.2018.07.048

Abstract[edit | edit source]

Life cycle assessment (LCA) is a comprehensive method used to investigate the environmental impacts and energy use of a product throughout its entire life cycle. For solar photovoltaic (PV) technologies, LCA studies need to be conducted to address environmental and energy issues and foster the development of PV technologies in a sustainable manner. This paper reviews and analyzes LCA studies on solar PV technologies, such as silicon, thin film, dye-sensitized solar cell, perovskite solar cell, and quantum dot-sensitized solar cell. The PV life cycle assumes a cradle-to-grave mechanism, starting from the extraction of raw materials until the disposal or recycling of the solar PV. Three impact assessment methods in LCA were reviewed and summarized, namely, cumulative energy demand (CED), energy payback time (EPBT), and GHG emission rate, based on data and information published in the literature. LCA results show that mono-crystalline silicon PV technology has the highest energy consumption, longest EPBT, and highest greenhouse gas emissions rate compared with other solar PV technologies.

6. Any records in Efficiency?[edit | edit source]

Z. Wang, P. Han, H. Lu, H. Qian, L. Chen, Q. Meng, N. Tang, F. Gao, Y. Jiang, J. Wu, W. Wu, H. Zhu, J. Ji, Z. Shi, A. Sugianto, L. Mai, B. Hallam, S. Wenham, Advanced PERC and PERL production cells with 20.3% record efficiency for standard commercial p‐type silicon wafers, Research in Photovoltaics, 2012 Volume 20 260-268 DOI: https://doi.org/10.1002/pip.2178

Abstract[edit | edit source]

Following intensive research and development, Suntech Power has successfully commercialised its Pluto technology with 0.5 GW annual production capacity, delivering up to 10% performance advantage over conventional screen‐printed cells. The next generation of Pluto involves the development of improved rear surface design based on the design features of passivated emitter and rear locally diffused cells. Cells with an average efficiency over 20% were fabricated on 155 cm2 commercial‐grade p‐type wafers using mass‐manufacturing processes and equipment, with the highest single‐cell efficiency independently confirmed at 20.3%. This is believed to be a record efficiency for this wafer type. Further optimisation work on contact pattern and rear surface passivation suggests the potential for further efficiency increase approaching 23%.

7. M. M. Lunardi, J. P. Alvarez-Gaitan, N. L. Chang, R. Corkish, Life cycle assessment on PERC solar modules, Solar Energy Materials and Solar Cells, 2018 Volume 187 154-189[edit | edit source]

DOI: https://doi.org/10.1016/j.solmat.2018.08.004

Abstract[edit | edit source]

The screen-printed aluminium back surface field (Al-BSF) technology is the current industry standard process for crystalline silicon solar cells but, due to the search for higher efficiency, much attention has been paid to the passivated emitter and rear cell (PERC), which is gaining significant share in the world market. We undertake an environmental analysis comparing Al-BSF and PERC monocrystalline solar modules. Through the life cycle assessment (LCA) method we calculate the global warming, human toxicity (cancer and non-cancer effects), freshwater eutrophication, freshwater ecotoxicity, abiotic depletion potentials and energy payback time of these technologies considering solar, electronic and upgraded metallurgical grade silicon feedstock. The functional unit considered is 1 kWh of energy delivered over the modules' lifetime. As a result of this work, we showed that PERC technology generates a slight improvement in the environmental impacts when compared with Al-BSF. The use of electronic and upgraded metallurgical grade silicon results in lower environmental impacts in most cases, compared with the other technologies analysed, based on the assumptions made in this LCA.

8. Some etching processes[edit | edit source]

G. A. Rozgonyi, S. Sivarajan, Silicon: Characterization by Etching, Reference Module in Materials Science and Materials Engineering 2017[edit | edit source]

DOI: https://doi.org/10.1016/B978-0-12-803581-8.03309-9

Abstract[edit | edit source]

Fabrication and research related to silicon devices, circuits and systems relies on the etching and characterization of silicon wafers. The etching process are used for different applications including micromachining, cleaning and defect delineation. Wet chemical etching principles used in silicon semiconductor defect analysis are described. Crystallographic effects and formation of pits during etching are explained. An extensive review of etchants used for a variety of materials is presented. The defects and impurities in silicon are examined by preferential etching and optical microscopy. This article presents the three configurations, namely plan view wafer surfaces, Bevel polish and etch and Cleavage face analysis to illustrate the applicability of defect analysis using etching.

