PV Quality and PV Soiling

Background

The accumulation of soiling on photovoltaic (PV) modules affects PV systems worldwide. Soiling consists of mineral dust, soot particles, aerosols, pollen, fungi and other contaminants that deposit on the surface of PV modules. Soiling absorbs, scatters, and reflects a fraction of the incoming sunlight, reducing the intensity that reaches the active part of the solar cell. Here, we provide some resources on the topic, as well as some presentations and publications in which Greg P. Smestad and Sol Ideas Technology Development have been involved.

PV Soiling: Selected Publications

• 2017 June 25-30 – A unique global investigation on the spectral effects of soiling losses of PV glass substrates: preliminary results; L. Micheli, E. F. Fernández, G. P. Smestad, et al., 2017 IEEE PVSC-44, Washington, D.C. Download Paper Download Poster
  • This is the progenitor for all of the work that Greg P. Smestad, Eduardo F. Fernández, and Leonardo Micheli published subsequently. It utilized somewhat problematic transmission data from the Perkin Elmer Lambda spectrometer. The main conclusions, however, have remained and are sound.
• 2017 October 23-25, 2017 – International PV Soiling Workshop, Dubai World Trade Center, Dubai United Arab Emirates, hosted by the Electricity & Water Authority (DEWA) Research and Development Centre, and the U.S. National Renewable Energy Laboratory (NREL), Waveband analysis for understanding the soiling impact on PV systems; E. F. Fernández – Download Presentation
  • An acknowledgement of Sol Ideas Tech. Dev., NREL and other collaborators was made at the end of the slides.
• 2017 Dec 6 – Optical Characterization of PV Glass Coupons and PV Modules Related to Soiling Losses, Atlas/NIST Workshop on PV Materials Durability; G. P. Smestad, L. Micheli, T. A. Germer, E. F. Fernández – View Presentation.
• 2018 March 14 – Optical Characteristics of PV Glass Coupons and PV Modules Related to Soiling Losses, IEEE Santa Clara Valley PhotoVoltaic Joint Society Chapter; G. P. Smestad, L. Micheli, T. A. Germer, E. F. Fernández – View Presentation.
• 2018 April 16-18 – Investigating the spectral nature of soiling and its impact on multi-junction CPV systems, 14th International Conference on Concentrator Photovoltaics (CPV-14) Puertollano, Spain; E. F. Fernández, F. M. Almonacid, L. Micheli, G. P. Smestad, M. Muller – Download Presentation
• 2018 May 08 – Optical Characterization of PV Glass Coupons and PV Modules Related to Soiling Losses; G. P. Smestad, L. Micheli, T. A. Germer, E. F. Fernández, PVQAT Soiling and Dust: Task Group 12 webinar.  
  Download Presentation
• 2018 May 14 – Optical Characterization of PV Glass Coupons and PV Modules Related to Soiling Losses; G. P. Smestad, L. Micheli, T. A. Germer, CLEO: OSA Nanophotonics Technical Group 20×20 Talks; San José Convention Center, San José, California. Download Presentation
• 2018 September 23-28 – Design and Indoor Validation of DUSST: A Novel Low-Maintenance Soiling Station; M. Muller, J. Morse, F. Almonacid, E. Fernadez, L. Micheli in 35th European PV Solar Energy Conference & Exhibition (EU PVSEC), Brussels, Belgium. Preprint available from National Renewable Energy Laboratory, Golden, CO: NREL/CP-5K00-71216
  • “A 2D drawing of the DUSST design, described in the provisional patent submitted to the U.S. Patent and Trademark Office [9], is shown in Figure 1.” Note references 9, 11 and 12.
• 2018 October 30 – November 1, 2018 – EQE Soiling Ratio and Transmission Losses; G. P. Smestad, T. Moriarty, L. Micheli, L. Simpson, B. Hamadani, T. A. Germer, G.S. TamizhMani (Mani), J. Oh, 2018 International PV Soiling Workshop, Denver Marriott West Hotel, Golden, Colorado.  
• 2019 May 16 – L. Micheli, J. A. Caballero, E. F. Fernandez, G. P. Smestad, G. Nofuentes, T. K. Mallick, F. M. Almonacid, “Correlating photovoltaic soiling losses to waveband and single-value transmittance measurements,” Energy, 180, 376-386, 2019. Download Paper   Read Online via article’s DOI.
• 2020 January 09 – G. P. Smestad, T. A. Germer, H. Alrashidi, et al.,“Modelling photovoltaic soiling losses through optical characterization,” Sci. Rep. 10:58, 2020. Download Paper – Read Online via article’s DOI – Download the Supplementary information – View Mendeley data repository
• 2020 April 20 – L. Micheli, E. F. Fernández, M. Muller, G. P. Smestad, F. M. Almonacid, “Selection of optimal wavelengths for optical soiling modelling and detection in photovoltaic modules,” Sol. Energy Mat. and Sol. Cells, 212, Article 110539, 2020.
  Download Paper – Read Online via article’s DOI
• 2021 October 18 – L. Micheli, G. P. Smestad, J. G. Bessa, M. Muller, E. F. Fernández and F. Almonacid, “Tracking Soiling Losses: Assessment, Uncertainty, and Challenges in Mapping,” in IEEE Journal of Photovoltaics, vol. 12, no. 1, pp. 114-118, Jan. 2022, doi: 10.1109/JPHOTOV.2021.3113858. Download paper via ResearchGate

• Refer to our publications page for an up-to-date selection of soiling-related papers.
• Refer to Presentations for a list of selected presentations.

PV Soiling: Other Groups

• Using the formalism described in the following paper, an estimation of wavelength dependent soiling and dust losses in photovoltaic modules can be made: Bergin, M. H., Greenwald, R., Xu, J., Berta, Y. and Chameides, W. L. (2001), “Influence of aerosol dry deposition on photosynthetically active radiation available to plants: A case study in the Yangtze Delta Region of China”. Geophys. Res. Lett., 28: 3605–3608. Download Paper   Read Online via article’s DOI.
• This has been done in “Large Reductions in Solar Energy Production Due to Dust and Particulate Air Pollution“, Mike H. Bergin, Chinmay Ghoroi, Deepa Dixit, James J. Schauer, and Drew T. Shindell, Environ. Sci. Technol. Lett., 2017. Read Online via article’s DOI.
• M. Valerino, M. Bergin, C. Ghoroi, A. Ratnaparkhi, G. P. Smestad, “Low-cost solar PV soiling sensor validation and size resolved soiling impacts: A comprehensive field study in Western India,” Solar Energy, 204, pp. 307-315, 2020.
  Download Paper – Read Online via article’s DOI

• H. Brahma, S. Pant, L. Micheli, G. P. Smestad, N. Sarmah, “Effect of Environmental Factors on Photovoltaic Soiling: Experimental and Statistical Analysis,” Energies 16, article 45, 2023.
  Download Paper – Read Online via article’s DOI – The supporting information can be downloaded here

Webinars

PVQAT (pron. “pee vee cat”) hosts webinars that are designed to facilitate international collaboration regarding soiling in PV and CSP systems. Learn more

Soiling Sensors

A procedure for measuring the soiling ratio at photovoltaic systems is given in IEC 61724-1. This standard proposes that two photovoltaic devices are used, where one is left to accumulate soil, and the other is held clean. Some examples include:

• Fracsun
• Atonometrics
• Kipp & Zonnen