Long-lasting strong electrostatic attraction and adhesion forces of dust particles on photovoltaic modules
- National Renewable Energy Lab. (NREL), Golden, CO (United States)
Photovoltaic (PV) energy-yield loss due to solar module soiling has become increasingly important as solar module deployment is now at the hundreds of gigawatts scale and continues to grow rapidly. The electrostatic attraction and adhesion force (Fes) of dust particles by the high voltages from solar panels have been reported to be 1 to 2 orders of magnitude stronger than the van der Waals and water capillary forces, which has been corroborated by observing the increase in system voltage-induced soiling rate by setting up an outdoor test. Here, we report another characteristic of Fes on soiling - long-lasting or slow decay after turning off the high voltage applied to solar panels. The Fes decay time varies across a wide time range of 1 to 10 h, depending on two factors: 1) whether the cell, the particle, or both were charged with high voltage before the voltages were turned off; and 2) how the cell was connected to the ground after the voltage was turned off - either connected through the power-supply electronics, directly connected to the ground, or electrically floated. The Fes decay is understood in terms of 1) net electrical charge dissipations in both particle and cell, 2) thermal disordering of dipole polarization in the module glass dielectrics, and 3) charge redistribution by the electrostatic interaction of particle and module glass. This long-lasting Fes for hours can affect the solar panel soiling after sunset, and it can have an even greater effect when combined with water condensation at night.
- Research Organization:
- National Renewable Energy Lab. (NREL), Golden, CO (United States)
- Sponsoring Organization:
- USDOE Office of Energy Efficiency and Renewable Energy (EERE), Renewable Power Office. Solar Energy Technologies Office
- Grant/Contract Number:
- AC36-08GO28308
- OSTI ID:
- 1572273
- Alternate ID(s):
- OSTI ID: 1598692
- Report Number(s):
- NREL/JA-5K00-70034
- Journal Information:
- Solar Energy Materials and Solar Cells, Vol. 204, Issue C; ISSN 0927-0248
- Publisher:
- ElsevierCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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