9. F. Schindler, A. Fell, R. Muler, J. Benick, A. Richter, F. Feldman, P. Krenckel, S. Riepe, M. C. Schubert, S. W. Glunz, Towards the efficiency limits of multicrystalline silicon solar cells, Solar Energy Materials and Solar Cells 2018 Volume 185 198-204[edit | edit source]

DOI: https://doi.org/10.1016/j.solmat.2018.05.006

Abstract[edit | edit source]

In this contribution, we present our recent results for high efficiency multicrystalline silicon solar cells. Based on n-type high-performance multicrystalline silicon substrates in combination with the TOPCon solar cell concept featuring a full area passivating back contact and a boron-diffused emitter as well as a plasma-etched black-silicon texture at the front side, a certified conversion efficiency of 22.3% has been achieved, which is currently the world record efficiency for multicrystalline silicon solar cells. A detailed loss analysis of the record solar cell batch discloses the nature of the remaining loss mechanisms, revealing the route for further improvements. We observe an efficiency gap between the multicrystalline and the FZ reference solar cells of ~1%abs. Compared to the FZ reference cells, the mc-Si cells also feature a significantly larger scattering in Voc and Jsc as well as a fill factor loss of ~1.5%abs. We show that the scattering in Jsc correlates with the area fraction of recombination-active structural crystal defects and the scattering in Voc additionally with lateral emitter-induced inhomogeneities. The fill factor loss is attributed to the general presence of strongly recombination-active grain boundaries. A detailed loss analysis of the record mc-Si solar cell shows that the major electrical losses are due to recombination at grain boundaries (0.7%abs) and recombination in the emitter (0.6%abs). By reducing these electrical loss channels, e.g. by an improved crystallization process together with a hydrogenation of the bulk and application of an adapted emitter, we expect to reach efficiencies for mc-Si solar cells in the range of 23%.

10. S. Zhong, B. Liu, Y. Xia, J. Liu, J. Liu, Z. Shen, Z. Xu, C. Li, The study on the properties of black multicrystalline silicon solar cell varying with the diffusion temperature, Energy Procedia 2012 Volume 14 505-511[edit | edit source]

DOI: https://doi.org/10.1016/j.egypro.2011.12.966

Abstarct[edit | edit source]

The black multi-crystalline silicon (mc-Si) has been successfully produced by plasma immersion ion implantation. The microstructure and the reflectance of the black mc-Si have been investigated by atomic force microscope and spectrophotometer, respectively. Results show that the black mc-Si exhibits a hillock structure with a low reflectance. Besides, with decreasing the diffusion temperature, the external quantum efficiency of the black mc-Si solar cell increases below ∼550 nm wavelength due to reduced surface recombination. The optimal conversion effieciency of the black mc-Si solar cell is 15.50% at the diffusion temperature of 825 °C. Furthermore, it is interesting to find that there are something different between black mc-Si and acid etched mc-Si on the impact of diffusion.

11. S. Werner, E. Lohmuller, P. Saint-Cast, J. Greulich, Key aspects for fabrication of p-type Cz-Si PERC solar cells exceeding 22% conversion efficiency, 33rd European PV Solar Energy Conference and Exhibition 2017[edit | edit source]

https://www.ise.fraunhofer.de/content/dam/ise/de/documents/publications/conference-paper/33-eupvsec-2017/Werner_2CO111.pdf

Abstract[edit | edit source]

