Antistatic effect of power-enhancement coating for photovoltaic modules

Photovoltaic (PV) modules are periodically cleaned, particularly in large grid-connect photovoltaic plants, in order to avoid losses caused by dust accumulation. However, this maintenance task is often expensive, especially in those areas with water shortage. A hydrophilic coating on the surface of PV modules is one of typical methods to reduce the dust accumulation. But it is not commonly used yet, because the electrical performance of PV modules with conventional hydrophilic coating was slightly degraded by the decrease of transmittance. We have already developed a new hydrophilic power enhancement coating and reported its fundamental characters and results of several ISO/IEC standard tests in SPIE Solar Energy + Technology in 2010. One of the important characters was an antistatic effect. It was showed that the surface resistances of the coated glass and the uncoated glass were 1.3 × 1010Ω and 5.3 × 1014Ω, respectively. It would be understood that lower surface resistance of the coated glass resulted in the antistatic characteristics, which reduce the dust attraction on the coated glass. With the surface resistance result, it could be elucidated that the 3% additional energy production resulted from the antistatic effect of the coating on PV modules in the exposure test after several months without rain in Spain. In this paper, it is shown the results of the antistatic effect performed under the several dust accumulation tests.