Modifying the surface roughness of solar glass: A passive mitigation method of soiling

Dust accumulation or soiling on solar photovoltaic (PV) panels significantly reduce power generation efficiency. While active claeaning methods and anti-soiling coatings are commonly employed, they present limitations related to water consumption, installation, and maintenance costs. This study presents a simple, cost-effective chemical etching technique to reduce soiling by modifying the surface roughness of solar glass. Samples were etched under acidic (HCl, 30, 120 and 180 min) or alkaline (NaOH, 30 and 120 min) conditions at different durations and their surface characteristics were evaluated in terms of roughness parameters and transmittance loss. A controlled soiling chamber was used to simulate outdoor dust deposition and assess surface coverage and particle agglomeration. The results showed that etched surfaces with negative skewness (Ssk < 0) and near-Gaussian kurtosis (Sku ≈ 3) reduced soiling. Solar glass etched with KOH 12M for 30 min exhibited a 64.7 % reduction in dust accumulation and only 13 % transmittance loss after indoor soiling tests, compared to 33 % in untreated glass and 27 % in anti-soiling and anti-reflective coated glass under the same conditions. These results demonstrate that surface roughness modification through chemical etching is a cost-effective and easily implementable strategy to mitigate soiling on PV surfaces.