This paper gives a close-up insight into recent and future developments that are performed with industrial focus at Fraunhofer ISE's PV-TEC pilot-line to increase the energy conversion efficiency of 6-inch p-type Czochralski-grown silicon (Cz-Si) passivated emitter and rear cells (PERC) to 22% and above. First, the current status of PERC solar cell fabrication allowing for conversion efficiencies up to 21.5% is discussed. Then, we examine four key aspects in detail that need to be considered for optimizing the cells' front side to boost the cell efficiency to the 22% regime. We demonstrate selective emitter laser doping out of the phosphosilicate glass layer, which is formed by a gas phase phosphorus oxychloride diffusion process. After diffusion and wet-chemical emitter etch back, the field emitter features a very low saturation current density of only 31 fA/cm² (textured, SiNx-passivated). Specific contact resistances of 1 mΩcm2 confirm the low-resistance contacting of the laser-doped surfaces using a commercially available silver screen printing paste. Apart from developing an accurate alignment procedure to match laserstructured and screen-printed layouts, we have also optimized our single-step screen-printing process for finger widths of 38 µm at 16 µm height. Based on simulations we find that efficiencies up to 22.5% are possible when the optimized process routes are integrated into PERC solar cells

12. S. Wasmer, A. Horst, P. Saint-Cast, J. Greulich, Modelling-free efficiency analysis of Passivated Emitter and Rear Silicon Cells, IEEE Journal of Photovoltaics, 2018 Volume 99 1-8[edit | edit source]

DOI: http://dx.doi.org/10.1109/JPHOTOV.2018.2804333

Abstarct[edit | edit source]

We introduce an approach to analyze and identify the predominant loss mechanisms in silicon solar cells. For this end, we focus on the potential efficiency gains to be acquired by suppressing each loss mechanism. All the losses are scaled to efficiency gains, leading to quantities similar to the derivative of the efficiency with respect to the loss mechanisms. All impacts are directly comparable to one another since the potential gains are quantified in the same units. The approach is solely based on measured data alone and we take injection-dependent lifetimes correctly into account by measuring at maximum power point like conditions. This approach is exemplarily applied to passivated emitter and rear cells (PERC) based on p-type mono- and multicrystalline silicon wafers. For our examined solar cells, we identify as bottlenecks the optical and recombination properties of the front-side metallization in case of the monocrystalline PERC cell and the reflection at the active area in the multicrystalline case with potential efficiency gains of 1.23%abs and 1.56%abs, respectively.

13. T. Tsoutsos, N. Frantzeskaki, V. Gekas, Environmental impacts from solar energy technologies, Energy Policy, 2005 Volume 33(3) 289-296[edit | edit source]

DOI: https://doi.org/10.1016/S0301-4215(03)00241-6

Abstract[edit | edit source]

Solar energy systems (photovoltaics, solar thermal, solar power) provide significant environmental benefits in comparison to the conventional energy sources, thus contributing, to the sustainable development of human activities. Sometimes however, their wide scale deployment has to face potential negative environmental implications. These potential problems seem to be a strong barrier for a further dissemination of these systems in some consumers.

To cope with these problems this paper presents an overview of an Environmental Impact Assessment. We assess the potential environmental intrusions in order to ameliorate them with new technological innovations and good practices in the future power systems. The analysis provides the potential burdens to the environment, which include—during the construction, the installation and the demolition phases, as well as especially in the case of the central solar technologies—noise and visual intrusion, greenhouse gas emissions, water and soil pollution, energy consumption, labour accidents, impact on archaeological sites or on sensitive ecosystems, negative and positive socio-economic effects.

14. V. M. Fthenakis, H. C. Kim, E. Alsema, Emissions from Photovoltaics Life Cycles', Environmental Science and Technology, 2008 Volume 42(6) 2168-2174[edit | edit source]

DOI: http://dx.doi.org/10.1021/es071763q/ https://pubs.acs.org/doi/pdf/10.1021/es071763q

Abstract[edit | edit source]

