Physik  |  Technik


Nicholas Kessler, 2004 | Auw, AG


This scientific study presents a novel approach to address the critical issue of sand-contamination on photovoltaic (PV) modules in desert environments. Contamination on PV modules leads to a substantial reduction in power output, and conventional cleaning methods are often ineffective. In this study, an electrostatic cleaning method is presented, utilizing electrostatic forces to remove contaminating particles. By electrically charging the particles on the PV module surface, an external electrode can attract and lift the particles off the surface. The study investigates the fundamental forces, the minimum humidity needed for water layer formation, and validates the electrostatic cleaning method using a self-synthesized titanium dioxide (TiO2) electrode. Efficiency tests demonstrated effective sand particle removal, affirming an eco-friendly PV module maintenance method. Maintenance cost calculations revealed a 160 $/module saved over the 30 year lifespan of the solar module installation, showcasing its economic viability.


The accumulation of micro-particles on the surface of PV modules is a significant issue, particularly in arid regions. Sand-contamination on PV modules leads to a reduction of 50 % power output within six months and even more on specific sites. This is typically addressed through costly and environmentally harmful water-based cleaning processes, requiring frequent maintenance, transportation, and numerous workers. The proposed electric cleaning method doesn’t require any water, thus offering a sustainable environmentally friendly and cost-effective solution.


The study employed an AFM instrument, various types of sand, a 6 kV power supply, a muffle furnace, fluorine tin oxide, and PV modules, among other equipment. The study conducted an assessment of the adhesive, gravitational, and electrostatic forces, which influence particle deposition. The humidity level for the water layer formation on sand particles was discovered using AFM equipment. Particle sizes and particle surface charges were analyzed utilizing digital imaging. A transparent TiO2 electrode film was synthesized via the sol-gel method. The TiO2 film was then coated onto a glass substrate using a self-made mayer rod. The efficiency of the electrostatic cleaning method was evaluated by measuring sand removal efficiency. The study examined the power consumption and correlated power loss of the electrostatic cleaning method, utilizing a computational approach for analysis.


The electrostatic method demonstrated efficient removal of particles ranging in radii from 0.1 to 70 mm. Particles larger or smaller were found to induce dielectric breakdown. A relative humidity threshold of 32 % was identified for the formation of a water layer. Charge measurements were consistent with estimations. Synthesis of TiO2 films yielded desirable characteristics at 3 to 6 coating cycles, resulting in film thicknesses ranging from 0.12 to 0.24 mm. However, all transparent conductive films (TCFs) exhibited low optical transmittance, leading to power losses in the PV modules.


The electrostatic cleaning method showcased effective cleaning performance across various sand compositions. The fluorine tin oxide electrode exhibited superior cleaning efficacy due to its advantageous conductivity properties. The method demonstrated negligible power consumption, thereby accentuating its eco-friendliness. Maintenance cost assessments compared automatic and manual cleaning approaches, with the manual method showing economic viability over the 30 year lifespan consistent with comparable literature from EPFL, whereas the automatic method did not. A challenge persists in achieving an optimal equilibrium between cleaning effectiveness and power efficiency. Further research efforts directed towards enhancing TCF performance are imperative for future advancements in the field.


This study introduces an electrostatic cleaning method for the issue of sand-contaminated PV modules, offering a cost-effective and sustainable solution. The study identifies optimal conditions for particle removal and explores the use of TiO2 electrodes. Experimental results confirm the method’s effectiveness and minimal power usage, but highlight potential power loss from the usage of TCFs. Cost calculations validate the economic benefit of the cleaning method. Further research is needed to balance cleaning efficiency with power generation. In summary, this approach holds promise for improving the sustainability and cost-effectiveness of PV power generation in arid climates and specifically deserts.



Würdigung durch den Experten

Prof. Dr. Franz Baumgartner

Herr Nicholas Kessler ist ein beachtlicher Kandidat, der interessante Ergebnisse belegt hat in den physikalischen Grundlagen: die Kräfte bei der elektrostatischen Reinigung, in der innovativen und soliden experimentellen Arbeit und der Analyse deren Ergebnisse, bis hin zur ersten Bewertung der Wirtschaftlichkeit eines solchen Systems. Die Arbeit zeichnet sich aus durch eigenständige experimentelle Arbeit und kritische Diskussion und Analyse. Die Arbeit könnte der Beginn einer Masterarbeit bilden.



Sonderpreis «Genius Olympiad – Science» gestiftet von der U.S. Embassy Bern




Kantonsschule Wohlen
Lehrer: Dr. Waldemar Feller