Photovoltaic (PV) technologies have shown remarkable progress recently in terms of annual production capacity and life cycle environmental performances, which necessitate timely updates of environmental indicators. Based on PV production data of 2004–2006, this study presents the life-cycle greenhouse gas emissions, criteria pollutant emissions, and heavy metal emissions from four types of major commercial PV systems: multicrystalline silicon, monocrystalline silicon, ribbon silicon, and thin-film cadmium telluride. Life-cycle emissions were determined by employing average electricity mixtures in Europe and the United States during the materials and module production for each PV system. Among the current vintage of PV technologies, thin-film cadmium telluride (CdTe) PV emits the least amount of harmful air emissions as it requires the least amount of energy during the module production. However, the differences in the emissions between different PV technologies are very small in comparison to the emissions from conventional energy technologies that PV could displace. As a part of prospective analysis, the effect of PV breeder was investigated. Overall, all PV technologies generate far less life-cycle air emissions per GWh than conventional fossil-fuel-based electricity generation technologies. At least 89% of air emissions associated with electricity generation could be prevented if electricity from photovoltaics displaces electricity from the grid.

15. G. Timilsina, L. Kurdgelashvili, P. A. Narbel, Solar energy: Markets, economics and policies, Renewable and Sustainable Energy Reviews, 2012 Volume 16(1) 449-465[edit | edit source]

DOI: https://doi.org/10.1016/j.rser.2011.08.009

Abstract[edit | edit source]

Solar energy has experienced phenomenal growth in recent years due to both technological improvements resulting in cost reductions and government policies supportive of renewable energy development and utilization. This study analyzes the technical, economic and policy aspects of solar energy development and deployment. While the cost of solar energy has declined rapidly in the recent past, it still remains much higher than the cost of conventional energy technologies. Like other renewable energy technologies, solar energy benefits from fiscal and regulatory incentives, including tax credits and exemptions, feed-in-tariff, preferential interest rates, renewable portfolio standards and voluntary green power programs in many countries. The emerging carbon credit markets are expected to provide additional incentives to solar energy deployment; however, the scale of incentives provided by the existing carbon market instruments, such as, the Clean Development Mechanism of the Kyoto Protocol is limited. Despite the huge technical potential, the development and large scale deployment of solar energy technologies world-wide still has to overcome a number of technical, financial, regulatory and institutional barriers. The continuation of policy supports might be necessary for several decades to maintain and enhance the growth of solar energy in both developed and developing countries.

16. L. Stamford, A. Azapagic, Environmental Impacts of Photovoltaics: The Effects of Technological Improvements and Transfer of Manufacturing from Europe to China, Energy Technology 2018 Volume 6(6)[edit | edit source]

DOI: https://doi.org/10.1002/ente.201800037 https://onlinelibrary.wiley.com/doi/epdf/10.1002/ente.201800037

Abstract[edit | edit source]

Solar power deployment is expanding rapidly alongside improvements in manufacturing processes and solar technology performance. This expansion has coincided with great cost reductions and a shift in manufacturing to China, but the environmental effects of these developments remain unclear. This study uses life cycle assessment (LCA) to estimate the environmental impacts for silicon‐based photovoltaic (PV) systems installed in two locations—the United Kingdom (UK) and Spain—in the years 2005 and 2015 to assess the changes that have occurred in the past decade. Manufacturing is considered in both Europe and China to analyze the effects of the aforementioned market shift. The results show that technological improvements have reduced the environmental impacts by an average of 45 %, ranging from 29 % (eutrophication) to 80 % (ozone layer depletion); the carbon footprint has been approximately cut in half. However, the shift of manufacturing to China has increased environmental impacts by an average of 9–13 % relative to manufacturing in Europe. Acidification is much higher for Chinese‐made systems, negating all of the technological progress that has been made over the past decade. Thus, the future impacts of PV are highly dependent upon environmental improvements in the Chinese energy mix. Learning rates for environmental impacts are estimated at 6–26 %, thereby leading to expected impact reductions of 8–34 % by the year 2025, which would bring the impacts of Chinese‐made PV systems back down to the levels currently achieved by systems made in Europe.

17. E. Alsema, M. J. de Wild, Environmental Impact of Crystalline Silicon Photovoltaic Module Production MRS Proceedings 2006 Volume 895[edit | edit source]

DOI: https://doi.org/10.1557/PROC-0895-G03-05 https://www.ecn.nl/publications/PdfFetch.aspx?nr=ECN-RX--06-041

Abstract[edit | edit source]

Together with a number of PV companies an extensive effort has been made to collect Life Cycle Inventory data that represents the current status of production technology for crystalline silicon modules. The new data covers all processes from silicon feedstock production to cell and module manufacturing. All commercial wafer technologies are covered, that is multi- and monocrystalline wafers as well as ribbon technology. The presented data should be representative for the technology status in 2004, although for monocrystalline Si crystallisation further improvement of the data quality is recommended. On the basis of the new data it is shown that PV systems on the basis of c-Si technology are in a good position to compete with other energy technologies. Energy Pay-Back Times of 1.7-2.7 yr are found for South-European locations, while life-cycle CO2 emission is in the 30-46 g/kWh range. Clear perspectives exist for further improvements with roughly 40-50%.

18. M. A. Green, The Passivated Emitter and Rear Cell (PERC): From conception to mass production, Solar Energy Materials and Solar Cells 2015 Volume 143 190-197[edit | edit source]

DOI: https://doi.org/10.1016/j.solmat.2015.06.055

Abstract[edit | edit source]

Improved solar cell efficiency is the key to ongoing photovoltaic cost reduction, particularly as economies of scale propel module-manufacturing costs towards largely immutable basic material costs and as installation costs become an increasingly large contributor to total system costs. To enable manufacturers to move past the 20% cell energy conversion efficiency figure in production, high-efficiency PERC (Passivated Emitter and Rear Cell) sequences are being increasingly brought online. Most new photovoltaic manufacturing capacity added in the second half of 2014 was PERC-based, making PERC now the cell technology with second-highest production capacity, with the latest industry roadmap anticipating PERC will become the dominant commercial cell technology by 2020. The first paper describing the PERC cell appeared in 1989, although the structure was conceived several years earlier. The attractive technical features were the reduction of rear surface recombination by a combination of dielectric surface passivation and reduced metal/semiconductor contact area while simultaneously increasing rear surface reflection by use of a dielectrically displaced rear metal reflector. The key issues in the development of this technology and its commercial implementation are described, including a review of recent adoption rates and the way these are likely to evolve in the future.

19. A.F.B. Braga, S.P. Moreira, P.R. Zampieri, J.M.G. Bcchin, P.R. Mei, New processes for the production of solar grade polycrystalline silicon: A review, Solar Energy Materials and Solar Cells 2008 Volume 92(4) 418-424[edit | edit source]

DOI: https://doi.org/10.1016/j.solmat.2007.10.003

Abstract[edit | edit source]

The global energy consumption is predicted to grow dramatically every year. Higher energy prices and public awareness for the global warming problem have opened up the market for solar cells. The generation of electricity with solar cells is considered to be one of the key technologies of the new century. The impressive growth is mainly based on solar cells made from polycrystalline silicon. This paper reviews the recent advances in chemical and metallurgical routes for photovoltaic (PV) silicon production.

20. A. Muller, M. Ghosh, R. Sonnenschein, P. Woditsch, Silicon for photovoltaic applications Materials Science and Engineering:B 2006 Volume 134(2-3) 257-262[edit | edit source]

DOI: https://doi.org/10.1016/j.mseb.2006.06.054

Abstract[edit | edit source]

Silicon is used in photovoltaics (PV) as the starting material for monocrystalline and multicrystalline wafers as well as for thin film silicon modules. More than 90% of the annual solar cell production is based on crystalline silicon wafers. Therefore, silicon is the most important material for PV today. The challenge which the PV-industry is currently facing is to decrease the manufacturing costs per Wp annually by 5%. Since approximately 70% of the costs for solar cells are caused by wafer costs, there are two main avenues to achieve the cost reduction. One is the development of cheap solar grade Si feedstock material, the other is the development of a cheap ingot manufacturing process for multicrystalline silicon wafers. Therefore, one aim of the PV-industry is to produce sufficiently pure solar grade silicon at low manufacturing costs. Three different routes for the production of solar grade Si are currently considered. Processes like decomposition of trichlorosilane by means of a fluidized bed reactor or decomposition and melting by means of a tube reactor are under development. Monosilane decomposition by means of a free space reactor is also in progress. Every process should be able to achieve the criteria for solar grade Si. Especially, the decomposition of monosilane by means of a free space reactor will be able to meet this challenge as will be explained in more detail. Within the last 10 years multicrystalline (mc) silicon ingots for PV with weights of 150, 240 and 300 kg have been developed and are produced today in the standard production process. The state of the art growth rate of these ingots is 0.5–1.5 cm/h. The two main targets of the PV-industry today are first to increase the ingot weight and second to accelerate the growth of multicrystalline silicon ingots. First, results of the preparation of very large ingots with an ingot weight of 400 kg or ingots grown with growth rates higher than 2 cm/h will be presented.

21. C. del Canizo, G. del Coso, W. C. Sinke, Crystalline silicon solar module technology: Towards the 1 € per watt‐peak goal Progress in Photovoltaics: Research and Applications 2008 Volume 17(3)[edit | edit source]

DOI: https://doi.org/10.1002/pip.878 https://onlinelibrary.wiley.com/doi/epdf/10.1002/pip.878

Abstract[edit | edit source]

Crystalline silicon solar module manufacturing cost is analysed, from feedstock to final product, regarding the equipment, labour, materials, yield losses and fixed cost contributions. Data provided by European industrial partners are used to describe a reference technology and to obtain its cost breakdown. The analysis of the main cost drivers allows to define new generation technologies suitable to reduce module cost towards the short‐term goal of 1 € per watt‐peak. This goal roughly corresponds with the cost level needed to enable 'grid parity': the situation solar electricity becomes competitive with retail electricity. The new technologies are described and their costs are analysed. Cost reductions due to scale effects in production are also assessed for next generation manufacturing plants with capacities in the range of several hundreds of megawatts to one gigawatt of module power per year, which are to come in the near future. The combined effects of technology development and economies of scale bring the direct manufacturing costs of wafer‐based crystalline silicon solar modules down into the range of 0·9–1·3 € per watt‐peak, according to current insights and information (the range results from differences between technologies as well as from uncertainties per technology). Copyright © 2008 John Wiley & Sons, Ltd.

22. D. Sarti, R. Einhaus, Silicon feedstock for the multi-crystalline photovoltaic industry Solar Energy Materials and Solar Cells 2002 Volume 72 27-40[edit | edit source]

DOI: https://doi.org/10.1016/S0927-0248(01)00147-7

Abstract[edit | edit source]

During the last 5 years the PV industry continues to experience a strong economic growth between 15% and 30% per year. Multi-crystalline silicon became the preferred material for PV production with a share of more than 50% of the shipped PV modules world-wide. For the first time, the available quantity of the classical silicon feedstock sources for the PV industry—electronic grade silicon rejects from the silicon and microelectronics industry—is close to be not sufficient to satisfy the requirements of the PV industry. From this situation arises the need to develop short- and long-term solutions to guarantee a sustainable supply of the PV industry with suitable silicon feedstock at acceptable costs. This paper presents a possible route for short- and long-term solutions to provide solar grade (SoG) silicon feedstock for the PV industry. On a short-term basis a twofold solution is proposed: (i) reduction of silicon consumption by reducing the wafer thickness and the introduction of recycling scenarios for silicon waste produced by the PV industry, (ii) introduction of very low-resistivity silicon (0.1 Ω cm). On long term, a route towards the establishment of a SoG silicon production based on widely available metallurgical grade silicon is proposed. This route includes the development of suitable purification techniques. First results that allowed to lower the impurity tolerances for SoG silicon are presented. The introduction of silicon feedstock with higher impurity concentrations which show a tendency to interact with crystal defects and lead to a degradation of the material performance also requires passivation concepts to achieve highly performing solar cells.

Cookies help us deliver our services. By using our services, you agree to our use of cookies.